Radar device, observation object detection method, and vehicle-mounted device

Abstract

A radar device (1) comprises: a first radar (12a) and a second radar (12b) which transmit frequency modulation signals having frequency gradients different from each other with the passage of time as radar signals and receive reflected waves of the radar signals; a calculation unit (38) which calculates a first spectrum obtained by Fourier transforming digital data of a beat signal in a distance direction and a second spectrum obtained by Fourier transforming the first spectrum in a relative speed direction, and calculates distance-speed information for each radar based on the beat frequency and Doppler frequency corresponding to a peak in the second spectrum; and a processing unit (11) which distinguishes a detection result of an observation object included in the distance-speed information and a false detection result caused by electromagnetic noise based on a comparison result of the distance-speed information calculated for each radar.

Description

Technical Field

[0001] The present disclosure relates to a radar device, an observation object detection method, and a vehicle-mounted device. Background Art

[0002] In the past, there are known radar devices of frequency modulated continuous wave (FMCW) method. For example, the radar device described in Patent Document 1 is mounted on a car, divides the frequency modulated signal into a transmission signal and a local oscillation signal, transmits the transmission signal as a radar signal, and receives the reflected wave of the radar signal reflected by the observed object. The radar device uses the spectrum of the baseband signal obtained by mixing the frequency of the reflected wave with the frequency of the local oscillation signal to measure the distance to the observed object.

[0003] Conventional FMCW radar devices perform filtering on baseband signals to minimize the Doppler frequency relative to vehicle speed when measuring the distance to an observation object. As a result, reflected waves from clutter (stationary objects other than the target) with the same frequency as the Doppler frequency relative to vehicle speed are suppressed as noise.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application No. 2017-522577 Summary of the invention

[0007] Problem that the invention aims to solve

[0008] In the radar device described in Patent Document 1, electromagnetic noise having a frequency different from the Doppler frequency relative to the vehicle speed is not considered, and there is a problem that it is impossible to distinguish between a false detection result caused by electromagnetic noise and a detection result of the observed object. Electromagnetic noise includes, for example, electromagnetic noise generated in components constituting the radar device and electromagnetic noise coming from outside the radar device.

[0009] The present disclosure is used to solve the above-mentioned problem, and its purpose is to obtain a radar device, an observed object detection method and a vehicle-mounted device that can distinguish the detection result of the observed object from the false detection result caused by electromagnetic noise.

[0010] Means used to solve problems

[0011] The radar device disclosed in the present invention comprises: a plurality of radars which transmit frequency modulation signals whose frequencies change linearly with the passage of time as radar signals, and receive reflected waves of the radar signals reflected at an observation object; a calculation unit which calculates distance-speed information indicating the distance to the observation object and the relative speed with respect to the observation object using digital data of a beat signal having a frequency which is a difference between the frequency of the radar signal and the frequency of the reflected wave; and a processing unit which detects the observation object based on the distance-speed information, wherein the plurality of radars transmit frequency modulation signals which are different from each other except that the ratio of the absolute value of the frequency gradient accompanying the passage of time is 1 as radar signals, and the calculation unit calculates the value obtained by Fourier transforming the digital data of the beat signal in the distance direction. A first spectrum and a second spectrum obtained by Fourier transforming the first spectrum in a relative speed direction, based on a beat frequency and a Doppler frequency corresponding to a peak in the second spectrum, distance-speed information is calculated for each radar, and a processing unit compares the distance-speed information calculated for each radar. If the distance and speed included in the distance-speed information are consistent between radars, the processing unit determines the distance and speed included in the distance-speed information as the distance to the observation object and the relative speed with the observation object. If the distance and speed included in the distance-speed information are inconsistent between radars due to a difference corresponding to a difference in the gradient of the frequency of the radar signal, the processing unit determines the distance and speed included in the distance-speed information as a false detection result caused by electromagnetic noise.

[0012] Effects of the Invention

[0013] According to the present disclosure, a plurality of radars transmit frequency modulation signals different from each other, with the ratio of the absolute value of the frequency gradient being 1, as radar signals, and receive reflected waves of the radar signals reflected at the observation object. Using digital data of a beat signal having a frequency that is the difference between the frequency of the radar signal and the frequency of the reflected wave, distance-speed information representing the distance to the observation object and the relative speed with respect to the observation object is calculated for each radar. Based on the comparison result of the distance-speed information of each radar, the detection result of the observation object contained in the distance-speed information and the false detection result caused by electromagnetic noise are distinguished. Thus, the radar device of the present disclosure can distinguish the detection result of the observation object from the false detection result caused by electromagnetic noise. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a block diagram showing the configuration of the radar device according to the first embodiment.

[0015] Figure 2 It is shown Figure 1 A block diagram of the structure of the processing unit.

[0016] Figure 3This is a block diagram showing the configurations of the first radar and the second radar in the first embodiment.

[0017] Figure 4 It is shown Figure 3 A block diagram of the structure of the calculation part.

[0018] Figure 5 This is a flowchart showing the observed object detection method according to the first embodiment.

[0019] Figure 6 It is shown Figure 5 A flowchart of the detailed processing of step ST1 is shown in FIG.

[0020] Figure 7 This is an explanatory diagram showing an outline of a calculation process of range-velocity information performed by a calculation unit included in the first radar.

[0021] Figure 8 This is an explanatory diagram showing an outline of a calculation process of range-velocity information performed by a calculation unit included in the second radar.

[0022] Fig. 9 This is an explanatory diagram showing an overview of the determination process of the detection result in the first embodiment.

[0023] Fig.10 This is a block diagram showing the structure of a radar device according to a second embodiment.

[0024] Fig.11 This is a block diagram showing the configurations of the first radar and the second radar in the second embodiment.

[0025] Fig.12 It is shown Fig.10 A block diagram of the structure of the processing unit.

[0026] Fig.13 This is a block diagram showing the structure of a modified example of the processing unit in the second embodiment.

[0027] Fig.14 It is shown Fig.13 A block diagram of the structure of the first calculation unit.

[0028] Fig.15 It is shown Fig.13 A block diagram of the structure of the second calculation unit.

[0029] Fig.16 It is shown by Fig.13 An explanatory diagram of an overview of processing performed by a first calculation unit and a second calculation unit.

[0030] Fig.17A is a block diagram showing a hardware configuration that realizes the functions of the radar device according to Embodiment 2. Fig. 17BThis is a block diagram showing a hardware configuration for executing software that realizes the functions of the radar device according to the second embodiment.

[0031] Fig.18 This is a block diagram showing the configuration of a vehicle-mounted device according to a third embodiment. DETAILED DESCRIPTION

[0032] Implementation method 1.

[0033] Figure 1 1 is a block diagram showing the structure of a radar device 1 according to Embodiment 1. The radar device 1 is mounted on a car, for example, and observes cars, pedestrians, or guardrails that exist around the car. Figure 1 In the embodiment, the radar device 1 includes a processing unit 11, a first radar 12a, and a second radar 12b. Figure 1 , but this is an example. The radar device 1 may also be a structure having three or more radars. In addition, the first radar 12a and the second radar 12b may be arranged near or separately as long as they are located at a position where they can detect the same observation object.

