RADAR DEVICE AND METHOD FOR DETECTING INTERFERENCE COUNTERMEASURES FOR A RADAR DEVICE

Abstract

Radar device, comprising: a beat signal generating unit (3) for receiving a receive signal that repeats a chirp signal corresponding to a chirp signal of a transmit signal due to a receive wave generated by reflecting a transmit wave at an observation target, which is attributable to the transmit signal repeating a chirp signal whose frequency changes over time, and for generating a beat signal with a frequency of a difference between respective frequencies of a chirp signal of the transmit signal and a chirp signal of the receive signal in a correspondence relationship; an AD converter unit (4) for outputting beat data, which is obtained by converting the beat signal generated by the beat signal generation unit into digital data; a distance spectrum calculation unit (51) to calculate a plurality of distance information spectra, each corresponding to a plurality of beat data received by the AD converter unit during a signal acquisition period; an interference countermeasure determination unit (52, 52A to 52E) to obtain a state value of each of the plurality of distance information spectra from data in an interference determination processing area in the plurality of distance information spectra calculated by the distance spectrum computation unit, to determine the necessity of an interference countermeasure from a number of unsuitable distance information spectra in the plurality of distance information spectra by comparing the obtained state value of each of the distance information spectra with an interference determination threshold to obtain the suitability of each of the plurality of distance information spectra, and to output an interference countermeasure signal for a chirp signal in a transmit signal when the interference countermeasure is necessary; and a distance and velocity information output unit (53) for calculating and outputting a distance to the observation target and a relative velocity with respect to the observation target from data in a detection target frequency range in the plurality of distance information spectra calculated by the distance spectrum calculation unit when the interference countermeasure determination unit determines that the interference countermeasure is unnecessary.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a so-called fast chirp FMCW radar device (hereinafter referred to as fast chirp FMCW) in which a transmission signal that intermittently repeats a chirp signal whose frequency changes with the passage of time a plurality of times is used. STATE OF THE ART

[0002] A frequency-modulated continuous wave (FMCW) radar device is known as a radar device that detects a distance to an observation target and a relative speed with respect to the observation target. Patent Literature 1 discloses a radar device that detects interference when a transmission wave from another radar device is received as a reception wave in this type of FMCW radar device.

[0003] The radar device disclosed in Patent Literature 1 includes an interference detection unit that calculates an average value of the received power of received signals corresponding to received waves received by a receiving antenna and determines that interference has occurred when a difference from a last calculated average value of the received power is equal to or greater than a threshold, or an interference detection unit that determines that interference has occurred when an average value of the received power corresponding to a long distance is equal to or greater than a threshold. REFERENCE LISTPATENT LITERATURE

[0004] Patent Literature 1: JP 2007-225602 A SUMMARY OF THE INVENTIONTECHNICAL PROBLEM

[0005] In the radar device disclosed in Patent Literature 1, it is determined whether or not interference has occurred based on whether a difference between a calculated average received power and a previously calculated average received power is equal to or greater than a threshold, or whether an average received power corresponding to a long distance is equal to or greater than a threshold for a radar device of an FMCW method using a slow chirp, and this is a method for detecting interference that is difficult to apply to a radar device of an FMCW method using a fast chirp.

[0006] The present disclosure has been made in consideration of the above points, and its object is to obtain a fast chirp FMCW radar device capable of accurately determining the need for an interference countermeasure. SOLUTION TO THE PROBLEM

[0007] A radar device according to the present disclosure includes a beat signal generation unit for receiving a reception signal that repeats a chirp signal corresponding to a chirp signal of a transmission signal due to a reception wave generated by reflecting a transmission wave at an observation target due to a transmission signal that repeats a chirp signal whose frequency changes with the passage of time, and generating a beat signal having a frequency of a difference between respective frequencies of a chirp signal of the transmission signal and a chirp signal of the reception signal in a correspondence relationship; an AD conversion unit for outputting beat data obtained by converting the beat signal generated by the beat signal generation unit into digital data;a range spectrum calculation unit for calculating a plurality of range information spectra corresponding to each of a plurality of beat data from the AD conversion unit received during a signal acquisition period;an interference countermeasure determination unit for obtaining a state value of each of the plurality of range information spectra from data in an interference determination processing area in the plurality of range information spectra calculated by the range spectrum calculation unit, determining the necessity of an interference countermeasure from a number of unsuitable range information spectra in the plurality of range information spectra by comparing the obtained state value of each of the range information spectra with an interference determination threshold to obtain the appropriateness of each of the plurality of range information spectra, and outputting an interference countermeasure signal for a chirp signal in a transmission signal when the interference countermeasure is necessary;and a distance and speed information output unit for calculating and outputting a distance to the observation target and a relative speed with respect to the observation target from data in a detection target frequency range in the plurality of distance information spectra calculated by the distance spectrum calculation unit when the interference countermeasure determination unit determines that the interference countermeasure is unnecessary.; ADVANTAGEOUS EFFECTS OF THE INVENTION

[0008] According to the present disclosure, the presence or absence of interference is determined for each of the repeated chirp signals, and the necessity of an interference countermeasure is determined based on the number of chirp signals for which interference was determined, so that it is possible to determine the necessity of countermeasures against interference with high accuracy. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a configuration diagram illustrating a radar device according to a first embodiment. Fig. 2 is a configuration diagram showing a signal processing unit of the radar device according to the first embodiment. Fig. 3 is an explanatory diagram showing the detection timings of a transmission signal, a reception signal, a beat signal, an interference signal, and digital data in the signal processing unit in a signal detection period in the radar device according to the first embodiment. Fig. 4 is a diagram showing an interference determination processing section in an interference countermeasure determination unit of the signal processing unit of the radar device according to the first embodiment. Fig. 5 is a diagram showing an example of a range information spectrum in a case where there is no interference signal in the interference countermeasure determination unit of the signal processing unit of the radar device according to the first embodiment. Fig. 6 is a diagram showing an example of a range information spectrum in a case where an interference signal is present in the interference countermeasure determination unit of the signal processing unit of the radar device according to the first embodiment. Fig. 7 is a flowchart showing the operation of the signal processing unit of the radar device according to the first embodiment. Fig. 8 is a configuration diagram showing a signal processing unit of a radar apparatus according to the second embodiment. Fig. 9 is a diagram showing an interference determination processing section in an interference countermeasure determination unit of the signal processing unit of the radar device according to the second embodiment. Fig. 10 is a diagram showing an example of a range information spectrum in a case where there is no interference signal in the interference countermeasure determination unit of the signal processing unit of the radar device according to the second embodiment. Fig. 11 is a diagram showing an example of a range information spectrum in a case where an interference signal is present in the interference countermeasure determination unit of the signal processing unit of the radar device according to the second embodiment. Fig. 12 is a flowchart illustrating the operation of the signal processing unit of the radar device according to the second embodiment. Fig. 13 is a configuration diagram showing a signal processing unit of a radar device according to a third embodiment. Fig. 14 is an explanatory diagram showing the detection timings of a transmission signal, a reception signal, a beat signal, an interference signal, and digital data in the signal processing unit in a signal detection period in the radar device according to the third embodiment. Fig. 15 is a diagram showing an interference determination processing section in an interference countermeasure determination unit of the signal processing unit of the radar device according to the third embodiment. Fig. 16 is a diagram showing an example of a range information spectrum in a case where there is no interference signal in the interference countermeasure determination unit of the signal processing unit of the radar device according to the third embodiment. Fig. 17 is a diagram showing an example of a range information spectrum in a case where an interference signal is present in the interference countermeasure determination unit of the signal processing unit of the radar device according to the third embodiment. Fig. 18 is a flowchart illustrating the operation of the signal processing unit of the radar device according to the third embodiment. Fig. 19 is a configuration diagram showing the signal processing unit of the radar device according to a fourth embodiment. Fig. 20 is a flowchart illustrating the operation of the signal processing unit of the radar device according to the fourth embodiment. Fig. 21 is a configuration diagram showing a signal processing unit of a radar apparatus according to a fifth embodiment. Fig. 22 is a flowchart illustrating the operation of the signal processing unit of the radar device according to the fifth embodiment. Fig. 23 is a configuration diagram showing a signal processing unit of a radar apparatus according to a sixth embodiment. Fig. 24 is a flowchart illustrating the operation of the signal processing unit of the radar device according to the sixth embodiment. Fig. 25 is a configuration diagram showing a signal processing unit of a radar apparatus according to a seventh embodiment. Fig. 26 is an explanatory diagram showing the detection timings of a transmission signal, a reception signal, a beat signal, an interference signal, and digital data in the signal processing unit in a signal detection period in the radar device according to the seventh embodiment. Fig. 27 is a diagram showing an interference determination processing section in the interference countermeasure determination unit of the signal processing unit of the radar device according to the seventh embodiment. Fig. 28 is a flowchart showing the operation of the signal processing unit of the radar apparatus according to the seventh embodiment. Fig. 29 is a configuration diagram showing a signal processing unit of a radar apparatus according to an eighth embodiment. Fig. 30 is a flowchart illustrating the operation of the signal processing unit of the radar device according to the eighth embodiment. Fig. 31 is a configuration diagram showing a signal processing unit of a radar apparatus according to a ninth embodiment. Fig. 32 is a flowchart illustrating the operation of the signal processing unit of the radar apparatus according to the ninth embodiment. Fig. 33 is a configuration diagram showing a signal processing unit of a radar apparatus according to a tenth embodiment. Fig. 34 is a flowchart showing the operation of the signal processing unit of the radar apparatus according to the tenth embodiment. Fig. 35 is a flowchart showing the operation of another example of the signal processing unit of the radar apparatus according to the tenth embodiment. DESCRIPTION OF THE EMBODIMENTSFirst embodiment

[0009] A fast chirp FMCW radar device according to a first embodiment will be described with reference to Fig. 1 to 7 described.

[0010] When the radar device according to the first embodiment is mounted on a vehicle such as a car, the observation target corresponds to another car, a pedestrian, a guardrail, or the like.

[0011] As in Fig. 1, the radar device according to the first embodiment includes a transmission signal output unit 1, a transmission and reception unit 2, a beat signal generation unit 3, an AD converter unit (analog-to-digital converter (ADC)) 4, a signal processing unit 5, and a display unit 6.

[0012] The transmission signal output unit 1 outputs a transmission signal that repeats a chirp signal, which is a frequency modulation signal whose frequency changes with the passage of time.

[0013] In the first embodiment, a chirp signal intermittently and repeatedly outputted from the transmission signal output unit 1 during a signal detection period in which an interference countermeasure is determined is used for the determination of an interference countermeasure.

[0014] That is, among the transmission signals output from the transmission signal output unit 1, a plurality of chirp signals output during the signal detection period are used to determine the interference countermeasure.

[0015] In the first embodiment, the plurality of chirp signals used to determine the interference countermeasure consists of K chirp signals, where K is a natural number equal to or greater than 2.

[0016] When an interference countermeasure signal is input from the signal processing unit 5, the transmission signal output unit 1 performs a preset interference countermeasure.

[0017] The interference countermeasure is, for example, a countermeasure for changing one or more center frequencies, a transmission start time, a frequency bandwidth, and a sweep time of the chirp signal in the transmission signal to be output.

[0018] The transmission signal output unit 1 comprises a control unit 11 and a signal source 12.

[0019] The control unit 11 outputs a control signal to the signal source 12 and the signal processing unit 5, which indicates the center frequency, the start time of the transmission, the frequency bandwidth and the sweep time of the chirp signal.

[0020] When the interference countermeasure signal is input from the signal processing unit 5, the control unit 11 outputs the control signal changed based on the interference countermeasure signal to the signal source 12 and the signal processing unit 5.

[0021] The control signal that is changed based on the interference countermeasure signal is a control signal that changes one or more of the center frequencies, the transmission start time, the frequency bandwidth, and the sweep time of the chirp signal.

[0022] When a control signal is input from the control unit 11, the signal source 12 outputs a transmission signal that intermittently repeats a chirp signal as a radar signal according to the control signal to the transmitting and receiving unit 2.

[0023] The transmission signal output from the signal source 12 is a signal that intermittently repeats a chirp signal, which is a frequency modulation signal whose frequency changes over time.

[0024] The transmitting and receiving unit 2 converts the transmitted signal output from the transmitted signal output unit 1 into a transmitted wave, transmits the converted transmitted wave toward the observation target, receives a transmitted wave reflected from the observation target as a reflected wave, converts the received reflected wave into a received signal, and outputs the received signal based on the reflected wave.

[0025] Like the transmit signal, the receive signal is a signal that intermittently repeats a chirp signal whose frequency changes over time. The chirp signal that forms the transmit signal and the chirp signal that forms the receive signal have a correspondence relationship for each chirp signal.

[0026] The transmitting and receiving unit 2 outputs the transmitting signal output from the transmitting signal output unit 1 and the receiving signal based on the received reflected wave to the beat signal generating unit 3.

[0027] The transmitting and receiving unit 2 comprises a distribution unit 21, a transmitting antenna 22 and a receiving antenna 23.

[0028] The distribution unit 21 divides the transmission signal output by the signal source 12 of the transmission signal output unit 1 into two transmission signals.

[0029] One of the distributed transmission signals is output to the transmission antenna 22, the other transmission signal is output as a local oscillation signal to the beat signal generation unit 3.

[0030] The transmitting antenna 22 converts the input transmission signal into a transmission wave and radiates (emits) the transmission wave into the room.

[0031] The transmission wave radiated into the space from the transmission antenna 22 is reflected by the observation target, and the reception antenna 23 receives the wave reflected from the observation target as a reception wave, converts the received reception wave into a reception signal, and outputs the reception signal to the beat signal generation unit 3.

[0032] The beat signal generation unit 3 receives inputs of the transmission signal output from the transmission and reception unit 2 and the reception signal output from the reception antenna 23, generates a beat signal having a frequency of a difference between the respective frequencies of the chirp signal of the transmission signal and the chirp signal of the reception signal, which are in the correspondence relationship, for each chirp signal, and outputs the generated beat signal to the AD conversion unit 4.

[0033] Fig. 3 shows a beat signal generated during the signal detection period in the beat signal generating unit 3.

[0034] During the signal acquisition period, as in Fig. 3, the beat signal generating unit 3 generates the beat signal in chirp 1 to chirp K, each having a difference between a chirp signal Lo(1) to a chirp signal Lo(K) in the transmission signal output from the transmission and reception unit 2 and a chirp signal Rx(1) to a chirp signal Rx(K) in the reception signal output from the transmission and reception unit 2.

[0035] K is the number of chirp signals (hereinafter referred to as the number of chirps) that intermittently repeat in the transmitted signal and the received signal during the signal detection period and is a natural number equal to or greater than 2.

[0036] Therefore, the number of chirps of the beat signal in the signal acquisition period is K, which is equal to the number of chirps of the transmitted signal and the received signal.

[0037] It should be noted that the beat signal generating unit 3 also generates a beat signal for each chirp signal in a period other than the signal detection period by using the chirp signal of the transmission signal and the chirp signal in the reception signal, which are in the same relationship as in the signal detection period.

[0038] The beat signal generation unit 3 comprises a frequency mixing unit 31 and a filter unit 32.

[0039] The frequency mixing unit 31 receives inputs of the transmission signal output from the distribution unit 21 and the reception signal output from the reception antenna 23, mixes the transmission signal and the reception signal, generates a beat signal having a frequency corresponding to the difference between the frequency of the chirp signal in the transmission signal and the frequency of the chirp signal in the reception signal for each chirp signal, and outputs the generated beat signal to the filter unit 32.

[0040] The filter unit 32 suppresses an unnecessary component such as noise included in the beat signal of the beat signal output from the frequency mixing unit 31, and outputs the beat signal in which the unnecessary component is suppressed to the AD conversion unit 4.

[0041] The filter unit 32 is, for example, a low-pass filter (LPF) or the like, which cuts off the beat signal output from the frequency mixing unit 31 with a cutoff frequency equal to or less than 1 / 2 of the sampling frequency fs of the AD converter unit 4 in order to take into account aliasing of the AD converter unit 4.

[0042] The AD conversion unit 4 converts the beat signal into digital data for each of the beat signals output from the beat signal generation unit 3, and outputs the converted digital data (hereinafter referred to as beat data) to the signal processing unit 5.

[0043] The signal processing unit 5 calculates the distance to the observation target and the relative speed with respect to the observation target using the beat data in chirp 1 to chirp K received from the AD conversion unit 4 in the signal detection period, detects interference from other radar devices, and determines the necessity of the interference countermeasure.

[0044] When the signal processing unit 5 determines that an interference countermeasure is required, the signal processing unit 5 outputs an interference countermeasure signal to the control unit resulting from the determination of whether an interference countermeasure is required.

[0045] As in Fig. 2, the signal processing unit 5 includes a distance spectrum calculation unit 51, an interference countermeasure determination unit 52, and a distance and speed information output unit 53, which includes a speed spectrum calculation unit 531 and a distance and speed information calculation unit 532.

[0046] The distance spectrum calculation unit 51 refers to the control signal output from the control unit 11 and indicates the signal detection period in which the interference countermeasure is determined.

[0047] The specified signal acquisition time is a period of time in which the AD conversion unit 4 generates (converts) digital data required for determining an interference countermeasure, in other words, a period of time in which a chirp signal required for determining the interference countermeasure in the transmission signal is output from the transmission signal output unit 1.

[0048] As in Fig. 3, the signal acquisition duration essentially corresponds to the total time of the repetition times Tr of the chirp signals Lo(1) to Lo(K) in the transmission signal of the transmitting and receiving unit 2.

[0049] The range spectrum calculation unit 51 performs a Fourier transform (FFT: Fast Fourier Transform) on the beat data in a range direction using the beat data in the signal acquisition period from the AD conversion unit 4, thereby calculating a range information spectrum corresponding to the distance to the observation target.

[0050] It should be noted that although the signal acquisition period of the AD conversion unit 4 is set by the range spectrum calculation unit 51, the AD conversion unit 4 may set the signal acquisition period by referring to the control signal output from the control unit 11 and output beat data from the AD conversion unit 4 to the range spectrum calculation unit 51 during the set signal acquisition period.

[0051] The range spectrum calculation unit 51 acquires each piece of beat data in chirp 1 to chirp K during the signal acquisition period at the signal acquisition time, performs a Fourier transform of the acquired beat data of each chirp at the N_smpl point in the range direction, and calculates a range information spectrum that is a frequency spectrum in each chirp 1 to chirp K.

[0052] When calculating a distance information spectrum, the range spectrum calculation unit 51 acquires digital data of N_smpl points for beat data per chirp and performs a Fourier transform.

[0053] That is, since the range spectrum calculation unit 51 performs a Fourier transform of the N_smpl point in the distance direction for the digital data of the N_smpl point in the beat data per chirp on the beat data from chirp 1 to chirp K, the range spectrum calculation unit 51 calculates K distance information spectra including the N_smpl points from chirp 1 to chirp K.

[0054] Therefore, there are multiple range information spectra during the signal acquisition period, and the number of chirps of the range information spectra is K, which is equal to the number of chirps of the beat signal.

[0055] As in Fig. 3, the signal acquisition time is a time at which each piece of beat data from chirps 1 to chirp K is acquired at the output of the AD converter unit 4.

[0056] The signal detection time is in a period in which each of the chirp signals Lo(1) to Lo(K) in the transmission signal is output from the transmitting and receiving unit 2.

[0057] The signal acquisition time is essentially the same as the start time of each of the chirp signals Lo(1) to Lo(K).

[0058] In order to reduce the storage space, the signal acquisition period can be divided for each chirp, and the beat data which has substantially the same length as the sweep time T (sweep time) from the signal acquisition time, that is, the beat data of the N_smpl point which is in Fig. 3 can be recorded.

[0059] The beat data of the chirp i obtained from the chirp signal Rx(i) in the reception signal output from the transmitting and receiving unit 2 is Fourier transformed in the distance direction by the range spectrum calculation unit 51, thereby integrating the spectral value of the beat data of the chirp i into the beat frequency Fsb_r expressed by the following equation (1).

[0060] Note that i represents 1 to K, respectively. Fsb_r=2⋅BW⋅R / c⋅T

[0061] It should be noted that R is a distance from the transmitting antenna 22 or the receiving antenna 23 to the observation target, c is a speed of light, T is a µs-order transit time of the chirp signal Lo(i) of the transmitting signal output from the transmitting and receiving unit 2, as shown in Fig. 3, and BW is the frequency bandwidth of the chirp signal Lo(i), as shown in Fig. 3 shown.

[0062] i represents 1 to K respectively.

[0063] The sweep time T and the frequency bandwidth BW are set so that the beat frequency Fsb_r at a maximum detection distance Rmax to the observation object is equal to or less than 1 / 2 of the sampling frequency fs in the AD converter unit 4 in order to take into account the aliasing in the AD converter unit 4.

[0064] Therefore, a detection target frequency range corresponding to the detection distance range is set to a frequency of 1 / 2 from 0 to the sampling frequency fs, and data of 1 / 2 sampling points from 1 to the N_smpl point are used to detect the distance from the transmitting antenna 22 or the receiving antenna 23 to the observation target.

[0065] The detection distance range is a range of distance or distance for detecting the observation target.

[0066] It should be noted that the detection target frequency range is not limited to the frequency range from 0 to 1 / 2 of the sampling frequency fs, but can also be a frequency range up to a frequency less than 1 / 2 of the sampling frequency fs or other frequency range.

[0067] Likewise, the data used to detect the distance to the observation target may be less than 1 / 2 or other sample points among points 1 to N_smpl.

[0068] In the first embodiment, the range spectrum calculation unit 51 outputs to the interference countermeasure determination unit 52 range information spectra of chirps 1 to K each including data of 1 / 2 sampling points of the points 1 to N_smpl corresponding to the sampling frequency that is the detection target frequency range.

[0069] The interference countermeasure determination unit 52 acquires data in the detection target frequency range of the plurality of distance information spectra output from the distance spectrum calculation unit 51.

[0070] Each of the plurality of range information spectra acquired by the interference countermeasure determining unit 52 is data of 1 / 2 sampling points of the points 1 to N_smpl constituting the detection target frequency range, but the interference countermeasure determining unit 52 may acquire data of all sampling points for each of the plurality of range information spectra.

[0071] In short, the interference countermeasure determination unit 52 is only required to acquire data in the detection target frequency range from the plurality of range information spectra calculated by the range spectrum calculation unit 51. In this case, the detection target frequency range preferably consists of data of the first half of the range information spectrum, which corresponds to 1 / 2 or less of the sampling frequency fs in the AD conversion unit 4.

[0072] The interference countermeasure determination unit 52 calculates a state value for each of the plurality of distance information spectra from the data in the interference determination processing area in the plurality of distance information spectra calculated by the distance spectrum calculation unit 51.

[0073] The interference countermeasure determination unit 52 compares the calculated state value of each of the range information spectra with an interference determination threshold to obtain the adequacy of each of the plurality of range information spectra, and determines the necessity of the interference countermeasure from the number of unsuitable range information spectra in the plurality of range information spectra.

[0074] The interference countermeasure determination unit 52 outputs an interference countermeasure signal for the chirp signal in the transmission signal to the control unit 11 when it is determined that the interference countermeasure is necessary, ie, required, and outputs a plurality of distance information spectra calculated by the distance spectrum calculation unit 51 to the distance and speed information output unit 53 when it is determined that the interference countermeasure is not necessary, ie, unnecessary.

[0075] The state value of the range information spectrum is an average value FN of the signal strengths of the data in the interference determination processing area in the range information spectrum.

[0076] The data in the interference determination processing area is a part of the data in the detection target frequency range used for signal processing.

[0077] In the first embodiment, the interference determination processing range for the detection target frequency range is set, for example, to the second half of the detection target frequency range, that is, to the range from the 3D range to the 4D range shown in Fig. 4 is represented by hatching. That is, the data from 0 to 1 / 2 N_smpl point (fs / 2) (corresponding to the detection target frequency range) in the range information spectrum is further divided into four, and the second half of the divided data, that is, the range from 3 * N_smpl / 8 to 4 * N_smpl / 8, is fixed.

[0078] In the second half of the detection target frequency range, which is defined as the interference determination processing range, the influence of the background noise due to the distance to the observation target as a result of the simulation is small, which is beneficial for the interference determination processing.

[0079] It should be noted that the interference determination processing range is not limited to the second half of the detection target frequency range, but can also be a part of the detection target frequency range.

[0080] In Fig. In Figure 4, the horizontal axis represents a range bin, and the vertical axis represents a chirp number. Data from 1 / 2 sampling points × the number of chirps K of the number N_smpl of the range information spectrum are represented. The brackets on the horizontal axis represent a frequency in the range information spectrum, and the acquisition target frequency range is equal to or less than 1 / 2 (4 * N_smpl / 8) of the sampling frequency fs of the AD converter unit 4.

