Signal processing device, radar device, radar operation method, and computer-readable recording medium

Abstract

The waveform shaping unit (220) accumulates the beat signal (S8) of the frame unit, that is, the beat signal (S9). The distance calculation unit (252) generates a histogram of the distance bin using the beat signal (S9), and calculates the distance based on the distance bin number corresponding to the peak in the histogram as the relative distance of the object. The speed calculation unit (253) generates the power spectrum of the Doppler bins of different time bands or different distance bins using the beat signal (S9), generates a difference statistical chart representing the statistical amount of the difference between the power spectra, and calculates the speed based on the Doppler bin number corresponding to the peak in the difference statistical chart as the relative speed of the object.

Description

Technical Field

[0001] The present disclosure relates to a radar for detecting an object. Background Art

[0002] A radar is a device for measuring the relative distance between the radar and the object, the relative speed between the radar and the object, etc. by irradiating an object with radio waves and measuring the reflected waves from the object.

[0003] The FMCW method is a radar measurement method that is inexpensive and has excellent ability to measure distance and speed. In particular, the fast FMCW method has a higher resolution than the conventional slow FMCW method. In the fast FMCW method, the scanning time of the chirp signal is relatively short, which is several microseconds.

[0004] FMCW is the abbreviation of Frequency Modulated Continuous Wave.

[0005] Electronic attack is a threat when using radar. Electronic attack is an attack that interferes with the detection of existing objects by inserting radio waves that interfere with the measurement into the radar's radio waves from the outside.

[0006] In Non-Patent Document 1, a high-level electronic attack is proposed in addition to the conventional electronic attack.

[0007] Previous electronic attacks involved sending slow chirps to fast chirps, but the impact of electronic attacks was suppressed to some extent by an object detection algorithm called CFAR.

[0008] CFAR is the abbreviation of Constant False Alarm Rate.

[0009] On the other hand, a high-level electronic attack is an attack that transmits radio waves that gradually shift in frequency in coordination with the radio waves to be interfered with, thereby masking the power generated by an existing object. Such an electronic attack is called a covering chirp interference.

[0010] Cover chirp jamming for the purpose of deceiving CFAR is a new type of electronic attack that has not been discussed so far.

[0011] Therefore, conventional countermeasures are not effective in covering chirp interference.

[0012] Prior art literature

[0013] Non-patent literature

[0014] Non-Patent Document 1: Motomoto Nashiimoto, Fukunaga, et al., "Attack Evaluation Simulation of MIMO Radar Using Fast FMCW Method", SCIS2020 2020 Symposium on Cryptography and Information Security Kochi, Japan, Jan. 28 - 31, 2020, The Institute of Electronics, Information and Communication Engineers. Summary of the Invention

[0015] Problems to be Solved by the Invention

[0016] An object of the present disclosure is to be able to calculate the relative distance of an object and the relative speed of the object even when chirp jamming is applied.

[0017] Means for Solving the Problems

[0018] The signal processing apparatus of the present disclosure includes: a waveform accumulation unit that accumulates beat signals in frame units, the beat signals being digital signals obtained from a mixed signal that is obtained by mixing a local wave and a received wave, the local wave being a wave transmitted for detecting an object, and the received wave being a wave received as a reflected wave corresponding to the local wave; a distance calculation unit that generates a histogram of distance bins using the beat signals in frame units and calculates the distance based on the distance bin number corresponding to the peak in the histogram as the relative distance of the object; and a speed calculation unit that generates a power spectrum of Doppler bins in different time bands or different distance bins using the beat signals in frame units, generates a differential statistical chart representing a statistic of the difference between the power spectra, and calculates the speed based on the Doppler bin number corresponding to the peak in the differential statistical chart as the relative speed of the object.

[0019] Effects of the Invention

[0020] According to the present disclosure, even when chirp jamming is applied, the relative distance of an object and the relative speed of the object can be calculated. Description of the Drawings

[0021] Figure 1 It is a structural diagram of the radar apparatus 100 in Embodiment 1.