[0034] The first radar 12a and the second radar 12b transmit frequency modulated signals whose frequencies change linearly with the passage of time as radar signals, and receive reflected waves of the radar signals reflected by the observed object. The processing unit 11 outputs a control signal specifying parameters to the first radar 12a and the second radar 12b, and the parameters determine the transmission cycle of the radar signal and the transmission waveform of the radar signal. The first radar 12a and the second radar 12b transmit radar signals of transmission waveforms with frequency gradients different from each other in space with the passage of time according to the control signal from the processing unit 11.

[0035] The first radar 12a and the second radar 12b calculate distance-speed information indicating the distance to the observation object and the relative speed to the observation object using digital data of a beat signal having a frequency that is a difference between the frequency of the transmitted radar signal and the frequency of the received reflected wave. The processing unit 11 detects the observation object based on the distance-speed information calculated by the first radar 12a and the second radar 12b.

[0036] Figure 2 is a block diagram showing the structure of the processing unit 11. Figure 2In the embodiment, the processing unit 11 includes a control processing unit 21 and a detection processing unit 22. The control processing unit 21 outputs a control signal corresponding to each radar to the first radar 12a and the second radar 12b. The detection processing unit 22 distinguishes the detection result of the observation object included in the distance speed information and the false detection result caused by electromagnetic noise based on the comparison result of the distance speed information output from the first radar 12a and the distance speed information output from the second radar 12b. Electromagnetic noise has a frequency different from the Doppler frequency relative to the speed of the vehicle equipped with the radar device 1, and is noise that cannot be suppressed as clutter.

[0037] Figure 3 1 is a block diagram showing the configuration of the first radar 12a and the second radar 12b. Figure 3 As shown, the first radar 12a and the second radar 12b include a radar control unit 31, a signal source 32, a distributor 33, a transmitting antenna 34, a receiving antenna 35, a frequency mixer 36, an analog-to-digital converter (hereinafter referred to as ADC) 37 and a calculator 38.

[0038] The radar control unit 31 outputs the parameters that determine the transmission cycle of the radar signal and the transmission waveform of the radar signal specified by the control signal from the control processing unit 21 to the signal source 32, and outputs the transmission cycle of the radar signal to the calculation unit 38. The signal source 32 intermittently and repeatedly outputs a frequency modulated signal whose frequency changes with the passage of time as a radar signal to the distribution unit 33 according to the transmission cycle input from the radar control unit 31. The distribution unit 33 distributes the radar signal output from the signal source 32 to the transmission antenna 34 and the frequency mixing unit 36.

[0039] The transmitting antenna 34 is an antenna that radiates the electromagnetic wave of the radar signal output from the distributor 33 into space. The receiving antenna 35 is an antenna that receives the reflected wave of the radar signal after it is reflected by the observation object. The reception signal of the reflected wave received by the receiving antenna 35 is output to the frequency mixing unit 36. The frequency mixing unit 36 ​​is a beat signal generating unit that generates a beat signal having a frequency that is the difference between the frequency of the radar signal and the frequency of the reflected wave by frequency mixing the frequency of the local oscillation signal, which is the radar signal output from the distributor 33, and the frequency of the reflected wave received by the receiving antenna 35.

[0040] ADC37 is a conversion unit that converts the beat signal generated by the frequency mixer 36 from analog data to digital data. Since the radar signal is intermittently and repeatedly output from the signal source 32 in each transmission cycle specified by the radar control unit 31, the frequency mixer 36 generates a beat signal in each transmission cycle. Thus, ADC37 converts a plurality of beat signals in each transmission cycle into digital data, and sequentially outputs the converted plurality of digital data to the calculation unit 38.

[0041] The calculation unit 38 calculates the first spectrum by Fourier transforming the digital data of the beat signal output from the ADC 37 in the distance direction, and calculates the second spectrum by Fourier transforming the first spectrum in the relative speed direction. In addition, the calculation unit 38 calculates the distance speed information for each radar based on the beat frequency and Doppler frequency corresponding to the peak in the second spectrum. The distance speed information calculated by the calculation unit 38 is output to the detection processing unit 22.

[0042] exist Figure 3 In the description, the description of the structures that radars usually have, such as amplifiers and filters, is omitted. For example, an amplifier may be configured on the input side of the transmitting antenna 34 or the output side of the receiving antenna 35, and a filter may be configured on the input side of the transmitting antenna 34 or the output side of the frequency mixer 36. In addition, Figure 3 The first radar 12 a and the second radar 12 b shown in the figure each have one transmitting antenna 34 and one receiving antenna 35 , but may be a radar having two or more transmitting antennas 34 and two or more receiving antennas 35 .

[0043] Figure 4 is a block diagram showing the structure of the calculation unit 38. Figure 4 In the embodiment, the calculation unit 38 includes a first spectrum calculation unit 41, a second spectrum calculation unit 42, a frequency extraction unit 43, and a distance speed information calculation unit 44. The first spectrum calculation unit 41 calculates a plurality of first spectrums by Fourier transforming the digital data of each transmission cycle specified by the radar control unit 31 among the digital data intermittently and repeatedly output from the ADC 37 in the distance direction. The second spectrum calculation unit 42 calculates a second spectrum by Fourier transforming the plurality of first spectrums calculated by the first spectrum calculation unit 41 in the relative speed direction.

[0044] The frequency extraction unit 43 extracts the beat frequency and the Doppler frequency corresponding to the peak in the second frequency spectrum. The distance-speed information calculation unit 44 calculates the distance to the observation object based on the beat frequency output from the frequency extraction unit 43, and calculates the relative speed with the observation object based on the Doppler frequency output from the frequency extraction unit 43, thereby calculating the distance-speed information indicating the calculated distance and relative speed. The distance-speed information calculated by the distance-speed information calculation unit 44 is output to the detection processing unit 22.

[0045] Figure 5 This is a flowchart showing the observed object detection method according to the first embodiment.

[0046] The first radar 12 a and the second radar 12 b transmit frequency modulation signals having frequency gradients different from each other with the passage of time as radar signals at each transmission cycle, and receive reflected waves of the radar signals reflected by the observation object.

[0047] Each calculation unit 38 provided in the first radar 12a and the second radar 12b calculates the distance speed information (step ST1). For example, the calculation unit 38 provided in the first radar 12a obtains the digital data of the beat signal, performs Fourier transform on the obtained digital data in the distance direction, and thereby calculates a plurality of first frequency spectra for each transmission cycle, wherein the beat signal has a frequency that is a difference between the frequency of the radar signal and the frequency of the reflected wave of the radar signal. The calculation unit 38 calculates the second frequency spectrum by performing Fourier transform on the plurality of first frequency spectra in the relative speed direction. Then, the calculation unit 38 calculates the distance speed information about the observed object based on the beat frequency and Doppler frequency corresponding to the peak in the second frequency spectrum. In the second radar 12b, the distance speed information about the same observed object is also calculated through the same steps.

[0048] Next, the processing unit 11 compares the distance and speed information output from the first radar 12a with the distance and speed information output from the second radar 12b to determine whether the distances and relative speeds they represent are consistent (step ST2). When the processing unit 11 determines that the distances and relative speeds they represent are consistent (step ST2; yes), the distance and relative speed represented by the distance and speed information are determined to be the detection results of the distance to the observed object and the relative speed between the observed object and the observed object (step ST3). In addition, when the processing unit 11 determines that the distances and relative speeds they represent are inconsistent (step ST2; no), the distance and relative speed represented by the distance and speed information are determined to be the result of false detection caused by electromagnetic noise (step ST4).

