Radar device and vehicle-mounted device having a radar device

Abstract

A radar apparatus (90) of the present technology has: a radar signal output section (1) that intermittently repeatedly outputs a linear frequency modulation as a radar signal; a transmission / reception section (4) that transmits the radar signal and receives the radar signal reflected from an observation target as a reflected wave; a beat signal generation section (8) that generates a beat signal from the radar signal and the reflected wave; an analog / digital conversion section (11) that converts the beat signal into digital data; and a signal processing section (12) that detects a range and a relative velocity of the observation target using the digital data. The signal processing section (12) includes: a frequency conversion section (31) that frequency-converts the digital data in a period in which the radar signal is not outputted among the digital data; a spectrum calculation section (41) that adds the digital data in a period in which the radar signal is outputted among the digital data and the digital data after the frequency conversion by the frequency conversion section (31), and performs a range FFT; a range-velocity spectrum calculation section (42) that performs a Doppler FFT on a first half of a result after the range FFT by the spectrum calculation section (41); and an electromagnetic noise spectrum calculation section (43) that performs a Doppler FFT on a second half of the result after the range FFT by the spectrum calculation section (41).

Description

TECHNICAL FIELD

[0001] The present technology relates to a radar device. BACKGROUND

[0002] A radar device of an FMCW (Frequency Modulated Continuous Wave) system is disclosed in Patent Literature 1.

[0003] The radar device disclosed in Patent Literature 1 distributes a radar signal modulated by FM (Frequency Modulated) to a transmission signal and a local signal, transmits the transmission signal as an electromagnetic wave, and receives an electromagnetic wave reflected by a target as a reflected wave.

[0004] The radar device disclosed in Patent Literature 1 measures a distance to an observation object and a relative velocity with the observation object based on digital data of a beat signal obtained by mixing a reception signal of the reflected wave and the local signal.

[0005] The radar device disclosed in Patent Literature 1 performs a process shown below, so that even if electromagnetic noise is input to an AD conversion section, it is possible to suppress deterioration of detection accuracy of the observation object and measure a true distance to the observation object and a true relative velocity with the observation object.

[0006] The radar device disclosed in Patent Literature 1 sets a period during which the radar signal is transmitted and a period during which the radar signal is not transmitted.

[0007] The radar device disclosed in Patent Literature 1 detects the observation object using digital data of the beat signal obtained in the period during which the radar signal is transmitted and digital data of a signal input to the AD conversion section in the period during which the radar signal is not transmitted, thereby preventing false detection of the target.

[0008] The radar device disclosed in Patent Literature 1 performs Fourier transform on a plurality of pieces of digital data in the period during which the transmission radar signal is repeatedly output in the distance direction, thereby measuring a plurality of frequency spectra of the observation object, performs Fourier transform on the plurality of measured frequency spectra in the relative velocity direction, thereby calculating a range-velocity spectrum of the observation object, detects a peak value of a spectrum value in the measured range-velocity spectrum, and thereby calculates range-velocity information. The Fourier transform in the distance direction is also referred to as Range-FFT, range FFT (hereinafter, referred to as "range FFT" in the present specification). Further, the Fourier transform in the relative velocity direction is also referred to as Doppler-FFT, Doppler FFT (hereinafter, referred to as "Doppler FFT" in the present specification).

[0009] Further, a plurality of frequency spectrums of the electromagnetic noise are calculated by performing a range FFT on the plurality of digital data in the period during which the radar signal is not transmitted, respectively, a plurality of Doppler spectrums are calculated by performing a Doppler FFT on the plurality of frequency spectrums obtained, a peak value of a spectrum value in the electromagnetic noise spectrum obtained is detected, and electromagnetic noise information is calculated.

[0010] Prior art document

[0011] Patent document

[0012] Patent document 1: International Publication No. 2020 / 165952 SUMMARY

[0013] Problems to be solved by the invention

[0014] The radar device of the prior art exemplified by Patent Document 1 detects an observation object using the same processing in range-velocity information and the electromagnetic noise information, and performs a plurality of Fourier transforms.

[0015] The present technology aims to reduce the number of Fourier transforms in a radar device and to reduce the signal processing load.

[0016] Means for solving the problem

[0017] The radar device of the present technology has: a radar signal output section that repeatedly outputs a linear frequency modulation as a radar signal intermittently; a transmission-reception section that transmits the radar signal and receives the radar signal reflected from an observation object as a reflected wave; a beat signal generation section that generates a beat signal based on the radar signal and the reflected wave; an analog-digital conversion section that converts the beat signal into digital data; and a signal processing section that detects a range and a relative velocity of the observation object using the digital data. The signal processing section includes: a frequency conversion section that performs a frequency conversion on the digital data in a period during which the radar signal is not output; a spectrum calculation section that adds the digital data in a period during which the radar signal is output and the digital data after the frequency conversion by the frequency conversion section and performs a range FFT; a range-velocity spectrum calculation section that performs a Doppler FFT on a first half of a result after the range FFT by the spectrum calculation section; and an electromagnetic noise spectrum calculation section that performs a Doppler FFT on a second half of the result after the range FFT by the spectrum calculation section.

[0018] Effects of the invention

[0019] The radar device of the present technology has the above structure, and thus can uniformly perform a range FFT at the same time in a period during which a radar signal is transmitted and a period during which a radar signal is not transmitted, and can reduce the number of Fourier transforms. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a configuration diagram showing a configuration of a radar device of Embodiment 1.

[0021] Figure 2 is a configuration diagram showing a configuration of a signal processing section of the radar device of Embodiment 1.

[0022] Figure 3 is a flowchart showing a calculation process of a distance to an observation object and a relative velocity between the observation object in the signal processing section of Embodiment 1.

[0023] Figure 4 is an explanatory diagram showing the calculation process of the distance to the observation object and the relative velocity between the observation object in the signal processing section of Embodiment 1.

[0024] Figure 5 is a configuration diagram showing a configuration of a radar device of Embodiment 2.

[0025] Figure 6 is a configuration diagram showing a configuration of a signal processing section of the radar device of Embodiment 2.

[0026] Figure 7 is a flowchart showing a calculation process of a distance to an observation object and a relative velocity between the observation object in the signal processing section of Embodiment 2.

[0027] Figure 8 is a configuration diagram showing a configuration of a signal processing section of a radar device of Embodiment 3.

[0028] Figure 9 is a flowchart showing a calculation process of a distance to an observation object and a relative velocity between the observation object in the signal processing section of Embodiment 3.

[0029] Figure 10 is an explanatory diagram showing the calculation process of the distance to the observation object and the relative velocity between the observation object in the signal processing section of Embodiment 3.

[0030] Figure 11 is a configuration diagram showing a configuration of a radar device of Embodiment 4.

[0031] Figure 12 is a configuration diagram showing a configuration of a signal processing section of the radar device of Embodiment 4.

[0032] Figure 13 is a flowchart showing a calculation process of a distance to an observation object and a relative velocity between the observation object in the signal processing section of Embodiment 4.

[0033] Figure 14 is a configuration diagram showing a configuration of a signal processing section of the radar apparatus of Embodiment 5.

[0034] Figure 15 is a configuration diagram showing a configuration of a signal processing section of the radar apparatus of Embodiment 6.

[0035] Figure 16 is a flowchart showing a calculation process of a distance to an observation object and a relative velocity between the observation object in the signal processing section of Embodiment 6.

[0036] Figure 17 is an explanatory diagram showing a calculation process of a distance to an observation object and a relative velocity between the observation object in the signal processing section of Embodiment 6.

[0037] Figure 18 is a configuration diagram showing a configuration of an in-vehicle apparatus of Embodiment 7. DETAILED DESCRIPTION

[0038] Embodiment 1

[0039] Figure 1 is a configuration diagram showing a configuration of the radar apparatus 90 of Embodiment 1. As shown in Figure 1 , the radar apparatus 90 of Embodiment 1 includes a radar signal output section 1, a transmission / reception section 4, a beat signal generation section 8, an analog / digital conversion section 11, and a signal processing section 12.

[0040] The radar signal output section 1 has a control section 2 and a signal source 3.

[0041] The transmission / reception section 4 has an allocation section 5, a transmission antenna 6, and a reception antenna 7.

[0042] The beat signal generation section 8 has a frequency mixing section 9 and a filter section 10.

[0043] The radar signal output section 1 is a structural element that generates a radar signal. The radar signal generated by the radar signal output section 1 is, for example, a frequency modulation signal whose frequency changes with the passage of time. The radar signal is intermittently repeatedly generated and is sent to the transmission / reception section 4.

[0044] The control section 2 has a function of generating a timing signal and synchronizing each section of the radar apparatus 90. Specifically, the control section 2 outputs a control signal indicating an output timing of a radar signal to the signal source 3 and the signal processing section 12, respectively.

[0045] The signal source 3 intermittently repeatedly generates a frequency modulation signal as a radar signal, for example, in accordance with an output timing indicated by the control signal output from the control section 2. The generated radar signal is output to the allocation section 5 of the transmission / reception section 4.