[0022] Figure 2 It is a structural diagram of the signal processing apparatus 200 in Embodiment 1.

[0023] Figure 3 It is a flowchart of the radar operation method in Embodiment 1.

[0024] Figure 4 This is a flowchart of step S110 in the first embodiment.

[0025] Figure 5 This is a flowchart of step S120 in the first embodiment.

[0026] Figure 6 This is a flowchart of step S130 in the first embodiment.

[0027] Figure 7 This is a flowchart of step S140 in the first embodiment.

[0028] Figure 8 3 is a diagram showing an image of the RD map 300 in the first embodiment.

[0029] Fig. 9 This is a schematic diagram of the RD diagram 300 in the first embodiment.

[0030] Fig.10 3 is a diagram showing an RD map 300 and a scanning window 301 in the first embodiment.

[0031] Fig.11 3 is a diagram showing an image of the median processing result 302 in the first embodiment.

[0032] Fig.12 Schematic diagram showing the median processing result 302 in the first embodiment.

[0033] Fig.13 This is a flowchart of step S160 in the first embodiment.

[0034] Fig.14 This is a flowchart of step S170 in the first embodiment.

[0035] Fig.15 This is a schematic diagram of the beat signal S9 in the first embodiment.

[0036] Fig.16 This is a diagram showing the power spectrum 310 in the first embodiment.

[0037] Fig.17 This is a diagram showing an image of the distance peak graph 311 in the first embodiment.

[0038] Fig.18 This is a schematic diagram of the distance peak graph 311 in the first embodiment.

[0039] Fig.19 This is a diagram showing the histogram 312 in the first embodiment.

[0040] Fig. 20 This is a flowchart of step S180 in the first embodiment.

[0041] Fig.21 This is a schematic diagram of the beat signal S9 in the first embodiment.

[0042] Fig. 22 This is a diagram showing two power spectra 320 in the first embodiment.

[0043] Fig.23 This is a diagram showing the difference graph 321 in the first embodiment.

[0044] Fig.24 This is a diagram showing the difference statistics graph 322 in the first embodiment.

[0045] Fig.25 It is a configuration diagram of radar device 100 in Embodiment 2 (Variation 1).

[0046] Fig.26 This is a flowchart of the radar operation method in Implementation Example 2 (Variant Example 1).

[0047] Fig. 27 It is a configuration diagram of the radar device 100 in Embodiment 2 (Variation 2).

[0048] Fig.28 This is a flowchart of the radar operation method in implementation example 2 (variant example 2).

[0049] Fig.29 2 is a hardware configuration diagram of the signal processing device 200 according to the embodiment. DETAILED DESCRIPTION

[0050] In the embodiments and the drawings, the same reference numerals are used to denote the same elements or corresponding elements, and the description of the elements denoted by the same reference numerals as the elements to be described will be appropriately omitted or simplified.

[0051] The arrows in the figure mainly show signal flow, data flow or processing flow. In addition, the branching parts where the signal or data flows in multiple directions are marked with black circles.

[0052] Implementation method 1.

[0053] based on Figures 1 to 24 The radar device 100 will be described.

[0054] The radar device 100 calculates the relative distance to the object and the relative speed of the object through radar measurement.

[0055] The target object is an object to be detected by radar measurement.

[0056] The relative distance of the object is the distance from the radar device 100 to the object.

[0057] The relative speed of the object is the speed of the object relative to the radar device 100. When the radar device 100 does not move during radar measurement, the relative speed of the object simply indicates the speed of the object.

[0058] ***Structure description***

[0059] based on Figure 1 The configuration of the radar device 100 will be described.

[0060] The radar device 100 includes an analog front end 110 and a signal processing device 200 .

[0061] The analog front end 110 is an analog circuit, and includes circuits such as a waveform generator 111, a VCO 112, a transmission antenna 113, a reception antenna 114, a mixer 115, a low-pass filter 116, and an ADC 117. These circuits are connected to each other via signal lines.

[0062] VCO is the abbreviation of Voltage-Controlled Ocillator.

[0063] ADC is the abbreviation of Analog-to-Digital Converter.