[0049] Figure 6 It is shown Figure 5 The flowchart of the detailed processing of step ST1 is shown in FIG. Figure 7 It is an explanatory diagram showing an outline of a calculation process of the distance-speed information performed by the calculation unit 38 included in the first radar 12 a . Figure 8 It is an explanatory diagram showing an outline of a calculation process of the distance-speed information performed by the calculation unit 38 included in the second radar 12 b. Fig. 9 This is an explanatory diagram showing an overview of the determination process of the detection result in the first embodiment.

[0050] Lo(1)a, Lo(2)a, Lo(3)a, ..., Lo(K)a are local oscillation signals (radar signals) output from the distributor 33 to the frequency mixer 36 in the first radar 12a. Rx(1)a, Rx(2)a, Rx(3)a, ..., Rx(K)a are reception signals of reflected waves of the radar signal reflected by the observation object and output from the receiving antenna 35 to the frequency mixer 36 in the first radar 12a. K is the number of times the radar signal is output in one frame, and is an integer greater than or equal to 2.

[0051] like Figure 7 As shown by the dotted line in the middle, electromagnetic noise of a continuous wave with a fixed frequency is input to ADC37, for example. The signal acquisition period A is a period during which the first spectrum calculation unit 41 obtains the digital data of the beat signal A from ADC37. In addition, the signal acquisition period A is included in the transmission period of the radar signal output from the signal source 32. The length of the signal acquisition period A is approximately the same as the length of one cycle of the local oscillation signal in the first radar 12a, or a length less than one cycle. Ta is the scanning time of the local oscillation signal Lo(k)a (k=1, 2, 3,..., K), which is a time in the order of microseconds. BWa is the frequency bandwidth of the local oscillation signal Lo(k)a.

[0052] exist Figure 7 In the figure, for the sake of simplicity, the case where the radar device 1 observes one object is shown. However, the radar device 1 may observe two or more objects. In addition, although one electromagnetic noise as a continuous wave with a fixed frequency is shown, a plurality of electromagnetic noises as continuous waves with a fixed frequency may be input to the ADC 37.

[0053] The first spectrum calculation unit 41 obtains the digital data output from the ADC 37 during the signal acquisition period A included in the transmission cycle of the radar signal specified by the radar control unit 31, and performs Fourier transform on the digital data of the beat signal A obtained during the signal acquisition period A in the distance direction, thereby calculating the first spectrum (step ST1a). Figure 7 and Figure 8 In the above equation, FFT(1) represents a fast Fourier transform (FFT) in the distance direction. By performing Fourier transform on the digital data of the beat signal A in the distance direction, the beat frequency F is expressed as sb＿r＿a The spectrum values ​​of the received signal Rx(k)a (k=1, 2, 3, ..., K) of the reflected wave are accumulated. In the following formula (1), R is the distance from the radar device 1 to the observed object, and c is the speed of light. In the first spectrum, the spectrum value corresponding to the observed object is accumulated as the value of the corresponding beat frequency.

[0054]

[0055] After Fourier transforming the digital data of the beat signal A in the distance direction, the frequency F of the electromagnetic noise in the first spectrum n＿r The spectrum values ​​corresponding to the electromagnetic noise are accumulated at Figure 7, the number of outputs of the radar signal from the signal source 32 is K times, so the first spectrum calculation unit 41 performs Fourier transform on the digital data of K different beat signals in the distance direction. Thus, K first spectrums are calculated. The data representing the K first spectrums are output to the second spectrum calculation unit 42.

[0056] The second spectrum calculation unit 42 calculates a second spectrum by Fourier transforming the K first spectrums calculated by the first spectrum calculation unit 41 in the relative speed direction (step ST2a). Figure 7 and Figure 8 In the above formula, FFT(2) represents the FFT in the relative velocity direction. After Fourier transforming the K first spectra in the relative velocity direction, the Doppler frequency F is expressed as sb＿v＿a The spectrum values ​​corresponding to the received signal Rx(k)a of the reflected wave are integrated. In the following equation (2), fa is the center frequency of the local oscillation signal Lo(k)a, and v is the relative speed between the radar device 1 and the observed object.

[0057]

[0058] In the second spectrum, at the Doppler frequency F corresponding to the relative speed between the radar device 1 and the source of the electromagnetic noise, n＿v At , the spectrum value of electromagnetic noise is accumulated. For example, at Figure 7 In the second spectrum, the relative speed between the radar device 1 and the source of electromagnetic noise is 0. Therefore, in the second spectrum, at the Doppler frequency F corresponding to the relative speed of 0, n＿v The spectrum values ​​corresponding to the electromagnetic noise are accumulated at the Doppler frequency corresponding to the relative speed between the radar device 1 and the source of the electromagnetic noise other than 0. Figure 7 In the example shown, continuous wave electromagnetic noise is input to ADC 37, and the frequency of the electromagnetic noise does not change. n＿r The spectrum values ​​corresponding to the electromagnetic noise are accumulated.

[0059] Next, the frequency extraction unit 43 detects a peak value from a plurality of spectrum values ​​included in the second spectrum, and extracts the beat frequency F corresponding to the peak value. sb＿r＿a and Doppler frequency F sb＿v＿a (Step ST3 a ) For example, the frequency extraction unit 43 detects the peak value using a constant false alarm rate (CFAR) process.

[0060] The beat frequency F corresponding to the peak sb＿r＿a is the beat frequency corresponding to the distance from the radar device 1 to the observed object, and the Doppler frequency F corresponding to the peak sb＿v＿ais the Doppler frequency corresponding to the relative speed between the radar device 1 and the observed object. The beat frequency F extracted by the frequency extraction unit 43 sb＿r＿a and Doppler frequency F sb＿v＿a The data is output to the distance and speed information calculation unit 44 .

[0061] When electromagnetic noise is generated, the frequency extracting unit 43 also detects the spectrum value corresponding to the electromagnetic noise as a peak. In this case, the frequency F of the electromagnetic noise n＿r Mistakenly detected as beat frequency F sb＿r＿a Then, the frequency extracting unit 43 outputs the Doppler frequency F corresponding to the relative speed between the radar device 1 and the source of the electromagnetic noise. n＿v , is also erroneously detected as the Doppler frequency F corresponding to the relative speed between the radar device 1 and the observed object. sb＿v＿a The data is output to the distance-speed information calculation unit 44 .

[0062] Next, the range speed information calculation unit 44 calculates the beat frequency F corresponding to the peak value extracted from the second frequency spectrum. sb＿r＿a and Doppler frequency F sb＿v＿a , calculates distance-speed information indicating the distance R from the radar device 1 to the observed object and the relative speed v between the radar device 1 and the observed object (step ST4a). For example, the distance-speed information calculation unit 44 uses the beat frequency F corresponding to the peak value sb＿r＿a , calculate the distance R from the radar device 1 to the observed object according to the following formula (3).