[0046] The transmission / reception section 4 transmits the radar signal output from the radar signal output section 1 toward an observation object, and receives the radar signal reflected by the observation object as a reflected wave. For example, in a case where the radar device 90 is mounted on a vehicle such as an automobile, the observation object is another automobile, a pedestrian, a guardrail, or the like.

[0047] The transmission / reception section 4 outputs the radar signal output from the radar signal output section 1 and the reflected wave to the beat signal generation section 8, respectively.

[0048] The distribution section 5 distributes the radar signal output from the signal source 3 into two, outputs one of the distributed radar signals to the transmission antenna 6, and outputs the other of the distributed radar signals to the frequency mixing section 9 as a local oscillation signal.

[0049] The transmission antenna 6 radiates the radar signal output from the distribution section 5 to space.

[0050] The reception antenna 7 receives the radar signal reflected by the observation object as a reflected wave after the radar signal is radiated to space from the transmission antenna 6, and outputs a reception signal of the received reflected wave to the frequency mixing section 9.

[0051] The beat signal generation section 8 generates a beat signal when the radar signal reflected by the observation object is received as a reflected wave by the reception antenna 7 during a period in which the radar signal is transmitted from the transmission / reception section 4. The beat signal has a difference frequency between the frequency of the radar signal transmitted from the transmission antenna 6 and the frequency of the reflected wave. The beat signal can also be generated using a mixer as an IF signal.

[0052] The beat signal generation section 8 outputs the generated beat signal to the analog / digital conversion section 11.

[0053] The frequency mixing section 9 mixes the local oscillation signal and the reception signal output from the reception antenna 7 during a period in which the local oscillation signal is output from the distribution section 5. The frequency mixing section 9 generates a beat signal having a difference frequency between the frequency of the local oscillation signal and the frequency of the reflected wave, based on the mixed signal.

[0054] The frequency mixing section 9 outputs the generated beat signal to the filter section 10.

[0055] Specifically, the filter section 10 is implemented by a low-pass filter or a band-pass filter, or the like.

[0056] The filter section 10 suppresses unnecessary components such as spurs included in the beat signal output from the frequency mixing section 9. The beat signal after the suppression of the unnecessary components is sent to the analog / digital conversion section 11.

[0057] The analog-digital conversion section 11 converts the beat signal generated by the beat signal generation section 8 during the period in which the radar signal is transmitted, into digital data, and outputs it to the signal processing section 12.

[0058] The analog-digital conversion section 11 converts the signal input to the analog-digital conversion section 11 during the period in which the radar signal is not transmitted, into digital data, and outputs it to the signal processing section 12.

[0059] The signal processing section 12 calculates the distance to the observation object and the relative speed with the observation object using the digital data output from the analog-digital conversion section 11.

[0060] Figure 1 The radar apparatus 90 shown is not provided with an amplifier, but an amplifier can be provided, for example, on the input side of the transmission antenna 6 or on the output side of the reception antenna 7.

[0061] Figure 2 is a block diagram showing the structure of the signal processing section 12 of the radar apparatus 90 of Embodiment 1. As shown in Figure 2 The signal processing section 12 includes a frequency conversion section 31, a spectrum calculation section 41, a distance speed spectrum calculation section 42, an electromagnetic noise spectrum calculation section 43, a distance speed information calculation section 51, an electromagnetic noise information calculation section 52, and a detection processing section 53.

[0062] The frequency conversion section 31 refers to the control signal output from the control section 2, and determines the period in which the radar signal is not output from the radar signal output section 1.

[0063] The frequency conversion section 31 performs multiplication by a complex number on the digital data in the digital data output from the analog-digital conversion section 11, which is determined to be in the period in which the radar signal is not present. The complex number is a complex number corresponding to a signal having an amplitude of 1 at a frequency (f0= (n-1 / 2)fs) of n-1 / 2 times (n is an arbitrary integer) the sampling frequency fs. If expressed in mathematical formula, the complex number is exp(jω0t). Multiplying the data expressed on the time axis by the complex number expressed on the unit circle of exp(jω0t) is equivalent to shifting the angular frequency by ω0=2πf0 in the result of the Fourier transform expressed on the frequency axis. The present technology utilizes this property of the Fourier transform. Specifically, the present technology distinguishes only the data in the period in which the radar signal is not output from among all the sampling data, by frequency shifting. Hereinafter, the complex number for frequency shifting is referred to as a "frequency shift complex number". The result after multiplication by the frequency shift complex number is sent to the spectrum calculation section 41. Note that the above is a description relating to the case of multiplication by a complex number in order to perform frequency shifting, but the present technology is not limited thereto. For example, the same effect can be obtained in the case of using the real part (for example, Cos(ω0t)) of the above frequency shift complex number.

[0064] During the period determined as the period in which the radar signal is not being output, the digital data from the analog-digital conversion section 11 is repeatedly output. The frequency conversion section 31 repeatedly performs the process of multiplying by the frequency shift complex number with respect to the plurality of digital data that are repeatedly output.

[0065] The spectrum calculation section 41 determines the period in which the radar signal is output from the radar signal output section 1 with reference to the control signal output from the control section 2.

[0066] The spectrum calculation section 41 adds the digital data in the period determined as the period in which the radar signal is being output from the digital data output from the analog-digital conversion section 11 and the digital data obtained from the frequency conversion section 31.

[0067] The spectrum calculation section 41 performs range FFT on the added data, thereby calculating a spectrum.

[0068] During the period determined as the period in which the radar signal is being output, the digital data from the analog-digital conversion section 11 and the digital data from the frequency conversion section 31 are repeatedly output. The spectrum calculation section 41 repeatedly performs the above-described addition process.

[0069] The spectrum calculation section 41 performs range FFT on the added digital data, respectively, thereby calculating a plurality of spectra.

[0070] The spectrum calculation section 41 outputs the calculated plurality of spectra to the range-velocity spectrum calculation section 42 and the electromagnetic noise spectrum calculation section 43.

[0071] The range-velocity spectrum calculation section 42 acquires the plurality of spectra output from the spectrum calculation section 41.

[0072] The range-velocity spectrum calculation section 42 performs Doppler FFT on the data of the first half of the acquired plurality of spectra, which corresponds to 1 / 2 or less of the sampling frequency fs, thereby calculating a range-velocity spectrum.

[0073] The range-velocity spectrum calculation section 42 outputs the range-velocity spectrum to the range-velocity information calculation section 51.

[0074] The electromagnetic noise spectrum calculation section 43 acquires the plurality of spectra output from the spectrum calculation section 41.

[0075] The electromagnetic noise spectrum calculation section 43 performs Doppler FFT on the data of the second half of the acquired plurality of spectra, which corresponds to 1 / 2 or more to 1 or less of the sampling frequency fs, thereby calculating an electromagnetic noise spectrum.

[0076] The electromagnetic noise spectrum calculation section 43 outputs the electromagnetic noise spectrum to the electromagnetic noise information calculation section 52.

[0077] The range-velocity information calculation section 51 detects a peak of a spectrum value in the range-velocity spectrum output from the range-velocity spectrum calculation section 42.

[0078] The distance velocity information calculating section 51 outputs the beat frequency of the detected peak of the distance velocity and the Doppler frequency to the detection processing section 53, respectively.

[0079] The electromagnetic noise information calculating section 52 detects a peak of a spectrum value in the electromagnetic noise spectrum output from the electromagnetic noise spectrum calculating section 43.

[0080] The electromagnetic noise information calculating section 52 outputs the frequency of the detected peak of the electromagnetic noise and the Doppler frequency to the detection processing section 53, respectively.

[0081] The detection processing section 53 calculates the distance to the observation object and the relative velocity between the observation object using the two kinds of frequencies. The two kinds of frequencies are the beat frequency of the distance velocity calculated by the distance velocity information calculating section 51 and the Doppler frequency, and the frequency of the electromagnetic noise and the Doppler frequency calculated by the electromagnetic noise information calculating section 52.

[0082] The calculation processing of the distance to the observation object and the relative velocity between the observation object in the signal processing section 12 is clarified by the following specific description.

[0083] Figure 3 is a flowchart showing the calculation processing of the distance to the observation object and the relative velocity between the observation object in the signal processing section 12.

[0084] Figure 4 is an explanatory diagram showing the calculation processing of the distance to the observation object and the relative velocity between the observation object in the signal processing section 12.

[0085] In Figure 4 , Lo(1),..., Lo(K) are local oscillation signals output from the distribution section 5 to the frequency mixing section 9. In Figure 4 , the oscillation signal shows an up chirp, but is not limited thereto. The oscillation signal can also be a down chirp, and can also be a combination of an up chirp and a down chirp. The present technology employs an oscillation signal having an idle time in which the radar signal is not oscillated between a chirp and a chirp.

[0086] Rx(1),..., Rx(K) are reception signals output from the reception antenna 7 to the frequency mixing section 9.

[0087] K is an index number of the chirp, and is reset in accordance with each time range in which the Doppler FFT described later is performed. That is, K is the number of chirps in the time range in which the Doppler FFT is performed. K is an integer of 2 or more.