[0081] The interference determination threshold is a first determination threshold TH1, which is a value obtained by multiplying an average value FN0 of the signal strengths of data in the interference determination processing area in the range information spectrum, which is obtained in a case where there is no reflected signal and no interference signal from the observation target before delivery or at the start of operation of the radar device, by a coefficient α (α is a natural number).

[0082] At that time, the mean FN0 of the signal strengths was 2.0 × 10 -4 .

[0083] The data in a case where there is no reflected signal and no interference signal from the observation target corresponds to the background noise of a receiver, and there is, for example, a method of obtaining it by disposing a radio wave absorber in front of the transmitting antenna 22 and the receiving antenna 23 before shipment, or a method of obtaining only ambient noise input to the receiving antenna 23 without outputting the transmitting signal from the signal source 12.

[0084] The calculation of the mean value FN0 of the signal strengths to determine the first determination threshold TH1 may use all or part of the data of the distance information spectrum.

[0085] The interference determination threshold value may be stored in an internal memory of the signal processing unit 5 or supplied to the signal processing unit 5 from outside the radar device.

[0086] In addition, a state value of a set distance information spectrum from the plurality of obtained distance information spectra can be used as the mean value FN0 of the signal strengths for determining the first determination threshold TH1. For example, the mean values ​​FN of the signal strengths corresponding to the Fig. 4 obtained, can be arranged in ascending order, and the i-th value, e.g., the fifth value from the smallest value, can be set as the mean value FN0 of the signal strengths to obtain the first determination threshold TH1.

[0087] A mean value FN i1 of the signal strengths of the data in the interference determination processing range (range from 3 * N_smpl / 8 to 4 * N_smpl / 8) in the distance information spectrum of a chirp i1 obtained when there is no interference signal is in Fig. 5 is shown as an example by a dashed line. At this time, the mean value FN i1 the signal strength is approximately 3.0 × 10 -4 .

[0088] On the other hand, an average value FNi2 of the signal strengths of the data in the interference determination processing range (range from 3 * N_smpl / 8 to 4 * N_smpl / 8) in the distance information spectrum of the chirp i2 obtained in the presence of the interference signal is shown by a dashed line in Fig. 6 is given as an example.

[0089] In the distance information spectrum of the Chirp i2, in a case where there is an interference signal, since the total noise floor due to the interference signal in the received signal is large, the mean value FN i2 the signal strengths are greater than the mean value FN i1 of the signal strengths, and the mean value FNi2 of the signal strength is 5.0 × 10 -3 .

[0090] Therefore, for example, the first determination threshold TH1 is set to a value of 1.0 × 10 3 (= 2.0 × 10 -4 × 5), which is calculated by multiplying the mean value FN0 of the signal strengths without reflected signal and without noise or interference signal from the observation target by a coefficient 5.

[0091] In the Fig. 5 and Fig. 6, the first determination threshold TH1 is represented by an alternating long and short dashed line.

[0092] In the Fig. 5 and Fig. 6, the horizontal axis represents a distance bin and the vertical axis represents a signal strength.

[0093] As from Fig. 5 and Fig. 6, the mean value FN i1 of the signal strengths is less than the first determination threshold TH1 and the mean value FNi2 of the signal strengths is equal to or greater than the first determination threshold TH1.

[0094] Therefore, by determining the average value FN of the signal strengths of the data in the interference determination processing area in the distance information spectrum, it can be determined whether the distance information spectrum is suitable or not with respect to the first determination threshold TH1, that is, whether the interference signal is superimposed or not.

[0095] Accordingly, regarding whether the determination in the distance information spectrum by the interference countermeasure determination unit 52 is appropriate or not, the distance information spectrum is determined to be “appropriate” when the average value FN of the signal strengths of the data in the interference determination processing area in the distance information spectrum is smaller than the first determination threshold TH1, and when the average value FN is equal to or larger than the first determination threshold TH1, the distance information spectrum is determined to be “unsuitable”.

[0096] In determining the necessity of the interference countermeasure by the interference countermeasure determining unit 52, instead of determining the necessity of the interference countermeasure by whether the determination is appropriate in a distance information spectrum, when the number of chirps of unsuitable distance information spectra in the plurality of distance information spectra is less than the interference countermeasure threshold, the interference countermeasure is determined as “unnecessary,” and when the number of chirps thereof is equal to or greater than the interference countermeasure threshold, the interference countermeasure is determined as “necessary.”

[0097] The reason why the need for interference countermeasure is determined by the number of chirps is that, as in Fig. 3, for example, it is assumed that an interference signal Rint from another radar device is received as a reception wave by the reception antenna 23 and input to the beat signal generation unit 3.

[0098] In many cases, the interference signal Rint has a transit time T and a frequency bandwidth BW different from those of a chirp signal of a reception signal, which is a received reflected wave of a transmission wave based on a transmission signal transmitted from the host radar device.

[0099] In addition, the repetition time Tr_i of the interference signal Rint often differs from the repetition time Tr of the chirp signal of the received signal.

[0100] In this case, the beat signal from the frequency mixing unit 31 is not constant and is propagated as background noise.

[0101] In addition, if the repetition time Tr of the chirp signal of the received signal differs from the repetition time Tr_i of the interference signal Rint, there is a case where the chirp does not occur in all chirps but only in some chirps.

[0102] Therefore, if the necessity of the interference countermeasure is determined based on whether the determination in a distance information spectrum is appropriate, it may be determined that the interference signal is not received even though the interference signal is received, and there is a possibility that it is erroneously detected.

[0103] In the first embodiment, the number of chirp signals of the transmission signal and the chirp signal of the reception signal in the signal detection period is K, the number of beat data having a frequency corresponding to a difference between the respective frequencies of the chirp signal of the transmission signal and the chirp signal of the reception signal is also K, and the number of range information spectra by the beat data is also K.

[0104] For each of the K range information spectra, the interference countermeasure determination unit 52 determines whether the range information spectrum is suitable or not based on the first determination threshold TH1, and calculates the number of chirps C1 of unsuitable range information spectra.

[0105] The interference countermeasure determining unit 52 compares the calculated number of chirps C1 with a first interference countermeasure threshold M1 and performs a determination of the necessity of the interference countermeasure to determine that the interference countermeasure is "unnecessary" when the number of chirps C1 is less than the first interference countermeasure threshold M1, and to determine that the interference countermeasure is "necessary" when the number of chirps C1 is equal to or greater than the first interference countermeasure threshold M1.

[0106] For example, the first interference countermeasure threshold M1 is equal to or less than 1 / 2 of the number of chirps K, assuming that the signal-to-noise ratio (SNR) at a distant observation target is low.

[0107] The first interference countermeasure threshold value M1 may be stored in the internal memory of the signal processing unit 5 or supplied to the signal processing unit 5 from outside the radar device.

[0108] In the distance and speed information output unit 53, the interference countermeasure determination unit 52 determines whether the interference countermeasure is unnecessary or not, that is, it determines that the interference countermeasure is unnecessary, and obtains data in the detection target frequency range in the plurality of distance information spectra calculated by the distance spectrum calculation unit 51 from the interference countermeasure determination unit 52.

[0109] After receiving the determination result that the interference countermeasure is unnecessary from the interference countermeasure determination unit 52, the distance and speed information output unit 53 may receive data in the detection target frequency range in the plurality of distance information spectra calculated by the range spectrum calculation unit 51 from the range spectrum calculation unit 51.

[0110] The distance and speed information output unit 53 calculates the distance to the observation target and the relative speed with respect to the observation target from the received data in the detection target frequency range in the plurality of distance information spectra calculated by the distance spectrum calculation unit 51.

[0111] The distance and speed information output unit 53 includes the speed spectrum calculation unit 531 and the distance and speed information calculation unit 532.

[0112] The speed spectrum calculation unit 531 performs a Fourier transform in the direction of relative speed on the data in the detection target frequency range in the plurality of received distance information spectra calculated by the range spectrum calculation unit 51 to calculate a distance and speed information spectrum.

[0113] That is, the speed spectrum calculation unit 531 calculates a speed information spectrum by performing a Fourier transform of K points in the relative speed direction for each frequency spectrum in the data in the detection target frequency range in each distance information spectrum, for example, data of 1 / 2 sampling points in N_smpl, and calculates a distance and speed information spectrum including a plurality of (N_smpl / 2) speed information spectra in this example.

[0114] The velocity spectrum calculation unit 531 performs a Fourier transform of 1 / 2 frequency spectra of N_smpl in the relative velocity direction in the data in the detection target frequency range in the K range information spectra, integrating the velocity information spectrum value into a Doppler frequency Fsb_v expressed by the following equation (2).

[0115] Note that i represents 1 to K, respectively. Fsb_v=2⋅fv / c

[0116] Note that the center frequency of the chirp signal is Lo(i) of the local oscillation signal, which is the transmitted signal, and v is the relative velocity between the radar device and the observation target.

[0117] The speed spectrum calculation unit 531 outputs a distance and speed information spectrum including the calculated N_smpl / 2 speed information spectra to the distance and speed information calculation unit 532.

[0118] The distance and speed information calculation unit 532 detects the peak value of the spectrum value in the distance and speed information spectrum calculated by the speed spectrum calculation unit 531, and calculates the distance to the observation target from the beat frequency Fsb_r related to the range speed of the detected peak value, and the relative speed with respect to the observation target from the Doppler frequency Fsb_v related to the range speed of the detected peak value.

[0119] The detection of the peak value of the spectrum value in the spectrum of the distance and speed information by the distance and speed information calculation unit 532 and the calculation of the distance to the observation target and the relative speed with respect to the observation target by the distance and speed information calculation unit 532 are performed by a well-known technique, so a detailed description is omitted.

[0120] The signal processing unit 5 includes a central processing unit (CPU), a random access memory (RAM), and a read-only memory (ROM). The above-described processes are performed by loading a program stored in the ROM into the RAM and executing various processes by the CPU based on the program loaded into the RAM. The signal processing unit 5 is controlled by a general-purpose operating system (OS).

[0121] The distance to the observation target determined by the distance and speed calculation unit 532 and the relative speed with respect to the observation target are each displayed on the display unit 6.

[0122] Next, the operation of the radar device according to the first embodiment will be described.

[0123] It should be noted that in order not to complicate the description, in the following description, the number of intermittent repetitions of the chirp signal in the signal detection period is referred to as K times and the sampling point in the AD converter unit 4 is referred to as N sampling point.

[0124] The transmission signal output unit 1 outputs to the transmitting and receiving unit 2 a transmission signal that intermittently repeats a chirp signal whose frequency changes over time.

[0125] The transmitting and receiving unit 2, which has received the transmission signal, converts the transmission signal into a transmission wave through the transmission antenna 22 and transmits the transmission wave toward the observation target.

[0126] Furthermore, the transmission wave radiated into the space from the transmission antenna 22 is reflected by the observation target, and the reception antenna 23 receives the wave reflected from the observation target as a reception wave.

[0127] The transmitting and receiving unit 2 converts the reception wave received by the receiving antenna 23 into a reception signal.

[0128] The reception signal output from the reception antenna 23 is a signal that intermittently repeats a chirp signal whose frequency changes over time.

[0129] The transmitting and receiving unit 2 distributes the transmission signal received from the transmission signal output unit 1 through the distribution unit 21 and outputs the distributed transmission signal as a local oscillation signal to the beat signal generation unit 3, and outputs the reception signal from the receiving antenna 23 to the beat signal generation unit 3.

[0130] The beat signal generation unit 3 causes the frequency mixing unit 31 to mix the chirp signal of the transmission signal output from the transmission and reception unit 2 and the chirp signal of the reception signal output from the reception antenna 23, generates a beat signal having a frequency corresponding to a difference between the respective frequencies of the chirp signal of the corresponding transmission signal and the chirp signal of the reception signal, and outputs the generated beat signal to the AD conversion unit 4 via the filter unit 32.

[0131] The AD converter unit 4 converts the beat signal into digital data and outputs the converted beat data to the signal processing unit 5.

[0132] The functioning of the signal processing unit 5 is explained using the Fig. 7 shown flowchart.

[0133] Fig. 7 is a flowchart showing the calculation processing of the distance to the observation target and the relative speed with respect to the observation target including the interference determination in the signal processing unit 5 during the signal acquisition period.

[0134] Step ST1 is a step for calculating a distance information spectrum.

[0135] In step ST1, the range spectrum calculation unit 51 sets a signal detection period with reference to the control signal output from the control unit 11.

[0136] The range spectrum calculation unit 51 performs a Fourier transform of the N_smpl points of each piece of the beat data in the range direction using the beat data in the signal acquisition period from the AD conversion unit 4, calculates K range information spectra including the N_smpl points, and proceeds to step ST2.

[0137] Step ST2 is a step for calculating the number of chirps C1.

[0138] In step ST2, the interference countermeasure determining unit 52 acquires data in the acquisition target frequency range of the K-range information spectra obtained in step ST1.

[0139] The interference countermeasure determination unit 52 calculates, for each of the K range information spectra, an average value FN of the signal strengths, which is a state value from the data in the interference determination processing area among the data in the detection target frequency area, and obtains an average value FN of the signal strengths of the K range information spectra.

[0140] The interference countermeasure determination unit 52 compares the mean value FN of the signal strengths of the distance information spectrum with the first determination threshold TH1 for each of the K distance information spectra and determines the adequacy with respect to the distance information spectrum.

[0141] The interference countermeasure determination unit 52 calculates the number of chirps C1 of unsuitable range information spectra in which the mean value FN of the signal strengths is equal to or greater than the first determination threshold TH1.

[0142] When the interference countermeasure determination unit 52 calculates the number of chirps C1 of the distance information spectrum, the process proceeds to step ST3.

[0143] Step ST3 is a step of determining the need for an interference countermeasure.

[0144] In step ST3, the interference countermeasure determining unit 52 compares the number of chirps C1 calculated in step ST2 with the first interference countermeasure threshold M1 and performs a necessity determination of the interference countermeasure to determine that the interference countermeasure is "unnecessary" when the number of chirps C1 is less than the first interference countermeasure threshold M1, and determines that the interference countermeasure is "necessary" when the number of chirps C1 is equal to or greater than the first interference countermeasure threshold M1.

[0145] As in Fig. 3, for example, it is assumed that an interference signal Rint from another radar device is input to the beat signal generating unit 3. In this case, as shown in Fig. 3, the beat signal of the frequency mixing unit 31 is not constant and is propagated by the interference signal as background noise when the interference signal Rint is in the same chirp as the chirp signal Lo(i) in the transmission signal and the chirp signal Rx(i) in the reception signal.

[0146] As a result, as in Fig. 6, the mean value FNi2 of the signal strengths of the data in the interference determination processing area in the distance information spectrum is equal to or greater than the first determination threshold TH1.

[0147] Further, in a case where the interference signal Rint is input to the beat signal generating unit 3, the number of chirps C1 in which the chirp signal Lo(i), the chirp signal Rx(i), and the interference signal Rint exist in the same chirp is equal to or greater than the first interference countermeasure threshold value M1.

[0148] Therefore, when the interference signal Rint is input to the beat signal generating unit 3, the number of chirps C1 calculated in step ST2 becomes equal to or greater than the first interference countermeasure threshold value M1, and the interference signal Rint is detected.

[0149] On the other hand, in a case where there is no interference signal from another radar device, the beat signal from the frequency mixing unit 31 becomes constant and depends only on the background noise of the received signal, and as shown in Fig. 5, the mean value FN i1the signal strengths of the data in the interference determination processing area in the distance information spectrum are smaller than the first determination threshold TH1, the number of chirps C1 calculated in step ST2 becomes smaller than the first interference countermeasure threshold M1, and the interference signal is not detected.

[0150] To simplify the description, Fig. 3 shows an example where there is an observation target and interference from another radar device.

[0151] However, this is only an example, and in a case where there are two or more observation targets, in a case where two or more interference signals are input to the frequency mixing unit 31 via the receiving antenna 23, and in a case where the interference signal is electromagnetic noise input to the AD conversion unit 4, the interference countermeasure determination unit 52 can similarly determine whether the range information spectrum is appropriate or not and whether the interference countermeasure is necessary or not.

[0152] As described above, when the interference countermeasure determining unit 52 determines that the interference countermeasure is necessary in step ST3, the process proceeds to step ST4, and the signal processing unit 5 outputs an interference countermeasure signal to the control unit 11 of the transmission signal output unit 1, and the process ends.

[0153] On the other hand, when the interference countermeasure determination unit 52 determines that the interference countermeasures are unnecessary, the process proceeds to step ST5.

[0154] Step ST5 is a step for calculating a range-velocity spectrum.

[0155] In step ST5, the speed spectrum calculation unit 531 calculates a speed information spectrum by performing Fourier transform at K points in the relative speed direction with respect to data in the detection target frequency range in each of the K range information spectra calculated by the range spectrum calculation unit 51, e.g., each frequency spectrum in data of 1 / 2 sampling points in N_smpl, and calculates a plurality of distance and speed information spectra including, in this example, 1 / 2 speed information spectra at N_smpl points, and the process proceeds to step ST6.

[0156] In step ST6, the distance to the observation target and the relative speed with respect to the observation target are calculated and output.

[0157] In step ST6, the distance and speed information calculation unit 532 detects a peak value of a spectrum value in a distance and speed information spectrum including 1 / 2 speed information spectra of the N_smpl point calculated in step ST5.

[0158] The distance to the observation target is calculated from the beat frequency Fsb_r with respect to the ranging speed of the peak value detected by the distance and speed information calculating unit 532.

[0159] The relative velocity with respect to the observation target is calculated from the Doppler frequency Fsb_v with respect to the range velocity of the peak value detected by the range and velocity information calculation unit 532.

[0160] The distance to the observation target calculated by the distance and speed calculation unit 532 and the relative speed with respect to the observation target are output to the display unit 6, and the process is terminated.

[0161] As described above, the radar device according to the first embodiment includes the range spectrum calculation unit 51 that calculates a plurality of range information spectra each corresponding to a plurality of data pieces of beat data obtained by converting into digital data a beat signal having a frequency of a difference between a frequency of a plurality of times of chirp signals received during a signal detection period in a transmission signal that repeats a chirp signal whose frequency changes with the passage of time and a frequency of a plurality of times of chirp signals in a reception signal that has a correspondence relationship to the plurality of times of chirp signals in a transmission signal received during the signal detection period, the interference countermeasure determination unit 52,which obtains the state value of each of the plurality of range information spectra from data in an interference determination processing area in the plurality of range information spectra, compares the obtained state value with an interference determination threshold to obtain appropriateness in each of the plurality of range information spectra, determines the necessity of interference countermeasures from the number of unsuitable range information spectra of the plurality of range information spectra, and outputs the interference countermeasure signal for the chirp signal in the transmission signal when the interference countermeasure is necessary, so that it is possible to determine the necessity of a highly accurate interference countermeasure in the radar device of the fast chirp FMCW method using a plurality of chirps.

[0162] Furthermore, the radar device according to the first embodiment can suppress the addition of a memory for determining the necessity of an interference countermeasure and suppress deterioration of the accuracy of determining whether an interference countermeasure is necessary or not. Second embodiment

[0163] A fast chirp FMCW radar device according to a second embodiment will be described with reference to Fig. 8 to 12 described.

[0164] In the radar device according to the second embodiment, only an interference countermeasure determination unit 52A of the signal processing unit 5 is different from the interference countermeasure determination unit 52 of the signal processing unit 5 in the radar device according to the first embodiment, and the other points are the same or similar.

[0165] In the Fig. 8 to 12 denote the same reference numerals as in the Fig. 1 to 7 the same or corresponding parts.

[0166] In the radar device according to the first embodiment, the state value of the range information spectrum obtained by the interference countermeasure determining unit 52 is set as the average value FN of the signal strengths of the data in the interference determination processing area in the range information spectrum.

[0167] On the other hand, in the radar device according to the second embodiment, the state value of the range information spectrum obtained by the interference countermeasure determining unit 52A is set as the signal strength ratio P / FN between the mean value FN of the signal strengths of the data in the interference determination processing area in the range information spectrum and the peak value P of the signal strength of the data in the detection target frequency range in the range information spectrum with respect to the mean value FN of the signal strengths, and the interference determination threshold is set as the first determination threshold TH1 and the second determination threshold TH2.

[0168] That is, the interference countermeasure determination unit 52A of the signal processing unit 5 in the radar device according to the second embodiment calculates the average value FN of the respective signal strengths of the plurality of range information spectra and the peak value P of the signal strength of the data in the detection target frequency range in each of the plurality of range information spectra calculated by the range spectrum calculation unit 51 from the data in the interference determination processing range in the plurality of range information spectra calculated by the range spectrum calculation unit 51.

[0169] The interference countermeasure determining unit 52A compares the mean value FN of the signal strengths with the first determination threshold TH1 and compares the signal strength ratio P / FN with the second determination threshold TH2 to determine whether the distance information spectrum is suitable or not, that is, whether the interference signal is superimposed.

[0170] When the mean value FN of the signal strengths is equal to or greater than the first determination threshold TH1 and the signal strength ratio P / FN is equal to or less than the second determination threshold TH2, the interference countermeasure determination unit 52A determines that the distance information spectrum is “unsuitable.”

[0171] The interference countermeasure determining unit 52A compares the number of chirps C1 with the distance information spectrum that is “unsuitable” with the first interference countermeasure threshold M1 and performs a determination of the necessity of the interference countermeasure to determine that the interference countermeasure is “unnecessary” when the number of chirps C1 is less than the first interference countermeasure threshold M1, and determines that the interference countermeasure is “necessary” when the number of chirps C1 is equal to or greater than the first interference countermeasure threshold M1.

[0172] As described above, by using the signal strength ratio P / FN based on the peak value P in the detection target frequency range in the distance information spectrum for the necessity of the interference countermeasure, for example, deterioration of the accuracy of determining the necessity of the interference countermeasure can be suppressed even when the peak value P of the signal strength increases due to the short distance of the observation target and the average value FN of the signal strengths in the detection target frequency range increases due to a phase jitter of the signal source 12.

[0173] Like the interference countermeasure determination unit 52 in the radar device according to the first embodiment, the interference countermeasure determination unit 52A can determine that the range information spectrum in which the mean value FN of the signal strengths is less than the first determination threshold TH1 is “suitable,” and can make a determination such that the signal strength ratio P / FN is compared with the second determination threshold TH2 with respect to the range information spectrum determined as “unsuitable” in which the mean value FN of the signal strengths is equal to or greater than the first determination threshold TH1, and the range information spectrum is changed to “suitable” when the signal strength ratio P / FN exceeds the second determination threshold TH2.

[0174] The radar device according to the second embodiment will be described below, focusing on the interference countermeasure determination unit 52A, which is different from the interference countermeasure determination unit 52 in the radar device according to the first embodiment.

[0175] The description of the same configuration as that of the radar device according to the first embodiment will be omitted as much as possible.

[0176] The interference countermeasure determination unit 52A acquires the data in the detection target frequency range from the plurality of range information spectra output from the range spectrum calculation unit 51.

[0177] The interference countermeasure determination unit 52A calculates, from the data in the interference determination processing area in the plurality of range information spectra calculated by the range spectrum calculation unit 51, the mean value FN of the respective signal strengths of the plurality of range information spectra and the peak value P of the signal strength of the data in the detection target frequency range in each of the plurality of range information spectra calculated by the range spectrum calculation unit 51.

[0178] The interference determination processing area is the same as the interference determination processing area in the radar device according to the first embodiment and is the second half, which is a part of the detection target frequency range, which is a range from 3D to a range 4D shown in Fig. 9 is indicated by continuous hatching.

[0179] In addition, the peak value P of the signal strength in Fig. 9 is shown shaded as an example.

[0180] The interference countermeasure determination unit 52A compares the mean value FN of the signal strengths with the first determination threshold TH1 and compares the signal strength ratio P / FN with the second determination threshold TH2.

[0181] A range information spectrum of a chirp i in a case where the observation target is at a short distance and no interference signal is present is shown in Fig. 10, and in Fig. For example, 10 is a mean value FN 01the signal strengths of the data in the interference determination processing range by a dashed line, the peak value P of the signal strength of the data in the detection target frequency range by a black circle, the first determination threshold TH1 by a one-dot chain line, and the difference between the peak value P of the signal strength and the mean value FN 01 the signal strengths are represented by a double-headed arrow.

[0182] On the other hand, a range information spectrum of a chirp i in a case where the observation target is at a short distance and an interference signal is present is Fig. 11, and in Fig. For example, 11 is a mean value FN 11the signal strengths of the data in the interference determination processing range by a dashed line, the peak value P of the signal strength of the data in the detection target frequency range by a black circle, the first determination threshold TH1 by a one-dot chain line, and the difference between the peak value P of the signal strength and the mean value FN 11 the signal strengths are represented by a double-headed arrow.