[0063]

[0064] The range-velocity information calculation unit 44 uses the Doppler frequency F corresponding to the peak extracted from the second frequency spectrum. sb＿v＿a The relative speed v between the radar device 1 and the observed object is calculated according to the following equation (4). The distance speed information calculation unit 44 generates distance speed information indicating the distance R and the relative speed v, and outputs it to the detection processing unit 22 as distance speed information corresponding to the observed object detected by the first radar 12a.

[0065]

[0066] The frequency F of the electromagnetic noise is input to the distance and speed information calculation unit 44. n＿r As the beat frequency F sb＿r＿a Therefore, the distance-speed information output from the distance-speed information calculation unit 44 to the detection processing unit 22 also includes the distance R which is a result of erroneous detection of the distance R due to electromagnetic noise. n＿a The distance R is calculated using the following formula (5): n＿a .

[0067]

[0068] Furthermore, the Doppler frequency F corresponding to the relative speed between the radar device 1 and the source of the electromagnetic noise is input to the distance speed information calculation unit 44. n＿v As the Doppler frequency F sb＿v＿a Therefore, the distance-speed information output from the distance-speed information calculation unit 44 to the detection processing unit 22 also includes the relative speed v which is the result of the erroneous detection of the relative speed v caused by the electromagnetic noise. n＿a The relative velocity v is calculated using the following formula (6): n＿a .

[0069]

[0070] Lo(1)b, Lo(2)b, Lo(3)b, ..., Lo(K)b are local oscillation signals (radar signals) output from the distributor 33 to the frequency mixer 36 in the second radar 12b. Rx(1)b, Rx(2)b, Rx(3)b, ..., Rx(K)b are reception signals of reflected waves output from the receiving antenna 35 to the frequency mixer 36 in the second radar 12b. K is the number of times the radar signal is output in one frame, and is an integer greater than or equal to 2.

[0071] like Figure 8 As shown by the middle dotted line, for example, electromagnetic noise of a continuous wave with a fixed frequency is input to the ADC 37. The signal acquisition period B is a period during which the first spectrum calculation unit 41 acquires digital data of the beat signal B from the ADC 37. In addition, the signal acquisition period B is included in the transmission period of the radar signal output from the signal source 32. The length of the signal acquisition period B is substantially the same as one cycle of the local oscillation signal in the second radar 12b, or is less than one cycle.

[0072] In addition, Tb is the scanning time of the local oscillation signal Lo(k)b (k=1, 2, 3, ..., K), which is a time in the order of microseconds. BWb is the frequency bandwidth of the local oscillation signal Lo(k)b. In order to realize different gradients in the frequency modulation signals transmitted by the first radar 12a and the second radar 12b, the scanning time Ta and the scanning time Tb are equal, and the frequency bandwidth BWb of the frequency modulation signal transmitted by the second radar 12b is set to twice the frequency bandwidth BWa of the frequency modulation signal transmitted by the first radar 12a. However, this is just an example, and the frequency bandwidth may not be twice. In addition, by changing the scanning time of the frequency of the radar signals transmitted by the first radar 12a and the second radar 12b, the transmission waveform of the frequency modulation signal with different gradients can be realized.

[0073] In the second radar 12b, the range speed information calculation unit 44 calculates the range speed information based on the beat frequency F corresponding to the peak value extracted by the frequency extraction unit 43. sb＿r＿b and Doppler frequency F sb＿v＿b , to calculate the distance R from the radar device 1 to the observed object and the distance speed information indicating the relative speed v between the radar device 1 and the observed object. Similar to the first radar 12a, the distance speed information calculation unit 44 uses the beat frequency F corresponding to the peak value sb＿r＿b According to the above formula (3), the distance R from the radar device 1 to the observed object is calculated.

[0074] The range-velocity information calculation unit 44 uses the Doppler frequency F corresponding to the peak value. sb＿v＿b According to the above formula (4), the relative speed v between the radar device 1 and the observed object is calculated. The distance speed information calculation unit 44 generates distance speed information indicating the distance R and the relative speed v, and outputs it to the detection processing unit 22 as distance speed information corresponding to the observed object detected by the second radar 12b.

[0075] The frequency F of the electromagnetic noise is input to the distance speed information calculation unit 44. n＿r As the beat frequency F sb＿r＿b Therefore, the distance-speed information output from the distance-speed information calculation unit 44 to the detection processing unit 22 also includes the distance R which is a result of erroneous detection of the distance R due to electromagnetic noise. n＿b The distance R is calculated using the following formula (7): n＿b .

[0076]

[0077] The Doppler frequency F corresponding to the relative speed between the radar device 1 and the source of the electromagnetic noise is input to the distance speed information calculation unit 44. n＿v As the Doppler frequency F sb＿v＿b Therefore, the distance-speed information output from the distance-speed information calculation unit 44 to the detection processing unit 22 also includes the relative speed v which is the result of the erroneous detection of the relative speed v caused by the electromagnetic noise. n＿b The relative velocity v is calculated using the following equation (8): n＿b .

[0078]

[0079] When the second frequency spectrum calculated by the calculation unit 38 included in the first radar 12a is compared with the second frequency spectrum calculated by the calculation unit 38 included in the second radar 12b, as shown in FIG. Fig. 9As shown in FIG. 1 , the spectrum value corresponding to the observation object detected by the first radar 12a and the spectrum value corresponding to the observation object detected by the second radar 12b become overlapping values ​​(consistent values). The detection processing unit 22 determines the distance and relative speed represented by the distance-speed information determined to be consistent as the detection result of the observation object indicating the distance R from the observation object and the relative speed v between the observation object and the observation object.

[0080] exist Figure 7 and Figure 8 In this example, the sweep time Ta and the sweep time Tb become equal, and the frequency bandwidth BWb is set to twice the frequency bandwidth BWa. Fig. 9 As shown, the distance R as a result of misdetection by the first radar 12a n＿a The distance R which is the result of the false detection in the second radar 12b n＿b Become R n＿a =2R n＿b The detection processing unit 22 determines that the distance and relative speed indicated by the distance-speed information determined to be inconsistent in this way are erroneous detection results caused by electromagnetic noise.

[0081] As described above, in the radar device 1 of the first embodiment, the frequency modulated signals with different frequency gradients are transmitted as radar signals by the first radar 12a and the second radar 12b, and the reflected waves of the radar signals reflected by the observed object are received. The distance speed information indicating the distance R from the observed object and the relative speed v with respect to the observed object is calculated for each radar using the digital data of the beat signal having the frequency of the difference between the frequency of the radar signal and the frequency of the reflected wave. Based on the comparison result of the distance speed information calculated by the first radar 12a and the second radar 12b, the detection result of the observed object contained in the distance speed information and the false detection result caused by electromagnetic noise are distinguished. Since the frequency gradients of the frequency modulated signals transmitted as radar signals are different from each other, the first radar 12a and the second radar 12b have different distance resolutions. The false detection results of the distance and relative speed caused by electromagnetic noise become different values ​​for each radar according to the difference in the distance resolution, and are inconsistent. In contrast, even if there is a difference in distance resolution, the detection results of the distance and relative speed related to the same observation object based on the first radar 12a and the second radar 12b are substantially the same value. As a result, the radar device 1 can distinguish the detection result of the observation object contained in the distance and speed information from the false detection result caused by electromagnetic noise. In addition, the radar device 1 can generate distance and speed information that does not contain the false detection result caused by electromagnetic noise, thereby reducing the degradation of the detection accuracy of the observation object. In addition, since the distance and speed information is calculated based on a plurality of radar signals contained in one frame, the radar device 1 can detect the observation object in the signal processing of one frame.