[0088] In the example of Figure 4 , the electromagnetic noise of the frequency-fixed continuous wave is input to the analog-digital conversion section 11.

[0089] The signal acquisition timing (1) refers to the timing of acquiring digital data output from the analog-to-digital converter 11 during the period of transmitting the radar signal. The signal acquisition timing (1) is included in the period of outputting the radar signal from the radar signal output unit 1, and the length of the signal acquisition timing (1) is approximately the same as one cycle of the local oscillation signal.

[0090] The signal acquisition timing (2) refers to the timing of acquiring digital data output from the analog-to-digital converter 11 during the period when no radar signal is transmitted. The length of the signal acquisition timing (2) is approximately the same as one cycle of the local oscillation signal.

[0091] T is the scan time of the local oscillator signal (Lo(k) (k = 1, ..., K)), which is in the microsecond range. BW is the bandwidth of the local oscillator signal (Lo(k)).

[0092] exist Figure 4 For simplicity, the example shown here has only one observation object. However, this is just one example; there can also be two or more observation objects. Figure 4 For the sake of simplicity, an example with one electromagnetic noise level is shown. However, this is just one example; two or more electromagnetic noise levels can also be input to the analog-to-digital converter 11.

[0093] The frequency conversion unit 31 determines the period during which radar signals are not output from the radar signal output unit 1 by referring to the control signal output from the control unit 2.

[0094] The frequency conversion unit 31 acquires digital data output from the analog-to-digital conversion unit 11 during the period when no radar signal is detected.

[0095] The frequency conversion unit 31 multiplies the digital data from the digital data output from the analog-to-digital conversion unit 11 during the period when no radar signal is determined by a complex frequency shift. There exists N... smpl (an even number of) data points multiplied by the complex frequency shift (more than 2) Figure 3 (Steps shown in ST11).

[0096] exist Figure 4 To simplify the explanation, an example is shown where the frequency is multiplied by a complex frequency shift of f0 = fs / 2. However, this is just one example; the frequency of the complex frequency shift only needs to be n-1 / 2 times the sampling frequency fs (where n is any integer).

[0097] The spectrum calculation unit 41 determines the period for outputting radar signals from the radar signal output unit 1 by referring to the control signal output from the control unit 2.

[0098] The spectrum calculation unit 41 acquires digital data output from the analog-to-digital converter 11 during the period when it is determined that a radar signal is being output.

[0099] The spectrum calculation unit 41 determines the period during which the radar signal is being output from the digital data output from the analog-to-digital converter 11. smpl The digital data and N obtained from the frequency conversion unit 31 smpl Add the numbers together.

[0100] The spectrum calculation unit 41 performs N on the summed digital data. smpl The range of points is FFT, from which the spectrum is calculated ( Figure 3 (Steps shown in ST12).

[0101] exist Figure 4 In this equation, FFT(1) denotes range FFT. By performing range FFT on the digital data, the spectral values ​​of the received signal (Rx(k) (k = 1, ..., K)) of the reflected wave are accumulated to the beat frequency (F) shown in the following equation (1). sb r ).

[0102]

[0103] In equation (1), R represents the distance from the radar device 90 to the observed object, and c represents the speed of light.

[0104] By performing a range FFT on the digital data of the signal acquired at timing (1) by the spectrum calculation unit 41, the spectral value of the electromagnetic noise during the output radar signal period is accumulated to the electromagnetic noise frequency F. n_r The part.

[0105] The digital data of the signal at timing (2) obtained by the spectrum calculation unit 41 is multiplied by a complex frequency shift of fs / 2. Then, a range FFT is performed on the digital data multiplied by the complex frequency shift. Through this process, the spectral value of the electromagnetic noise during the period when no radar signal is output is accumulated to the electromagnetic noise frequency F. n_r The part is +fs / 2.

[0106] exist Figure 4 In the example, the transmitted radar signal is K times, therefore, the spectrum calculation unit 41 calculates the signals for each of the different N signals. smpl Perform N operations on N numerical data K times. smpl Range FFT of points. Through K range FFTs, the spectral calculation unit 41 calculates K points from N. smpl The spectrum formed by points.

[0107] The spectrum calculation unit 41 calculates the K values ​​from N smplThe frequency spectra composed of K points are output to the range-velocity spectrum calculation section 42 and the electromagnetic noise spectrum calculation section 43, respectively.

[0108] The range-velocity spectrum calculation section 42 acquires the plurality of frequency spectra output from the spectrum calculation section 41.

[0109] The range-velocity spectrum calculation section 42 performs K-point Doppler FFT on data of the first half (1 to N smpl / 2) of the frequency spectra among the acquired plurality of frequency spectra. By this process, a range-velocity spectrum (S(k)) composed of K points is calculated. Figure 3

[0110] In the example of Fig. 6, the electromagnetic noise of the continuous wave is input to the analog-digital conversion section 11, and the frequency of the electromagnetic noise does not change, so the spectrum value of the electromagnetic noise is accumulated to the frequency (F n_r ) of the electromagnetic noise. Figure 4

[0111] In formula (2), f denotes the center frequency of the local oscillation signal (Lo(k)), and v denotes the relative velocity between the radar device 90 and the observation object.

[0112] Further, in the Doppler frequency (F n_v ) corresponding to the relative velocity between the radar device 90 and the source of the electromagnetic noise, the spectrum value of the electromagnetic noise is accumulated.

[0113] In the example of Fig. 6, the electromagnetic noise of the continuous wave is input to the analog-digital conversion section 11, and the frequency of the electromagnetic noise does not change, so the spectrum value of the electromagnetic noise is accumulated to the frequency (F n_r ) of the electromagnetic noise.

[0114] Figure 4 In the example of Fig. 6, the electromagnetic noise of the continuous wave is input to the analog-digital conversion section 11, and the frequency of the electromagnetic noise does not change, so the spectrum value of the electromagnetic noise is accumulated to the frequency (F smpl / 2) of the electromagnetic noise.

[0115] In the example of Fig. 6, the electromagnetic noise of the continuous wave is input to the analog-digital conversion section 11, and the frequency of the electromagnetic noise does not change, so the spectrum value of the electromagnetic noise is accumulated to the frequency (F smpl / 2) of the electromagnetic noise. Figure 4 In the example of Fig. 6, the electromagnetic noise of the continuous wave is input to the analog-digital conversion section 11, and the frequency of the electromagnetic noise does not change, so the spectrum value of the electromagnetic noise is accumulated to the frequency (F smpl / 2) of the electromagnetic noise.

[0116] The range-velocity spectrum calculation section 42 outputs the range-velocity spectrum to the range-velocity information calculation section 51.

[0117] Figure 3 The electromagnetic noise spectrum calculation section 43 performs K-point Doppler FFT on data of the second half (N smpl / 2+1 to N smpl ​Perform a K-point Doppler FFT on the data. Then, calculate the electromagnetic noise spectrum consisting of the K points. Figure 3 (Steps shown in ST14).

[0118] exist Figure 4 In this context, FFT(3) represents the Doppler FFT. The Doppler frequency (F) corresponding to the relative velocity between the radar device 90 and the electromagnetic noise source is calculated by the electromagnetic noise spectrum calculation unit 43. n_v In the ), the cumulative electromagnetic noise spectral value.

[0119] exist Figure 4 In the example, the electromagnetic noise of the continuous wave is input to the analog-to-digital converter 11. Since the frequency of the electromagnetic noise does not change, the spectral value of the electromagnetic noise is accumulated to the frequency (F) of the electromagnetic noise. n_r ).

[0120] exist Figure 4 The diagram shows the latter half (N) of the spectrum used. smpl / 2+1~N smpl The electromagnetic noise spectrum calculation unit 43 performs N calculations on the K different digital data. smpl / 2 times K-point Doppler FFT, calculate N smpl / 2 electromagnetic noise spectra consisting of K points.

[0121] The electromagnetic noise spectrum calculation unit 43 outputs the electromagnetic noise spectrum to the electromagnetic noise information calculation unit 52.

[0122] After receiving the range velocity spectrum from the range velocity spectrum calculation unit 42, the range velocity information calculation unit 51 detects the peak value of the spectral value in the range velocity spectrum.

[0123] The processing of peak values ​​in the detection spectrum is a well-known technique, therefore, detailed explanations are omitted here.

[0124] The distance-velocity information calculation unit 51 uses the beat frequency of the detected peak as the beat frequency (F) corresponding to the distance to the observed object. sb_r The output is sent to the detection and processing unit 53.

[0125] The distance-velocity information calculation unit 51 uses the Doppler frequency of the detected peak value as the Doppler frequency (F) corresponding to the relative velocity between itself and the observed object. sb_v The output is sent to the detection and processing unit 53.