[0183] The first determination threshold TH1 is the same value as the first determination threshold TH1 used in the radar device according to the first embodiment.

[0184] In the Fig. 10 and Fig. 11, the horizontal axis represents the distance bin and the vertical axis represents the signal strength.

[0185] As from Fig. 10, in a case where an observation target is at a short distance and the signal strength is high, the mean value FN01 of the signal strengths due to the phase jitter of the signal source 12, and the mean value FN 01 of the signal strengths can be equal to or greater than the first determination threshold TH1. At this time, a peak in the signal strength occurs, which depends on the observation target, but the peak value P of the signal strength with respect to the mean value FN 01 the signal strength is large, and the signal strength ratio P / FN 01 is a large value. The peak value P of the signal strength in relation to the mean value FN 01 the signal strength is about 30 times, and the signal strength ratio P / FN 01 ≈ 30

[0186] As from Fig. 11, the mean value FN 11 the signal strength is greater than the mean value FN 01 the signal strength, and the mean value FN 11 of the signal strength is closer to the peak value P of the signal strength than the mean value FN 01the signal strength, since the total background noise caused by the interference signal is large.

[0187] The difference between the mean FN 11 of the signal strength and the peak value P of the signal strength is low, and the signal strength ratio P / FN 11 is a small value. The peak value P of the signal strength in relation to the mean value FN 11 the signal strength is about 2.5 times, and the signal strength ratio P / FN 01 ≈ 2.5.

[0188] Therefore, the second determination threshold TH2 is set to 5 as an example.

[0189] Therefore, in a case where there is an observation target at a short distance and the signal strength is high, in a case where there is no interference signal, and in a case where there is an interference signal, the mean value FN 01 the signal strength and the mean value FN 11the signal strength is equal to or greater than the first determination threshold TH1, but the signal strength ratio P / FN 01 in a case where there is no interference signal is greater than the second determination threshold TH2, and the signal strength ratio P / FN 01 in a case where an interference signal is present, is equal to or less than the second determination threshold TH2.

[0190] Although the mean signal strength FN is equal to or greater than the first determination threshold TH1, by comparing and determining the signal strength ratio P / FN with respect to the second determination threshold TH2, it is possible to determine whether interference occurs in the target's chirp. That is, it is possible to determine whether the range information spectrum is suitable.

[0191] For each of the K range information spectra, the interference countermeasure determination unit 52A determines whether the range information spectrum is suitable or not based on the first determination threshold TH1 and the second determination threshold TH2, and calculates the number of chirps C1 of unsuitable range information spectra.

[0192] That is, the interference countermeasure determining unit 52A determines, among the K range information spectra, the number of chirps C1 of the range information spectrum in which the mean value FN of the signal strengths is equal to or greater than the first determination threshold TH1 and the signal strength ratio P / FN is equal to or less than the second determination threshold TH2.

[0193] The interference countermeasure determining unit 52A compares the number of chirps C1 with the distance information spectrum that is “unsuitable” with the first interference countermeasure threshold M1 and performs a determination of the necessity of the interference countermeasure to determine that the interference countermeasure is “unnecessary” when the number of chirps C1 is less than the first interference countermeasure threshold M1, and determines that the interference countermeasure is “necessary” when the number of chirps C1 is equal to or greater than the first interference countermeasure threshold M1.

[0194] The interference countermeasure determination unit 52A outputs an interference countermeasure signal for the transmission signal to the control unit 11 when it is determined that the interference countermeasure is necessary, ie, required, and outputs a plurality of distance information spectra calculated by the distance spectrum calculation unit 51 to the distance and speed information output unit 53 when it is determined that the interference countermeasure is not necessary, ie, unnecessary.

[0195] The operation of the radar device according to the second embodiment is described below.

[0196] The operation is the same as the operation of the radar device according to the first embodiment until the beat data of K chirps is output from the AD converter unit 4 to the signal processing unit 5, and therefore the description thereof is omitted.

[0197] The operation of the signal processing unit 5, into which the beat data of K-chirps are input, is explained using the Fig. 12 shown flowchart.

[0198] Fig. 12 is a flowchart illustrating the calculation processing of the distance to the observation target and the relative speed with respect to the observation target including the interference determination in the signal processing unit 5.

[0199] The step ST1 of calculating the range information spectrum is the same as the step ST1 of the radar device according to the first embodiment.

[0200] Step ST2A is a step for calculating the number of chirps C1 and corresponds to step ST2 of the radar device according to the first embodiment.

[0201] In step ST2A, the interference countermeasure determination unit 52A acquires data in the acquisition target frequency range of the K-range information spectra obtained in step ST1.

[0202] For each of the K range information spectra, the interference countermeasure determination unit 52A calculates the mean value FN of the signal strengths, which are one of the state values, from the data in the interference determination processing area among the data in the detection target frequency area, and obtains a mean value FN of the signal strengths of the K range information spectra.

[0203] For each of the K range information spectra, the interference countermeasure determining unit 52A acquires the peak value P of the data in the detection target frequency range, calculates the signal strength ratio P / FN which is one of the state values, and obtains the signal strength ratios P / FN of the K range information spectra.

[0204] The interference countermeasure determining unit 52A compares the mean value FN of the signal strength of the distance information spectrum with the first determination threshold TH1 and the signal strength ratio P / FN with the second determination threshold TH2 with respect to each of the K distance information spectra and obtains the adequacy with respect to the distance information spectrum.

[0205] The interference countermeasure determination unit 52A calculates the number of chirps C1 of the inappropriate range information spectrum in which the mean value FN of the signal strengths is equal to or greater than the first determination threshold TH1 and the signal strength ratio P / FN is equal to or less than the second determination threshold TH2.

[0206] When the interference countermeasure determination unit 52A calculates the number of chirps C1 of the distance information spectrum, the process proceeds to step ST3.

[0207] The process after step ST3 is the same as the process after step ST3 of the radar device according to the first embodiment, and when the interference countermeasure determination unit 52A determines that the interference countermeasure is necessary in step ST3, the process proceeds to step ST4, and the signal processing unit 5 outputs an interference countermeasure signal to the control unit 11 of the transmission signal output unit 1, and the process ends.

[0208] When the interference countermeasure determination unit 52A determines in step ST3 that the interference countermeasure is unnecessary, the process proceeds to steps ST5 and ST6, and the distance to the observation target and the relative speed with respect to the observation target calculated by the distance and speed information calculation unit 532 are output to the display unit 6, and the process ends.

[0209] As described above, the radar device according to the second embodiment has a similar effect to the radar device according to the first embodiment, and even in a case where the peak value P of the signal strength increases due to the short distance of the observation target, it is possible to determine the necessary high-precision interference countermeasures in the radar device of the fast chirp FMCW method using a plurality of chirps. Third embodiment

[0210] A fast chirp FMCW radar device according to a third embodiment will be described with reference to FIG. Fig. 13 to 18 described.

[0211] In the radar device according to the third embodiment, only an interference countermeasure determination unit 52B of the signal processing unit 5 is different from the interference countermeasure determination unit 52 of the signal processing unit 5 in the radar device according to the first embodiment, and the other points are the same or similar.

[0212] In the Fig. 13 to 18 denote the same reference numerals as in the Fig. 1 to 7 the same or corresponding parts.

[0213] In the radar device according to the first embodiment, the state value of the range information spectrum obtained by the interference countermeasure determining unit 52 is set as the average value FN of the signal strengths of the data in the interference determination processing area in the range information spectrum.

[0214] On the other hand, in the radar device according to the third embodiment, the state value of the range information spectrum obtained by the interference countermeasure determining unit 52B is set as the signal strength ratio P / FN of the peak value P of the signal strength of the data in the detection target frequency range in the range information spectrum to the average value FN of the signal strengths of the data in the interference determination processing range in the range information spectrum, and the interference determination threshold is set as a third determination threshold TH3.

[0215] The third determination threshold TH3 can be the same value as the second determination threshold TH2.

[0216] That is, the interference countermeasure determination unit 52B of the signal processing unit 5 in the radar device according to the third embodiment acquires the data in the detection target frequency range from the plurality of range information spectra output from the range spectrum calculation unit 51.

[0217] The interference countermeasure determination unit 52B calculates the average value FN of the respective signal strengths of the plurality of range information spectra and the peak value P of the signal strength of the data in the detection target frequency range in each of the plurality of range information spectra calculated by the range spectrum calculation unit 51 from the data in the interference determination processing range in the plurality of range information spectra calculated by the range spectrum calculation unit 51.

[0218] By comparing the signal strength ratio P / FN with the third determination threshold TH3, the interference countermeasure determination unit 52B determines the distance D at which there is a peak value at which the signal strength ratio P / FN in the distance information spectrum is equal to or greater than the third determination threshold TH3, and the number of range information spectra having a peak value at which the signal strength ratio P / FN is equal to or greater than the third determination threshold TH3 at the distance D, that is, the number of chirps C1.

[0219] The interference countermeasure determining unit 52B compares the number of chirps C1 at which a peak value exists at which the signal strength ratio P / FN at the distance D is equal to or greater than the third determination threshold TH3 with a second interference countermeasure threshold M2, and performs a necessity determination of the interference countermeasure to determine that the interference countermeasure is “unnecessary” when the number of chirps C1 is outside the range of the second interference countermeasure threshold M2, and to determine that the interference countermeasure is “necessary” when the number of chirps C1 is within the range of the second interference countermeasure threshold M2.

[0220] As described above, by using the number of chirps C1 at which there is a peak at which the signal strength ratio P / FN at the distance D is equal to or greater than the third determination threshold TH3 for the necessity of the interference countermeasure, it can be accurately determined whether the interference signal is superimposed or not when the slope at which the frequency of the interference signal changes is the same as the slope at which the frequency of the chirp signal of the reception signal changes.

[0221] The radar device according to the first embodiment is suitable when the interference signal is different from the chirp signal of the reception signal in the transit time T and the frequency bandwidth BW, that is, when the slope at which the frequency changes is different, and the radar device according to the third embodiment is suitable when the interference signal is the same as the chirp signal of the reception signal in the transit time T and the frequency bandwidth BW, that is, when the slope at which the frequency changes is the same.

[0222] Both the interference countermeasure determination unit 52 and the interference countermeasure determination unit 52B can be mounted on the radar device as an interference countermeasure determination unit, and both can be used for replacement.

[0223] Next, the radar device according to the third embodiment will be described, focusing on an interference countermeasure determination unit 52B, which is different from the interference countermeasure determination unit 52 in the radar device according to the first embodiment.

[0224] The description of the same configuration as that of the radar device according to the first embodiment will be omitted as much as possible.

[0225] As in Fig. 14, it is assumed that the interference signal Rint from another radar device having the same sweep time T and frequency bandwidth BW but a different repetition time Tr_i than the repetition time Tr is received by the receiving antenna 23 as a reception wave with respect to each of the chirp signal Lo(1) to the chirp signal Lo(K) in the transmission signal output from the transmission and reception unit 2 and the chirp signal Rx(1) to the chirp signal Rx(K) in the reception signal output from the transmission and reception unit 2.

[0226] When the transit time T and the frequency bandwidth BW of the interference signal Rint are equal, the frequency mixing unit 31 generates a beat signal having a frequency corresponding to the difference between the frequency of the interference signal Rint and the frequency of the chirp signal in the transmission signal.

[0227] On the other hand, since the repetition time Tr_i of the interference signal Rint differs from the repetition time Tr of the chirp signal in the transmission signal, the beat signal by the interference signal Rint does not appear in all chirps, and the beat signal by the interference signal Rint only appears in some chirps.

[0228] It should be noted that Fig. 14 shows an example in which the transit time T and the frequency bandwidth BW of the chirp signal in the received signal are equal to the transit time T and the frequency bandwidth BW of the interference signal for the purpose of simplifying the description, but even in a case where the slope of the frequency of the chirp signal in the received signal (the ratio of the transit time T and the frequency bandwidth BW) and the slope of the frequency of the interference signal are equal, a peak occurs due to the interference signal, and therefore the interference countermeasure determining unit 52 can determine whether the distance information spectrum is appropriate or not and whether the interference countermeasure is necessary or not.

[0229] To simplify the description, Fig. 14 shows an example where there is an observation target and interference from the other radar device.

[0230] However, this is only an example, and even in a case where there are two or more observation targets and in a case where two or more interference signals are input to the frequency mixing unit 31 via the receiving antenna 23, the interference countermeasure determining unit 52B can similarly determine whether the range information spectrum is appropriate or not and whether the interference countermeasure is required or not for the interference signals having the same pitch at which the frequency changes and having different repetition times.

[0231] The interference countermeasure determination unit 52B acquires the data in the detection target frequency range of the plurality of distance information spectra output from the distance spectrum calculation unit 51.

[0232] The interference countermeasure determination unit 52B calculates the average value FN of the respective signal strengths of the plurality of range information spectra, the peak value P of the signal strength of the data in the detection target frequency range in each of the plurality of range information spectra calculated by the range spectrum calculation unit 51, and the distance D at the peak value P of the signal strength of the data in the interference determination processing range in the plurality of range information spectra calculated by the range spectrum calculation unit 51.

[0233] The interference determination processing area is the same as the interference determination processing area in the radar device according to the first embodiment and is the second half which is a part of the detection target frequency range, that is, the area from the 3D area to the 4D area shown in Fig. 15 is represented by continuous hatching.

[0234] As an example, the peak value P of the signal strength, which is Fig. 15 is shaded, and the distances to the peak value P are given as D1 and D2.

[0235] For example, the peak P present at distance D1 appears in (K -2) chirps, and the peak P present at distance D2 appears in two chirps.

[0236] The peak value P present at the distance D1 is a peak value resulting from the reception of a wave reflected from the object under observation.

[0237] The peak value P present at the distance D2 is a peak value due to the reception of a transmission wave from the other radar device which has the same sweep time T and frequency bandwidth BW but a different repetition time Tr_i than the repetition time Tr.

[0238] The interference countermeasure determining unit 52B compares the signal strength ratio P / FN with the third determination threshold TH3 to determine the peak value in the target frequency range of the distance information spectrum and the distance D at which the peak value exists.

[0239] Fig. Figure 16 shows a range information spectrum of the chirp i when the transmission wave of the other radar device is not received and no interference signal is present. Fig. For example, 16 is a mean value FN 02 the signal strength of the data in the interference determination processing range by a dashed line, the peak value P of the signal strength of the data in the acquisition target frequency range by a black circle, and the difference between the peak value P of the signal strength and the mean value FN 02 the signal strength is represented by a two-headed arrow.

[0240] On the other hand, Fig. 17 shows a range information spectrum of the chirp i in the case where a transmission wave is received by another radar device and an interference signal is present. Fig. 17 is, for example, the mean FN 12 the signal strength of the data in the interference determination processing range by a dashed line, the peak value P of the signal strength of the data in the acquisition target frequency range by a black circle, and the difference between the peak value P of the signal strength and the mean value FN 02 the signal strength is represented by a two-headed arrow.

[0241] In the Fig. 16 and Fig. 17, the horizontal axis represents the distance bin and the vertical axis represents the signal strength.

[0242] If there is no interference signal from the other radar device, as in Fig. As shown in Figure 16, there is only one peak value, which is due to the reception of a wave reflected from the observation target.

[0243] However, if there is an interference signal from the other radar device, as in Fig. 17, there is a peak value (in Fig. 17 marked by a black circle), which is due to the reception of a transmission wave from the other radar device, as well as a peak value (in Fig. 17 marked by a white circle), which is due to the reception of a wave reflected from the observation target.

[0244] Since the propagation distance of the transmitted wave from the other radar device is shorter than the propagation distance of the reflected wave from the observation target, the peak value (black circle in Fig. 17) due to the reception of the transmission wave from the other radar device is normally larger than the peak value (white circle in Fig. 17) due to the reception of the reflected wave from the observation target.

[0245] Therefore, when the signal strength ratio P / FN is equal to or greater than the third determination threshold TH3, the peak value can be calculated regardless of the presence or absence of an interference signal by the other radar device, and in a case where there is an interference signal by the other radar device, the peak value appearing in the distance information spectrum appears at a distance due to the reception of the transmission wave from the other radar device.

[0246] In addition, the influence of receiving the transmission wave from the other radar device does not appear in the range information spectra of all chirps, but the influence of receiving the transmission wave from the other radar device only appears in the range information spectra of some chirps.

[0247] Therefore, if the number of chirps with the peak occurring at the distance D2 is within the range of the second interference countermeasure threshold M2, it can be determined that there is an interference signal due to the reception of the transmission wave of the other radar device.

[0248] In the Fig. In the example shown in Figure 15, the peak value P at distance D1 appears in (K - 2) chirps and the peak value P at distance D2 appears in two chirps.

[0249] For example, when the second interference countermeasure threshold value M2 is in the range of 1 to 10, since the peak value P appears at the distance D2 in the two chirps, it can be determined that the transmission wave of the other radar device is received.

[0250] Therefore, the interference countermeasure determining unit 52B compares the signal strength ratio P / FN with the third determination threshold TH3 in each distance information spectrum, and performs the necessity determination of the interference countermeasure to determine that the interference countermeasure is “necessary” when the number of range information spectra in which the signal strength ratio P / FN is equal to or greater than the third determination threshold TH3 at the same distance D, that is, the number of chirps C1 is within the range of the second interference countermeasure threshold M2.

[0251] When the number of chirps at which the signal strength ratio P / FN is equal to or greater than the third determination threshold TH3 is outside the range of the second interference countermeasure threshold M2, that is, when the number of chirps is zero, it can be determined that no transmission wave has been received from the other radar device at the distance D, and when the number of chirps exceeds 10, it can be determined that a peak occurs at the distance D due to the reception of a reflected wave from the observation target.

[0252] Therefore, when the number of chirps C1 at which the signal strength ratio P / FN is equal to or greater than the third determination threshold TH3 is within the range of the second interference countermeasure threshold M2 at the same distance D, the interference countermeasure determination unit 52B determines that the interference countermeasure is “necessary” and outputs an interference countermeasure signal for the transmission signal to the control unit 11.

[0253] When there is no number of chirps C1 where the signal strength ratio P / FN is equal to or higher than the third determination threshold TH3 within the range of the second interference countermeasure threshold M2 at the same distance D, the interference countermeasure determination unit 52B determines that no transmission wave has been received from the other radar device, determines that the interference countermeasure is “unnecessary,” and outputs the plurality of range information spectra calculated by the range spectrum calculation unit 51 to the distance and speed information output unit 53.

[0254] As described above, by using the signal strength ratio P / FN based on the mean value FN of the signal strengths of the data in the interference determination processing area in the range information spectrum and the peak value P in the detection target frequency area in the range information spectrum, and determining that the interference countermeasure is necessary when the number of chirps C1 at which the signal strength ratio P / FN at the same distance D is equal to or greater than the third determination threshold TH3 falls within the range of the second interference countermeasure threshold M2, the deterioration of the accuracy of determining the necessity of the interference countermeasure can be suppressed even when the interference signal due to a transmission wave is transmitted via the receiving antenna 23 from the other radar device with the same transit time T and frequency bandwidth BW,but with a different repetition time Tr_i compared to the repetition time Tr of the transmission signal is input into the frequency mixing unit 31.

[0255] The operation of the radar device according to the third embodiment is described below.

[0256] The operation is the same as the operation of the radar device according to the first embodiment until the beat data of K chirps is output from the AD converter unit 4 to the signal processing unit 5, and therefore the description thereof is omitted.

[0257] The operation of the signal processing unit 5, into which the beat data of K-chirps are input, is explained using the Fig. 18 described flowchart.

[0258] Fig. 18 is a flowchart illustrating the calculation processing of the distance to the observation target and the relative speed with respect to the observation target including the interference determination in the signal processing unit 5.

[0259] The step ST1 of calculating the range information spectrum is the same as the step ST1 of the radar device according to the first embodiment.

[0260] Step ST2B is a step for calculating the number of chirps C1 and corresponds to step ST2 of the radar device according to the first embodiment.

[0261] In step ST2B, the interference countermeasure determination unit 52B acquires data in the acquisition target frequency range of the K-range information spectra obtained in step ST1.

[0262] For each of the K range information spectra, the interference countermeasure determining unit 52B acquires the peak value of the data in the detection target frequency range, calculates the signal strength ratio P / FN which is one of the state values, and obtains the signal strength ratios P / FN of the K range information spectra.

[0263] The interference countermeasure determination unit 52B assigns the signal strength ratio P / FN of the K range information spectra to the distance D.

[0264] The interference countermeasure determination unit 52B calculates the number of chirps C1 associated with the distance D and whose signal strength ratio P / FN is equal to or greater than the third determination threshold TH3.

[0265] When the interference countermeasure determination unit 52B calculates the number of chirps C1 associated with the distance D, the process proceeds to step ST3B.

[0266] Step ST3B is a step for performing the determination of the necessity of the interference countermeasure and corresponds to step ST3 of the radar device according to the first embodiment.

[0267] In step ST3B, the interference countermeasure determining unit 52B compares the number of chirps C1 associated with the distance D calculated by the interference countermeasure determining unit 52 in step ST2B with the second interference countermeasure threshold M2, and performs a necessity determination of the interference countermeasure to determine that the interference countermeasure is necessary when the

[0268] Number of chirps C1 is within the range of the second interference countermeasure threshold M2, and to determine that the interference countermeasure is "unnecessary" if there is no chirp C1 within the range of the second interference countermeasure threshold M2.

[0269] When the interference countermeasure determination unit 52 determines that the interference countermeasure is necessary in step ST3B, the process proceeds to step ST4, and the signal processing unit 5 outputs an interference countermeasure signal to the control unit 11 of the transmission signal output unit 1, and the process ends.

[0270] On the other hand, when the interference countermeasure determination unit 52B determines that the interference countermeasure is unnecessary, the process proceeds to step ST5.

[0271] The operations in and after step ST5 are the same as the operations in and after step ST5 of the radar device according to the first embodiment, and the distance to the observation target calculated by the distance and speed information calculation unit 532 and the relative speed with respect to the observation target are output to the display unit 6, and the operation ends.

[0272] As described above, in the radar device according to the third embodiment, since the interference countermeasure determining unit 52B determines whether or not interference countermeasure is required depending on whether or not the number of chirps C1 at which the signal strength ratio P / FN at the same distance is equal to or greater than the third determination threshold TH3 is within the range of the second interference countermeasure threshold M2, even when an interference signal due to a transmission wave is input to the frequency mixing unit 31 via the receiving antenna 23 from another radar device having the same sweep time T and frequency bandwidth BW but a different repetition time Tr_i than the repetition time Tr of the transmission signal,to determine the need for high-accuracy interference countermeasure in the radar device of the fast chirp FMCW system using a variety of chirps. Fourth embodiment

[0273] A fast chirp FMCW radar device according to a fourth embodiment will be described with reference to Fig. 19 and Fig. 20 described.

[0274] In the radar device according to the fourth embodiment, only an interference countermeasure determination unit 52C of the signal processing unit 5 is different from the interference countermeasure determination unit 52 of the signal processing unit 5 in the radar device according to the first embodiment, and the other points are the same or similar.

[0275] In the Fig. 19 and Fig. 20 denote the same reference numerals as in the Fig. 1 to 7 the same or corresponding parts.

[0276] The radar device according to the first embodiment sets the state value of the range information spectrum obtained by the interference countermeasure determining unit 52 as the average value FN of the signal strengths of the data in the interference determination processing area in the range information spectrum, and determines the necessity of the interference countermeasure from the number of range information spectra in which the average value FN of the signal strengths is equal to or greater than the first determination threshold.

[0277] On the other hand, the radar device according to the fourth embodiment sets the state value of the range information spectrum obtained by the interference countermeasure determination unit 52C as the mean value FN of the signal strengths of the data in the interference determination processing area in the range information spectrum and the signal strength ratio P / FN between the peak value P of the signal strength of the data in the detection target frequency area in the range information spectrum and the mean value FN of the signal strengths, and performs a first determination of the necessity of the interference countermeasure based on the number of range information spectra in which the mean value FN of the signal strengths is equal to or greater than the first determination threshold TH1, and a second determination of the necessity of the interference countermeasure based on the number of range information spectra,in which the signal strength ratio P / FN is equal to or greater than the fourth determination threshold TH4, if the first determination determines that the interference countermeasure is necessary.

[0278] The interference countermeasure determination unit 52C includes a first determination unit 52C1 and a second determination unit 52C2.

[0279] The first determination unit 52C1 is a determination unit corresponding to the interference countermeasure determination unit 52 of the radar device according to the first embodiment.

[0280] The first determination threshold TH1 and the first interference countermeasure threshold M1 are the same values ​​as the first determination threshold TH1 and the first interference countermeasure threshold M1 used in the radar device according to the first embodiment.