[0064] based on Figure 2 The structure of the signal processing device 200 will be described.

[0065] The signal processing device 200 is a computer including hardware such as a processor 201, a memory 202, and an input / output interface 203. These hardware are connected to each other via signal lines.

[0066] The processor 201 is an IC that performs calculations and controls other hardware. For example, the processor 201 is a CPU, a DSP, or a GPU.

[0067] IC is the abbreviation of Integrated Circuit.

[0068] CPU is the abbreviation of Central Processing Unit.

[0069] DSP is the abbreviation of Digital Signal Processor.

[0070] GPU is the abbreviation of Graphics Processing Unit.

[0071] The memory 202 is at least one of a volatile storage device and a nonvolatile storage device. A specific example of a volatile storage device is a RAM. A specific example of a nonvolatile storage device is a ROM, a HDD, or a flash memory.

[0072] RAM is the abbreviation of Random Access Memory.

[0073] ROM is the abbreviation of Read Only Memory.

[0074] HDD is the abbreviation of Hard Disk Drive.

[0075] The input / output interface 203 is an interface for input / output. For example, the input / output interface 203 is a serial communication interface. Specific examples of the serial communication interface are SPI, UART, or I2C.

[0076] SPI is the abbreviation of Serial Peripheral Interface.

[0077] UART is the abbreviation of Universal Asynchronous Receiver Transmitter.

[0078] I2C is the abbreviation of Inter-Integrated Circuit.

[0079] The signal processing device 200 includes elements such as a waveform control unit 210, a waveform shaping unit 220, a waveform storage unit 230, an information calculation unit 240, and an attack countermeasure unit 250. The attack countermeasure unit 250 includes elements such as an attack determination unit 251, a distance calculation unit 252, and a speed calculation unit 253. These elements are implemented by software.

[0080] The memory 202 stores a radar operation program for causing the computer to function as the waveform control unit 210 , the waveform shaping unit 220 , the waveform storage unit 230 , the information calculation unit 240 , and the attack countermeasure unit 250 . The radar operation program is executed by the processor 201 .

[0081] The memory 202 also stores an OS. The OS is executed by the processor 201.

[0082] The processor 201 executes the radar application program while executing the OS.

[0083] OS is the abbreviation of Operating System.

[0084] Input and output data of the radar application program are stored in the memory 202 .

[0085] The signal processing device 200 may include a plurality of processors instead of the processor 201 .

[0086] The radar application program can be recorded (stored) in a computer-readable form on a non-volatile recording medium such as an optical disk or a flash memory.

[0087] ***Action description***

[0088] The operation steps of the radar device 100 correspond to the radar operation method, and the operation steps of the signal processing device 200 correspond to the signal processing method. In addition, the operation steps of the signal processing device 200 correspond to the processing steps performed by the radar operation program.

[0089] based on Figure 3 The following describes how to use radar.

[0090] In step S110 , the analog front end 110 transmits the local wave S3 .

[0091] based on Figure 4 The procedure of step S110 will be described.

[0092] In step S111, the waveform control unit 210 generates a control signal S1 and outputs the generated control signal S1. The control signal S1 is a signal for instructing the generation of the ramp signal S2.

[0093] The output control signal S1 is input to the waveform generator 111 .

[0094] In step S112, the waveform generator 111 generates a ramp signal S2 according to the control signal S1, and outputs the generated ramp signal S2. The ramp signal S2 is a signal indicating a sloped voltage waveform.

[0095] Among the radar measurement methods, there is a method called FMCW. When FMCW is used, the slope of the voltage waveform of the ramp signal S2 is expressed as "Bw / Ts." "Bw" refers to bandwidth, and "Ts" refers to scanning time.

[0096] The output ramp signal S2 is input to the VCO 112 .

[0097] In step S113, the VCO 112 generates a local wave S3 at an oscillation frequency based on the ramp signal S2, and outputs the generated local wave S3. The local wave S3 is a signal having a waveform with a frequency corresponding to the waveform of the ramp signal S2.