[0126] The range and velocity information calculation unit 51 also detects the spectral value of electromagnetic noise during the output radar signal as the peak value. Therefore, the range and velocity information calculation unit 51 also calculates the frequency (F) of the electromagnetic noise. n_r ) as the beat frequency (F) corresponding to the distance to the observed object.sb_r ) to the detection processing section 53. Further, the distance velocity information calculation section 51 outputs, as the Doppler frequency (F n_v ) corresponding to the relative velocity with the observation target, the Doppler frequency (F sb_v ) corresponding to the relative velocity with the electromagnetic noise generation source to the detection processing section 53 Figure 3 (step shown by ST15 of FIG. 18).

[0127] The electromagnetic noise information calculation section 52 detects the peak value of the spectrum value of the electromagnetic noise spectrum after receiving the electromagnetic noise spectrum from the electromagnetic noise spectrum calculation section 43.

[0128] The process of detecting the peak value of the spectrum value is a publicly known technique, and thus the detailed description thereof is omitted here.

[0129] The electromagnetic noise information calculation section 52 detects the spectrum value of the electromagnetic noise during the period in which the radar signal is not output as the peak value. Thus, the electromagnetic noise information calculation section 52 outputs, as the beat frequency (F n_r ) corresponding to the distance to the observation target, the frequency (F sb_r ) of the spectrum value of the electromagnetic noise during the period in which the radar signal is not output at the time of output from the spectrum calculation section 41. Here, note that the frequency of the spectrum value of the electromagnetic noise during the period in which the radar signal is not output at the time of output from the spectrum calculation section 41 is F n_r + fs / 2. The electromagnetic noise spectrum calculation section 43 uses the data of the latter half (N smpl / 2 + 1 ~ N smpl ) of the 1st spectrum at the time of Doppler FFT. Thus, the frequency of the spectrum value of the electromagnetic noise becomes F n_r + fs / 2 - fs / 2 = F n_r Further, the electromagnetic noise information calculation section 52 outputs, as the Doppler frequency (F n_v ) corresponding to the relative velocity with the electromagnetic noise generation source, the Doppler frequency (F sb_v ) corresponding to the relative velocity with the observation target to the detection processing section 53 Figure 3 (step shown by ST16 of FIG. 18).

[0130] The detection processing section 53 acquires the set of the beat frequency (F sb_r ) and the Doppler frequency (F sb_v ) output from the distance velocity information calculation section 51.

[0131] In the example of the distance velocity information calculation result of Figure 4 , there are two peak values corresponding to one observation target and one electromagnetic noise, and thus the detection processing section 53 acquires two sets of the beat frequency (F sb_r ) and the Doppler frequency (F sb_v ) from the distance velocity information calculation section 51.

[0132] The detection processing unit 53 acquires the frequency (F) of the electromagnetic noise output from the electromagnetic noise information calculation unit 52. n_r ) and Doppler frequency (F n_v ) group.

[0133] exist Figure 4 In the example of the electromagnetic noise information calculation results, there is a peak value corresponding to one electromagnetic noise. Therefore, the detection processing unit 53 obtains the frequency (F) of one electromagnetic noise from the electromagnetic noise information calculation unit 52. n_r ) and Doppler frequency (F n_v ) group.

[0134] The detection processing unit 53 compares the two sets of information obtained from the distance and speed information calculation unit 51 with the one set of information obtained from the electromagnetic noise information calculation unit 52.

[0135] Beat frequency (F) sb_r ) and Doppler frequency (F sb_v One of the two groups is the frequency (F) of the electromagnetic noise obtained from the electromagnetic noise information calculation unit 52. n_r ) and Doppler frequency (F n_v ) is consistent with one group.

[0136] Specifically, the two beat frequencies (F) sb_r One beat frequency (F) in ) sb_r ) and the frequency of electromagnetic noise (F) n_r Consistent with the frequency of electromagnetic noise (F). n_r Consistent beat frequency (F) sb_r The corresponding Doppler frequency (F) sb_v ) and Doppler frequency (F n_v Consistent.

[0137] like Figure 4 As shown, the detection processing unit 53 discards beat frequencies (F). sb_r ) and Doppler frequency (F sb_v The two groups of electromagnetic noise (F) n_r ) and Doppler frequency (F n_v The group that is consistent with the group.

[0138] Figure 4 The detection processing results show the beat frequency (F) corresponding to the distance to the observed object. sb_r ) and the Doppler frequency (F) corresponding to the relative velocity between the observed object and the observed object. sb_v (Illustrative diagram)

[0139] The detection processing section 53 calculates the distance to the observation object from the beat frequency (F sb_r ) included in the group that is not discarded and retained.

[0140] The detection processing section 53 calculates the relative speed with the observation object from the Doppler frequency (F sb_v ) included in the group that is not discarded and retained. Figure 3 ) included in the group that is not discarded and retained (step illustrated in ST17 of FIG. 17).

[0141] The process of calculating the distance to the observation object from the beat frequency (F sb_r ) itself is a publicly known technique, and thus detailed description thereof is omitted here. Further, the process of calculating the relative speed with the observation object from the Doppler frequency (F sb_v ) itself is also a publicly known technique, and thus detailed description thereof is omitted here.

[0142] As described above, the radar device 90 of Embodiment 1 has the above-described structure, and thus can unify the range FFT of the digital data for the period during which the radar signal is transmitted and the period during which the radar signal is not transmitted. Therefore, the radar device 90 of Embodiment 1 can reduce the number of times of Fourier transform, and can suppress the degradation of the detection accuracy of the observation object, as compared with the past.

[0143] Embodiment 2

[0144] In the radar device 90 of Embodiment 1, the frequency conversion section 31 of the signal processing section 12 performs the frequency conversion process for the digital data in the period during which the radar signal is not transmitted, among the digital data output from the analog-digital conversion section 11.

[0145] The radar device 90 of Embodiment 2 has a frequency conversion section 62. The frequency conversion section 62 can be constituted by an analog circuit, for example.

[0146] In Embodiment 2, the same reference numerals as those of the structural elements used in Embodiment 1 are used except for the case where the description is explicitly described for the purpose of distinction. Further, in Embodiment 2, the description repeated in Embodiment 1 is appropriately omitted.

[0147] Figure 5 is a structural diagram illustrating the structure of the radar device 90 of Embodiment 2. As Figure 5 illustrated, the radar device 90 of Embodiment 2 has a control section 61, a frequency conversion section 62, and a signal processing section 68 that are different from those of Embodiment 1, respectively.

[0148] The control section 61 outputs a control signal (1) that instructs the output of the radar signal to the signal source 3. The signal source 3 outputs the frequency modulated signal of the continuous wave as the radar signal to the distribution section 5 upon acceptance of the control signal (1) from the control section 61.

[0149] Further, the control section 61 outputs a control signal (2) indicating the output timing of the radar signal to the frequency conversion section 62 and the signal processing section 68, respectively.

[0150] The frequency conversion section 62 has a first switch 63, a second switch 64, a frequency mixing section 65, a filter section 66, and a second signal source 67.

[0151] One end of the first switch 63 is connected to one end of the output side of the second switch 64, and the other end is connected to the input side of the frequency mixing section 65.

[0152] The first switch 63 switches to the input side of the second switch 64 during the period in which the radar signal is output, and switches to the input side of the frequency mixing section 65 during the period in which the radar signal is not output, in accordance with the output timing indicated by the control signal (2) output from the control section 61.

[0153] The frequency mixing section 65 mixes the beat signal output from the first switch 63 and the local oscillation signal output from the second signal source 67, thereby generating a second beat signal having a difference frequency between the frequency output from the first switch 63 and the frequency of the local oscillation signal.

[0154] The frequency mixing section 65 outputs the generated second beat signal to the filter section 66.

[0155] The filter section 66 is implemented by an LPF or a BPF, or the like.

[0156] The filter section 66 suppresses unnecessary components such as spurs included in the second beat signal output from the frequency mixing section 65, and outputs the second beat signal after the suppression of the unnecessary components to the second switch 64.

[0157] The second signal source 67 is implemented by a local oscillator or a PLL (Phase Locked Loop) synthesizer, or the like. Further, the second signal source 67 can also be implemented using a frequency divider or a multiplier in common with the clock signal of the analog-digital conversion section 11.

[0158] The second signal source 67 outputs a local oscillation signal of a frequency (f0 = (n-1 / 2)fs) that is n-1 / 2 times (n is an arbitrary integer) of the sampling frequency fs to the frequency mixing section 65.

[0159] In Embodiment 1, the frequency shift complex number of the frequency f0 is used to frequency shift only the data during the period in which the radar signal is not output. In Embodiment 2, the local oscillation signal of the frequency f0 is used in the frequency conversion process. The situation seen in Embodiment 2 can also be said to be that the vibration of the local oscillation signal of a single frequency is amplitude-modulated by the received signal during the period in which the radar signal is not output. The vibration of the side that is modulated in the amplitude modulation is called a carrier wave.

[0160] One end of the second switch 64 is connected to the output side of the first switch 63, and the other end is connected to the output side of the filter section 66.

[0161] The second switch 64 repeatedly switches to the output side of the first switch 63 during the period in which the radar signal is output and to the output side of the filter section 66 during the period in which the radar signal is not output, in accordance with the output timing indicated by the control signal (2) output from the control section 61.