[0281] The first determination unit 52C1 acquires the data in the detection target frequency range of the plurality of distance information spectra output from the distance spectrum calculation unit 51.

[0282] The first determination unit 52C1 calculates the mean value FN of the signal strengths, which is one of the state values ​​of each of the plurality of distance information spectra, from the data calculated by the range spectrum calculation unit 51 in the interference determination processing area in the plurality of distance information spectra.

[0283] The first determination unit 52C1 compares the calculated average value FN of the respective signal strengths of the distance information spectra with the first determination threshold TH1, which is one of the interference determination thresholds, to obtain the adequacy in each of the plurality of distance information spectra, and determines whether or not an interference countermeasure is required based on the number of unsuitable distance information spectra in the plurality of distance information spectra.

[0284] Regarding whether the determination in the distance information spectrum by the first determination unit 52C1 is appropriate or not, the distance information spectrum is determined to be “appropriate” when the average value FN of the signal strengths of the data in the interference determination processing area in the distance information spectrum is smaller than the first determination threshold TH1, and when the average value FN is equal to or larger than the first determination threshold TH1, the distance information spectrum is determined to be “unsuitable”.

[0285] When determining the necessity of the interference countermeasure by the first determination unit 52C1, the interference countermeasure is determined to be “unsuitable” when the number of chirps C1 of unsuitable distance information spectra in the plurality of distance information spectra is less than the first interference countermeasure threshold M1, and when the number of chirps C1 is equal to or greater than the first interference countermeasure threshold M1, the interference countermeasure is determined to be “necessary”.

[0286] When the first determination unit 52C1 determines that the interference countermeasure is necessary, ie, required, it outputs the plurality of distance information spectra calculated by the distance spectrum calculation unit 51 and the average value FN of the calculated signal strengths to the second determination unit 52C2.

[0287] When the first determination unit 52C1 determines that the interference countermeasure is not necessary, that is, is not necessary, the first determination unit outputs the plurality of distance information spectra calculated by the distance spectrum calculation unit 51 to the distance and speed information output unit 53.

[0288] When the first determination unit 52C1 determines that the interference countermeasure is necessary, the second determination unit 52C2 acquires the plurality of distance information spectra calculated by the distance spectrum calculation unit 51 and the mean value FN of the signal strength calculated by the first determination unit 52C1 from the first determination unit 52C1.

[0289] The second determination unit 52C2 calculates the peak value P of the signal strength of the data in the detection target frequency range in each of the plurality of distance information spectra calculated by the distance spectrum calculation unit 51.

[0290] The second determination unit 52C2 compares the signal strength ratio P / FN with the fourth determination threshold TH4 in each distance information spectrum and calculates the number of distance information spectra in which the signal strength ratio P / FN is equal to or greater than the fourth determination threshold TH4, ie, the number of chirps C2.

[0291] The second determination unit 52C2 compares the number of chirps C2 with the third interference countermeasure threshold M3 and performs a necessity determination of the interference countermeasure to determine that the interference countermeasure is necessary when the number of chirps C2 is equal to or less than the third interference countermeasure threshold M3, and to determine that the interference countermeasure is not necessary when the number of chirps C2 is greater than the third interference countermeasure threshold M3.

[0292] The second determination unit 52C2 outputs an interference countermeasure signal for the transmission signal to the control unit 11 when it is determined that the interference countermeasure is necessary, ie, required, and outputs a plurality of distance information spectra calculated by the distance spectrum calculation unit 51 to the distance and speed information output unit 53 when it is determined that the interference countermeasure is not necessary, ie, unnecessary.

[0293] As described above, since the interference countermeasure determining unit 52C includes the first determining unit 52C1 and the second determining unit 52C2, and the second determining unit 52C2 further determines the necessity of the interference countermeasure with respect to the interference countermeasure determined as necessary by the first determining unit 52C1, it is possible to avoid unnecessary processing of the interference countermeasure under the conditions where the SNR of the observation target is high and the observation target can be detected by Fourier transform in the relative velocity direction by the distance and velocity information output unit 53.

[0294] Next, the operation of the radar device according to the fourth embodiment will be described.

[0295] The operation is the same as the operation of the radar device according to the first embodiment until the beat data of K chirps is output from the AD converter unit 4 to the signal processing unit 5, and therefore the description thereof is omitted.

[0296] The operation of the signal processing unit 5, into which the beat data of K-chirps are input, is explained using the Fig. 20 flowchart shown.

[0297] Fig. 20 is a flowchart illustrating the calculation processing of the distance to the observation target and the relative speed with respect to the observation target including the interference determination in the signal processing unit 5.

[0298] The step ST1 of calculating the range information spectrum, the step ST2 of calculating the number of chirps C1, and the step ST3 of performing the necessity determination of the first interference countermeasure are the same as the steps ST1, ST2, and ST3 of the radar device according to the first embodiment.

[0299] The processing in step ST2 is performed by the first determination unit 52C1 of the interference countermeasure determination unit 52C.

[0300] In step ST3, when the first determination unit 52C1 of the interference countermeasure determination unit 52C determines that the interference countermeasure is necessary, the process proceeds to step ST7, and when it is determined that the interference countermeasure is not necessary, the process proceeds to step ST5.

[0301] Step ST7 is a step for calculating the number of chirps C2.

[0302] In step ST7, when the first determination unit 52C1 determines that the interference countermeasure is required, the second determination unit 52C2 acquires the distance information spectra K calculated by the distance spectrum calculation unit 51 and the mean value FN of the signal strength calculated by the first determination unit 52C1 from the first determination unit 52C1.

[0303] The second determination unit 52C2 calculates the peak value P of the signal strength of the data in the detection target frequency range in each of the K range information spectra calculated by the range spectrum calculation unit 51, and obtains the signal strength ratio P / FN of the K range information spectra.

[0304] The second determination unit 52C2 compares the signal strength ratio P / FN with the fourth determination threshold TH4 for each of the K range information spectra to obtain the suitability with respect to the range information spectrum.

[0305] The second determination unit 52C2 calculates the number of chirps C2 of unsuitable range information spectra for which the signal strength ratio P / FN is equal to or greater than the fourth determination threshold TH4.

[0306] When the second determination unit 52C2 calculates the number of chirps C2 of the distance information spectrum, the process proceeds to step ST8.

[0307] In step ST8, the necessity of the second interference countermeasure is determined.

[0308] In step ST8, the second determination unit 52C2 compares the number of chirps C2 calculated in step ST7 with the third interference countermeasure threshold M3 and performs a necessity determination of the interference countermeasure to determine that the interference countermeasure is "necessary" when the number of chirps C2 is less than the third interference countermeasure threshold M3, and to determine that the interference countermeasure is "unnecessary" when the number of chirps C2 is equal to or greater than the third interference countermeasure threshold M3.

[0309] In step ST8, when the second determination unit 52C2 determines that the interference countermeasure is necessary, the process proceeds to step ST4, and the signal processing unit 5 outputs the interference countermeasure signal to the control unit 11 of the transmission signal output unit 1, and the process ends.

[0310] On the other hand, if the second determination unit 52C2 determines that no interference countermeasure is taken, the process proceeds to step ST5.

[0311] The operations in and after step ST5 are the same as the operations in and after step ST5 of the radar device according to the first embodiment, and the distance to the observation target calculated by the distance and speed information calculation unit 532 and the relative speed with respect to the observation target are output to the display unit 6, and the operation ends.

[0312] As described above, the radar device according to the fourth embodiment has the same effects as the radar device according to the first embodiment, and can avoid unnecessary processing of interference countermeasures under conditions where the SNR of the observation target is high and the observation target can be detected by Fourier transform in the direction of relative velocity. Fifth embodiment

[0313] A fast chirp FMCW radar device according to a fifth embodiment will be described with reference to FIG. Fig. 21 and Fig. 22 described.

[0314] In the radar device according to the fifth embodiment, only an interference countermeasure determination unit 52D of the signal processing unit 5 is different from the interference countermeasure determination unit 52A of the signal processing unit 5 in the radar device according to the second embodiment, and the other points are the same or similar.

[0315] In the Fig. 21 and Fig. 22 denote the same reference numerals as in the Fig. 8 to 12 the same or corresponding parts.

[0316] In the radar device according to the second embodiment, the interference countermeasure determining unit 52A determines whether or not an interference countermeasure is required based on the number of range information spectra in which the mean value FN of the signal strengths is equal to or greater than the first determination threshold TH1 and the signal strength ratio P / FN is equal to or less than the second determination threshold TH2.

[0317] On the other hand, in the radar device according to the fifth embodiment, the interference countermeasure determining unit 52D performs the first determination of the necessity of the interference countermeasure based on the number of range information spectra in which the mean value FN of the signal strengths is equal to or greater than the first determination threshold TH1 and the signal strength ratio P / FN is equal to or less than the second determination threshold TH2, and the second determination of the necessity of the interference countermeasure based on the number of range information spectra in which the signal strength ratio P / FN is equal to or greater than the fourth determination threshold TH4, when it is determined that the interference countermeasure is necessary based on the first determination.

[0318] The interference countermeasure determination unit 52D includes a first determination unit 52D1 and a second determination unit 52D2.

[0319] The first determination unit 52D1 is a determination unit corresponding to the determination unit 52A of the radar device according to the second embodiment.

[0320] The second determination unit 52D2 is a determination unit corresponding to the second determination unit 52C2 of the radar device according to the fourth embodiment.

[0321] The first determination threshold TH1, the second determination threshold TH2, and the first interference countermeasure threshold M1 are the same values ​​as the first determination threshold TH1, the second determination threshold TH2, and the first interference countermeasure threshold M1 used in the radar device according to the second embodiment.

[0322] The fourth determination threshold TH4 and the third interference countermeasure threshold M3 are the same values ​​as the fourth determination threshold TH4 and the third interference countermeasure threshold M3 used in the radar device according to the fourth embodiment.

[0323] The first determination unit 52D1 acquires the data in the detection target frequency range of the plurality of distance information spectra output from the distance spectrum calculation unit 51.

[0324] The first determination unit 52D1 calculates the average value FN of the respective signal strengths of the plurality of distance information spectra and the peak value P of the signal strength of the data in the detection target frequency range in each of the plurality of distance information spectra calculated by the range spectrum calculation unit 51 from the data in the interference determination processing range in the plurality of distance information spectra calculated by the range spectrum calculation unit 51.

[0325] The first determination unit 52D1 compares the mean value FN of the signal strengths with the first determination threshold TH1 and compares the signal strength ratio P / FN with the second determination threshold TH2.

[0326] For each of the K distance information spectra, the first determination unit 52D1 determines whether the distance information spectrum is suitable or not based on the first determination threshold TH1 and the second determination threshold TH2, and calculates the number of chirps C1 of unsuitable distance information spectra.

[0327] The first determination unit 52D1 determines, among the K distance information spectra, the number of chirps C1 of the distance information spectrum for which the mean value FN of the signal strength is equal to or greater than the first determination threshold TH1 and the signal strength ratio P / FN is equal to or less than the second determination threshold TH2.

[0328] The first determination unit 52D1 compares the calculated number of chirps C1 with the distance information spectrum that is “unnecessary” with the first interference countermeasure threshold M1 and performs a necessity determination of the interference countermeasure to determine that the interference countermeasure is “unnecessary” when the number of chirps C1 is less than the first interference countermeasure threshold M1, and to determine that the interference countermeasure is “necessary” when the number of chirps C1 is equal to or greater than the first interference countermeasure threshold M1.

[0329] The first determination unit 52D1 outputs the calculated signal strength ratio P / FN to the second determination unit 52D2 when it determines that the interference countermeasure is necessary, ie, required, and outputs the plurality of distance information spectra calculated by the distance spectrum calculation unit 51 to the distance and speed information output unit 53 when it determines that the interference countermeasure is not necessary, ie, unnecessary.

[0330] When the first determination unit 52D1 determines that the interference countermeasure is necessary, the second determination unit 52D2 acquires the signal strength ratio P / FN calculated by the first determination unit 52D1.

[0331] The second determination unit 52D2 compares the signal strength ratio P / FN with the fourth determination threshold TH4 in each distance information spectrum and calculates the number of distance information spectra in which the signal strength ratio P / FN is equal to or greater than the fourth determination threshold TH4, ie, the number of chirps C2.

[0332] The second determination unit 52D2 compares the number of chirps C2 with the third interference countermeasure threshold M3 and performs a necessity determination of the interference countermeasure to determine that the interference countermeasure is necessary when the number of chirps C2 is equal to or less than the third interference countermeasure threshold M3, and to determine that the interference countermeasure is not necessary when the number of chirps C2 is greater than the third interference countermeasure threshold M3.

[0333] The second determination unit 52D2 outputs an interference countermeasure signal for the transmission signal to the control unit 11 when it is determined that the interference countermeasure is necessary, ie, required, and outputs a plurality of distance information spectra calculated by the distance spectrum calculation unit 51 to the distance and speed information output unit 53 when it is determined that the interference countermeasure is not necessary, ie, unnecessary.

[0334] As described above, since the interference countermeasure determining unit 52D includes the first determining unit 52D1 and the second determining unit 52D2, and the second determining unit 52D2 further determines the necessity of the interference countermeasure with respect to the interference countermeasure determined as necessary by the first determining unit 52D1, it is possible to avoid unnecessary processing of the interference countermeasure under the conditions where the SNR of the observation target is high and the observation target can be detected by Fourier transform in the relative velocity direction by the distance and velocity information output unit 53.

[0335] Next, the operation of the radar device according to the fifth embodiment will be described.

[0336] The operation is the same as the operation of the radar device according to the first embodiment until the beat data of K chirps is output from the AD converter unit 4 to the signal processing unit 5, and therefore the description thereof is omitted.

[0337] The operation of the signal processing unit 5, into which the beat data of K-chirps are input, is described in Fig. 22 described flowchart.

[0338] Fig. 22 is a flowchart illustrating the calculation processing of the distance to the observation target and the relative speed with respect to the observation target including the interference determination in the signal processing unit 5.

[0339] The step ST1 of calculating the range information spectrum, the step ST2A of calculating the number of chirps C1, and the step ST3 of performing the necessity determination of the first interference countermeasure are the same as the steps ST1, ST2A, and ST3 of the radar device according to the second embodiment.

[0340] The processing in step ST2A is performed by the first determination unit 52D1 of the interference countermeasure determination unit 52D.

[0341] In step ST3, when the first determination unit 52D1 of the interference countermeasure determination unit 52D determines that the interference countermeasure is necessary, the process proceeds to step ST7, and when it is determined that the interference countermeasure is not necessary, the process proceeds to step ST5.

[0342] Step ST7 is a step of calculating the number of chirps C2, and like the second determination unit 52C2 in step ST7 of the radar device according to the fourth embodiment, when the first determination unit 52D1 determines that the interference countermeasure is necessary, the second determination unit 52D2 calculates the number of chirps C2 of unsuitable range information spectra in which the signal strength ratio P / FN detected by the first determination unit 52D1 is equal to or greater than the fourth determination threshold TH4.

[0343] When the second determination unit 52D2 calculates the number of chirps C2 of the distance information spectrum, the process proceeds to step ST8, and like the second determination unit 52C2 in step ST8 of the radar device according to the fourth embodiment, the second determination unit 52D2 performs processing, and when it is determined that the interference countermeasure is necessary, the process proceeds to step ST4, the signal processing unit 5 outputs the interference countermeasure signal to the control unit 11 of the transmission signal output unit 1, and the process ends.

[0344] On the other hand, when the second determination unit 52D2 determines that the interference countermeasure is not required, the process proceeds to step ST5.

[0345] The operations in and after step ST5 are the same as the operations in and after step ST5 of the radar device according to the first embodiment, and the distance to the observation target calculated by the distance and speed information calculation unit 532 and the relative speed with respect to the observation target are output to the display unit 6, and the operation ends.

[0346] As described above, the radar device according to the fifth embodiment has the same effects as the radar device according to the second embodiment, and can avoid unnecessary processing of interference countermeasures under conditions where the SNR of the observation target is high and the observation target can be detected by Fourier transform in the direction of relative velocity. Sixth embodiment

[0347] A fast chirp FMCW radar device according to a sixth embodiment will be described with reference to FIG. Fig. 23 and Fig. 24 described.

[0348] In the radar device according to the sixth embodiment, only an interference countermeasure determination unit 52E of the signal processing unit 5 is different from the interference countermeasure determination unit 52B of the signal processing unit 5 in the radar device according to the third embodiment, and the other points are the same or similar.

[0349] In the Fig. 23 and Fig. 24 denote the same reference numerals as in the Fig. 13 to 18 the same or corresponding parts.

[0350] In the radar device according to the third embodiment, the interference countermeasure determining unit 52B determines whether or not an interference countermeasure is required based on the number of range information spectra having a peak value at which the signal strength ratio P / FN at the distance D is equal to or greater than the third determination threshold TH3.

[0351] On the other hand, in the radar device according to the sixth embodiment, the interference countermeasure determining unit 52E performs the first determination of the necessity of the interference countermeasure based on the number of range information spectra having a peak value in which the signal strength ratio P / FN at the distance D is equal to or greater than the third determination threshold TH3, and the second determination of the necessity of the interference countermeasure based on the number of range information spectra in which the signal strength ratio P / FN at the distance D is equal to or greater than the fourth determination threshold TH4, after determining the necessity of the interference countermeasure by the first determination.

[0352] The interference countermeasure determination unit 52E includes a first determination unit 52E1 and a second determination unit 52E2.

[0353] The first determination unit 52E1 is a determination unit corresponding to the interference countermeasure determination unit 52B of the radar device according to the third embodiment.

[0354] The second determination unit 52E2 is a determination unit corresponding to the second determination unit 52C2 of the radar device according to the fourth embodiment.

[0355] The third determination threshold TH3 and the second interference countermeasure threshold M2 are the same values ​​as the third determination threshold TH3 and the second interference countermeasure threshold M2 used in the radar device according to the third embodiment.

[0356] The fourth determination threshold TH4 and the third interference countermeasure threshold M3 are the same values ​​as the fourth determination threshold TH4 and the third interference countermeasure threshold M3 used in the radar device according to the fourth embodiment.

[0357] The first determination unit 52E1 acquires the data in the detection target frequency range of the plurality of distance information spectra output from the distance spectrum calculation unit 51.

[0358] The first determination unit 52E1 calculates the average value FN of the respective signal strengths of the plurality of distance information spectra and the peak value P of the signal strength of the data in the detection target frequency range in each of the plurality of distance information spectra calculated by the range spectrum calculation unit 51 from the data in the interference determination processing range in the plurality of distance information spectra calculated by the range spectrum calculation unit 51.

[0359] By comparing the signal strength ratio P / FN with the third determination threshold TH3, the first determination unit 52E1 determines the distance D at which there is a peak value at which the signal strength ratio P / FN in the distance information spectrum is equal to or greater than the third determination threshold TH3, and the number of distance information spectra having a peak value at which the signal strength ratio P / FN is equal to or greater than the third determination threshold TH3 at the distance D, that is, the number of chirps C1.

[0360] The first determination unit 52E1 compares the number of chirps C1 at which there is a peak value with which the signal strength ratio P / FN at the distance D is equal to or greater than the third determination threshold TH3 with the second interference countermeasure threshold M2, and performs a necessity determination of the interference countermeasure to determine that the interference countermeasure is “unnecessary” when the number of chirps C1 is outside the range of the second interference countermeasure threshold M2, and to determine that the interference countermeasure is “necessary” when the number of chirps C1 is within the range of the second interference countermeasure threshold M2.

[0361] The first determination unit 52E1 outputs the calculated signal strength ratio P / FN to the second determination unit 52E2 when it determines that the interference countermeasure is necessary, ie, required, and outputs the plurality of distance information spectra calculated by the distance spectrum calculation unit 51 to the distance and speed information output unit 53 when it determines that the interference countermeasure is not necessary, ie, unnecessary.

[0362] When the first determination unit 52E1 determines that the interference countermeasure is necessary, the second determination unit 52E2 acquires the signal strength ratio P / FN calculated by the first determination unit 52E1.

[0363] The second determination unit 52E2 compares the signal strength ratio P / FN with the fourth determination threshold TH4 in each distance information spectrum and calculates the number of distance information spectra in which the signal strength ratio P / FN is equal to or greater than the fourth determination threshold TH4, ie, the number of chirps C2.

[0364] The second determination unit 52E2 compares the number of chirps C2 with the third interference countermeasure threshold M3 and performs a necessity determination of the interference countermeasure to determine that the interference countermeasure is necessary when the number of chirps C2 is equal to or less than the third interference countermeasure threshold M3, and to determine that the interference countermeasure is not necessary when the number of chirps C2 is greater than the third interference countermeasure threshold M3.

[0365] The second determination unit 52E2 outputs an interference countermeasure signal for the transmission signal to the control unit 11 when it is determined that the interference countermeasure is necessary, ie, required, and outputs a plurality of distance information spectra calculated by the distance spectrum calculation unit 51 to the distance and speed information output unit 53 when it is determined that the interference countermeasure is not necessary, ie, unnecessary.

[0366] As described above, since the interference countermeasure determining unit 52E includes the first determining unit 52E1 and the second determining unit 52E2, and the second determining unit 52E2 further determines the necessity of the interference countermeasure with respect to the interference countermeasure determined as necessary by the first determining unit 52E1, it is possible to avoid unnecessary processing of the interference countermeasure under the conditions where the SNR of the observation target is high and the observation target can be detected by Fourier transform in the relative velocity direction by the distance and velocity information output unit 53.

[0367] The operation of the radar device according to the sixth embodiment will be described below.

[0368] The operation is the same as the operation of the radar device according to the first embodiment until the beat data of K chirps is output from the AD converter unit 4 to the signal processing unit 5, and therefore the description thereof is omitted.

[0369] A functioning of the signal processing unit 5, into which the beat data of K-chirps are input, is explained with reference to the Fig. 24 flowchart shown.

[0370] Fig. 24 is a flowchart illustrating the calculation processing of the distance to the observation target and the relative speed with respect to the observation target including the interference determination in the signal processing unit 5.

[0371] The step ST1 of calculating the range information spectrum, the step ST2B of calculating the number of chirps C1, and the step ST3B of performing the determination of the necessity of the first interference countermeasure are the same as the steps ST1, ST2B, and ST3B of the radar device according to the third embodiment.

[0372] The processing in steps ST2B and ST3B is performed by the first determination unit 52E1 of the interference countermeasure determination unit 52E.

[0373] In step ST3B, when the first determination unit 52E1 of the interference countermeasure determination unit 52E determines that the interference countermeasure is necessary, the process proceeds to step ST7, and when it is determined that the interference countermeasure is not necessary, the process proceeds to step ST5.

[0374] Step ST7 is a step of calculating the number of chirps C2, and like the second determination unit 52C2 in step ST7 of the radar device according to the fourth embodiment, when the first determination unit 52E1 determines that the interference countermeasure is necessary, the second determination unit 52E2 calculates the number of chirps C2 of unsuitable range information spectra in which the signal strength ratio P / FN detected by the first determination unit 52E1 is equal to or greater than the fourth determination threshold TH4.

[0375] When the second determination unit 52E2 calculates the number of chirps C2 of the distance information spectrum, the process proceeds to step ST8, and like the second determination unit 52C2 in step ST8 of the radar device according to the fourth embodiment, the second determination unit 52E2 performs processing, and when it is determined that the interference countermeasure is necessary, the process proceeds to step ST4, the signal processing unit 5 outputs the interference countermeasure signal to the control unit 11 of the transmission signal output unit 1, and the process ends.

[0376] On the other hand, if the second determination unit 52E2 determines that no interference countermeasure is taken, the process proceeds to step ST5.

[0377] The operations in and after step ST5 are the same as the operations in and after step ST5 of the radar device according to the first embodiment, and the distance to the observation target calculated by the distance and speed information calculation unit 532 and the relative speed with respect to the observation target are output to the display unit 6, and the operation ends.

[0378] As described above, the radar device according to the sixth embodiment has the same effects as the radar device according to the third embodiment, and can avoid unnecessary processing of interference countermeasures under conditions where the SNR of the observation target is high and the observation target can be detected by Fourier transform in the direction of relative velocity. Seventh embodiment

[0379] A fast chirp FMCW radar device according to a seventh embodiment will be described with reference to FIG. Fig. 25 to 28 described.

[0380] In the radar device according to the seventh embodiment, only an interference countermeasure determination unit 52F of the signal processing unit 5 is different from the interference countermeasure determination unit 52B of the signal processing unit 5 in the radar device according to the third embodiment, and the other points are the same or similar.

[0381] In the Fig. 25 to 28 denote the same reference numerals as in the Fig. 1 to 7 and Fig. 13 to 18 the same or corresponding parts.