[0082] Implementation method 2.

[0083] Fig.10 1 is a block diagram showing the configuration of a radar device 1A according to Embodiment 2. The radar device 1A includes a processing unit 13, a first radar 14a, and a second radar 14b. Fig.10 , a radar device having two radars is described, but this is an example. The radar device 1A may also be a structure having three or more radars. In addition, the first radar 14a and the second radar 14b may be arranged in the vicinity or separately as long as they are located at a position where they can observe the same observation object.

[0084] The first radar 14a and the second radar 14b transmit frequency modulated signals whose frequencies change linearly with the passage of time as radar signals, and receive reflected waves of the radar signals reflected by the observation object. The processing unit 13 outputs a control signal for specifying parameters to the first radar 14a and the second radar 14b, and the parameters determine the transmission cycle of the radar signal and the transmission waveform of the radar signal. The first radar 14a and the second radar 14b transmit radar signals with frequency gradients different from each other in space with the passage of time according to the control signal from the processing unit 13.

[0085] The first radar 14a and the second radar 14b generate a beat signal having a frequency equal to the difference between the frequency of the radar signal and the frequency of the reflected wave, convert the generated beat signal into digital data, and output it to the processing unit 13. The processing unit 13 calculates distance-speed information indicating the distance to the observed object and the relative speed with the observed object using the digital data of the beat signal output from the first radar 14a and the second radar 14b, and detects the observed object based on the distance-speed information.

[0086] Fig.11 14a and 14b are block diagrams showing the configurations of the first radar 14a and the second radar 14b. Fig.11 As shown in the figure, the first radar 14a and the second radar 14b include a radar control unit 31, a signal source 32, a distribution unit 33, a transmission antenna 34, a reception antenna 35, a frequency mixer 36, and an ADC 37, but do not include a calculation unit. The digital data of the beat signal converted by the ADC 37 is output to the processing unit 13. In addition, the radar control unit 31, the signal source 32, the distribution unit 33, the transmission antenna 34, the reception antenna 35, the frequency mixer 36, and the ADC 37 operate in the same manner as in the first embodiment.

[0087] Fig.12 1 is a block diagram showing the structure of the processing unit 13. Fig.12 As shown in FIG. 1 , the processing unit 13 includes a control processing unit 21, a detection processing unit 22, a first calculation unit 38a, and a second calculation unit 38b. The control processing unit 21 outputs a control signal corresponding to each radar to the first radar 14a and the second radar 14b. The detection processing unit 22 distinguishes the detection result of the observation object included in the distance-speed information and the false detection result caused by electromagnetic noise based on the comparison result of the distance-speed information output from the first calculation unit 38a and the distance-speed information output from the second calculation unit 38b.

[0088] The first calculation unit 38a is a calculation unit provided corresponding to the first radar 14a, and the second calculation unit 38b is a calculation unit provided corresponding to the second radar 14b. Figure 4The calculation unit 38 shown in the figure similarly includes a first spectrum calculation unit 41, a second spectrum calculation unit 42, a frequency extraction unit 43, and a distance speed information calculation unit 44. The control signal output from the control processing unit 21 to the first radar 14a is also output to the first calculation unit 38a, and the control signal output from the control processing unit 21 to the second radar 14b is also output to the second calculation unit 38b. Fig.12 , the second calculation unit 38b is shown as receiving the control signal via the first calculation unit 38a, but the present invention is not limited thereto. For example, the second calculation unit 38b and the control processing unit 21 may be connected in a manner capable of transmitting signals, and the second calculation unit 38b may directly receive the control signal from the control processing unit 21.

[0089] The first calculation unit 38a uses the control signal from the control processing unit 21 and the digital data of the beat signal from the first radar 14a, and the first spectrum calculation unit 41, the second spectrum calculation unit 42, the frequency extraction unit 43 and the distance speed information calculation unit 44 calculate the distance speed information according to the control signal from the control processing unit 21 and the digital data of the beat signal from the first radar 14a. Figure 6 The second calculation unit 38b uses the control signal from the control processing unit 21 and the digital data of the beat signal from the second radar 14b, and the first spectrum calculation unit 41, the second spectrum calculation unit 42, the frequency extraction unit 43 and the distance speed information calculation unit 44 are used to calculate the distance speed information. Figure 6 The steps shown are to calculate distance speed information.

[0090] Fig.13 is shown as Fig.12 A block diagram of the structure of a processing unit 13A of a modified example of the processing unit 13 is shown. Fig.13 As shown in FIG. 1 , the processing unit 13A includes a control processing unit 21, a detection processing unit 22, a first calculation unit 23, and a second calculation unit 24. The control processing unit 21 outputs a control signal corresponding to each radar to the first radar 14a and the second radar 14b. The detection processing unit 22 distinguishes the detection result of the observation object included in the distance-speed information and the false detection result caused by electromagnetic noise based on the comparison result of the distance-speed information output from the first calculation unit 23 and the distance-speed information output from the second calculation unit 24.

[0091] The first calculation unit 23 is a calculation unit provided corresponding to the first radar 14a, and the second calculation unit 24 is a calculation unit provided corresponding to the second radar 14b. The control signal output from the control processing unit 21 to the first radar 14a is also output to the first calculation unit 23, and the control signal output from the control processing unit 21 to the second radar 14b is also output to the second calculation unit 24. Fig.13, the second calculation unit 24 is shown as receiving the control signal via the first calculation unit 23, but the present invention is not limited thereto. For example, the second calculation unit 24 and the control processing unit 21 may be connected to each other in a signal-transmitting manner, and the second calculation unit 24 may receive the control signal directly from the control processing unit 21.

[0092] Fig.14 is a block diagram showing the structure of the first calculation unit 23. Fig.14 As shown in FIG. 1 , the first calculation unit 23 includes a first spectrum calculation unit 41a, a second spectrum calculation unit 42a, a frequency extraction unit 43a, and a distance speed information calculation unit 44a. The first spectrum calculation unit 41a performs Fourier transform on the digital data of the beat signal output from the ADC 37 of the first radar 14a in the distance direction, for each transmission cycle of the radar signal represented by the control signal, thereby calculating a plurality of first spectrums. In addition, the first spectrum calculation unit 41a outputs the control signal from the control processing unit 21 to the second radar 14b to the second calculation unit 24.

[0093] The second spectrum calculation unit 42a calculates the second spectrum by Fourier transforming the plurality of first spectrums calculated by the first spectrum calculation unit 41a in the relative speed direction. The frequency extraction unit 43a extracts the beat frequency and Doppler frequency corresponding to the peak of the second spectrum, and outputs the extracted beat frequency and Doppler frequency to the range-speed information calculation unit 44a. In addition, the frequency extraction unit 43a also outputs the extracted beat frequency to the second calculation unit 24.

[0094] The distance-speed information calculation unit 44a calculates the distance R to the observation object based on the beat frequency output from the frequency extraction unit 43a, and calculates the relative speed v with respect to the observation object based on the Doppler frequency output from the frequency extraction unit 43a. The distance-speed information calculation unit 44a outputs the distance-speed information indicating the calculated distance R and relative speed v to the detection processing unit 22.