[0162] The second switch 64 outputs the beat signal to the analog-digital conversion section 11 during the period in which the radar signal is output and outputs the second beat signal to the analog-digital conversion section 11 during the period in which the radar signal is not output.

[0163] The signal processing section 68 calculates the distance to the observation object and the relative velocity with the observation object using the digital data output from the analog-digital conversion section 11, respectively.

[0164] The operation of the radar apparatus 90 of Embodiment 2 is made clear by the following description along with Figures 5-7 .

[0165] Figure 6 is a block diagram showing the structure of the signal processing section 68 of the radar apparatus 90 of Embodiment 2. As shown in Figure 6 , the signal processing section 68 of the radar apparatus 90 of Embodiment 2 has a spectrum calculation section 44 that is different from that of Embodiment 1. The signal processing section 68 has the spectrum calculation section 44 instead of the frequency conversion section 31 and the spectrum calculation section 41 of Embodiment 1.

[0166] The spectrum calculation section 44 refers to the control signal (2) output from the control section 61 to determine the period in which the radar signal is output from the radar signal output section 1 and the period in which the radar signal is not output from the radar signal output section 1.

[0167] The spectrum calculation section 44 adds the digital data (A) and the digital data (B) among the digital data output from the analog-digital conversion section 11. The digital data (A) is the digital data determined to be in the period in which the radar signal is being output. The digital data (B) is the digital data determined to be in the period in which there is no radar signal.

[0168] The spectrum calculation section 44 performs range FFT on the added data, thereby calculating a spectrum.

[0169] The digital data (A) is digital data in a period in which the radar signal is output. The digital data (B) is digital data in a period in which the radar signal is not output.

[0170] The spectrum calculation section 44 performs range FFT on the added digital data, thereby calculating a plurality of spectra.

[0171] The spectrum calculation section 44 outputs the calculated plurality of spectra to the range-velocity spectrum calculation section 42 and the electromagnetic noise spectrum calculation section 43.

[0172] Figure 7 is a flowchart showing a calculation process of a distance to an observation object and a relative velocity between the observation object in the signal processing section 68 of Embodiment 2.

[0173] The spectrum calculation section 44 refers to the control signal output from the control section 61, and determines a period in which the radar signal is output from the radar signal output section 1 and a period in which the radar signal is not output from the radar signal output section 1.

[0174] The spectrum calculation section 44 acquires digital data output from the analog-digital conversion section 11 at a signal acquisition timing (1) included in the period determined as being in which the radar signal is being output.

[0175] The spectrum calculation section 44 acquires digital data output from the analog-digital conversion section 11 at a signal acquisition timing (2) included in the period determined as being in which there is no radar signal.

[0176] The spectrum calculation section 44 adds digital data (A) and digital data (B) in the digital data output from the analog-digital conversion section 11. The digital data (A) is N smpl point digital data in the period determined as being in which the radar signal is being output. The digital data (B) is N smpl point digital data in the period determined as being in which there is no radar signal.

[0177] The spectrum calculation section 44 performs N smpl point range FFT on the added digital data, thereby calculating a spectrum (step shown by ST21). Figure 7

[0178] As with the case of the structure of Embodiment 1, the spectrum calculation section 44 performs K times of N smpl point range FFT on N smpl point digital data different from each other, and calculates K spectra. smpl ​The calculated spectrum is output to the distance velocity spectrum calculation section 42 and the electromagnetic noise spectrum calculation section 43.

[0179] As described above, the radar device 90 of Embodiment 2 has the above-described structure, and thus, can uniformly perform range FFT for digital data of both the period during which the radar signal is transmitted and the period during which the radar signal is not transmitted. Thus, as with the structure of Embodiment 1, the radar device 90 of Embodiment 2 can reduce the number of Fourier transforms compared with the past, and can suppress degradation of detection accuracy of the observation object.

[0180] Embodiment 3

[0181] The radar device 90 of Embodiment 3 performs modulation-demodulation processing on the beat signal in the period during which the radar signal is not output. Thus, range FFT can be uniformly performed for digital data of both the period during which the radar signal is transmitted and the period during which the radar signal is not transmitted. The uniform range FFT is performed by the signal processing section 71 of Embodiment 3.

[0182] In Embodiment 3, the same reference numerals as those of the structural elements used in the already appeared embodiments are used except for cases where explicitly described for distinction. Further, in Embodiment 3, the description repeated with the already appeared embodiments is appropriately omitted.

[0183] Figure 8 is a structural diagram showing the structure of the signal processing section 71 of the radar device 90 of Embodiment 3. As shown in Figure 8 The signal processing section 71 of Embodiment 3 has a modulation section 32 and a demodulation section 33 instead of the frequency conversion section 31 of Embodiment 1.

[0184] The operation unique to Embodiment 3 of the radar device 90 is made clear by the following description.

[0185] Figure 8 The modulation section 32 shown in refers to the control signal output from the control section 2, and determines the period during which the radar signal is not output from the radar signal output section 1.

[0186] The modulation section 32 performs modulation processing on the digital data in the digital data output from the analog-digital conversion section 11, which is determined as being in the period during which the radar signal is not present, and outputs the same to the spectrum calculation section 45.

[0187] The digital data in the period determined as being in the period during which the radar signal is not present is repeatedly output from the analog-digital conversion section 11, and thus, the modulation section 32 performs modulation processing on the plurality of digital data repeatedly output, respectively. The plurality of digital data after the modulation processing is performed is output to the spectrum calculation section 45, respectively.

[0188] The spectrum calculation section 45 refers to the control signal output from the control section 2, and determines a period in which the radar signal is output from the radar signal output section 1.

[0189] The spectrum calculation section 45 adds the digital data (A) and the digital data (B') in the digital data output from the analog-digital conversion section 11. The digital data (A) is digital data determined to be in the period in which the radar signal is being output. The digital data (B') is digital data obtained from the modulation section 32.

[0190] The spectrum calculation section 45 performs range FFT on the added data, thereby calculating a spectrum.

[0191] In the period determined to be in which the radar signal is being output, the digital data from the analog-digital conversion section 11 and the digital data from the modulation section 32 are repeatedly output. The spectrum calculation section 45 repeatedly performs the above-described addition processing.

[0192] The spectrum calculation section 45 performs range FFT on the added digital data, respectively, thereby calculating a plurality of spectra.

[0193] The spectrum calculation section 45 outputs the calculated plurality of spectra to the range-velocity spectrum calculation section 42 and the demodulation section 33.

[0194] The demodulation section 33 performs demodulation processing on the spectrum output from the spectrum calculation section 45, and outputs it to the electromagnetic noise spectrum calculation section 46.

[0195] The spectrum is repeatedly output from the spectrum calculation section 45. The demodulation section 33 performs demodulation processing on the plurality of spectra repeatedly output, respectively. The plurality of spectra on which the demodulation processing is performed are output to the electromagnetic noise spectrum calculation section 46.

[0196] The electromagnetic noise spectrum calculation section 46 acquires the plurality of spectra output from the demodulation section 33.

[0197] The electromagnetic noise spectrum calculation section 46 performs Doppler FFT on data in the first half of the acquired plurality of spectra, which corresponds to 1 / 2 or less of the sampling frequency fs, thereby calculating an electromagnetic noise spectrum.

[0198] The electromagnetic noise spectrum calculation section 46 outputs the electromagnetic noise spectrum to the electromagnetic noise information calculation section 52.

[0199] Figure 9 Fig. 8 is a flowchart showing the calculation processing of the distance to the observed object and the relative velocity between the observed object in the signal processing section 71 of Embodiment 3.

[0200] Figure 10 Fig. 9 is an explanatory diagram showing the calculation processing of the distance to the observed object and the relative velocity between the observed object in the signal processing section 71 of Embodiment 3.

[0201] The modulation unit 32 determines the period during which radar signals are not output from the radar signal output unit 1 by referring to the control signal output from the control unit 2.

[0202] The modulation unit 32 acquires digital data output from the analog-to-digital converter 11 during the signal acquisition timing (2) included in the period when no radar signal is determined.

[0203] The modulation unit 32 determines the N period in the digital data output from the analog-to-digital converter 11 during which no radar signal is detected. smpl (an even number of) digital data (more than 2) are modulated. Figure 9 (Steps shown in ST31).

[0204] To simplify the explanation, Figure 10 The example shown is a modulation scheme multiplied by 1 or -1. However, this is just one example, and other modulation schemes can also be used.

[0205] The spectrum calculation unit 45 determines the period for outputting radar signals from the radar signal output unit 1 by referring to the control signal output from the control unit 2.

[0206] The spectrum calculation unit 45 acquires digital data output from the analog-to-digital converter 11 during the period when it is determined that a radar signal is being output.

[0207] The spectrum calculation unit 45 determines the period during which the radar signal is being output from the digital data output from the analog-to-digital converter 11. smpl The digital data and N obtained from the modulation unit 32 smpl Add the numbers together.

[0208] The spectrum calculation unit 45 performs N on the summed digital data. smpl The range of points is FFT, from which the spectrum is calculated ( Figure 9 (Steps shown in ST32).