[0382] In the radar device according to the third embodiment, the state value of the range information spectrum obtained by the interference countermeasure determining unit 52B is set as the signal strength ratio P / FN of the peak value P of the signal strength of the data in the detection target frequency range in the range information spectrum to the average value FN of the signal strengths of the data in the interference determination processing range in the range information spectrum.

[0383] On the other hand, in the radar device according to the seventh embodiment, the state value of the range information spectrum obtained by the interference countermeasure determining unit 52F is set as a plurality of signal strength ratios, and the interference determination threshold value is set as a fifth determination threshold value TH5.

[0384] The plurality of signal strength ratios are signal strength ratios P / FN and P2 / FN of multiple peak values ​​P and P2 of the signal strength of the data in the detection target frequency range in the range information spectrum to the mean value FN of the signal strengths of the data in the interference determination processing range in the range information spectrum.

[0385] The fifth determination threshold TH5 can be the same value as the third determination threshold TH3 or the second determination threshold TH2.

[0386] In the radar device according to the seventh embodiment, the plurality of peak values ​​of the signal strength are set as the peak value P and the second peak value P2 with the signal strength smaller than the peak value P, and the plurality of signal strength ratios are set as the signal strength ratio P / FN at the peak value P and the signal strength ratio P2 / FN at the second peak value P2.

[0387] It should be noted that the state value is not limited to the two signal strength ratios, and a signal strength ratio can be added at the third and subsequent peak values.

[0388] To simplify the description, a radar device that uses two signal strength ratios P / FN and P2 / FN as state values ​​is referred to as a radar device according to the seventh embodiment.

[0389] The radar device according to the seventh embodiment can determine the need for high-precision interference countermeasures with respect to the second observation target even in a case where there are two observation targets, there is interference from another radar device, one observation target (hereinafter referred to as the first observation target) is located at a shorter distance than the propagation distance of the other radar device, and another observation target (hereinafter referred to as the second observation target) is located farther than the propagation distance of the other radar device.

[0390] That is, when the first observation target is located at a close distance to the propagation distance of the other radar device, the peak value due to reception of the transmission wave from the other radar device is smaller than the peak value due to reception of the reflected wave from the first observation target.

[0391] Therefore, by using the signal strength ratio P / FN at the peak value P as the state value, as in the radar device according to the third embodiment, there is no erroneous determination of the necessity of the interference countermeasure with respect to the first observation target, and it is possible to determine the necessity of the high-accuracy interference countermeasure with respect to the first observation target.

[0392] On the other hand, since the propagation distance of the transmission wave from the other radar device is shorter than the propagation distance of the reflected wave from the second observation target, the peak value due to reception of the transmission wave from the other radar device is larger than the peak value due to reception of the reflected wave from the second observation target and is the second peak value.

[0393] As a result, the reception signal based on the reflected wave from the second observation target is affected by the interference signal due to the transmission wave of the other radar device.

[0394] Since the radar device according to the seventh embodiment uses the signal strength ratio P2 / FN at the second peak P2 as a state value and also determines whether or not interference countermeasure is required based on the second peak value, it is possible to detect the second peak value based on the interference signal due to the transmission wave from the other radar device, and thus there is no erroneous determination of the necessity of interference countermeasure with respect to the second observation target, so that it is possible to determine the necessity of interference countermeasure with high accuracy with respect to the second observation target.

[0395] In short, the interference countermeasure determination unit 52F of the signal processing unit 5 in the radar device according to the third embodiment acquires the data in the detection target frequency range from the plurality of range information spectra output from the range spectrum calculation unit 51.

[0396] The interference countermeasure determination unit 52F calculates the average value FN of the respective signal strengths of the plurality of range information spectra, the peak value P of the signal strength of the data in the detection target frequency range in each of the plurality of range information spectra calculated by the range spectrum calculation unit 51, and the second peak value P2 of the signal strength of the data in the detection target frequency range in each of the plurality of range information spectra calculated by the range spectrum calculation unit 51 from the data in the interference determination processing area in the plurality of range information spectra calculated by the range spectrum calculation unit 51.

[0397] The interference countermeasure determining unit 52F compares the signal strength ratio P / FN at the peak value P with the fifth determination threshold TH5 and compares the signal strength ratio P2 / FN at the second peak value with the fifth determination threshold TH5 to determine the distance D at which there is a peak value at which the signal strength ratio P / FN in the distance information spectrum is equal to or greater than the fifth determination threshold TH5, and the number of distance information spectra in which there is a peak value at which the signal strength ratio P / FN is equal to or greater than the fifth determination threshold TH5 at the distance D, and the distance D at which there is a peak value at which the signal strength ratio P2 / FN in the distance information spectrum is equal to or greater than the fifth determination threshold TH5, and the number of distance information spectra in which there is a peak value,where the signal strength ratio P2 / FN is equal to or greater than the fifth determination threshold TH5, at distance D.

[0398] The number of distance information spectra in which a peak value at which the signal strength ratio P / FN is equal to or greater than the fifth determination threshold TH5 exists at the distance D, and the number of distance information spectra in which a peak value at which the signal strength ratio P2 / FN is equal to or greater than the fifth determination threshold TH5 exists at the distance D are the number of chirps C3.

[0399] It should be noted that although the same D is used for the distance D at the distance D at which there is a peak value at which the signal strength ratio P / FN in the distance information spectrum is equal to or greater than the fifth determination threshold TH5 and the distance D at which there is a peak value at which the signal strength ratio P2 / FN in the distance information spectrum is the fifth determination threshold TH5, the distances D are used to indicate a general distance and do not necessarily agree with each other.

[0400] That is, the distance D at which the peak value P exists due to the reception of the reflected wave from the first observation target and the distance D at which the peak value P2 exists due to the reception of the transmitted wave from the other radar device are generally different.

[0401] Thus, there is a case where the number of chirps C3 is the number of range information spectra in which a peak at which the signal strength ratio P / FN is equal to or greater than the fifth determination threshold TH5 exists at the distance D, and a case where the number of chirps C3 is the number of range information spectra in which a peak at which the signal strength ratio P2 / FN is equal to or greater than the fifth determination threshold TH5 exists at the distance D. It is not necessarily intended to express the total number of both.

[0402] That is, the number of chirps C3 is the number of chirps, which is the number of range information spectra in which a peak at which the signal strength ratio P / FN is equal to or greater than the fifth determination threshold TH5 exists at the distance D, and the number of chirps, which is the number of range information spectra in which a peak at which the signal strength ratio P2 / FN is equal to or greater than the fifth determination threshold TH5 exists at the distance D.

[0403] In the following description, D of the distance D is an indication to indicate a general distance as described above.

[0404] The interference countermeasure determination unit 52F compares the number of chirps C3 representing the number of range information spectra in which the peak P at which the signal strength ratio P / FN at the distance D is equal to or greater than the fifth determination threshold TH5 is present, and the number of range information spectra in which the peak P2 at which the signal strength ratio P2 / FN is equal to or greater than the fifth determination threshold TH5 is present at the distance D, with a fourth interference countermeasure threshold M4.The interference countermeasure determining unit 52F performs the determination of the necessity of the interference countermeasure to determine that the interference countermeasure is “unnecessary” when the number of chirps C3 is outside the range of the fourth interference countermeasure threshold M4, and to determine that the interference countermeasure is determined to be “necessary” when the number of chirps C3 is within the range of the fourth interference countermeasure threshold M4.

[0405] The fourth interference countermeasure threshold M4 may be the same value as the second interference countermeasure threshold M2.

[0406] As described above, by using the number of chirps C3, which represents the number of range information spectra in which there is a peak at which the signal strength ratio P / FN at the distance D is equal to or greater than the fifth determination threshold TH5, and the number of range information spectra in which there is a peak at which the signal strength ratio P2 / FN at the distance D is equal to or greater than the fifth determination threshold TH5, for the necessity of the interference countermeasure when the slope at which the frequency of the interference signal changes is the same as the slope at which the frequency of the chirp signal of the reception signal changes, and the first observation target of the two observation targets is located at a short distance from the radar device, it is possible to accurately determinewhether the interference signal is superimposed on both the first observation target and the second observation target.

[0407] The radar device according to the third embodiment is suitable in a case where the interference signal has the same transit time T and frequency bandwidth BW as the chirp signal of the reception signal, that is, when the slope at which the frequency changes is the same and there is an observation target, and the radar device according to the seventh embodiment is suitable in a case where the interference signal has the same transit time T and frequency bandwidth BW as the chirp signal of the reception signal, that is, in a case where the slope at which the frequency changes is the same and there are two observation targets, one of which is located at a short distance from the radar device.

[0408] It should be noted that even in a case where there are plural, three or more, observation targets and one of the observation targets is located at a short distance from the radar device, the idea can be applied in the radar device according to the seventh embodiment.

[0409] Next, the radar device according to the seventh embodiment will be described, focusing on an interference countermeasure determining unit 52F, which is different from the interference countermeasure determining unit 52B for determining the countermeasure in the radar device according to the third embodiment.

[0410] The description of the same configurations as those of the radar device according to the third embodiment and the radar device according to the first embodiment will be omitted as much as possible.

[0411] Now, as in Fig. 26, assume that the interference signal Rint from another radar device, which has the same sweep time T and frequency bandwidth BW but a repetition time Tr_i different from the repetition time Tr, is received by the receiving antenna 23 as a reception wave with respect to each of the chirp signals Lo(1) to Lo(K) in the transmission signal output from the transmission and reception unit 2, each of the chirp signals Rx(1) to Rx(K) in the reception signal of the first observation target output from the transmission and reception unit 2, and each of the chirp signals Rx2(1) to Rx2(K) in the reception signal of the second observation target.

[0412] When the transit time T and the frequency bandwidth BW of the interference signal Rint are equal, the frequency mixing unit 31 generates a beat signal having a frequency corresponding to the difference between the frequency of the interference signal Rint and the frequency of the chirp signal in the transmission signal.

[0413] On the other hand, since the repetition time Tr_i of the interference signal Rint differs from the repetition time Tr of the chirp signal in the transmission signal, the beat signal by the interference signal Rint does not appear in all chirps, and the beat signal by the interference signal Rint only appears in some chirps.

[0414] It should be noted that Fig. 26 shows an example in which the transit time T and the frequency bandwidth BW of the chirp signal in the received signal are equal to the transit time T and the frequency bandwidth BW of the interference signal for the purpose of simplifying the description, but even in a case where the slope of the frequency of the chirp signal in the received signal (the ratio of the transit time T and the frequency bandwidth BW) and the slope of the frequency of the interference signal are equal, a peak occurs due to the interference signal, and therefore the interference countermeasure determining unit 52 can determine whether the distance information spectrum is appropriate or not and whether the interference countermeasure is necessary or not.

[0415] To simplify the description, Fig. 26 shows an example where there are two observation targets and interference occurs from the other radar device.

[0416] However, this is only an example, and in a case where there are three or more observation targets, the interference countermeasure determining unit 52F can determine whether the spectrum of the distance information is appropriate or not and whether the interference countermeasures are necessary or not by using the third and subsequent peak values ​​for determination.

[0417] The interference countermeasure determination unit 52F acquires the data in the detection target frequency range from the plurality of range information spectra output from the range spectrum calculation unit 51.

[0418] The interference countermeasure determination unit 52F calculates the average value FN of the respective signal strengths of the plurality of range information spectra, the peak value P of the signal strength of the data in the detection target frequency range in each of the plurality of range information spectra calculated by the range spectrum calculation unit 51, the distance D at the peak value P of the signal strength, the second peak value P2 of the signal strength of the data in the detection target frequency range in each of the plurality of range information spectra calculated by the range spectrum calculation unit 51, and the distance D at the second peak value P2 of the signal strength from the data in the interference determination processing range in the plurality of range information spectra calculated by the range spectrum calculation unit 51.

[0419] The interference determination processing area is the same as the interference determination processing area in the radar device according to the third embodiment and the interference determination processing area in the radar device according to the first embodiment, and is the second half which is a part of the detection target frequency range, that is, the range from the 3D area to the 4D area shown in Fig. 27 is indicated by continuous hatching.

[0420] Furthermore, the peak value P of the signal strength and the second peak value P2 of the signal strength are Fig. 27 is shown as an example by shaded parts, and the distance between the peak P and the second peak P2 is given as D1 to D3.

[0421] For example, the peak P present at distance D1 appears in K chirps, the second peak P2 present at distance D2 appears in two chirps, and the second peak P2 present at distance D3 appears in (K - 2) chirps.

[0422] The peak value P present at the distance D1 is a peak value due to the reception of a reflected wave from the first observation target at a short distance from the radar device.

[0423] The second peak value P2, present at the distance D2, indicates the peak value due to the reception of a transmission wave of the other radar device which has the same sweep time T and frequency bandwidth BW, but a different repetition time Tr_i than the repetition time Tr.

[0424] The second peak value P2 existing at the distance D3 gives the second peak value due to the reception of the reflected wave from the second observation target which has a longer propagation distance of the reflected wave to the radar device than the propagation distance of the transmitted wave from other radar device to the radar device.

[0425] The interference countermeasure determination unit 52F compares the signal strength ratio P / FN with the fifth determination threshold TH5 to determine the peak value in the target frequency range of the distance information spectrum and the distance D at which the peak value exists. In this example, the distance D is the Fig. Distance D1 shown in Figure 27.

[0426] The interference countermeasure determination unit 52F compares the signal strength ratio P2 / FN with the fifth determination threshold TH5 to determine the second peak value P2 in the detection target frequency range of the distance information spectrum and the distance D at which the second peak value P2 exists. In this example, the distance D is the Fig. Distance D2 and D3 shown in Figure 27.

[0427] In a case where the transmission wave from the other radar device is not received and there is no interference signal, only the peak value P due to the reception of the reflected wave from the first observation target and the peak value P2 due to the reception of the reflected wave from the second observation target are calculated by the interference countermeasure determining unit 52F.

[0428] However, in a case where there is an interference signal from the other radar device, in addition to the peak value P and the peak value P2 due to the reception of the respective reflected waves from the first observation target and the second observation target, the peak value P2 due to the reception of the transmission wave from the other radar device is calculated by the interference countermeasure determining unit 52F.

[0429] The peak value P due to the reception of the reflected wave from the first observation target at a short distance from the radar device is larger than the peak value P2 due to the reception of the transmitted wave from the other radar device.

[0430] On the other hand, the peak value P2 due to the reception of the transmission wave from the other radar device which has a shorter propagation distance of the transmission wave to the radar device than the propagation distance of the reflected wave from the second observation target to the radar device is larger than the peak value due to the reception of the reflected wave from the second observation target and is the second peak value P2.

[0431] Therefore, when the signal strength ratio P2 / FN is equal to or greater than the fifth determination threshold TH5, the second peak can be calculated even when an observation target is at a short distance, and when there is an interference signal from the other radar device, the second peak appears in the distance information spectrum at a distance due to the reception of the transmission wave from the other radar device.

[0432] In a case where neither of the two observation targets is located at a close distance from the radar device, that is, in a case where the propagation distances of the reflected waves from the two observation targets to the radar device are longer than the propagation distance of the transmission wave from the other radar device to the radar device, the peak value due to reception of the transmission wave from the other radar device becomes larger than the peak value due to reception of the reflected wave from each of the two observation targets and appears as the first peak value P in the distance due to reception of the transmission wave from the other radar device.

[0433] In addition, the influence of receiving the transmission wave of the other radar device does not appear in the range information spectra of all chirps, but the influence of receiving the transmission wave from the other radar device appears in the range information spectra of some chirps.

[0434] Therefore, if the number of chirps C3 in which the second peak occurs is within the range of the fourth interference countermeasure threshold M4, it can be determined that there is an interference signal due to the reception of the transmission wave of the other radar device.

[0435] In the Fig. In the example shown in Figure 27, the peak P present at distance D1 appears in K chirps, the second peak P2 present at distance D2 appears in two chirps, and the second peak P2 present at distance D3 appears in (K - 2) chirps.

[0436] For example, when the fourth interference countermeasure threshold M4 is in the range of 1 to 10, the peak value P appears in two chirps at the distance D2, so that it can be determined that the transmission wave of the other radar device is received.

[0437] Therefore, the interference countermeasure determination unit 52F performs a determination of the necessity of the interference countermeasure to determine that the interference countermeasure is “necessary” when the number of range information spectra whose signal strength ratio P / FN is compared with the fifth determination threshold TH5 in each range information spectrum and the signal strength ratio P / FN is equal to or greater than the fifth determination threshold TH5 at the same distance D1, and the number of range information spectra in which the signal strength ratio P2 / FN in each range information spectrum is compared with the fifth determination threshold TH5 and the signal strength ratio P2 / FN is equal to or greater than the fifth determination threshold TH5 at the same distance D2, that is, the number of chirps C3 is in the range of the fourth interference countermeasure threshold M4.

[0438] Furthermore, at the same distance D, when the number of chirps C3, which represents the number of chirps at which the signal strength ratio P / FN is equal to or greater than the fifth determination threshold TH5, and the number of chirps at which the signal strength ratio P2 / FN is equal to or greater than the fifth determination threshold TH5, are outside the range of the fourth interference countermeasure threshold M4, that is, when the number of chirps C3 is zero, it can be determined that no transmission wave from the other radar device has been received at the distance D, and when the number of chirps C3 is greater than 10, it can be determined that a peak occurs at the distance D due to the reception of the reflected wave from the observation target.

[0439] This means that in a case where the transmission wave of the other radar device is not received, for example in the Fig. 27, when the peak P present at the distance D1 appears in the K chirps, the second peak P2 present at the distance D3 appears in the (K - 2) chirps, and the peak P and the second peak P2 do not exist at other distances D, it can be determined that the peak P appears due to the reception of the reflected wave of the first observation target at the distance D1, the peak P2 appears due to the reception of the reflected wave of the second observation target at the distance D3, and the transmission wave of the other radar device is not received.

[0440] Therefore, when the number of chirps C3, which represents the number of chirps at which the signal strength ratio P / FN is equal to or greater than the fifth determination threshold TH5, and the number of chirps at which the signal strength ratio P2 / FN is equal to or greater than the fifth determination threshold TH5, are within the range of the fourth interference countermeasure threshold M4 at the same distance D, the interference countermeasure determining unit 52F determines that the interference countermeasure is “necessary” and outputs an interference countermeasure signal for the transmission signal to the control unit 11.

[0441] When there is no number of chirps C3 representing the number of chirps at which the signal strength ratio P / FN is equal to or greater than the number of chirps at which the signal strength ratio P2 / FN is equal to or greater than the fifth determination threshold TH5 at the same distance D, within the range of the fourth interference countermeasure threshold M4, the interference countermeasure determining unit 52F determines that no transmission wave has been received from the other radar device, determines that the interference countermeasure is “unnecessary”, and outputs a plurality of range information spectra calculated by the range spectrum calculating unit 51 to the distance and speed information output unit 53.

[0442] As described above, by using the mean value FN of the signal strength of the data in the interference determination processing area in the distance information spectrum, the signal strength ratio P / FN based on the peak value P in the detection target frequency range in the distance information spectrum, and the signal strength ratio P2 / FN based on the second peak value P2 in the detection target frequency range in the distance information spectrum, and determining that the interference countermeasure is necessary when the number of chirps C3, which represents the number of chirps at which the signal strength ratio P / FN at the same distance D is equal to or greater than the fifth determination threshold TH5, and the number of chirps at which the signal strength ratio P2 / FN at the same distance D is equal to or greater than the fifth determination threshold TH5, is within the fourth interference countermeasure threshold M4,a deterioration in the accuracy of determining the necessity of the interference countermeasure can be suppressed even when there are two observation targets, the first observation target is present at a short distance from the radar device, and an interference signal due to a transmission wave is fed via the receiving antenna 23 from the other radar device into the frequency mixing unit 31, which has the same transit time T and frequency bandwidth BW, but a different repetition time Tr_i than the repetition time Tr of the transmission signal.

[0443] Next, the operation of the radar device according to the seventh embodiment will be described.

[0444] The operation is the same as the operation of the radar device according to the third embodiment, that is, the operation of the radar device according to the first embodiment until the beat data of K chirps is output from the AD conversion unit 4 to the signal processing unit 5, and therefore its description is omitted.

[0445] The operation of the signal processing unit 5, into which the beat data of K-chirps are input, is explained using the Fig. 28 described flowchart.

[0446] Fig. 28 is a flowchart illustrating the calculation processing of the distance to the observation target and the relative speed with respect to the observation target including the interference determination in the signal processing unit 5.

[0447] The step ST1 of calculating the range information spectrum is the same as the step ST1 of the radar device according to the third embodiment, that is, the step ST1 of the radar device according to the first embodiment.

[0448] The step ST2C is a step for calculating the number of chirps C3 and corresponds to the step ST2B of the radar device according to the third embodiment.

[0449] In step ST2C, the interference countermeasure determination unit 52F acquires data in the acquisition target frequency range of the K-range information spectra obtained in step ST1.

[0450] For each of the K range information spectra, the interference countermeasure determining unit 52F acquires the peak value P of the data in the detection target frequency range, calculates the signal strength ratio P / FN which is one of the state values, and obtains the signal strength ratios P / FN of the K range information spectra.

[0451] For each of the K range information spectra, the interference countermeasure determining unit 52F acquires the second peak value P2 of the data in the acquisition target frequency range, calculates the signal strength ratio P2 / FN to the second peak value P2, which is one of the state values, and obtains the signal strength ratio P2 / FN of the K range information spectra.

[0452] The interference countermeasure determining unit 52B assigns the signal strength ratio P / FN of the K range information spectra to the distance D and assigns the signal strength ratio P2 / FN of the K range information spectra to the distance D.

[0453] The interference countermeasure determination unit 52F calculates the number of chirps at which the signal strength ratio P / FN associated with the distance D is equal to or greater than the fifth determination threshold TH5, and calculates the number of chirps at which the signal strength ratio P2 / FN associated with the distance D is equal to or greater than the fifth determination threshold TH5, thereby calculating the number of chirps C3 representing both numbers of chirps.

[0454] When the interference countermeasure determination unit 52F calculates the number of chirps C3 associated with the distance D, the process proceeds to step ST3C.

[0455] Step ST3C is a step for performing the determination of the necessity of the interference countermeasure and corresponds to step ST3B of the radar device according to the third embodiment.

[0456] In step ST3C, the interference countermeasure determining unit 52F compares the number of chirps C3 associated with the distance D calculated by the interference countermeasure determining unit 52F in step ST2C with the fourth interference countermeasure threshold M4, and performs a necessity determination of the interference countermeasure to determine that the interference countermeasure is necessary when the number of chirps C3 is within the range of the fourth interference countermeasure threshold M4, and to determine that the interference countermeasure is “unnecessary” when there is no chirp C3 within the range of the fourth interference countermeasure threshold M4.

[0457] In step ST3C, when the interference countermeasure determination unit 52F determines that the interference countermeasure is necessary, the process proceeds to step ST4, and the signal processing unit 5 outputs an interference countermeasure signal to the control unit 11 of the transmission signal output unit 1, and the process ends.

[0458] On the other hand, when the interference countermeasure determination unit 52F determines that there are no interference countermeasures, the process proceeds to step ST5.

[0459] The operations in and after step ST5 are the same as the operations in and after step ST5 of the radar device according to the third embodiment, that is, the operations in and after step ST5 of the radar device according to the first embodiment, and the distance to the observation target calculated by the distance and speed information calculation unit 532 and the relative speed with respect to the observation target are output to the display unit 6, and the process ends.

[0460] As described above, in the radar device according to the seventh embodiment, the interference countermeasure determining unit 52F determines whether interference countermeasure is required or not depending on whether the number of chirps C3, which represents the number of chirps at which the signal strength ratio P / FN at the same distance is equal to or greater than the fifth determination threshold TH5, and the number of chirps at which the signal strength ratio P2 / FN at the same distance D is equal to or greater than the fifth determination threshold TH5, is within the range of the fourth interference countermeasure threshold M4, even when there are two observation targets, the first observation target is located at a short distance from the radar device, and an interference signal due to a transmission wave is input to the frequency mixing unit 31 via the receiving antenna 23 from the other radar device,which has the same sweep time T and frequency bandwidth BW, but a different repetition time Tr_i than the repetition time Tr of the transmitted signal, it is possible to determine the need for interference countermeasure with high accuracy in the radar device of the fast chirp FMCW system using a plurality of chirps. Eighth embodiment

[0461] A fast chirp FMCW radar device according to an eighth embodiment will be described with reference to Fig. 29 and Fig. 30 described.

[0462] In the radar device according to the eighth embodiment, only an interference countermeasure determination unit 52G of the signal processing unit 5 is different from the interference countermeasure determination unit 52 of the signal processing unit 5 in the radar device according to the first embodiment, and the other points are the same or similar.