[0098] The output local wave S3 is input to the transmission antenna 113 and the mixer 115 respectively.

[0099] In step S114 , the transmission antenna 113 transmits the local wave S3 as a radio wave in order to detect the object.

[0100] Back to Figure 3 , the description continues from step S120.

[0101] In step S120 , the analog front end 110 obtains the received wave S4 and generates a beat signal S7 .

[0102] based on Figure 5 The procedure of step S120 will be described.

[0103] In step S121 , the receiving antenna 114 receives the radio wave as the received wave S4 , and outputs the received received wave S4 .

[0104] The received wave S4 is equivalent to the local wave S3 (radio wave) reflected by the object, etc. When the radio wave is reflected by the object, the frequency of the radio wave changes. Therefore, the received wave S4 contains information on the frequency change caused by the relative distance and relative speed of the object.

[0105] The output reception wave S4 is input to the mixer 115 .

[0106] In step S122, the mixer 115 mixes the received wave S4 with the local wave S3 input in step S113.

[0107] Mixing is equivalent to multiplication of signals and can be expressed by equation (1).

[0108] cos(f s t)·cos(f r t)=[cos{(f s -f r )t}+cos{(f s +f r )t}] / 2 Formula (1)

[0109] “f s " indicates the frequency of the local wave S3. "f r " represents the frequency of the received wave S4. "cos" represents the cosine function. "t" represents time. "f s ” and “f r ” typically indicates a frequency that changes with the passage of time. Specifically, “f s ” and “f r ” indicates the frequency corresponding to the chirp signal.

[0110] The signal generated by this mixing is referred to as a mixed signal S5.

[0111] The mixer 115 outputs the generated mixed signal S5.

[0112] The output mixed signal S5 is input to the low-pass filter 116 .

[0113] In step S123, the low-pass filter 116 filters the components other than the low-frequency components of the mixed signal S5. The signal generated in this way is called a filtered signal S6. The filtered signal S6 is equivalent to the low-frequency components extracted from the mixed signal S5.

[0114] The low-frequency component is a component with a frequency lower than a predetermined frequency, and is also called a low-frequency component. Specifically, the frequency is (f s -f r ) is a low-frequency component. s +f r )The components above are not low-frequency components.

[0115] The filtered signal S6 can be expressed by equation (2) based on equation (1).

[0116] cos{(f s -f r )t} / 2Formula (2)

[0117] Based on this, the filtered signal S6 has information on the frequency difference between the local wave S3 and the received wave S4.

[0118] The low-pass filter 116 outputs the generated filtered signal S6.

[0119] The output filtered signal S6 is input to the ADC 117 .

[0120] In step S117, the ADC 117 converts the filter signal S6, which is an analog signal, into a digital signal. Specifically, the ADC 117 quantizes the filter signal S6.

[0121] The digital signal generated in this way is referred to as a beat signal S7. The beat signal S7 is equivalent to the digitized filter signal S6.

[0122] The ADC 117 outputs the generated beat signal S7 .

[0123] The output beat signal S7 is input to the signal processing device 200 .

[0124] Back to Figure 3 , the description continues from step S130.

[0125] In step S130 , the waveform accumulation unit 230 accumulates the beat signal S8 in frame units.

[0126] based on Figure 6 The procedure of step S130 will be described.

[0127] In step S131 , the waveform shaping section 220 shapes the beat signal S7 .

[0128] A specific example of shaping is a process called blanking. Blanking is a process of removing the sampling time at both ends of the signal. By blanking, the parts with large frequency differences in the repetition interval of the beat signal S7 are removed, and only the (f s -f r ) frequency.

[0129] The shaped beat signal S7 is referred to as a beat signal S8.

[0130] In step S132, the waveform storage unit 230 stores the beat signal S8 in the memory 202 in units of frames. The stored beat signal S8 is handled as the beat signal S8 in units of frames.

[0131] The beat signal S8 in frame units will be described.

[0132] Among the radar measurement methods, there is a method called fast FMCW. In fast FMCW, the relative distance and relative speed are calculated based on a set of multiple waveforms. These multiple waveforms constitute one frame.