[0209] exist Figure 10 In this equation, FFT(1) represents range FFT. By performing range FFT on the digital data, the spectral values ​​of the received signal (Rx(k) (k=1,…,K)) of the reflected wave are accumulated to the beat frequency (F) shown in equation (1). sb_r ).

[0210] The spectrum calculation unit 45 performs a range FFT on the digital data of the signal acquisition timing (1), thereby accumulating the spectral value of the electromagnetic noise during the output radar signal period to the frequency of the electromagnetic noise F. n_r The part.

[0211] By performing a range FFT on the digital data of the signal acquisition timing (2) by the spectrum calculation unit 45, the spectrum value of the electromagnetic noise during the period when no radar signal is output is accumulated to the electromagnetic noise frequency F. n_r The part.

[0212] Similar to the structure of Embodiment 1, the spectral calculation unit 45 calculates N values ​​that are different from each other. smpl Perform N operations on N numerical data K times. smpl Range FFT of points. Calculate K points from N using K range FFTs. smpl The spectrum is composed of points. The calculated spectrum is output to the distance-velocity spectrum calculation unit 42 and the demodulation unit 33.

[0213] The demodulation unit 33 acquires the spectrum output from the spectrum calculation unit 45.

[0214] The demodulation unit 33 performs demodulation processing on the acquired spectrum in the same manner as the modulation processing of the modulation unit 32. Figure 9 (Steps shown in ST33).

[0215] To simplify the explanation, Figure 10 An example is shown where demodulation is performed by multiplying -1 by 1, which is multiplied in the modulation process.

[0216] The demodulation unit 33 outputs the demodulated first spectrum to the electromagnetic noise spectrum calculation unit 46.

[0217] The electromagnetic noise spectrum calculation unit 46 obtains multiple demodulated first spectra output from the demodulation unit 33.

[0218] The distance velocity spectrum calculation unit 42 acquires multiple spectra output from the spectrum calculation unit 45.

[0219] The distance velocity spectrum calculation unit 42 calculates the first half (1 to N) of the multiple acquired spectra. smpl Perform a K-point Doppler FFT on the data from / 2). Then, calculate the range-velocity spectrum formed by the K points. Figure 9 (Steps shown in ST13).

[0220] exist Figure 10 In this equation, FFT(2) represents Doppler FFT. The Doppler FFT is performed on the K spectra by the range-velocity spectrum calculation unit 42, thereby accumulating the spectral values ​​of the received signal (Rx(k)) of the reflected wave to the Doppler frequency (F) shown in equation (2). sb_v ).

[0221] The Doppler frequency (F) corresponding to the relative velocity between the radar device 90 and the electromagnetic noise source that is outputting radar signals. n_v In ), the cumulative electromagnetic noise spectral value. In Implementation Method 1 Figure 4In the example, the electromagnetic noise of the continuous wave is input to the analog-to-digital converter 11. Since the frequency of the electromagnetic noise does not change, the spectral value of the electromagnetic noise is accumulated to the frequency (F) of the electromagnetic noise. n_r ).

[0222] Furthermore, the Doppler frequency corresponding to the relative velocity between the radar device 90 and the electromagnetic noise source without radar signal is modulated, so it is not accumulated and diffused.

[0223] Figure 10 This shows the use of the first half of the first spectrum (1 to N). smpl / 2) is an example of data. In this example, the spectral calculation unit 41 performs N operations on K different digital data. smpl The K-point Doppler FFT is performed twice. The spectral calculation unit 45 calculates N by performing the Doppler FFT. smpl / 2 Distance-velocity spectra consisting of K points.

[0224] The distance-velocity spectrum calculation unit 42 outputs the distance-velocity spectrum to the distance-velocity information calculation unit 51.

[0225] The electromagnetic noise spectrum calculation unit 46 calculates the first half (1 to N) of the multiple demodulated spectra obtained. smpl The data from / 2) is subjected to a K-point Doppler FFT. By performing the Doppler FFT, the electromagnetic noise spectrum calculation unit 46 calculates the electromagnetic noise spectrum composed of the K points. Figure 9 (The steps shown in ST35).

[0226] exist Figure 10 In this context, FFT(3) represents the Doppler FFT. The Doppler frequency (F) corresponding to the relative velocity between the radar device 90 and an electromagnetic noise source without radar signal is calculated by the electromagnetic noise spectrum calculation unit 46. n_v In the context of electromagnetic noise, the spectral values ​​of the cumulative electromagnetic noise are shown. Figure 10 In the example, the electromagnetic noise of the continuous wave is input to the analog-to-digital converter 11. Since the frequency of the electromagnetic noise does not change, the spectral value of the electromagnetic noise is accumulated to the frequency (F) of the electromagnetic noise. n_r ).

[0227] exist Figure 10 In this process, the spectrum of the received signal (Rx(k)) of the reflected wave is demodulated, so the Doppler frequency is not accumulated and diffused.

[0228] Furthermore, the Doppler frequency corresponding to the relative velocity between the radar device 90 and the received signal and electromagnetic noise generation source during the transmission of the radar signal is demodulated, so it is not accumulated and diffused.

[0229] Figure 10An example of data using the first half (1 to N smpl The electromagnetic noise spectrum calculating section 46 in this example performs K-point Doppler FFT of N smpl / 2 times on K pieces of digital data that are different from each other. By performing the Doppler FFT, the electromagnetic noise spectrum calculating section 46 calculates N smpl / 2 pieces of electromagnetic noise spectrum constituted of K points.

[0230] The electromagnetic noise spectrum calculating section 46 outputs the electromagnetic noise spectrum to the electromagnetic noise information calculating section 52.

[0231] As described above, the radar device 90 of Embodiment 3 has the above-described structure, and thus, can unify the range FFT of the digital data for the period during which the radar signal is transmitted and the period during which the radar signal is not transmitted. Thus, as with the already-described embodiments, the radar device 90 of Embodiment 3 can reduce the number of Fourier transforms compared to the past, and can suppress degradation of the detection accuracy of the observation target.

[0232] Embodiment 4

[0233] Embodiment 3 has a structure in which the modulation section 32 of the signal processing section 71 performs modulation processing on the digital data in the period during which the radar signal is not transmitted.

[0234] The radar device 90 of Embodiment 4 has a modulation processing section 82. The modulation processing section 82 can be constituted of, for example, an analog circuit.

[0235] In Embodiment 4, the same reference numerals as those of the structural elements used in the already-described embodiments are used except for cases where the description is explicitly made for the purpose of distinction. Further, in Embodiment 4, the description that is repeated from the already-described embodiments is appropriately omitted.

[0236] Figure 11 is a structural diagram showing the structure of the radar device 90 of Embodiment 4. As Figure 11 shown, the radar device 90 of Embodiment 4 includes the modulation processing section 82 on the basis of the structure of Embodiment 1.

[0237] The modulation processing section 82 has a 1st switch 83, a 2nd switch 84, and a modulation section 85.

[0238] The control section 81 outputs a control signal (1) that indicates the output of the radar signal to the signal source 3. The signal source 3 outputs a frequency modulated signal of a continuous wave as the radar signal to the distribution section 5 after accepting the control signal (1) from the control section 81.

[0239] Further, the control section 81 outputs a control signal (2) that indicates the output timing of the radar signal to the modulation processing section 82 and the signal processing section 86, respectively.

[0240] One end of the first switch 83 is connected to one end of the output side of the second switch 84, and the other end is connected to the input side of the modulation section 85.

[0241] The first switch 83 repeatedly switches to the input side of the second switch 84 during a period in which the radar signal is output, and switches to the input side of the modulation section 85 during a period in which the radar signal is not output, in accordance with the output timing indicated by the control signal (2) output from the control section 81.

[0242] The modulation section 85 performs a modulation process on the beat signal output from the first switch 83, and generates a second beat signal.

[0243] The modulation section 85 outputs the generated second beat signal to the second switch 84.

[0244] The second switch 84 repeatedly switches to the output side of the first switch 83 during a period in which the radar signal is output, and switches to the output side of the modulation section 85 during a period in which the radar signal is not output, in accordance with the output timing indicated by the control signal (2) output from the control section 81.

[0245] The second switch 84 outputs the beat signal to the analog-digital conversion section 11 during a period in which the radar signal is output, and outputs the second beat signal to the analog-digital conversion section 11 during a period in which the radar signal is not output.

[0246] The signal processing section 86 calculates the distance to the observation object and the relative speed with the observation object, respectively, using the digital data output from the analog-digital conversion section 11.

[0247] Figure 12 is a block diagram showing the structure of the signal processing section 86 of the radar apparatus 90 of Embodiment 4. The operation peculiar to Embodiment 4 is made clear by following the explanation along the drawing.

[0248] Figure 12 The spectrum calculation section 47 determines the period in which the radar signal is output from the radar signal output section 1 and the period in which the radar signal is not output from the radar signal output section 1, with reference to the control signal (2) output from the control section 81.