[0463] In the Fig. 29 and Fig. 30 denote the same reference numerals as in the Fig. 1 to 7 the same or corresponding parts.

[0464] The radar device according to the first embodiment sets the state value of the range information spectrum obtained by the interference countermeasure determining unit 52 as the mean value FN of the signal strengths of the data in the interference determination processing area in the range information spectrum, calculates the number of chirps C1, which is the number of range information spectra in which the mean value FN of the signal strengths is equal to or greater than the first determination threshold TH1, and compares the number of chirps C1 with the first interference countermeasure threshold M1 to determine whether an interference countermeasure is required or not.

[0465] On the other hand, in the radar device according to the eighth embodiment, the state value of the range information spectrum obtained by the interference countermeasure determining unit 52G is set as the mean value FN of the signal strengths of the data in the interference determination processing area in the range information spectrum, and the interference countermeasure determining unit 52G calculates the first index In1 based on all chirps of the mean value FN of the signal strengths, which are state values ​​of each of the plurality of range information spectra obtained by the interference countermeasure determining unit 52G, in this example, the maximum value and the minimum value among the K, and determines the necessity of the interference countermeasure by comparing the first index In1 with the fifth interference countermeasure threshold value M5, which is the interference countermeasure threshold value.

[0466] The first index In1 is a value obtained by dividing the difference between the maximum value FNmax and the minimum value FNmin in the mean value FN of the signal strengths, which are state values ​​of each of the plurality of range information spectra, by the sum of the maximum value FNmax and the minimum value FNmin, that is, a value calculated by the following equation (3). In1=(FNmax−FNmin) / (FNmax+FNmin)

[0467] It should be noted that in the above equation (3), FNmax represents the maximum value in all chirps of the calculated mean FN of the signal strength, and FNmin represents the minimum value in all chirps of the calculated mean FN of the signal strength.

[0468] The fifth interference countermeasure threshold M5 is a value greater than 0 and less than 1 and is set to a value as close to 0 as possible.

[0469] That is, the interference countermeasure determination unit 52G of the signal processing unit 5 in the radar device according to the eighth embodiment calculates the average value FN of the respective signal strengths of the plurality of range information spectra from the data in the interference determination processing area in the plurality of range information spectra calculated by the range spectrum calculation unit 51.

[0470] The interference countermeasure determining unit 52G calculates the first index In1 by the above equation (3) based on the maximum value and the minimum value of the average value FN of the respective signal strengths of the plurality of calculated range information spectra.

[0471] The interference countermeasure determination unit 52G compares the first index In1 with the fifth interference countermeasure threshold M5 and performs a necessity determination of the interference countermeasure to determine that the interference countermeasure is not necessary when the first index In1 is equal to or less than the fifth interference countermeasure threshold M5, and to determine that the interference countermeasure is necessary when the first index In1 is greater than the fifth interference countermeasure threshold M5.

[0472] As described above, in the radar device according to the eighth embodiment, it is possible to perform the necessity determination of the interference countermeasure by using the average value FN of the respective signal strengths of the plurality of range information spectra and the maximum value and the minimum value of the average value FN of the plurality of signal strengths, and thus it is possible to more easily perform the necessity determination of the interference countermeasure with high accuracy.

[0473] Next, the radar device according to the eighth embodiment will be described, focusing on the interference countermeasure determination unit 52G, which is different from the interference countermeasure determination unit 52 in the radar device according to the first embodiment.

[0474] The description of the same configuration as that of the radar device according to the first embodiment will be omitted as much as possible.

[0475] The interference countermeasure determination unit 52G acquires data in a detection target frequency range of a plurality of, in this example, K range information spectra output from the range spectrum calculation unit 51.

[0476] The interference countermeasure determination unit 52G calculates the average value FN of the respective signal strengths of the plurality of distance information spectra from the data in the interference determination processing area in the plurality of distance information spectra calculated by the distance spectrum calculation unit 51.

[0477] The interference determination processing area is the same as the interference determination processing area in the radar device according to the first embodiment and is the second half, which is a part of the detection target frequency range, which is a range from 3D to a range 4D shown in Fig. 4 is represented by continuous hatching.

[0478] The interference countermeasure determining unit 52G calculates the first index In1 from the mean value FN of the signal strengths using the above equation (3).

[0479] The interference countermeasure determination unit 52G compares the first index In1 with the fifth interference countermeasure threshold M5 and performs a necessity determination of the interference countermeasure to determine that the interference countermeasure is "unnecessary" when the first index In1 is equal to or less than the fifth interference countermeasure threshold M5, and to determine that the interference countermeasure is "necessary" when the first index In1 is greater than the fifth interference countermeasure threshold M5.

[0480] When there is no interference due to the transmission wave from another radar device, the first index In1 is close to 0 because the maximum value FNmax and the minimum value FNmin in the mean value FN of the signal strengths of the K-range information spectra indicate values ​​close to each other, and when there is interference due to the transmission wave from the other radar device, the first index In1 is close to 1 because the difference between the maximum value FNmax and the minimum value FNmin in the mean value FN of the signal strengths is large.

[0481] Since the fifth interference countermeasure threshold M5 is a value greater than 0 and less than 1, when the first index In1 is equal to or less than the fifth interference countermeasure threshold M5, it can be determined that there is no interference due to transmission waves from other radar devices, and the interference countermeasure determining unit 52G determines that the interference countermeasure is “unnecessary”.

[0482] When the first index In1 is greater than the fifth interference countermeasure threshold M5, it can be determined that there is interference by transmission waves from other radar devices, and the interference countermeasure determining unit 52G determines that the interference countermeasure is “necessary”.

[0483] The interference countermeasure determination unit 52G outputs an interference countermeasure signal for the transmission signal to the control unit 11 when it is determined that the interference countermeasure is necessary, ie, required, and outputs a plurality of distance information spectra calculated by the distance spectrum calculation unit 51 to the distance and speed information output unit 53 when it is determined that the interference countermeasure is not necessary, ie, unnecessary.

[0484] The operation of the radar device according to the eighth embodiment is described below.

[0485] The operation is the same as the operation of the radar device according to the first embodiment until the beat data of K chirps is output from the AD converter unit 4 to the signal processing unit 5, and therefore the description thereof is omitted.

[0486] The operation of the signal processing unit 5, into which the beat data of K-chirps are input, is explained using the Fig. 30 flowchart shown.

[0487] Fig. 30 is a flowchart illustrating the calculation processing of the distance to the observation target and the relative speed with respect to the observation target including the interference determination in the signal processing unit 5.

[0488] The step ST1 of calculating the range information spectrum is the same as the step ST1 of the radar device according to the first embodiment.

[0489] The step ST2D is a step for calculating the first index In1 and corresponds to the step ST2 of the radar device according to the first embodiment.

[0490] In step ST2D, the interference countermeasure determining unit 52G acquires data in the acquisition target frequency range of the K-range information spectra obtained in step ST1.

[0491] For each of the K range information spectra, the interference countermeasure determination unit 52G calculates the mean value FN of the signal strengths, which are one of the state values, from the data in the interference determination processing area among the data in the detection target frequency area, and obtains a mean value FN of the signal strengths of the K range information spectra.

[0492] The interference countermeasure determining unit 52G calculates the first index In1 from the above equation (3) using the maximum value FNmax and the minimum value FNmin of the average value FN of the signal strengths of the K range information spectra.

[0493] Step ST3D is a step for determining the necessity of the countermeasure and corresponds to step ST3 of the radar device according to the first embodiment.

[0494] In step ST3D, the interference countermeasure determining unit 52 compares the first index In1 calculated in step ST2D with the fifth interference countermeasure threshold M5 and performs a necessity determination of the interference countermeasure to determine that the interference countermeasure is "unnecessary" when the first index In1 is equal to or less than the fifth interference countermeasure threshold M5, and to determine that the interference countermeasure is "necessary" when the first index In1 is greater than the fifth interference countermeasure threshold M5.

[0495] The operations in and after step ST3D are the same as the operations in and after step ST3 of the radar device according to the first embodiment. If the interference countermeasure determination unit 52G determines that the interference countermeasure is necessary in step ST3D, the process proceeds to step ST4, and the signal processing unit 5 outputs an interference countermeasure signal to the control unit 11 of the transmission signal output unit 1, and the process ends. If the interference countermeasure determination unit 52G determines that the interference countermeasure is unnecessary in step ST3D, the process proceeds to steps ST5 and ST6, and the distance to the observation target and the relative speed with respect to the observation target calculated by the distance and speed information calculation unit 532 are output to the display unit 6, and the process ends.

[0496] As described above, the radar device according to the eighth embodiment has a similar effect to the radar device according to the first embodiment and can perform the determination of the necessity of the interference countermeasure by using the average value FN of the respective signal strengths of the plurality of range information spectra and the maximum value and the minimum value of the average value FN of the plurality of signal strengths, and therefore, the radar device of the fast chirp FMCW scheme using the plurality of chirps can more easily determine the necessity of the interference countermeasure with high accuracy. Ninth embodiment

[0497] A fast chirp FMCW radar device according to a ninth embodiment will be described with reference to Fig. 31 and Fig. 32 described.

[0498] In the radar device according to the ninth embodiment, only an interference countermeasure determination unit 52H of the signal processing unit 5 is different from the interference countermeasure determination unit 52 of the signal processing unit 5 in the radar device according to the first embodiment, and the other points are the same or similar.

[0499] In the Fig. 31 and Fig. 32 denote the same reference numerals as in the Fig. 1 to 7 the same or corresponding parts.

[0500] The radar device according to the first embodiment sets the state value of the range information spectrum obtained by the interference countermeasure determining unit 52 as the mean value FN of the signal strengths of the data in the interference determination processing area in the range information spectrum, calculates the number of chirps C1, which is the number of range information spectra in which the mean value FN of the signal strengths is equal to or greater than the first determination threshold TH1, and compares the number of chirps C1 with the first interference countermeasure threshold M1 to determine whether an interference countermeasure is required or not.

[0501] On the other hand, in the radar device according to the ninth embodiment, the state value of the range information spectrum obtained by the interference countermeasure determining unit 52H is set as the mean value FN of the signal strengths of the data in the interference determination processing area in the range information spectrum, and the interference countermeasure determining unit 52G calculates the second index In2 based on all the chirps of the mean value FN of the signal strengths, which are state values ​​of each of the plurality of range information spectra obtained by the interference countermeasure determining unit 52G, in this example, all the chirps of the minimum value among K chirps and the mean value FN of the signal strengths, in this example, the sum of the K values ​​(hereinafter referred to as a total value), and compares the second index In2 with the sixth interference countermeasure threshold value M6.which is the interference countermeasure threshold to determine whether the interference countermeasure is necessary or not.

[0502] The second index In2 is a value obtained by dividing the total value of the mean values ​​FN of the signal strengths, which are state values ​​of the plurality of range information spectra, by a multiplication value obtained by multiplying the minimum value of the mean values ​​FN of the signal strengths, which are state values ​​of the plurality of range information spectra, by the number of the plurality of range information spectra, that is, K, which in this example is the number of all chirps, that is, a value calculated by the following equation (4). In2=(FNtotal) / (K×FNmin)

[0503] It should be noted that in the above equation (4), FNmin is a minimum value in all chirps of the calculated mean value FN of the signal strength, FNtotal is all chirps of the calculated mean value FN of the signal strength, in this example, a total value of K chirps, and K is the number of all chirps, that is, the number of a plurality of range information spectra, and is the number of chirp signals.

[0504] Furthermore, the sixth interference countermeasure threshold M6 is a value greater than 1 and is set to a value slightly greater than 1 by taking into account a multiplication value (K × FNmin) when there is no interference by a transmission wave from the other radar device.

[0505] That is, the interference countermeasure determination unit 52H of the signal processing unit 5 in the radar device according to the ninth embodiment calculates the average value FN of the respective signal strengths of the plurality of range information spectra from the data in the interference determination processing area in the plurality of range information spectra calculated by the range spectrum calculation unit 51.

[0506] The interference countermeasure determining unit 52H calculates the second index In2 according to the above equation (4) based on the minimum value and the total value of the average values ​​FN of the respective signal strengths of the plurality of calculated range information spectra.

[0507] The interference countermeasure determination unit 52H compares the second index In2 with the sixth interference countermeasure threshold M6 and performs a necessity determination of the interference countermeasure to determine that the interference countermeasure is not necessary when the second index In2 is equal to or less than the sixth interference countermeasure threshold M6, and to determine that the interference countermeasure is necessary when the second index In2 is greater than the sixth interference countermeasure threshold M6.

[0508] As described above, in the radar device according to the ninth embodiment, it is possible to perform the necessity determination of the interference countermeasure by using the average value FN of the respective signal strengths of the plurality of range information spectra and the minimum value and the total value of the average value FN of the plurality of signal strengths, and thus it is possible to more easily perform the necessity determination of the interference countermeasure with high accuracy.

[0509] Next, the radar device according to the ninth embodiment will be described, focusing on an interference countermeasure determination unit 52H, which is different from the interference countermeasure determination unit 52 in the radar device according to the first embodiment.

[0510] The description of the same configuration as that of the radar device according to the first embodiment will be omitted as much as possible.

[0511] The interference countermeasure determination unit 52H acquires data in a detection target frequency range of a plurality of, in this example, K range information spectra output from the range spectrum calculation unit 51.

[0512] The interference countermeasure determination unit 52H calculates the average value FN of the respective signal strengths of the plurality of distance information spectra from the data in the interference determination processing area in the plurality of distance information spectra calculated by the distance spectrum calculation unit 51.

[0513] The interference determination processing area is the same as the interference determination processing area in the radar device according to the first embodiment and is the second half, which is a part of the detection target frequency range, which is a range from 3D to a range 4D shown in Fig. 4 is represented by continuous hatching.

[0514] The interference countermeasure determination unit 52H calculates the second index In2 from the mean value FN of the signal strengths using the above equation (4).

[0515] The interference countermeasure determination unit 52H compares the second index In2 with the sixth interference countermeasure threshold M6 and performs a necessity determination of the interference countermeasure to determine that the interference countermeasure is “unnecessary” when the second index In2 is equal to or less than the sixth interference countermeasure threshold M6, and to determine that the interference countermeasure is “necessary” when the second index In2 is greater than the sixth interference countermeasure threshold M6.

[0516] In a case where there is no interference by a transmission wave of the other radar device, the second index In2 is very close to 1 because the total value FNtotal of the mean values ​​FN of the signal strengths of the K range information spectra is close to a multiplication value obtained by multiplying the minimum value FNmin of the mean values ​​FN of the signal strengths of the K range information spectra by the number K of chirp signals.

[0517] When interference occurs due to a transmission wave of the other radar device, the second index In2 takes a value greater than 1, since the total value FNtotal of the mean values ​​FN of the signal strengths is greater than the multiplied value of the minimum value FNmin of the mean values ​​FN of the signal strengths.

[0518] Based on the above points, the sixth interference countermeasure threshold M6 is set to a value slightly more than 1, where (FNtotal) / (K × FNmin) is taken as the lower limit when there is no interference from a transmission wave of the other radar device, and (FNtotal) / (K × FNmin) is taken as the upper limit when there is interference from a transmission wave of the other radar device.

[0519] Therefore, when the second index In2 is equal to or less than the sixth interference countermeasure threshold M6, it can be determined that there is no interference due to the transmission wave of the other radar device, and the interference countermeasure determining unit 52H determines that the interference countermeasure is “unnecessary”.

[0520] Furthermore, when the second index In2 is greater than the sixth countermeasure threshold M6, it can be determined that there is interference due to transmission waves of other radar devices, and the interference countermeasure determination unit 52H determines that interference countermeasures are “necessary”.

[0521] The interference countermeasure determination unit 52H outputs an interference countermeasure signal for the transmission signal to the control unit 11 when it is determined that the interference countermeasure is necessary, ie, required, and outputs a plurality of distance information spectra calculated by the distance spectrum calculation unit 51 to the distance and speed information output unit 53 when it is determined that the interference countermeasure is not necessary, ie, unnecessary.

[0522] Next, the operation of the radar device according to the ninth embodiment will be described.

[0523] The operation is the same as the operation of the radar device according to the first embodiment until the beat data of K chirps is output from the AD converter unit 4 to the signal processing unit 5, and therefore the description thereof is omitted.

[0524] The operation of the signal processing unit 5, into which the beat data of K-chirps are input, is explained using the Fig. 32 flowchart shown.

[0525] Fig. 32 is a flowchart illustrating the calculation processing of the distance to the observation target and the relative speed with respect to the observation target including the interference determination in the signal processing unit 5.

[0526] The step ST1 of calculating the range information spectrum is the same as the step ST1 of the radar device according to the first embodiment.

[0527] The step ST2E is a step for calculating the second index In2 and corresponds to the step ST2 of the radar device according to the first embodiment.

[0528] In step ST2E, the interference countermeasure determination unit 52H acquires data in the acquisition target frequency range of the K-range information spectra obtained in step ST1.

[0529] For each of the K range information spectra, the interference countermeasure determination unit 52H calculates the average value FN of the signal strengths, which are one of the state values, from the data in the interference determination processing area among the data in the detection target frequency area, and obtains an average value FN of the signal strengths of the K range information spectra.

[0530] The interference countermeasure determination unit 52H calculates the second index In2 from the above equation (4) using the minimum value FNmin and the total value FNtotal of the average values ​​FN of the signal strengths of the K range information spectra.

[0531] Step ST3E includes a step of performing the necessity determination of an interference countermeasure and is a step corresponding to step ST3 of the radar device according to the first embodiment.

[0532] In step ST3E, the interference countermeasure determining unit 52H compares the second index In2 calculated in step ST2E with the sixth interference countermeasure threshold M6 and performs a necessity determination of the interference countermeasure to determine that the interference countermeasure is "unnecessary" when the second index In2 is equal to or less than the sixth interference countermeasure threshold M6, and to determine that the interference countermeasure is "necessary" when the second index In2 is greater than the sixth interference countermeasure threshold M6.

[0533] The operations in and after step ST3E are the same as the operations in and after step ST3 of the radar device according to the first embodiment, and in step ST3E, when the interference countermeasure determination unit 52H determines that the interference countermeasure is necessary, the process proceeds to step ST4, and the signal processing unit 5 outputs an interference countermeasure signal to the control unit 11 of the transmission signal output unit 1, and the process ends.

[0534] When the interference countermeasure determination unit 52H determines in step ST3E that the interference countermeasure is unnecessary, the process proceeds to steps ST5 and ST6, and the distance to the observation target and the relative speed with respect to the observation target calculated by the distance and speed information calculation unit 532 are output to the display unit 6, and the process ends.

[0535] As described above, the radar device according to the ninth embodiment has a similar effect to the radar device according to the first embodiment and can perform the determination of the necessity of the interference countermeasure by using the average value FN of the respective signal strengths of the plurality of range information spectra and the minimum value and the total value of the average value FN of the plurality of signal strengths, and therefore, the radar device of the fast chirp FMCW scheme using the plurality of chirps can more easily determine the necessity of the interference countermeasure with high accuracy.

[0536] Note that the first index In1 used in the radar device according to the eighth embodiment and the second index In2 used in the radar device according to the ninth embodiment may be combined to determine the interference countermeasure.

[0537] That is, the interference countermeasure determination unit 52G in the radar device according to the eighth embodiment includes a first determination unit and a second determination unit.

[0538] The first determination unit compares the first index In1 with the fifth interference countermeasure threshold M5 and performs a determination of the necessity of the interference countermeasure to determine that the interference countermeasure is "unnecessary" when the first index In1 is equal to or less than the fifth interference countermeasure threshold M5, and to determine that the interference countermeasure is "necessary" when the first index In1 is greater than the fifth interference countermeasure threshold M5.

[0539] When the first determination unit determines that the interference countermeasure is “necessary,” the second determination unit compares the second index In2 with the sixth interference countermeasure threshold M6 and performs a new determination, and performs a necessity determination of the interference countermeasure to determine that the interference countermeasure is “unnecessary” when the second index In2 is equal to or less than the sixth interference countermeasure threshold M6, and to determine that the interference countermeasure is “necessary” when the second index In2 is greater than the sixth interference countermeasure threshold M6.

[0540] Furthermore, in the radar device according to the ninth embodiment, the interference countermeasure determination unit 52H includes a first determination unit and a second determination unit.

[0541] The first determination unit compares the second index In2 with the sixth interference countermeasure threshold M6 and performs a determination of the necessity of the interference countermeasure to determine that the interference countermeasure is "unnecessary" when the second index In2 is equal to or less than the sixth interference countermeasure threshold M6, and to determine that the interference countermeasure is "necessary" when the second index In2 is greater than the sixth interference countermeasure threshold M6.

[0542] When the first determination unit determines that the interference countermeasure is “necessary,” the second determination unit compares the first index In1 with the fifth interference countermeasure threshold M5 and redetermines and performs a necessity determination of the interference countermeasure to determine that the interference countermeasure is “unnecessary” when the first index In1 is equal to or less than the fifth interference countermeasure threshold M5, and to determine that the interference countermeasure is “necessary” when the first index In1 is greater than the fifth interference countermeasure threshold M5. Tenth embodiment

[0543] A fast chirp FMCW radar device according to a tenth embodiment will be described with reference to Fig. 33 and Fig. 34 described.

[0544] In the radar device according to the tenth embodiment, only an interference countermeasure determination unit 52I of the signal processing unit 5 is different from the interference countermeasure determination unit 52G of the signal processing unit 5 in the radar device according to the eighth embodiment, and the other points are the same or similar.

[0545] In the Fig. 33 and Fig. 34 denote the same reference numerals as in the Fig. 29 and Fig. 31 the same or corresponding parts.

[0546] In the radar device according to the eighth embodiment, the state value of the range information spectrum obtained by the interference countermeasure determining unit 52G is set as the mean value FN of the signal strengths of the data in the interference determination processing area in the range information spectrum, the interference countermeasure determining unit 52G calculates the first index In1 based on the maximum value and the minimum value of all chirps of the mean value FN of the signal strengths, which are state values ​​of each of the plurality of range information spectra obtained by the interference countermeasure determining unit 52G, and determines the necessity of the interference countermeasure by comparing the first index In1 with the fifth interference countermeasure threshold value M5, which is the interference countermeasure threshold value.

[0547] On the other hand, in the radar device according to the tenth embodiment, the state value of the range information spectrum obtained by the interference countermeasure determination unit 52I is set as the mean value FN of the signal strengths of the data in the interference determination processing area in the range information spectrum and the signal strength ratio P / FN between the peak value P of the signal strength of the data in the detection target frequency area in the range information spectrum and the mean value FN of the signal strengths, the interference countermeasure determination unit 52I calculates the first index In1 based on the maximum value and the minimum value of all chirps of the mean value FN of the signal strengths, which are state values ​​of each of the plurality of range information spectra obtained by the interference countermeasure determination unit 52I, and performs a first determination to determinewhether the interference countermeasure is necessary or not by comparing the first index In1 with the fifth interference countermeasure threshold M5, which is the interference countermeasure threshold, and the interference countermeasure determination unit 52I calculates the third index In3 based on the total chirp of the signal strength ratio P / FN of the peak value P of the signal strength, the state values ​​of each of the plurality of range information spectra obtained by the interference countermeasure determination unit 52I, in this example, the sum of K (hereinafter referred to as a total value), and performs a second determination to determine whether the interference countermeasure is necessary or not by comparing the third index In3 with the seventh interference countermeasure threshold M7, which is the interference countermeasure threshold.

[0548] The third index In3 is a total value of the signal strength ratio P / FN of the peak value P of the signal strength, which is the state value of each of the plurality of range information spectra, that is, a total value P / FNtotal, expressed by the following equation (5). In3=P / FNtotal

[0549] In the above equation (5), P / FNtotal is the total chirp of the calculated signal strength ratio P / FN, that is, the total value of K in this example.

[0550] In addition, the seventh interference countermeasure threshold M7 is set to a value sufficiently larger than the number of chirps, ie, K in this example.

[0551] That is, the interference countermeasure determination unit 52I of the signal processing unit 5 in the radar device according to the tenth embodiment includes the first determination unit 52I1 and the second determination unit 52I2.

[0552] The first determination unit 52I1 is a determination unit corresponding to the interference countermeasure determination unit 52G in the radar device according to the eighth embodiment.

[0553] The fifth interference countermeasure threshold M5 is the same value as the fifth interference countermeasure threshold M5 used in the radar device according to the eighth embodiment.

[0554] The first determination unit 52I1 acquires the data in the detection target frequency range of the plurality of distance information spectra output from the distance spectrum calculation unit 51.