[0133] The beat signal S8 in frame units is referred to as a beat signal S9.

[0134] Back to Figure 3 , the description continues from step S140.

[0135] In step S140 , the attack determination unit 251 determines the presence or absence of cover chirp interference based on the beat signal S9 , and outputs an attack determination result S10 .

[0136] Coverage chirp jamming is a type of electronic attack.

[0137] Step S140 will be described in detail later.

[0138] When the attack determination result S10 indicates that coverage chirp interference exists, the process proceeds to step S160.

[0139] When the attack determination result S10 indicates that there is no coverage chirp interference, the process proceeds to step S150.

[0140] In step S150 , the information calculation unit 240 calculates the relative distance to the object and the relative speed of the object based on the beat signal S9 .

[0141] Specifically, the information calculation unit 240 calculates the relative distance to the object and the relative speed of the object by performing 2D-FFT on the beat signal S9 .

[0142] 2D-FFT is the abbreviation of 2 Dimensional-Fast Fourier Transform. 2D-FFT refers to an FFT processing method that uses both the range FFT and Doppler FFT described below.

[0143] FFT is a type of Fourier transform.

[0144] In step S160, the distance calculation unit 252 calculates the relative distance of the object based on the beat signal S9. However, the calculation method is different from the method in step S150.

[0145] Furthermore, the speed calculation unit 253 calculates the relative speed of the object based on the beat signal S9. However, the calculation method is different from the method in step S150.

[0146] Step S160 will be described in detail later.

[0147] based on Figure 7 The attack determination process (S140) will be described.

[0148] In step S141, the attack determination unit 251 performs 2D-FFT on the beat signal S9, thereby generating an RD diagram.

[0149] RD refers to Range-Doppler.

[0150] exist Figure 8 and Fig. 9 RD diagram 300 is shown in FIG. Figure 8 An image showing an RD diagram 300 is shown. Fig. 9 300 is a schematic diagram of an RD diagram. The RD diagram 300 is a specific example of an RD diagram.

[0151] In the RD graph 300, the vertical axis represents continuous Doppler bins and the horizontal axis represents continuous range bins. The Doppler bin is the unit of the range of the Doppler and the range bin is the unit of the range of the range. In the FFT, the signal is processed in quadratic units (called NFFT) and the range (range) and Doppler (speed) are decomposed according to the units. The bins are the same as the equally spaced intervals used when drawing a histogram.

[0152] More specifically, the Doppler bin is obtained by converting the frequency (Doppler frequency) when converted to the frequency domain by FFT into Doppler information based on equation (3). Similarly, the range bin is obtained by converting the frequency (range frequency) when converted to the frequency domain by FFT into range information based on equation (4).

[0153] f d =2v d / λ Formula (3)

[0154] f r =2R / c×Bw / T s Formula (4)

[0155] Here, f d is the Doppler frequency, v d is the relative velocity (Doppler information), λ is the wavelength, and f r is the distance frequency, R is the distance (distance information), and c is the speed of light.

[0156] The identifier of each Doppler bin is referred to as a Doppler bin number, and the identifier of each range bin is referred to as a range bin number.

[0157] In the situation where the RD graph 300 is obtained, there are two objects, and one of the objects is being covered with chirp interference.

[0158] exist Fig. 9 In FIG. 1 , part (A) indicates the range affected by coverage chirp interference, and part (T) indicates the location of the object. The location of another object is included in part (A).

[0159] Back to Figure 7 , and the description continues from step S142.

[0160] In step S142, the attack determination unit 251 sets a scanning window for the RD map. For example, the scanning window is set at the upper left corner of the RD map.

[0161] The scanning window is a frame with a specific size. For example, the size of the scanning window is determined based on the resolution of the Doppler bin and the resolution of the range bin. The scanning window is large enough relative to the resolution of the Doppler bin and the resolution of the range bin.

[0162] exist Fig.10 RD diagram 300 is shown in FIG. 3 with scan window 301 set at the upper left corner.