[0249] The spectrum calculation section 47 adds the digital data (A) and the digital data (B) among the digital data output from the analog-digital conversion section 11. The digital data (A) is digital data determined to be in the period in which the radar signal is being output. The digital data (B) is digital data determined to be in the period in which there is no radar signal.

[0250] The spectrum calculation section 47 performs a range FFT on the added data, thereby calculating the spectrum.

[0251] The digital data is repeatedly output from the analog-digital conversion section 11, and therefore the spectrum calculation section 47 repeatedly adds the digital data (A) and the digital data (B).

[0252] The spectrum calculation section 47 performs range FFT on the added digital data, respectively, and thereby calculates a plurality of spectra.

[0253] The spectrum calculation section 47 outputs the calculated plurality of spectra to the range-velocity spectrum calculation section 42 and the demodulation section 33.

[0254] Figure 13 Fig. 16 is a flowchart showing a calculation process of the distance to the observation object and the relative velocity between the observation object in the signal processing section 86 of Embodiment 4.

[0255] The spectrum calculation section 47 refers to the control signal output from the control section 81, and determines a period during which the radar signal is output from the radar signal output section 1 and a period during which the radar signal is not output from the radar signal output section 1.

[0256] The spectrum calculation section 47 acquires the digital data output from the analog-digital conversion section 11 at the signal acquisition timing (1) included in the period during which it is determined that the radar signal is being output.

[0257] The spectrum calculation section 47 acquires the digital data output from the analog-digital conversion section 11 at the signal acquisition timing (2) included in the period during which it is determined that there is no radar signal.

[0258] The spectrum calculation section 47 adds the digital data (A) and the digital data (B) in the digital data output from the analog-digital conversion section 11. The digital data (A) is the N smpl point digital data during the period during which it is determined that the radar signal is being output. The digital data (B) is the N smpl point digital data during the period during which it is determined that there is no radar signal.

[0259] The spectrum calculation section 47 performs N smpl point range FFT on the added digital data, and thereby calculates a spectrum (step shown by ST41). Figure 13

[0260] As with the structure of Embodiment 3, the spectrum calculation section 47 performs K times of N smpl point range FFT on N smpl point digital data different from each other, and calculates K first spectra each composed of N smpl points. The calculated spectra are output to the range-velocity spectrum calculation section 42 and the demodulation section 33.

[0261] ​As described above, the radar device 90 according to Embodiment 4 has the above-described structure, and thus, it is possible to unify the range FFT of the digital data for the period during which the radar signal is transmitted and the period during which the radar signal is not transmitted. Thus, as with the already-described embodiments, the radar device 90 according to Embodiment 4 can reduce the number of Fourier transforms compared with the past, and can suppress degradation of the detection accuracy of the observation target.

[0262] Embodiment 5

[0263] Figure 14 is a block diagram illustrating a structure of the signal processing section 12 of the radar device 90 according to Embodiment 5. As Figure 14 indicated, the signal processing section 12 according to Embodiment 5 has both the structure of Embodiment 1 and the structure of Embodiment 3. Specifically, the signal processing section 12 according to Embodiment 5 has, in order from the upstream, the frequency conversion section 31, the modulation section 32, the spectrum calculation section 41, and the demodulation section 33.

[0264] The structure combining Embodiment 1 and Embodiment 3 is particularly effective in a case where a peak frequency of a foldback occurs in the range FFT and in a case where the background noise is large.

[0265] Thus, Embodiment 5 is a combination of Embodiment 1 and Embodiment 3, but the combination of the embodiments described in the present specification is not limited to this.

[0266] The structure combining Embodiment 1 and Embodiment 4, Embodiment 2 and Embodiment 3, and Embodiment 2 and Embodiment 4, and the like is also particularly effective in a case where a peak frequency of a foldback occurs and in a case where the background noise is large.

[0267] Embodiment 6

[0268] The radar device 90 according to Embodiment 6 is characterized in the electromagnetic noise spectrum calculation section 48. The electromagnetic noise spectrum calculation section 48 according to Embodiment 6 limits the processing range of the digital data used to calculate the Doppler frequency (F n_v ) corresponding to the relative speed between the electromagnetic noise generation source on the basis of the beat frequency obtained by the range-velocity information calculation section 51.

[0269] In Embodiment 6, the same reference numerals as those of the structural elements used in the already-described embodiments are used except for cases where they are explicitly described for the purpose of distinction. Further, in Embodiment 6, the description overlapping with the already-described embodiments is appropriately omitted.

[0270] Figure 15 is a block diagram illustrating a structure of the signal processing section 12 of the radar device 90 according to Embodiment 6. As Figure 15As shown, the signal processing section 12 of Embodiment 6 has an electromagnetic noise spectrum calculation section 48 unique to Embodiment 6.

[0271] As with Embodiment 1, the distance velocity information calculation section 51 calculates two frequencies using the distance velocity spectrum obtained from the distance velocity spectrum calculation section 42. The calculated frequencies are beat frequencies (F sb_r ) corresponding to the distance to the observation target and Doppler frequencies (F sb_v ) corresponding to the relative velocity between the observation target.

[0272] As with Embodiment 1, the distance velocity information calculation section 51 also detects the spectrum value of the electromagnetic noise during the period in which the radar signal is output as a peak value. Therefore, the frequency (F n_r ) of the electromagnetic noise is also calculated as the beat frequency (F sb_r ) corresponding to the distance to the observation target. Further, the distance velocity information calculation section 51 also calculates the Doppler frequency (F n_v ) corresponding to the relative velocity between the electromagnetic noise generation source as the Doppler frequency (F sb_v ) corresponding to the relative velocity between the observation target.

[0273] The distance velocity information calculation section 51 outputs the calculated beat frequency (F sb_r ) and the calculated Doppler frequency (F sb_v ) to the detection processing section 53, respectively.

[0274] Further, the distance velocity information calculation section 51 outputs the calculated beat frequency (F sb_r ) to the electromagnetic noise spectrum calculation section 48.

[0275] In a case where one or more beat frequencies are input by the distance velocity information calculation section 51, the electromagnetic noise spectrum calculation section 48 limits the range of the digital data of the plurality of spectra that have been acquired in accordance with the input beat frequency information, and performs K-point Doppler FFT. Thereby, the electromagnetic noise spectrum composed of K points is calculated.

[0276] The electromagnetic noise spectrum calculation section 48 outputs the calculated electromagnetic noise spectrum to the electromagnetic noise information calculation section 52.

[0277] The operation of the signal processing section 12 unique to Embodiment 6 is clarified by the following description. As described above, the signal processing section 12 of Embodiment 6 is the same as Embodiment 1 except for the electromagnetic noise spectrum calculation section 48. The operation unique to Embodiment 6 is the calculation processing of the third spectrum performed by the electromagnetic noise spectrum calculation section 48.

[0278] Figure 16This is a flowchart illustrating the calculation process of the distance to the observed object and the relative speed between the observed object and the signal processing unit 12 in Embodiment 6.

[0279] Figure 17 This is an explanatory diagram showing the calculation and processing of the distance to the observed object and the relative speed between the observed object and the signal processing unit 12.

[0280] Similar to Embodiment 1, the distance-velocity information calculation unit 51 calculates the beat frequency (F) corresponding to the distance to the observed object. sb_r ) and the Doppler frequency (F) corresponding to the relative velocity between the observed object and the observed object. sb_v ).

[0281] Similar to Embodiment 1, the distance and velocity information calculation unit 51 calculates the beat frequency (F) sb_r ) and the calculated Doppler frequency (F sb_v The outputs are respectively sent to the detection and processing unit 53.

[0282] In addition, the distance and speed information calculation unit 51 calculates the beat frequency (F) sb_r The information is output to the electromagnetic noise spectrum calculation unit 48.

[0283] The distance and speed information calculation unit 51 outputs the beat frequency (F). sb_r After obtaining the information, the electromagnetic noise spectrum calculation unit 48 obtains the beat frequency (F). sb_r (information).

[0284] After the spectrum calculation unit 41 outputs K spectra, the electromagnetic noise spectrum calculation unit 48 obtains K spectra.

[0285] Electromagnetic noise spectrum calculation unit 48 uses only the beat frequency (F) input from distance and velocity information calculation unit 51. sb_r The digital data corresponding to the information is processed similarly to that in Implementation Method 1, using Doppler FFT on the obtained K spectra. Thus, the electromagnetic noise spectrum (EMS) is calculated. Figure 16 (The steps shown in ST51).

[0286] exist Figure 17 In this context, FFT(3) represents Doppler FFT. The electromagnetic noise spectrum calculation unit 48 uses only the beat frequency (F) input from the distance-velocity information calculation unit 51. sb_r The digital data corresponding to the information is used to perform a Doppler FFT on the K first-order spectra. Thus, the spectral values ​​of the electromagnetic noise are accumulated to the Doppler frequency (F) corresponding to the relative velocity between the electromagnetic noise source and the source. n_v ).

[0287] Figure 17The case where the beat frequency information obtained from the distance velocity information calculation section 51 is 2 is exemplified. In this case, the Doppler FFT is performed on the digital data at 2 places, and 2 electromagnetic noise spectra are calculated.