[0095] Fig.15 2 is a block diagram showing the structure of the second calculation unit 24. Fig.15 As shown, the second calculation unit 24 includes a first spectrum calculation unit 41b, a second spectrum calculation unit 42b, a frequency extraction unit 43b, and a distance speed information calculation unit 44b. The first spectrum calculation unit 41b performs Fourier transform on the digital data of the beat signal output from the ADC 37 of the second radar 14b in the distance direction, for each transmission cycle of the radar signal represented by the control signal input via the first calculation unit 23, thereby calculating a plurality of first spectrums.

[0096] The second spectrum calculation unit 42b calculates a second spectrum by Fourier transforming only spectrum values ​​corresponding to the beat frequency extracted by the frequency extraction unit 43a among the spectrum values ​​included in the first spectrum calculated by the first spectrum calculation unit 41b in the relative speed direction.

[0097] The frequency extraction unit 43b extracts the beat frequency and Doppler frequency corresponding to the peak in the second frequency spectrum, and outputs the extracted beat frequency and Doppler frequency to the distance-speed information calculation unit 44b. The distance-speed information calculation unit 44b calculates the distance R to the observation object based on the beat frequency output from the frequency extraction unit 43b, and calculates the relative speed v with the observation object based on the Doppler frequency output from the frequency extraction unit 43b. The distance-speed information calculation unit 44b outputs the distance-speed information indicating the distance R and the relative speed v to the detection processing unit 22.

[0098] Fig.16 1 is an explanatory diagram showing an overview of the processing performed by the first calculation unit 23 and the second calculation unit 24. For the sake of simplicity, the radar device 1A shows a case where the observation object is one. However, the radar device 1A may also be two or more observation objects. Although one electromagnetic noise as a continuous wave with a fixed frequency is shown, a plurality of electromagnetic noises as continuous waves with fixed frequencies may be input to the ADC 37. Fig.16 In FIG. 1 , FFT(1) shows the Fourier transform in the distance direction, and FFT(2) shows the Fourier transform in the relative speed direction.

[0099] In the first calculation unit 23, the second spectrum calculation unit 42a uses Figure 7 And follow the above steps, such as Fig.16 The second spectrum A including the spectrum value corresponding to the observation object and the spectrum value corresponding to the electromagnetic noise is calculated as shown in FIG. The frequency extracting unit 43a extracts the beat frequency F corresponding to the peak value in the second spectrum A. sb＿r＿a and Doppler frequency F sb＿v＿a , the extracted beat frequency F sb＿r＿a and Doppler frequency F sb＿v＿a The beat frequency F is output to the distance speed information calculation unit 44a. sb＿r＿a Output to the second calculation unit 24. Fig.16 In the information indicating the beat frequency output from the frequency extracting unit 43a to the second calculating unit 24, in addition to the beat frequency F corresponding to the distance R from the observation object, sb＿r＿a1 In addition, it also includes the beat frequency F corresponding to the frequency of electromagnetic noise sb＿r＿a2 .

[0100] In the second calculation unit 24, the first spectrum calculation unit 41b uses Figure 8According to the above steps, the digital data of the beat signal B is Fourier transformed in the distance direction, thus Fig.16 The K first spectra B are calculated as shown. The K first spectra B are output to the second spectrum calculation unit 42b. The second spectrum calculation unit 42b calculates only the spectrum values ​​included in the K first spectra B in the relative speed direction, which are in agreement with the beat frequency F output from the frequency extraction unit 43a. sb＿r＿a1 and F sb＿r＿a2 The corresponding spectrum values ​​are Fourier transformed, thereby calculating the second spectrum B.

[0101] exist Fig.16 In the embodiment, the frequency gradient of the radar signal (frequency modulation signal) transmitted from the second radar 14b is twice the frequency gradient of the radar signal transmitted from the first radar 14a, and the distance resolution is doubled. The second spectrum calculation unit 42b calculates the frequency spectrum values ​​corresponding to the beat frequency F in the relative speed direction from among the plurality of spectrum values ​​included in the K first spectrums B. sb＿r＿a1 and F sb＿r＿a2 The corresponding spectrum values ​​at four locations are Fourier transformed, thus, Fig.16 Four second spectra B are calculated as shown.

[0102] The frequency extraction unit 43b extracts the beat frequencies F corresponding to the four peaks in the second spectrum B. sb＿r＿b and Doppler frequency F sb＿v＿b , the extracted beat frequency F sb＿r＿b and Doppler frequency F sb＿v＿b The distance-speed information calculation unit 44b uses the beat frequency F extracted from the four second frequency spectra B to calculate the distance-speed information. sb＿r＿b and Doppler frequency F sb＿v＿b , according to the above formula (3) to the above formula (6), calculate the distance speed information.

[0103] The detection processing unit 22 distinguishes the detection result of the observation object contained in the distance and speed information and the false detection result caused by electromagnetic noise based on the comparison result of the distance and speed information from the first calculation unit 23 and the distance and speed information from the second calculation unit 24. For example, when the detection processing unit 22 determines that the distance and relative speed represented by the distance and speed information of both parties are consistent, the distance and relative speed represented by these distance and speed information are determined as the detection result of the observation object. In addition, when the detection processing unit 22 determines that the distance and relative speed represented by the distance and speed information are inconsistent, it is determined that it is a false detection result caused by electromagnetic noise.

[0104] Next, a hardware configuration for realizing the functions of the radar device 1A will be described.

[0105] The functions of the control processing unit 21, the detection processing unit 22, the first calculation unit 38a, and the second calculation unit 38b in the radar device 1A are implemented by the processing circuit. Figure 5 The processing circuit of each process from step ST1 to step ST4 shown in the figure may be dedicated hardware or a CPU (Central Processing Unit) that executes a program stored in a memory.

[0106] Fig.17A It shows the realization Fig.10 A block diagram of the functional hardware structure of the radar device 1A. Fig. 17B It shows the implementation Fig.10 This is a block diagram of the hardware and software structure of the radar device 1A. Fig.17A and Fig. 17B In the embodiment, the input interface 100 is, for example, an interface for relaying digital data of beat signals output from the first radar 14a and the second radar 14b and inputting it to the processing unit 13. The output interface 101 is an interface for relaying a control signal output from the processing unit 13 and outputting it to the first radar 14a and the second radar 14b.

[0107] The processing circuit is Fig.17A In the case of the dedicated hardware processing circuit 102 shown, the processing circuit 102 corresponds to, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a combination thereof. The functions of the control processing unit 21, the detection processing unit 22, the first calculation unit 38a, and the second calculation unit 38b in the radar device 1A may be implemented by different processing circuits or may be implemented by one processing circuit.

[0108] The processing circuit is Fig. 17B In the case of the processor 103 shown in FIG. 1 , the functions of the control processing unit 21, the detection processing unit 22, the first calculation unit 38a, and the second calculation unit 38b in the radar device 1A are implemented by software, firmware, or a combination of software and firmware. In addition, the software or firmware is described in the form of a program and stored in the memory 104.