[0555] The first determination unit 52I1 calculates the average value FN of the respective signal strengths of the plurality of distance information spectra from the data in the interference determination processing area in the plurality of distance information spectra calculated by the distance spectrum calculation unit 51.

[0556] The first determination unit 52I1 calculates the first index In1 by the above equation (3) based on the maximum value and the minimum value of the average values ​​FN of the respective signal strengths of the plurality of calculated distance information spectra.

[0557] The first determination unit 52I1 compares the first index In1 with the fifth interference countermeasure threshold M5 and performs a first necessity determination of the interference countermeasure to determine that the interference countermeasure is not necessary when the first index In1 is equal to or less than the fifth interference countermeasure threshold M5, and to determine that the interference countermeasure is necessary when the first index In1 is greater than the fifth interference countermeasure threshold M5.

[0558] When the first determination unit 52I1 determines that the interference countermeasure is necessary, ie, required, it outputs the plurality of distance information spectra calculated by the distance spectrum calculation unit 51 and the average value FN of the calculated signal strengths to the second determination unit 52I2.

[0559] When the first determination unit 52I1 determines that the interference countermeasure is not necessary, that is, is not necessary, the first determination unit 52I1 outputs the plurality of distance information spectra calculated by the distance spectrum calculation unit 51 to the distance and speed information output unit 53.

[0560] When the first determination unit 52I1 determines that the interference countermeasure is necessary through the first necessity determination, the second determination unit 52I2 acquires the plurality of distance information spectra calculated by the distance spectrum calculation unit 51 and the average value FN of the signal strength calculated by the first determination unit 52I1 from the first determination unit 52I1.

[0561] The second determination unit 52I2 calculates the peak value P of the signal strength of the data in the detection target frequency range in each of the plurality of distance information spectra detected by the first determination unit 52I1.

[0562] The second determination unit 52I2 calculates the third index In3 from the total value P / FNtotal of the signal strength ratios P / FN in the plurality of distance information spectra calculated by the range spectrum calculation unit 51. In this example, the third index In3 is a total value P / FNtotal of the peak values ​​P of the signal strengths K.

[0563] The second determination unit 52I2 compares the third index In3 with the seventh interference countermeasure threshold M7 and performs a necessity determination of the interference countermeasure in which the interference countermeasure is maintained as necessary when the third index In3 is smaller than the seventh interference countermeasure threshold M7, and the interference countermeasure is changed from necessary to unnecessary when the third index In3 is equal to or larger than the seventh interference countermeasure threshold M7.

[0564] The second determination unit 52I2 outputs an interference countermeasure signal for the transmission signal to the control unit 11 when it is determined that the interference countermeasure is necessary, ie, required, and outputs a plurality of distance information spectra calculated by the distance spectrum calculation unit 51 to the distance and speed information output unit 53 when it is determined that the interference countermeasure is not necessary, ie, unnecessary.

[0565] As described above, since the interference countermeasure determining unit 52I includes the first determining unit 52I1 and the second determining unit 52I2, and the second determining unit 52I2 redetermines the necessity of the interference countermeasure with respect to the interference countermeasure determined as necessary by the first determining unit 52I1, it is possible to avoid unnecessary processing of the interference countermeasure under the conditions where the SNR of the observation target is high and the observation target can be detected by Fourier transform in the relative velocity direction by the distance and velocity information output unit 53.

[0566] Next, the radar device according to the tenth embodiment will be described, focusing on an interference countermeasure determination unit 52I, which is different from the interference countermeasure determination unit 52G in the radar device according to the eighth embodiment.

[0567] The description of the same configuration as that of the radar device according to the eighth embodiment will be omitted as much as possible.

[0568] The first determination unit 52I1 acquires the data in the detection target frequency range of the plurality of distance information spectra output from the distance spectrum calculation unit 51.

[0569] Like the interference countermeasure determination unit 52G in the radar device according to the eighth embodiment, the first determination unit 52I1 calculates the average value FN of the respective signal strengths of the plurality of range information spectra from the data in the interference determination processing area in the plurality of range information spectra calculated by the range spectrum calculation unit 51, and calculates the first index In1 from the average value FN of the signal strength using the above equation (3).

[0570] The first determination unit 52I1 compares the first index In1 with the fifth interference countermeasure threshold M5 and performs a first necessity determination of the interference countermeasure to determine that the interference countermeasure is “not necessary” when the first index In1 is equal to or less than the fifth interference countermeasure threshold M5, and to determine the interference countermeasure as “necessary” when the first index In1 is greater than the fifth interference countermeasure threshold M5.

[0571] The first determination unit 52I1 outputs the plurality of distance information spectra calculated by the distance spectrum calculation unit 51 and the mean value FN of the calculated signal strengths to the second determination unit 52I2 when it determines that the interference countermeasure is necessary, ie, required, and outputs the plurality of distance information spectra calculated by the distance spectrum calculation unit 51 to the distance and speed information output unit 53 when it determines that the interference countermeasure is not necessary, ie, unnecessary.

[0572] When the first determination unit 52I1 determines that the interference countermeasure is necessary through the first necessity determination, the second determination unit 52I2 acquires the plurality of distance information spectra calculated by the distance spectrum calculation unit 51 and the average value FN of the signal strength calculated by the first determination unit 52I1 from the first determination unit 52I1.

[0573] The second determination unit 52I2 calculates the peak value P of the signal strength of the data in the detection target frequency range in each of the plurality of distance information spectra detected by the first determination unit 52I1.

[0574] The interference determination processing area is the same as the interference determination processing area in the radar device according to the first embodiment, and is the latter half, which is a part of the detection target frequency range, which is a range from 3D to a range 4D described in the second embodiment. Fig. 9 is represented by a continuous hatching. The area from 3D to the area 4D, which is Fig. 9 is shown by solid diagonal lines, is the same as the area from 3D to the area 4D shown in Fig. 4 is represented by solid diagonal lines, as described in the first exemplary embodiment.

[0575] In addition, the peak value P of the signal strength is the same as the peak value shown by the hatched parts in Fig. 9 is displayed.

[0576] The second determination unit 52I2 calculates the signal strength ratio P / FN of the peak value P of the signal strength from the peak value P of the signal strength of the data in the detection target frequency range and the average value FN of the signal strength calculated by the first determination unit 52I1 in each of the plurality of distance information spectra acquired by the calculated first determination unit 52I1, and calculates the third index In3 from the signal strength ratio P / FN of the peak value P of the signal strength using the above equation (5).

[0577] The second determination unit 52I2 compares the third index In3 with the seventh interference countermeasure threshold M7, determines that the interference countermeasure is still necessary when the third index In3 is smaller than the seventh interference countermeasure threshold M7, and performs a redetermination as the second necessity determination of the interference countermeasure to determine that the interference countermeasure is changed from necessary to unnecessary when the third index In3 is equal to or greater than the seventh interference countermeasure threshold M7.

[0578] In the third index In3, in a case where there is no interference due to a transmission wave from the other radar device, the minimum value P / FNmin of the signal strength ratio P / FN of the peak values ​​P of the signal strengths through the K range information spectra is greater than 1, and the total value P / FNtotal of the peak values ​​P of the K signal strengths also becomes larger in (K × 1), so that K is also larger.

[0579] Furthermore, in a case where there is interference due to a transmission wave from the other radar device, the third index In3 is close to K because the minimum value P / FNmin of the signal strength ratio P / FN of the peak values ​​P of the signal strengths through the K range information spectra takes a value close to 1 and the total value P / FNtotal of the peak values ​​P of the K signal strengths is close to (K × 1).

[0580] Based on the above points, the seventh interference countermeasure threshold M7 is set to a value sufficiently larger than (1 × the number of chirp signals K) with the upper limit of P / FNtotal in a case where there is no interference due to a transmission wave from the other radar device and the lower limit of P / FNtotal in a case where there is interference due to a transmission wave from the other radar device.

[0581] Therefore, when the third index In3 is less than the seventh threshold value M7 for the interference countermeasure, it can be determined that there is no interference due to the transmission wave from the other radar device, and the second determination unit 52I2 can determine that the interference countermeasure is still necessary, and when the third index In3 is equal to or greater than the seventh threshold value M7 for the interference countermeasure, it can be determined that there is interference due to the transmission wave from the other radar device, and the second determination unit 52I2 performs the determination of the necessity of the interference countermeasure to change the interference countermeasure from necessary to unnecessary.

[0582] The second determination unit 52I2 outputs an interference countermeasure signal for the transmission signal to the control unit 11 when it is determined that the interference countermeasure is necessary, ie, required, and outputs a plurality of distance information spectra calculated by the distance spectrum calculation unit 51 to the distance and speed information output unit 53 when it is determined that the interference countermeasure is not necessary, ie, unnecessary.

[0583] Next, the operation of the radar device according to the tenth embodiment will be described.

[0584] The operation is the same as the operation of the radar device according to the eighth embodiment, that is, the operation of the radar device according to the first embodiment until the beat data of K chirps is output from the AD conversion unit 4 to the signal processing unit 5, and therefore its description is omitted.

[0585] The operation of the signal processing unit 5, into which the beat data of K-chirps are input, is explained using the Fig. 34 flowchart shown.

[0586] Fig. 34 is a flowchart illustrating the calculation processing of the distance to the observation target and the relative speed with respect to the observation target including the interference determination in the signal processing unit 5.

[0587] The step ST1 of calculating the range information spectrum is the same as the step ST1 of the radar device according to the eighth embodiment, that is, the step ST1 of the radar device according to the first embodiment.

[0588] The step ST2D1 is a step for calculating the first index In1 and corresponds to the step ST2D of the radar device according to the eighth embodiment.

[0589] In step ST2D1, the first determination unit 52I1 of the interference countermeasure determination unit 52I acquires data in the acquisition target frequency range of the K-range information spectra obtained in step ST1.

[0590] For each of the K distance information spectra, the first determination unit 52I1 calculates the average value FN of the signal strengths, which are one of the state values, from the data in the interference determination processing area among the data in the detection target frequency area, and obtains an average value FN of the signal strengths of the K distance information spectra.

[0591] The first determination unit 52I1 calculates the first index In1 from the above equation (3) using the maximum value FNmax and the minimum value FNmin of the mean value FN of the signal strengths of the K-range information spectra.

[0592] Step ST3D1 is a step corresponding to step ST3D of the radar device according to the eighth embodiment.

[0593] In step ST3D1, the first determination unit 52I1 compares the first index In1 calculated in step ST2D1 with the fifth interference countermeasure threshold M5 and performs a determination of the necessity of the interference countermeasure to determine that the interference countermeasure is "unnecessary" when the first index In1 is equal to or less than the fifth interference countermeasure threshold M5, and to determine that the interference countermeasure is "necessary" when the first index In1 is greater than the fifth interference countermeasure threshold M5.

[0594] In step ST3D1, when the interference countermeasure determination unit 52G determines that an interference countermeasure is required, the process proceeds to step ST7A.

[0595] If the interference countermeasure determination unit 52G determines that there are no interference countermeasures in step ST3D1, the process proceeds to steps ST5 and ST6, and similar to the processes in steps ST5 and ST6 of the radar device according to the eighth embodiment, that is, steps ST5 and ST6 of the radar device according to the first embodiment, the distance to the observation target and the relative speed to the observation target calculated by the distance and speed information calculation unit 532 are output to the display unit 6, and the process ends.

[0596] Step ST7A is a step for calculating the third index In3.

[0597] In step ST7A, the second determination unit 52I2 of the interference countermeasure determination unit 52I receives the K-range information spectra calculated by the range spectrum calculation unit 51 and the mean value FN of the signal strengths calculated by the first determination unit 52I1 from the first determination unit 52I1.

[0598] The second determination unit 52I2 calculates the peak value P of the signal strength of the data in the detection target frequency range in each of the K range information spectra detected by the first determination unit 52I1.

[0599] The second determination unit 52I2 calculates the signal strength ratio P / FN of the peak value P of the signal strength from the peak value P of the signal strength of the data in the acquisition target frequency range and the average value FN of the signal strength calculated by the first determination unit 52I1 in each of the K range information spectra acquired by the calculated first determination unit 52I1, and calculates the third index In3 from the signal strength ratio P / FN of the peak value P of the signal strength using the above equation (5).

[0600] When the second determination unit 52I2 calculates the third index In3, the process proceeds to step ST8A.

[0601] Step ST8A is a step for performing a redetermination, which is the second necessity determination of the interference countermeasure.

[0602] In step ST8A, the second determination unit 52I2 compares the third index In3 calculated in step ST7A with the seventh threshold value M7 for the interference countermeasure, and when the third index In3 is less than the seventh interference countermeasure threshold M7, an interference countermeasure remains necessary, and when the third index In3 is equal to or greater than the seventh interference countermeasure threshold M7, it is determined that the interference countermeasure should be changed from “necessary” to “unnecessary”.

[0603] In step STA8, when the second determination unit 52I2 determines that the interference countermeasure is necessary, the process proceeds to step ST4, and the signal processing unit 5 outputs the interference countermeasure signal to the control unit 11 of the transmission signal output unit 1, and the process ends.

[0604] On the other hand, when the second determination unit 52I2 determines that there is no interference countermeasure, the process proceeds to steps ST5 and ST6, and the distance to the observation target and the relative speed with respect to the observation target calculated by the distance and speed information calculation unit 532 are output to the display unit 6, and the process ends.

[0605] As described above, the radar device according to the tenth embodiment has the same effects as the radar device according to the first embodiment and the radar device according to the eighth embodiment, and can avoid unnecessary processing of interference countermeasures under the conditions where the SNR of the observation target is high and the observation target can be detected by Fourier transform in the relative velocity direction.

[0606] Note that the first determination unit 52I1 of the interference countermeasure determination unit 52I in the radar device according to the tenth embodiment is a determination unit corresponding to the interference countermeasure determination unit 52G in the radar device according to the eighth embodiment, but the first determination unit 52I1 may be a determination unit corresponding to the interference countermeasure determination unit 52H in the radar device according to the ninth embodiment.

[0607] In this case, the first determination unit 52I1, like the interference countermeasure determination unit 52H in the radar device according to the ninth embodiment, calculates the average value FN of the respective signal strengths of the plurality of range information spectra from the data in the interference determination processing area in the plurality of range information spectra calculated by the range spectrum calculation unit 51, and calculates the second index In2 by the above equation (4) based on the minimum value and the total value of the calculated average values ​​FN of the signal strengths of the plurality of range information spectra.

[0608] The first determination unit 52I1 compares the second index In2 with the sixth interference countermeasure threshold M6 and performs the first necessity determination of the interference countermeasure, in which the interference countermeasure is determined to be “unnecessary” when the second index In2 is equal to or less than the sixth interference countermeasure threshold M6, and the interference countermeasure is determined to be “necessary” when the second index In2 is greater than the sixth interference countermeasure threshold M6.

[0609] Fig. 35 is a flowchart showing the calculation processing of the distance to the observation target and the relative speed with respect to the observation target including the interference determination in the signal processing unit 5 in this example.

[0610] As in Fig. 35, steps ST2E1 and ST3E1 differ from those in Fig.34 shown steps ST2D1 and ST3D1, but the other points are identical.

[0611] In step ST2E1, the first determination unit 52I1 calculates the second index In2 using the minimum value FNmin and the total value FNtotal of the mean values ​​FN of the signal strengths of the K range information spectra.

[0612] In step ST3E1, the first determination unit 52I1 compares the second index In2 with the sixth interference countermeasure threshold M6 and performs a determination of the necessity of the interference countermeasure to determine that the interference countermeasure is "unnecessary" when the second index In2 is equal to or less than the sixth interference countermeasure threshold M6, and to determine that the interference countermeasure is "necessary" when the second index In2 is greater than the sixth interference countermeasure threshold M6.

[0613] Further, the first determination unit 52I1 of the interference countermeasure determination unit 52I in the radar device according to the tenth embodiment can determine the interference countermeasure by combining the first index In1 used in the radar device according to the eighth embodiment and the second index In2 used in the radar device according to the ninth embodiment, as another example in the ninth embodiment.

[0614] That is, the first determination unit 52I1 includes two determination units, and one determination unit (functioning as a first determination unit) of the first determination unit 52I1 compares the first index In1 with the fifth interference countermeasure threshold M5, and performs a necessity determination of the interference countermeasure to determine that the interference countermeasure is "unnecessary" when the first index In1 is equal to or less than the fifth interference countermeasure threshold M5, and to determine that the interference countermeasure is "necessary" when the first index In1 is greater than the fifth interference countermeasure threshold M5.

[0615] When one determination unit of the first determination unit 52I1 determines that the interference countermeasure is "necessary," the other determination unit (operating as a second determination unit) of the first determination unit 52I1 compares the second index In2 with the sixth interference countermeasure threshold M6 and performs a new determination such that, when the second index In2 is equal to or less than the sixth interference countermeasure threshold M6, the other determination unit of the first determination unit 52I1 determines that the interference countermeasure is "unnecessary" and causes the process to proceed to step ST5, and when the second index In2 is greater than the sixth interference countermeasure threshold M6, the other determination unit of the first determination unit 52I1 determines that the interference countermeasure is "necessary" and causes the process to proceed to step ST7A.

[0616] In this example, the second determination unit 52I2 acts as the third determination unit.

[0617] Alternatively, a determination unit (functioning as a first determination unit) of the first determination unit 52I1 compares the second index In2 with the sixth interference countermeasure threshold M6 and performs a necessity determination of the interference countermeasure to determine that the interference countermeasure is “unnecessary” when the second index In2 is equal to or less than the sixth interference countermeasure threshold M6, and to determine that the interference countermeasure is “necessary” when the second index In2 is greater than the sixth interference countermeasure threshold M6.

[0618] If one determination unit of the first determination unit 52I1 determines that the interference countermeasure is "necessary," the other determination unit (functioning as the second determination unit) of the first determination unit 52I1 compares the first index In1 with the fifth interference countermeasure threshold M5 and performs a new determination. If the first index In1 is equal to or less than the fifth interference countermeasure threshold M5, the other determination unit of the first determination unit 52I1 determines that the interference countermeasure is "unnecessary" and causes the process to proceed to step ST5. If the first index In1 is greater than the fifth interference countermeasure threshold M5, the other determination unit of the first determination unit 52I1 determines that the interference countermeasure is "necessary" and causes the process to proceed to step ST7A.

[0619] In this example, the second determination unit 52I2 acts as the third determination unit.

[0620] It should be noted that free combinations of the respective embodiments, changes of any components of the respective embodiments or the omission of any components in the respective embodiments are possible. INDUSTRIAL APPLICABILITY

[0621] A radar device according to the present disclosure is suitable for a vehicle radar device mounted on a vehicle, e.g., an automobile. LIST OF REFERENCE SYMBOLS

[0622] 1: Transmitting signal output unit, 11: Control unit, 12: Signal source, 2: Transmitting and receiving unit, 21: Distribution unit, 22: Transmitting antenna, 23: Receiving antenna, 3: Beat signal generation unit, 31: Frequency mixing unit, 32: Filtering unit, 4: AD converter unit, 5: Signal processing unit, 51: Distance spectrum calculation unit, 52, 52A to 52I: Interference countermeasure determination unit, 53: Distance and speed information output unit, 531: Speed ​​spectrum calculation unit, 532: Distance and speed information calculation unit, 6: Display unit