[0163] In step S143, the attack determination unit 251 performs smoothing processing on the area within the scanning window. The area within the scanning window is referred to as a "scanning area".

[0164] The specific smoothing process is a process of finding a median (median process). However, other smoothing processes such as a process of finding an arithmetic mean (arithmetic mean process) may be performed.

[0165] In step S144 , the attack determination unit 251 calculates a representative value of the scanning area based on the result of the smoothing process.

[0166] For example, the representative value is a maximum value, an arithmetic mean, a median, a variance, a standard deviation, or the like.

[0167] In step S145 , the attack determination unit 251 determines whether scanning using the scanning window has been completed for the entire area of ​​the RD map.

[0168] When the scanning is completed, the process proceeds to step S147.

[0169] If the scan is not completed, the process proceeds to step S146.

[0170] In step S146 , the attack determination unit 251 updates the position of the scanning window.

[0171] Specifically, the attack determination unit 251 shifts the scanning window in the RD map in at least one of the range bin direction and the Doppler bin direction by a specific amount (see Fig.10 ). For example, the specific amount in the range bin direction is 1 unit in the range bin direction, and the specific amount in the Doppler bin direction is 1 unit in the Doppler bin direction. However, the scanning window may be greatly offset, for example, by 5 units.

[0172] After step S146, the process proceeds to step S143.

[0173] In step S147 , the attack determination unit 251 determines the presence or absence of coverage chirp interference based on the representative value of each scanning area.

[0174] For example, the attack determination unit 251 calculates the overall representative value of the RD graph based on the representative value of each scanning area. Then, the attack determination unit 251 compares the overall representative value with the threshold. When the overall representative value is greater than the threshold, the attack determination unit 251 determines that coverage chirp interference exists.

[0175] For example, the attack determination unit 251 compares the representative value of each scanning area with the first threshold value, and counts the number of representative values ​​greater than the first threshold value. Then, the attack determination unit 251 compares the counted number with the second threshold value. When the counted number is greater than the second threshold value, the attack determination unit 251 determines that coverage chirp interference exists.

[0176] exist Fig.11 and Fig.12 The median processing result 302 is shown in FIG. Fig.11 An image showing the median processing result 302 is shown. Fig.12 302 is a schematic diagram of the median processing result 302. The median processing result 302 is equivalent to the RD graph 300 after the median processing (refer to Figures 8 to 10 ).

[0177] In the RD diagram 300, the power of the coverage chirp interference appears to be larger than the power of the object. Therefore, when the scanning window 301 exists in the area (A) affected by the coverage chirp interference, the power of the coverage chirp interference exists in the entire area of ​​the scanning window 301, and the median becomes a larger value. On the other hand, when the scanning window 301 exists in the area not affected by the coverage chirp interference, even if there is an object, if the scanning window 301 is large enough, the median becomes a smaller value.

[0178] Therefore, if the median is calculated for the entire area of ​​the RD map 300 while shifting the scan window 301, Fig.11 and Fig.12 The median processing result 302 is shown.

[0179] Then, by comparing the representative value of each area of ​​the median processing result 302 with the threshold value, the area affected by the coverage chirp interference can be detected.

[0180] based on Fig.13 Step S160 will be described.

[0181] In step S170 , the distance calculation unit 252 calculates the relative distance of the object based on the beat signal S9 .

[0182] based on Fig.14 The procedure of the distance calculation process ( S170 ) will be described.

[0183] In step S171, the distance calculation unit 252 selects a beat signal of one waveform from the beat signal S9. The selected beat signal is referred to as a "selected beat signal".

[0184] In step S172, the distance calculation unit 252 performs range FFT on the selected beat signal. Range FFT is an FFT for obtaining a range by performing FFT on the beat signal in the sampling time direction. The range FFT can be used to find the frequency change caused by the round-trip time, thereby obtaining the distance.

[0185] Then, the distance calculation unit 252 calculates the power for each distance for the data obtained by the range FFT, and generates a power spectrum for each range bin.

[0186] exist Fig.15 A schematic diagram of the beat signal S9 is shown in FIG.