[0109] The processor 103 realizes the functions of the control processing unit 21, the detection processing unit 22, the first calculation unit 38a, and the second calculation unit 38b in the radar device 1A by reading and executing the program stored in the memory 104. For example, the radar device 1A includes the memory 104 for storing the program, and the program is executed when the processor 103 executes the program. Figure 5 The memory 104 may be a computer-readable storage medium storing a program for causing the computer to function as the control processing unit 21, the detection processing unit 22, the first calculation unit 38a, and the second calculation unit 38b.

[0110] The memory 104 corresponds to, for example, nonvolatile or volatile semiconductor memories such as RAM (Random Access Memory), ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable ROM), EEPROM (Electrically-EPROM), magnetic disks, floppy disks, optical disks, high-density disks, mini disks, DVDs, etc.

[0111] The functions of the control processing unit 21, the detection processing unit 22, the first calculation unit 38a, and the second calculation unit 38b in the radar device 1A may be partially realized by dedicated hardware and partially realized by software or firmware. For example, the control processing unit 21 and the detection processing unit 22 realize their functions by the processing circuit 102 as dedicated hardware, and the first calculation unit 38a and the second calculation unit 38b realize their functions by the processor 103 reading and executing the program stored in the memory 104. In this way, the processing circuit can realize the above functions by hardware, software, firmware, or a combination thereof.

[0112] As described above, in the radar device 1A of the second embodiment, the processing unit 13 includes the first calculation unit 38a and the second calculation unit 38b. The first calculation unit 38a calculates the distance speed information using the digital data of the beat signal output from the first radar 14a, and the second calculation unit 38b calculates the distance speed information using the digital data of the beat signal output from the second radar 14b. The processing unit 13 uses the distance speed information calculated by the first calculation unit 38a and the distance speed information calculated by the second calculation unit 38b to distinguish the detection result and the false detection result of the observed object. Thus, the radar device 1A can distinguish the false detection caused by electromagnetic noise in the same way as in the first embodiment.

[0113] In the radar device 1A of the second embodiment, the second spectrum calculation unit 42b performs Fourier transform on the digital data corresponding to the beat frequency extracted by the frequency extraction unit 43a in the digital data of the first spectrum B in the relative speed direction, thereby calculating the second spectrum B. The frequency extraction unit 43a extracts the beat frequency and Doppler frequency corresponding to the peak of the second spectrum B, and outputs the extracted beat frequency to the second spectrum calculation unit 42b. As a result, the radar device 1A can reduce the processing load required for calculating the second spectrum compared to the radar device 1 of the first embodiment. However, this is an example, and the second spectrum calculation unit 42b shown in the first embodiment is not limited to the second spectrum calculation unit 42b. Figure 4 The beat frequency information calculated by the distance-speed information calculation unit 44 of one of the radars may also be used by the distance-speed information calculation unit 44 of the radars other than the radar. The beat frequency information output from the distance-speed information calculation unit 44 may be input via the processing unit 11 or directly from the radar.

[0114] Furthermore, when the processing unit 13A includes three or more calculation units, the beat frequency information extracted by the frequency extraction unit included in any calculation unit may be used by the second spectrum calculation units included in the remaining calculation units.

[0115] Implementation method 3.

[0116] Fig.18 1 is a block diagram showing the structure of a vehicle-mounted device according to Embodiment 3. The vehicle-mounted device 10 is mounted on a vehicle such as a car. Fig.18 As shown, the vehicle includes a radar device 1 or 1A and a control unit 60. The control unit 60 controls the engine, steering wheel, brakes or various sensors of the vehicle. Among the various sensors, there are radar devices, laser radars, cameras or ultrasonic sensors that are separately provided from the radar device 1 or 1A.

[0117] The control unit 60 obtains electromagnetic noise information in the controlled device and outputs the electromagnetic noise information to the radar device 1 or 1A. The electromagnetic noise information may be information indicating the presence of electromagnetic noise or information indicating the frequency of electromagnetic noise. In the radar device 1 or 1A, the first radar and the second radar perform independent individual actions or cooperative actions. For example, the cooperative action is an action in which the radars cooperate with each other to increase the detection function of the observed object to a higher resolution.

[0118] The radar device 1 or 1A transmits a frequency modulation signal having frequency gradients different from each other as a radar signal by using a first radar and a second radar. A calculation unit included in the radar device 1 or 1A calculates a first frequency spectrum and a second frequency spectrum, and calculates distance-speed information for each radar based on a beat frequency and a Doppler frequency corresponding to a peak of the second frequency spectrum. A processing unit included in the radar device 1 or 1A distinguishes a detection result of an observation object included in the distance-speed information from a false detection result caused by electromagnetic noise based on a comparison result of the distance-speed information calculated for each radar.

[0119] For example, in the case where electromagnetic noise is not generated in the previous stage of obtaining electromagnetic noise information from the control unit 60, the radar device 1 or 1A causes the first radar and the second radar to operate independently and transmit frequency modulated signals with the same frequency gradient, thereby detecting the observed object. When electromagnetic noise is generated and electromagnetic noise information is obtained from the control unit 60, the radar device 1 or 1A causes the first radar and the second radar to operate in cooperation and transmit frequency modulated signals with different frequency gradients, thereby detecting the observed object described in the first or second embodiment. The radar device 1 or 1A distinguishes the detection result of the observed object included in the distance speed information and the false detection result caused by the electromagnetic noise, and therefore outputs only the detection result of the observed object. In this way, the processing of the radar device 1 or 1A is switched according to whether electromagnetic noise is generated, thereby effectively utilizing the resources of the radar device.

[0120] The processing unit of the radar device 1 or 1A may output the distance R from the observation object and the relative speed v between the observation object and the observation object to the control unit 60, or may output the false detection result caused by electromagnetic noise to the control unit 60. For example, the control unit 60 uses the distance R and the relative speed v to predict the distance from the car equipped with the vehicle-mounted device 10 to the observation object, and determines the possibility of contact between the car and the observation object based on the prediction result. When the control unit 60 determines that the possibility of contact between the car and the observation object is high, the driving of the car is controlled to avoid contact with the observation object. For example, the control unit 60 operates the brakes of the car, or controls the steering wheel to switch the direction of travel of the car.

[0121] The control unit 60 can use the detection information of objects existing around the vehicle detected by various sensors, as well as the distance R from the observation object and the relative speed v between the observation object and the observation object obtained from the radar device 1 or 1A, to predict the state of the vehicle's forward route in sequence, and perform automatic driving of the vehicle based on the prediction results.

[0122] Since the radar device 1 or 1A distinguishes the detection result of the observed object and the false detection result caused by electromagnetic noise, it is possible to output only the detection result of the observed object. However, depending on the generation condition of electromagnetic noise, there is a possibility that the above-mentioned distinction is reduced. For example, when the number of peaks corresponding to the false detection results caused by electromagnetic noise in the second spectrum exceeds the threshold, the processing unit of the radar device 1 or 1A determines that the reliability of the detection result (distance R and relative speed v) of the observed object is low, and when it is below the threshold, it determines that the reliability of the detection result of the observed object is high.

[0123] When the control unit 60 determines that the reliability of the detection result of the observation object obtained from the radar device 1 or 1A is high, the control unit 60 uses the distance R and the relative speed v indicated by the detection result of the observation object to perform the automatic driving of the vehicle. When the control unit 60 determines that the reliability of the detection result of the observation object is low, the control unit 60 uses the detection result of other sensors (for example, laser radar or camera) mounted on the vehicle to perform the automatic driving in priority to the detection result of the observation object.