Claims

[1] Radar device comprising: a beat signal generating unit (3) for receiving a reception signal repeating a chirp signal corresponding to a chirp signal of a transmission signal due to a reception wave generated by reflecting a transmission wave at an observation target, which is attributable to the transmission signal repeating a chirp signal whose frequency changes with the lapse of time, and for generating a beat signal having a frequency of a difference between respective frequencies of a chirp signal of the transmission signal and a chirp signal of the reception signal in a correspondence relationship; an AD converter unit (4) for outputting beat data obtained by converting the beat signal generated by the beat signal generating unit into digital data; a range spectrum calculation unit (51) for calculating a plurality of range information spectra each corresponding to a plurality of beat data received by the AD conversion unit during a signal detection period; an interference countermeasure determination unit (52, 52A to 52E) for obtaining a state value of each of the plurality of range information spectra from data in an interference determination processing area in the plurality of range information spectra calculated by the range spectrum calculation unit, determining a necessity of an interference countermeasure from a number of unsuitable range information spectra in the plurality of range information spectra by comparing the obtained state value of each of the range information spectra with an interference determination threshold value to obtain the suitability of each of the plurality of range information spectra, and outputting an interference countermeasure signal for a chirp signal in a transmission signal when the interference countermeasure is necessary; and a distance and speed information output unit (53) for calculating and outputting a distance to the observation target and a relative speed with respect to the observation target from data in a detection target frequency range in the plurality of distance information spectra calculated by the distance spectrum calculation unit when the interference countermeasure determination unit determines that the interference countermeasure is unnecessary. [2] The radar device according to claim 1, wherein the data in the interference determination processing area is a part of the data in the detection target frequency range corresponding to a distance range for detecting the observation target. [3] The radar device according to claim 2, wherein the data in the detection target frequency range is data in a frequency range up to a frequency of 1 / 2 of a sampling frequency in the AD conversion unit. [4] Radar device according to one of claims 1 to 3, wherein the state value of the distance information spectrum obtained by the interference countermeasure determination unit is an average value of the signal strengths of the data in the interference determination processing area in the distance information spectrum, the interference determination threshold is a first determination threshold with respect to the signal strength, the comparison between the state value and the interference determination threshold in the interference countermeasure determination unit is a comparison between the mean value of the signal strengths and the first determination threshold, and the determination of the necessity of the interference countermeasure in the interference countermeasure determination unit is made from a number of the distance information spectra in which the mean value of the signal strengths is equal to or greater than the first determination threshold. [5] The radar device according to claim 4, wherein the first determination threshold value is a value obtained by multiplying the average value of the signal strengths of the data in the interference determination processing area of ​​a range information spectrum obtained in a case where there is no reflected signal and no interference signal from the observation target by a coefficient. [6] The radar device according to claim 4, wherein the first determination threshold value is a value obtained by multiplying a state value of a set range information spectrum among the plurality of range information spectra by a coefficient. [7] The radar device according to claim 4, wherein the first determination threshold value is a value obtained by multiplying an average value of the signal strengths of the data in the interference determination processing area of ​​a range information spectrum obtained in a case where there is no interference with a predetermined observation target by a coefficient. [8] Radar device according to one of claims 1 to 3, wherein the state value of the distance information spectrum obtained by the interference countermeasure determination unit is a signal strength ratio between an average value of the signal strengths of the data in the interference determination processing range in the distance information spectrum and a peak value of the signal strength of the data in the detection target frequency range in the distance information spectrum with respect to the average value of the signal strength, the interference determination threshold is a first determination threshold for the signal strength and a second determination threshold for the signal strength ratio, the comparison between the state value and the interference determination threshold in the interference countermeasure determination unit is a comparison between the mean value of the signal strengths and the first determination threshold and a comparison between the signal strength ratio and the second determination threshold, and the determination of the necessity of the interference countermeasure in the interference countermeasure determination unit is made from a number of the distance information spectra in which the mean value of the signal strengths is equal to or greater than the first determination threshold and the signal strength ratio is equal to or less than the second determination threshold. [9] The radar device according to claim 8, wherein the first determination threshold value is a value obtained by multiplying the average value of the signal strengths of the data in the interference determination processing area of ​​a range information spectrum obtained in a case where there is no reflected signal and no interference signal from the observation target by a coefficient. [10] The radar device according to claim 8, wherein the first determination threshold value is a value obtained by multiplying a state value of a predetermined range information spectrum among the plurality of range information spectra by a coefficient. [11] The radar device according to claim 8, wherein the first determination threshold value is a value obtained by multiplying an average value of the signal strengths of the data in the interference determination processing area of ​​a range information spectrum obtained in a case where there is no interference with a predetermined observation target by a coefficient. [12] Radar device according to one of claims 1 to 3, wherein the state value of the distance information spectrum obtained by the interference countermeasure determination unit is a signal strength ratio of a peak value of the signal strength of the data in the detection target frequency range in the distance information spectrum with respect to an average value of the signal strengths of the data in the interference determination processing range in the distance information spectrum, the interference determination threshold is a third determination threshold for the signal strength ratio, the comparison between the state value and the interference determination threshold in the interference countermeasure determination unit is a comparison between the signal strength ratio and the third determination threshold, and the determination of the necessity of the interference countermeasure in the interference countermeasure determination unit is made from a number of distance information spectra in which the signal strength ratio at the same distance is equal to or greater than the third determination threshold. [13] Radar device according to one of claims 1 to 3, wherein the state value of the distance information spectrum obtained by the interference countermeasure determination unit is a signal strength ratio between an average value of the signal strengths of the data in the interference determination processing range in the distance information spectrum and a peak value of the signal strength of the data in the detection target frequency range in the distance information spectrum with respect to the average value of the signal strength, the interference determination threshold is a first determination threshold for the signal strength and a fourth determination threshold for the signal strength ratio, the comparison between the state value and the interference determination threshold in the interference countermeasure determination unit is a comparison between the mean value of the signal strengths and the first determination threshold and a comparison between the signal strength ratio and the fourth determination threshold, and the determination of the necessity of the interference countermeasure in the interference countermeasure determination unit comprises a first determination based on a number of the distance information spectra in which the mean value of the signal strength is equal to or greater than the first determination threshold, and a second determination based on a number of the distance information spectra in which the signal strength ratio is equal to or greater than the fourth determination threshold, when it is determined by the first determination that the interference countermeasure is necessary. [14] Radar device according to one of claims 1 to 3, wherein the state value of the distance information spectrum obtained by the interference countermeasure determination unit is a signal strength ratio between an average value of the signal strengths of the data in the interference determination processing range in the distance information spectrum and a peak value of the signal strength of the data in the detection target frequency range in the distance information spectrum with respect to the average value of the signal strength, the interference determination thresholds are a first determination threshold for the signal strength, a second determination threshold and a fourth determination threshold for the signal strength ratio, the comparison between the state value and the interference determination threshold in the interference countermeasure determination unit is a comparison between the mean value of the signal strengths and the first determination threshold, a comparison between the signal strength ratio and the second determination threshold, and a comparison between the signal strength ratio and the fourth determination threshold, and the determination of the necessity of the interference countermeasure in the interference countermeasure determination unit comprises a first determination based on a number of the distance information spectra in which the mean value of the signal strengths is equal to or greater than the first determination threshold and the signal strength ratio is equal to or less than the second determination threshold, and a second determination based on a number of the distance information spectra in which the signal strength ratio is equal to or greater than the fourth determination threshold when it is determined by the first determination that the interference countermeasure is necessary. [15] Radar device according to one of claims 1 to 3, wherein the state value of the distance information spectrum obtained by the interference countermeasure determination unit is a signal strength ratio between a peak value of the signal strength of the data in the detection target frequency range in the distance information spectrum with respect to an average value of the signal strengths of the data in the interference determination processing range in the distance information spectrum, the interference determination threshold is a third determination threshold and a fourth determination threshold for the signal strength ratio, the comparison between the state value and the interference determination threshold in the interference countermeasure determination unit is a comparison between the signal strength ratio and the third determination threshold and a comparison between the signal strength ratio and the fourth determination threshold, and the determination of the necessity of the interference countermeasure in the interference countermeasure determination unit comprises a first determination based on a number of the distance information spectra in which the signal strength ratio at the same distance is equal to or greater than the third determination threshold, and a second determination based on a number of the distance information spectra in which the signal strength ratio is equal to or greater than the fourth determination threshold, if it is determined by the first determination that the interference countermeasure is necessary. [16] Radar device according to one of claims 1 to 3, wherein each of the state values ​​of the distance information spectra obtained by the interference countermeasure determination unit is a plurality of signal strength ratios between a plurality of peak values ​​of signal strengths of the data in the detection target frequency range in the distance information spectrum with respect to an average value of signal strengths of the data in the interference determination processing range in the distance information spectrum, the interference determination threshold is a fifth determination threshold for the signal strength ratio, the comparison between the state value and the interference determination threshold in the interference countermeasure determination unit is a comparison between each of the plurality of signal strength ratios and the fifth determination threshold, and the determination of the necessity of the interference countermeasure in the interference countermeasure determination unit is made from a number of the distance information spectra in which the plurality of signal strength ratios at an equal distance are equal to or greater than the fifth determination threshold. [17] Radar device comprising: a beat signal generating unit (3) for receiving a reception signal repeating a chirp signal corresponding to a chirp signal of a transmission signal due to a reception wave generated by reflecting a transmission wave at an observation target, which is attributable to the transmission signal repeating a chirp signal whose frequency changes with the lapse of time, and for generating a beat signal having a frequency of a difference between respective frequencies of a chirp signal of the transmission signal and a chirp signal of the reception signal in a correspondence relationship; an AD converter unit (4) for outputting beat data obtained by converting the beat signal generated by the beat signal generating unit into digital data; a distance spectrum calculation unit (51) for calculating a plurality of distance information spectra corresponding to each of a plurality of pieces of beat data from the AD conversion unit received during a signal detection period, an interference countermeasure determining unit (52G) for obtaining a state value of each of the plurality of distance information spectra, which is an average value of the signal strengths of the data in the interference determination processing area in the distance information spectrum, from data in an interference determination processing area in the plurality of distance information spectra calculated by the distance spectrum calculating unit, determining the necessity of an interference countermeasure by comparing a fifth interference countermeasure threshold value with a first index, which is a value obtained by dividing a difference between a maximum value and a minimum value in an average value of signal strengths, which are state values ​​of the plurality of distance information spectra, by a sum of the maximum value and the minimum value, to determine that the interference countermeasure is unnecessary,if the first index is equal to or less than the fifth interference countermeasure threshold, and to determine that the interference countermeasure is necessary if the first index is greater than the fifth interference countermeasure threshold, and to output an interference countermeasure signal for a chirp signal in a transmission signal if the interference countermeasure is necessary; and, a speed information output unit (53) for calculating and outputting a distance to the observation target and a relative speed with respect to the observation target from data in a detection target frequency range in the plurality of distance information spectra calculated by the distance spectrum calculation unit when the interference countermeasure determination unit determines that the interference countermeasure is unnecessary. [18] Radar device comprising: a beat signal generating unit (3) for receiving a reception signal repeating a chirp signal corresponding to a chirp signal of a transmission signal due to a reception wave generated by reflecting a transmission wave at an observation target, which is attributable to the transmission signal repeating a chirp signal whose frequency changes with the lapse of time, and for generating a beat signal having a frequency of a difference between respective frequencies of a chirp signal of the transmission signal and a chirp signal of the reception signal in a correspondence relationship; an AD converter unit (4) for outputting beat data obtained by converting the beat signal generated by the beat signal generating unit into digital data; a range spectrum calculation unit (51) for calculating a plurality of range information spectra corresponding to each of a plurality of pieces of beat data from the AD conversion unit received during a signal detection period; an interference countermeasure determination unit (52H) for obtaining a state value of each of the plurality of distance information spectra, which is an average value of the signal strengths of the data in the interference determination processing area in the distance information spectrum, from data in an interference determination processing area in the plurality of distance information spectra calculated by the distance spectrum calculation unit, to determine the necessity of an interference countermeasure by comparing a sixth interference countermeasure threshold value with a second index, which is a value obtained by dividing a sum of all average values ​​of signal strengths, which are respective state values ​​of the plurality of distance information spectra, by a value obtained by multiplying a minimum value of the average value of the signal strengths by a number of the plurality of distance information spectra,to determine that the interference countermeasure is unnecessary if the second index is equal to or less than the sixth interference countermeasure threshold, and to determine that the interference countermeasure is necessary if the second index is greater than the sixth interference countermeasure threshold, and to output an interference countermeasure signal for a chirp signal in a transmission signal if the interference countermeasure is necessary; and, a speed information output unit (53) for calculating and outputting a distance to the observation target and a relative speed with respect to the observation target from data in a detection target frequency range in the plurality of distance information spectra calculated by the distance spectrum calculation unit when the interference countermeasure determination unit determines that the interference countermeasure is unnecessary. [19] Radar device comprising: a beat signal generating unit (3) for receiving a reception signal repeating a chirp signal corresponding to a chirp signal of a transmission signal due to a reception wave generated by reflecting a transmission wave at an observation target, which is attributable to the transmission signal repeating a chirp signal whose frequency changes with the lapse of time, and for generating a beat signal having a frequency of a difference between respective frequencies of a chirp signal of the transmission signal and a chirp signal of the reception signal in a correspondence relationship; an AD converter unit (4) for outputting beat data obtained by converting the beat signal generated by the beat signal generating unit into digital data; a range spectrum calculation unit (51) for calculating a plurality of range information spectra corresponding to each of a plurality of pieces of beat data from the AD conversion unit received during a signal detection period; an interference countermeasure determining unit (52G, 52H) for obtaining a state value of each of the plurality of distance information spectra, which is an average value of the signal strengths of the data in the interference determination processing area in the distance information spectrum, from data in an interference determination processing area in the plurality of distance information spectra calculated by the distance spectrum calculating unit, determining the necessity of an interference countermeasure using a first determining unit for comparing a fifth interference countermeasure threshold value with a first index, which is a value obtained by dividing a difference between a maximum value and a minimum value in an average value of signal strengths, which are state values ​​of each of the plurality of distance information spectra, by a sum of the maximum value and the minimum value, and determiningthat an interference countermeasure is unnecessary when the first index is equal to or less than the fifth interference countermeasure threshold, and to determine that an interference countermeasure is necessary when the first index is greater than the fifth interference countermeasure threshold, and a second determination unit for, when it is determined by the first determination unit that the interference countermeasure is necessary, comparing a sixth interference countermeasure threshold with a second index, which is a value obtained by dividing a sum of all mean values ​​of signal strengths, which are state values ​​of each of the plurality of distance information spectra, by a value obtained by multiplying a minimum value of the mean values ​​of the signal strengths by a number of the plurality of distance information spectra, to change the interference countermeasure from necessary to unnecessary,if the second index is equal to or less than the sixth interference countermeasure threshold, and maintain the interference countermeasure as necessary if the second index is greater than the sixth interference countermeasure threshold using the obtained state value of each of the range information spectra, and output an interference countermeasure signal for a chirp signal in a transmission signal if the interference countermeasure is necessary; and, a speed information output unit (53) for calculating and outputting a distance to the observation target and a relative speed with respect to the observation target from data in a detection target frequency range in the plurality of distance information spectra calculated by the distance spectrum calculation unit when the first determination unit and the second determination unit in the interference countermeasure determination unit determine that the interference countermeasure is unnecessary. [20] Radar device comprising: a beat signal generating unit (3) for receiving a reception signal repeating a chirp signal corresponding to a chirp signal of a transmission signal due to a reception wave generated by reflecting a transmission wave at an observation target, which is attributable to the transmission signal repeating a chirp signal whose frequency changes with the lapse of time, and for generating a beat signal having a frequency of a difference between respective frequencies of a chirp signal of the transmission signal and a chirp signal of the reception signal in a correspondence relationship; an AD converter unit (4) for outputting beat data obtained by converting the beat signal generated by the beat signal generating unit into digital data; a range spectrum calculation unit (51) for calculating a plurality of range information spectra corresponding to each of a plurality of pieces of beat data from the AD conversion unit received during a signal detection period; an interference countermeasure determining unit (52G, 52H) for obtaining a state value of each of the plurality of distance information spectra, which is an average value of the signal strengths of the data in the interference determination processing area in the distance information spectrum, from data in an interference determination processing area in the plurality of distance information spectra calculated by the distance spectrum calculating unit, determining a necessity of an interference countermeasure using a first determining unit to compare a sixth interference countermeasure threshold value with a second index, which is a value obtained by dividing a sum of all average values ​​of signal strengths, which are state values ​​of each of the plurality of distance information spectra, by a value,which is obtained by multiplying a minimum value of the average of the signal strengths by a number of the plurality of distance information spectra, to determine that interference countermeasures are unnecessary when the second index is equal to or less than the sixth interference countermeasure threshold, and to determine that interference countermeasures are necessary when the second index is greater than the sixth interference countermeasure threshold, and a second determination unit for, when it is determined by the first determination unit that the interference countermeasure is necessary, comparing a fifth interference countermeasure threshold with a first index, which is a value obtained by dividing a difference between a maximum value and a minimum value in an average of signal strengths that are state values ​​of each of the plurality of distance information spectra,obtained by a sum of the maximum value and the minimum value, to change the interference countermeasure from necessary to unnecessary when the first index is equal to or less than the fifth interference countermeasure threshold, and to maintain the interference countermeasure as necessary when the first index is greater than the fifth interference countermeasure threshold, and to output an interference countermeasure signal for a chirp signal in a transmission signal when the interference countermeasure is necessary; and, a speed information output unit (53) for calculating and outputting a distance to the observation target and a relative speed with respect to the observation target from data in a detection target frequency range in the plurality of distance information spectra calculated by the distance spectrum calculation unit when the first determination unit and the second determination unit in the interference countermeasure determination unit determine that the interference countermeasure is unnecessary. [21] Radar device comprising: a beat signal generating unit (3) for receiving a reception signal repeating a chirp signal corresponding to a chirp signal of a transmission signal due to a reception wave generated by reflecting a transmission wave at an observation target, which is attributable to the transmission signal repeating a chirp signal whose frequency changes with the lapse of time, and for generating a beat signal having a frequency of a difference between respective frequencies of a chirp signal of the transmission signal and a chirp signal of the reception signal in a correspondence relationship; an AD converter unit (4) for outputting beat data obtained by converting the beat signal generated by the beat signal generating unit into digital data; a range spectrum calculation unit (51) for calculating a plurality of pieces of range information spectra corresponding to each of a plurality of beat data from the AD conversion unit received during a signal detection period; an interference countermeasure determining unit (52I) for obtaining a state value of each of the plurality of range information spectra, which is a signal strength ratio between an average value of the signal strengths of the data in the interference determination processing area in the range information spectrum and a peak value of the signal strength of the data in the detection target frequency range in the range information spectrum with respect to the average value of the signal strength, from data in an interference determination processing area in the plurality of range information spectra calculated by the range spectrum calculating unit, the necessity of an interference countermeasure using a first determining unit for comparing a fifth interference countermeasure threshold value with a first index, which is a value obtained by dividing a difference between a maximum value and a minimum value in an average value of signal strengths,the state values ​​of each of the plurality of distance information spectra are obtained by a sum of the maximum value and the minimum value, and determine that the interference countermeasure is unnecessary when the first index is equal to or less than the fifth interference countermeasure threshold, and determine that the interference countermeasure is necessary when the first index is greater than the fifth interference countermeasure threshold, and a second determination unit for, when it is determined by the first determination unit that the interference countermeasure is necessary, comparing a seventh interference countermeasure threshold with a third index, which is a sum of all signal strength ratios of peak values ​​of signal strengths, which are state values ​​of each of the plurality of distance information spectra, to change the interference countermeasure from necessary to unnecessary,if the third index is equal to or greater than the seventh interference countermeasure threshold, and to retain the interference countermeasure as necessary if the third index is less than the seventh interference countermeasure threshold, and to output an interference countermeasure signal for a chirp signal in a transmission signal if the interference countermeasure is necessary; and, a speed information output unit (53) for calculating and outputting a distance to the observation target and a relative speed with respect to the observation target from data in a detection target frequency range in the plurality of distance information spectra calculated by the distance spectrum calculation unit when the first determination unit and the second determination unit in the interference countermeasure determination unit determine that the interference countermeasure is unnecessary. [22] Radar device comprising: a beat signal generating unit (3) for receiving a reception signal repeating a chirp signal corresponding to a chirp signal of a transmission signal due to a reception wave generated by reflecting a transmission wave at an observation target, which is attributable to the transmission signal repeating a chirp signal whose frequency changes with the lapse of time, and for generating a beat signal having a frequency of a difference between respective frequencies of a chirp signal of the transmission signal and a chirp signal of the reception signal in a correspondence relationship; an AD converter unit (4) for outputting beat data obtained by converting the beat signal generated by the beat signal generating unit into digital data; a range spectrum calculation unit (51) for calculating a plurality of range information spectra corresponding to each of a plurality of pieces of beat data from the AD conversion unit received during a signal detection period; an interference countermeasure determining unit (52I) for obtaining a state value of each of the plurality of distance information spectra, which is a signal strength ratio between an average value of the signal strengths of the data in the interference determination processing area in the distance information spectrum and a peak value of the signal strength of the data in the detection target frequency range in the distance information spectrum with respect to the average value of the signal strength, from data in an interference determination processing area in the plurality of distance information spectra calculated by the range spectrum calculating unit, determining a necessity of an interference countermeasure by using a first determining unit to compare a sixth interference countermeasure threshold value with a second index, which is a value obtained by calculating a sum of all the average values ​​of signal strengths,the state values ​​of each of the plurality of distance information spectra are divided by a value obtained by multiplying a minimum value in an average of the signal strengths by a number of the plurality of distance information spectra, determining that the interference countermeasure is unnecessary when the second index is equal to or less than the sixth interference countermeasure threshold, and determining that the interference countermeasure is necessary when the second index is greater than the sixth interference countermeasure threshold, and a second determining unit for, when it is determined by the first determining unit that the interference countermeasure is necessary, comparing a seventh interference countermeasure threshold with a third index which is a sum of all signal strength ratios of peak values ​​of signal strengths,the state values ​​of each of the plurality of range information spectra are to change the interference countermeasure from necessary to unnecessary when the third index is equal to or greater than the seventh interference countermeasure threshold, and to keep the interference countermeasure as necessary when the third index is less than the seventh interference countermeasure threshold, and to output an interference countermeasure signal for a chirp signal in a transmission signal when the interference countermeasure is necessary; and , a speed information output unit (53) for calculating and outputting a distance to the observation target and a relative speed with respect to the observation target from data in a detection target frequency range in the plurality of distance information spectra calculated by the distance spectrum calculation unit when the first determination unit and the second determination unit in the interference countermeasure determination unit determine that the interference countermeasure is unnecessary. [23] Radar device comprising: a beat signal generating unit (3) for receiving a reception signal repeating a chirp signal corresponding to a chirp signal of a transmission signal due to a reception wave generated by reflecting a transmission wave at an observation target, which is attributable to the transmission signal repeating a chirp signal whose frequency changes with the lapse of time, and for generating a beat signal having a frequency of a difference between respective frequencies of a chirp signal of the transmission signal and a chirp signal of the reception signal in a correspondence relationship; an AD converter unit (4) for outputting beat data obtained by converting the beat signal generated by the beat signal generating unit into digital data; a range spectrum calculation unit (51) for calculating a plurality of range information spectra corresponding to each of a plurality of pieces of beat data from the AD conversion unit received during a signal detection period; an interference countermeasure determining unit (52I) for obtaining a state value of each of the plurality of distance information spectra, which is a signal strength ratio between an average value of the signal strengths of the data in the interference determination processing area in the distance information spectrum and a peak value of the signal strength of the data in the detection target frequency range in the distance information spectrum with respect to the average value of the signal strength, from data in an interference determination processing area in the plurality of distance information spectra calculated by the range spectrum calculating unit, determining a necessity of an interference countermeasure by using a first determining unit to compare a fifth interference countermeasure threshold value with a first index, which is a value,which is obtained by dividing a difference between a maximum value and a minimum value in an average value of signal strengths, which are state values ​​of each of the plurality of distance information spectra, by a sum of the maximum value and the minimum value, to determine that the interference countermeasure is unnecessary when the first index is equal to or less than the fifth interference countermeasure threshold, and to determine that the interference countermeasure is necessary when the first index is greater than the fifth interference countermeasure threshold, a second determining unit for, when it is determined by the first determining unit that the interference countermeasure is necessary, comparing a sixth interference countermeasure threshold with a second index, which is a value obtained by dividing a sum of all the average values ​​of signal strengths, which are state values ​​of each of the plurality of distance information spectra,by a value obtained by multiplying a minimum value in an average of the signal strengths by a number of the plurality of distance information spectra, changing the interference countermeasure from necessary to unnecessary when the second index is equal to or less than the sixth interference countermeasure threshold, and maintaining the interference countermeasure as necessary when the second index is greater than the sixth interference countermeasure threshold, and a third determination unit for, when it is determined by the second determination unit that the interference countermeasure is still necessary, comparing a seventh interference countermeasure threshold with a third index that is a sum of all signal strength ratios of peak values ​​of signal strengths that are state values ​​of each of the plurality of distance information spectra, changing the interference countermeasure from necessary to unnecessary,if the third index is equal to or greater than the seventh interference countermeasure threshold, and to leave the interference countermeasure as necessary if the third index is less than the seventh interference countermeasure threshold, and to output an interference countermeasure signal for a chirp signal in a transmission signal if the interference countermeasure is necessary; and, a speed information output unit (53) for calculating and outputting a distance to the observation target and a relative speed with respect to the observation target from data in a detection target frequency range in the plurality of distance information spectra calculated by the distance spectrum calculation unit when the first determination unit to the third determination unit in the interference countermeasure determination unit determine that the interference countermeasure is unnecessary. [24] Radar device comprising: a beat signal generating unit (3) for receiving a reception signal repeating a chirp signal corresponding to a chirp signal of a transmission signal due to a reception wave generated by reflecting a transmission wave at an observation target, which is attributable to the transmission signal repeating a chirp signal whose frequency changes with the lapse of time, and for generating a beat signal having a frequency of a difference between respective frequencies of a chirp signal of the transmission signal and a chirp signal of the reception signal in a correspondence relationship; an AD converter unit (4) for outputting beat data obtained by converting the beat signal generated by the beat signal generating unit into digital data; a range spectrum calculation unit (51) for calculating a plurality of range information spectra corresponding to each of a plurality of pieces of beat data from the AD conversion unit received during a signal detection period; an interference countermeasure determining unit (52I) for obtaining a state value of each of the plurality of distance information spectra, which is a signal strength ratio between an average value of the signal strengths of the data in the interference determination processing area in the distance information spectrum and a peak value of the signal strength of the data in the detection target frequency range in the distance information spectrum with respect to the average value of the signal strength, from data in an interference determination processing area in the plurality of distance information spectra calculated by the range spectrum calculating unit, determining a necessity of an interference countermeasure by using a first determining unit to compare a sixth interference countermeasure threshold value with a second index, which is a value obtained by calculating a sum of all the average values ​​of signal strengths,the state values ​​of each of the plurality of range information spectra are divided by a value obtained by multiplying a minimum value in an average of the signal strengths by a number of the plurality of range information spectra, determining that the interference countermeasure is unnecessary when the second index is equal to or less than the sixth interference countermeasure threshold, and determining that the interference countermeasure is necessary when the second index is greater than the sixth interference countermeasure threshold, and a second determining unit for, when it is determined by the first determining unit that the interference countermeasure is necessary, comparing a fifth interference countermeasure threshold with a first index, which is a value obtained by dividing a difference between a maximum value and a minimum value in an average of signal strengths,the state values ​​of each of the plurality of distance information spectra are obtained by a sum of the maximum value and the minimum value, to change the interference countermeasure from necessary to unnecessary when the first index is equal to or less than the fifth interference countermeasure threshold, and to keep the interference countermeasure as necessary when the first index is greater than the fifth interference countermeasure threshold, and a third determination unit for, when it is determined by the second determination unit that the interference countermeasure is kept necessary, comparing a seventh interference countermeasure threshold with a third index which is a sum of all signal strength ratios of peak values ​​of signal strengths, which are state values ​​of each of the plurality of distance information spectra, to change the interference countermeasure from necessary to unnecessary,if the third index is equal to or greater than the seventh interference countermeasure threshold, and to leave the interference countermeasure as necessary if the third index is less than the seventh interference countermeasure threshold, and to output an interference countermeasure signal for a chirp signal in a transmission signal if the interference countermeasure is necessary; and, a speed information output unit (53) for calculating and outputting a distance to the observation target and a relative speed with respect to the observation target from data in a detection target frequency range in the plurality of distance information spectra calculated by the distance spectrum calculation unit when the first determination unit to the third determination unit in the interference countermeasure determination unit determine that the interference countermeasure is unnecessary. [25] A radar device according to any one of claims 17 to 24, wherein the data in the interference determination processing area is a part of the data in the detection target frequency range corresponding to a distance range for detecting the observation target. [26] A radar device according to claim 25, wherein the data in the detection target frequency range is data in a frequency range up to a frequency of 1 / 2 of a sampling frequency in the AD conversion unit. [27] A method for detecting interference countermeasures of a radar device, the method comprising: a step of receiving a plurality of chirp signals received during a signal detection period in a transmission signal that repeats a chirp signal whose frequency changes with the passage of time, and a plurality of chirp signals received during the signal detection period in a reception signal due to a reception wave generated by reflection of a transmission wave due to the transmission signal at an observation target, and calculating a plurality of range information spectra corresponding to beat data obtained by converting a beat signal having a frequency that is a difference between frequencies of a chirp signal of the transmission signal and a chirp signal of the reception signal into digital data in a correspondence relationship; and a step of obtaining, by an interference countermeasure determining unit, a state value of each of the plurality of range information spectra from data in an interference determination processing area in the plurality of range information spectra, obtaining suitability in each of the plurality of range information spectra by comparing the obtained state value with an interference determination threshold value, determining the necessity of an interference countermeasure from the number of unsuitable range information spectra in the plurality of range information spectra, and outputting an interference countermeasure signal for a chirp signal in a transmission signal when the interference countermeasure is necessary.

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