[0288] The electromagnetic noise spectrum calculation section 48 outputs the calculated 2 electromagnetic noise spectra to the electromagnetic noise information calculation section 52.

[0289] As described above, the radar device 90 of Embodiment 6 has the above-described structure, and thus, compared with the structure shown in Embodiment 1, it is possible to suppress the detection accuracy deterioration of the observation object by a smaller number of Fourier transforms. Further, even if the method shown in Embodiment 6 is applied to any one of Embodiments 2 to 5, the same effect is obtained.

[0290] Embodiment 7

[0291] The in-vehicle device of Embodiment 7 is an in-vehicle device in which the radar device 90 of the present technology exemplified in Embodiments 1 to 6 is installed.

[0292] In Embodiment 7, the same reference numerals as those of the structural elements used in the already appeared embodiments are used except for the cases where they are explicitly described in order to distinguish. Further, in Embodiment 7, the description repeated from the already appeared embodiments is appropriately omitted.

[0293] Figure 18 is a structural diagram showing the structure of the in-vehicle device of Embodiment 7. As shown in Figure 18 , the in-vehicle device has the radar device 90. Further, the radar device 90 is configured to send the output result to a control unit 91 of an automobile located outside the in-vehicle device.

[0294] The radar device 90 outputs the distance to the observation object and the relative velocity with the observation object calculated by the detection processing section 53 to the control unit 91 of the automobile, respectively.

[0295] Further, the radar device 90 outputs the frequency (F n_r ) of the electromagnetic noise and the Doppler frequency (F n_v ) corresponding to the relative velocity with the electromagnetic noise generation source calculated by the electromagnetic noise information calculation section 52 to the control unit 91 of the automobile, respectively.

[0296] The control unit 91 of the automobile is a device that controls the engine, the steering gear, or the brake, or the like of the automobile.

[0297] The operation of the in-vehicle device of Embodiment 7 is made clear by the following description.

[0298] After the detection processing section 53 calculates the distance to the observation object and the relative speed with the observation object, respectively, the radar device 90 outputs the distance to the observation object and the relative speed with the observation object to the control unit 91 of the automobile, respectively.

[0299] The frequency (F n_r ) and the Doppler frequency (F n_v ) of the electromagnetic noise are calculated by the electromagnetic noise information calculation section 52, respectively. The radar device 90 outputs the calculated frequency (F n_r ) and the Doppler frequency (F n_v ) of the electromagnetic noise to the control unit 91 of the automobile, respectively.

[0300] The control unit 91 of the automobile determines the danger of collision of the automobile having the on-vehicle device with the observation object, for example, based on the distance to the observation object and the relative speed with the observation object obtained from the radar device 90, respectively. The method of determining the danger of collision can be an arbitrary determination method. The control unit 91 of the automobile can use a known determination method.

[0301] The control unit 91 of the automobile can cause the brake of the automobile to operate automatically, for example, when it is determined that there is a danger of collision.

[0302] Further, the control unit 91 of the automobile can also control the steering device to switch the traveling direction of the automobile, for example, when it is determined that there is a danger of collision.

[0303] Further, the control unit 91 of the automobile can also implement the automatic driving of the automobile, for example, based on the combination of the sensor information detected by the sensor not shown and the obtained distance to the observation object and the obtained relative speed with the observation object.

[0304] The control unit 91 of the automobile can also determine the reliability based on the frequency (F n_r ) and the Doppler frequency (F n_v ) of the electromagnetic noise output from the radar device 90, respectively. The objects to be determined, for example, can be the obtained distance to the observation object and the obtained relative speed with the observation object, respectively. The method of determining the reliability can be an arbitrary determination method. The control unit 91 of the automobile can use a known determination method.

[0305] The control unit 91 of the automobile can also implement the automatic driving of the automobile, for example, using the obtained distance to the observation object and the obtained relative speed with the observation object, respectively, when it is determined that the reliability is high.

[0306] The control unit 91 of the automobile can also not use the distance to the observed object that has been acquired and the relative speed with the observed object that has been acquired, respectively, in a case where reliability is low, for example, when automatic driving of the automobile is being implemented.

[0307] As described above, the on-vehicle device of Embodiment 7 has the above-described structure, and thus the control unit 91 of the automobile using information from the radar device 90 can determine the risk of collision and improve reliability with respect to automatic driving.

[0308] Industrial Applicability

[0309] The present technology can be applied to a radar device and an on-vehicle device having the radar device, and has industrial applicability.

[0310] Explanation of Reference Numerals

[0311] 1: radar signal output section; 2: control section (Embodiments 1, 3, 5, 6); 3: signal source; 4: transmission / reception section; 5: distribution section; 6: transmission antenna; 7: reception antenna; 8: beat signal generation section; 9: frequency mixing section; 10: filter section; 11: analog / digital conversion section; 12: signal processing section (Embodiments 1, 5, 6); 31: frequency conversion section (Embodiments 1, 5, 6); 32: modulation section (Embodiments 3, 5); 33: demodulation section (Embodiments 3, 4, 5); 41: spectrum calculation section (Embodiments 1, 5, 6); 42: distance / velocity spectrum calculation section; 43: electromagnetic noise spectrum calculation section (Embodiments 1, 2, 5); 44: spectrum calculation section (Embodiment 2); 45: spectrum calculation section (Embodiment 3); 46: electromagnetic noise spectrum calculation section (Embodiments 3, 4); 47: spectrum calculation section (Embodiment 4); 48: electromagnetic noise spectrum calculation section (Embodiment 6); 51: distance / velocity information calculation section; 52: electromagnetic noise information calculation section; 53: detection processing section; 61: control section (Embodiment 2); 62: frequency conversion section (Embodiment 2); 63: 1st switch (Embodiment 2); 64: 2nd switch (Embodiment 2); 65: frequency mixing section (Embodiment 2); 66: filter section (Embodiment 2); 67: 2nd signal source (Embodiment 2); 68: signal processing section (Embodiment 2); 71: signal processing section (Embodiment 3); 81: control section (Embodiment 4); 82: modulation processing section (Embodiment 4); 83: 1st switch (Embodiment 4); 84: 2nd switch (Embodiment 4); 85: modulation section (Embodiment 4); 86: signal processing section (Embodiment 4); 90: radar device; 91: control unit of automobile.

Claims

1. A radar device, the radar device comprising: The radar signal output unit intermittently and repeatedly outputs linear frequency modulation as a radar signal; The transmitting and receiving unit transmits the radar signal and receives the radar signal reflected from the observed object as a reflected wave. A beat signal generation unit generates a beat signal based on the radar signal and the reflected wave; An analog-to-digital converter converts the beat signal into digital data; and The signal processing unit uses the digital data to detect the range and relative velocity of the observed object. The signal processing unit includes: A frequency conversion unit performs frequency conversion on the digital data during the period when the radar signal is not output; The spectrum calculation unit adds the digital data during the period of outputting the radar signal and the digital data after frequency transformation by the frequency transformation unit, and performs a range FFT. The distance-velocity spectrum calculation unit performs a Doppler FFT on the first half of the result after the range FFT is performed by the spectrum calculation unit. as well as An electromagnetic noise spectrum calculation unit performs a Doppler FFT on the latter half of the result after performing a range FFT on the spectrum calculation unit.

2. The radar device according to claim 1, wherein, Instead of the frequency conversion unit, it has a modulation unit and a demodulation unit. The modulation unit modulates the digital data during the period when the radar signal is not output. The demodulation unit performs demodulation processing on the digital data output from the spectrum calculation unit.

3. The radar device according to claim 2, wherein, The modulation process is frequency conversion.

4. A radar device, the radar device comprising: The radar signal output unit intermittently and repeatedly outputs linear frequency modulation as a radar signal; The transmitting and receiving unit transmits the radar signal and receives the radar signal reflected from the observed object as a reflected wave. A beat signal generation unit generates a beat signal based on the radar signal and the reflected wave; The frequency conversion unit performs frequency conversion only on the beat signal during the period when the radar signal is not output; An analog-to-digital converter converts the beat signal during the output of the radar signal and the beat signal after frequency conversion by the frequency conversion unit into digital data; and The signal processing unit uses the digital data to detect the range and relative velocity of the observed object. The signal processing unit includes: The spectrum calculation unit adds the digital data during the period of outputting the radar signal and the digital data after frequency transformation by the frequency transformation unit, and performs a range FFT. The distance-velocity spectrum calculation unit performs a Doppler FFT on the first half of the result after the range FFT is performed by the spectrum calculation unit. as well as An electromagnetic noise spectrum calculation unit performs a Doppler FFT on the latter half of the result after performing a range FFT on the spectrum calculation unit.

5. The radar device according to any one of claims 1 to 4, wherein, When the electromagnetic noise spectrum calculation unit calculates more than one beat frequency based on the result of the range FFT, it performs Doppler FFT only on the digital data corresponding to the beat frequency in the digital data.

6. A vehicle-mounted device having a radar device according to any one of claims 1 to 5.

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