[0124] As described above, in the vehicle-mounted device 10 of the third embodiment, when the electromagnetic noise information is output from the control unit 60, the radar device 1 or 1A transmits frequency modulation signals having frequency gradients different from each other as radar signals through the first radar and the second radar, thereby detecting the observation object described in the first embodiment or the second embodiment. The radar device 1 or 1A can be operated based on the electromagnetic noise information obtained by the control unit 60.

[0125] In the vehicle-mounted device 10 of Embodiment 3, the control unit 60 controls the vehicle based on the detection results of the distance R from the observation object and the relative speed v with the observation object, and the false detection results caused by electromagnetic noise. Thus, the control unit 60 can control the vehicle according to the generation status of electromagnetic noise.

[0126] In addition, in the combination of each embodiment, or in the modification of arbitrary constituent elements of each embodiment, or in each embodiment, arbitrary constituent elements may be omitted.

[0127] Industrial Applicability

[0128] The radar device of the present disclosure can be used as a sensor mounted on a vehicle to detect obstacles, for example.

[0129] Description of Reference Numerals

[0130] 1, 1A radar device, 10 vehicle-mounted device, 11, 13, 13A processing unit, 12a, 14a first radar, 12b, 14b second radar, 21 control processing unit, 22 detection processing unit, 23, 38a first calculation unit, 24, 38b second calculation unit, 31 radar control unit, 32 signal source, 33 distribution unit, 34 transmitting antenna, 35 receiving antenna, 36 frequency mixing unit, 37 ADC, 38 calculation unit, 41, 41a, 41b first spectrum calculation unit, 42, 42a, 42b second spectrum calculation unit, 43, 43a, 43b frequency extraction unit, 44, 44a, 44b distance and speed information calculation unit, 60 control unit, 100 input interface, 101 output interface, 102 processing circuit, 103 processor, 104 memory.

Claims

1. A radar device, characterized in that: The radar device comprises: A plurality of radars that transmit frequency modulated signals whose frequencies change linearly with the passage of time as radar signals, and receive reflected waves of the radar signals reflected from an observation object; a calculation unit that calculates distance-speed information indicating a distance to the observation object and a relative speed to the observation object using digital data of a beat signal having a frequency that is a difference between a frequency of the radar signal and a frequency of the reflected wave; and a processing unit that detects the observed object based on the distance and speed information, The plurality of radars transmit, as the radar signals, frequency modulation signals different from each other except that the ratio of the absolute value of the frequency gradient accompanying the passage of time is 1. The calculation unit calculates a first spectrum obtained by Fourier transforming digital data of the beat signal in a distance direction and a second spectrum obtained by Fourier transforming the first spectrum in a relative speed direction, and calculates the distance speed information for each radar based on a beat frequency and a Doppler frequency corresponding to a peak in the second spectrum. The processing unit compares the distance and speed information calculated according to each of the radars. If the distance and speed included in the distance and speed information are consistent between the radars, the processing unit determines the distance and speed included in the distance and speed information as the distance to the observation object and the relative speed with the observation object. If the distance and speed included in the distance and speed information are inconsistent between the radars due to a difference corresponding to a difference in frequency gradient of the radar signal, the processing unit determines the distance and speed included in the distance and speed information as a false detection result caused by electromagnetic noise.

2. The radar device according to claim 1, characterized in that A plurality of said radars have: a beat signal generating unit that generates the beat signal; and a conversion unit that converts the beat signal into digital data and outputs the digital data, The calculation unit has: a first spectrum calculation unit that calculates the first spectrum obtained by Fourier transforming the digital data of the beat signal output from the conversion unit in a distance direction; a second spectrum calculation unit that calculates the second spectrum obtained by Fourier transforming the first spectrum in a relative speed direction; a frequency extraction unit configured to extract a beat frequency and a Doppler frequency corresponding to the peak from the second frequency spectrum; as well as A range-velocity information calculation unit calculates the range-velocity information based on a beat frequency and a Doppler frequency corresponding to the peak.

3. The radar device according to claim 2, characterized in that The processing unit includes the calculation unit for each of the radars.

4. The radar device according to claim 3, characterized in that The second spectrum calculation unit calculates the second spectrum by performing Fourier transform on a spectrum value corresponding to the beat frequency corresponding to the peak among a plurality of spectrum values ​​of the first spectrum in the relative speed direction, The frequency extraction unit extracts a beat frequency and a Doppler frequency corresponding to the peak, and outputs the extracted beat frequency to the second spectrum calculation unit.

5. An observation object detection method, which is an observation object detection method of a radar device, wherein the radar device transmits frequency modulation signals different from each other, whose absolute value ratio of frequency gradients accompanying the passage of time is other than 1, as radar signals through multiple radars, and receives reflected waves of the radar signals reflected at the observation object, characterized in that: The observed object detection method comprises the following steps: a calculation unit calculating a first frequency spectrum obtained by Fourier transforming digital data of a beat signal in a distance direction and a second frequency spectrum obtained by Fourier transforming the first frequency spectrum in a relative speed direction, and calculating distance-speed information indicating a distance to the observation object and a relative speed with the observation object for each of the radars based on a beat frequency and a Doppler frequency corresponding to a peak in the second frequency spectrum, wherein the beat signal has a frequency that is a difference between a frequency of the radar signal and a frequency of the reflected wave; and The processing unit compares the distance and speed information calculated according to each of the radars. If the distance and speed included in the distance and speed information are consistent between the radars, the processing unit determines that the distance and speed included in the distance and speed information are the distance to the observation object and the relative speed with the observation object. If the distance and speed included in the distance and speed information are inconsistent between the radars due to a difference corresponding to a difference in the frequency gradient of the radar signal, the processing unit determines that the distance and speed included in the distance and speed information are a false detection result caused by electromagnetic noise.

6. A vehicle-mounted device, characterized in that: The vehicle-mounted device comprises: A radar device according to any one of claims 1 to 4 mounted on a vehicle; as well as a control unit mounted on the vehicle, acquiring electromagnetic noise information and outputting the information to the radar device, When the electromagnetic noise information is output from the control unit, The plurality of radars transmit frequency modulated signals having frequency gradients different from each other as the radar signals, The calculation unit calculates the first frequency spectrum and the second frequency spectrum, and calculates the range speed information for each of the radars based on a beat frequency and a Doppler frequency corresponding to a peak in the second frequency spectrum. The processing unit compares the distance and speed information calculated according to each of the radars. If the distance and speed included in the distance and speed information are consistent between the radars, the processing unit determines the distance and speed included in the distance and speed information as the distance to the observation object and the relative speed with the observation object. If the distance and speed included in the distance and speed information are inconsistent between the radars due to a difference corresponding to a difference in frequency gradient of the radar signal, the processing unit determines the distance and speed included in the distance and speed information as a false detection result caused by electromagnetic noise.

7. The vehicle-mounted device according to claim 6, characterized in that: The control unit controls the vehicle based on the detection results of the distance to the observation object and the relative speed to the observation object output from the processing unit and the false detection result caused by electromagnetic noise.

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