[0187] The beat signal S9 includes a plurality of beat signals having different waveforms. In other words, the beat signal S9 includes a plurality of beat signals having different waveforms.

[0188] The distance calculation unit 252 selects beat signals one waveform at a time from the beat signal S9 ( S171 ), and performs range FFT on the beat signal of each waveform ( S172 ).

[0189] Back to Fig.14 , and the description continues from step S173.

[0190] In step S173 , the distance calculation unit 252 identifies each peak in the power spectrum of the range bin, identifies the range bin corresponding to each peak, and stores the range bin number corresponding to each peak.

[0191] The peaks are also called local peaks or distance peaks.

[0192] Each peak is determined by a method such as the mountain climbing method. For example, the distance calculation unit 252 determines a point where a monotonically increasing value changes to a monotonically decreasing value as a local peak.

[0193] exist Fig.16 2 shows a power spectrum 310. The power spectrum 310 is a specific example of a power spectrum of a range bin.

[0194] The power spectrum 310 shows the power of each range bin. The downward black triangle indicates a local peak. The local peak (A) is a local peak corresponding to coverage chirp interference, and the local peaks (T1) and (T2) are local peaks corresponding to the object.

[0195] The situation shown by the power spectrum 310 is similar to that shown by the RD diagram 300 (see Figure 8 and Fig. 9 ) is the same as the situation shown in FIG. That is, there are two objects, and one of the objects is performing covering chirp interference. Moreover, the power of the covering chirp interference is dominant, and the local peak (T2) corresponding to the one object is buried.

[0196] Back to Fig.14 , and the description continues from step S174.

[0197] In step S174 , the distance calculation unit 252 determines whether or not there is a beat signal of an unselected waveform.

[0198] When there is a beat signal of a waveform that is not selected, the process proceeds to step S171 .

[0199] When there is no beat signal of an unselected waveform, the process proceeds to step S175 .

[0200] exist Fig.18 , a distance peak graph 311 is shown.

[0201] The range peak graph 311 is a specific example of a graph showing the range bins corresponding to the local peaks in the power spectrum obtained from the beat signal of each waveform, and is generated using the result of step S173 .

[0202] The range bins (T1) and (T2) are range bins of local peaks corresponding to the objects, and do not change according to the waveform. Therefore, in the range peak graph 311, point clouds corresponding to the respective objects are arranged in the waveform direction.

[0203] The range bin (A) is the range bin of the local peak corresponding to the coverage chirp interference, and varies according to the waveform. In the range peak graph 311, the point cloud corresponding to the coverage chirp interference is arranged in a straight line in the oblique direction. This is because the frequency gradually shifts in the coverage chirp interference.

[0204] Back to Fig.14 , and the description continues from step S175.

[0205] In step S175, the distance calculation unit 252 calculates the number of times the distance bin is determined to correspond to the peak for each distance bin. Specifically, the distance calculation unit 252 calculates the number of times the distance bin number is stored in step S173 for each distance bin.

[0206] The counted number refers to the sum or the additive average, and is called the "peak number", "occurrence number" or "local peak occurrence number".

[0207] Then, the distance calculation unit 252 generates a histogram indicating the number of peaks in each distance bin. The generated histogram is referred to as a "temporary histogram".

[0208] In step S176, the distance calculation unit 252 performs smoothing processing on the provisional histogram. A specific example of the smoothing processing is a process of obtaining a moving average (moving average processing).

[0209] The provisional histogram after smoothing is called a histogram of a range bin.

[0210] In step S177 , the distance calculation unit 252 identifies a peak in the histogram of distance bins, and identifies a distance bin corresponding to the peak.

[0211] Then, the distance calculation unit 252 calculates the relative distance of the object based on the distance bin number corresponding to the peak.

[0212] exist Fig.19 , a histogram 312 is shown. The histogram 312 is a specific example of a histogram of distance bins.

[0213] By using the histogram 312, it is possible to ignore the power with strong interference from the cover chirp, focus on the frequency of occurrence of the peak, and determine the range bin number corresponding to the object (T1) (T2).

[0214] Back to Fig.13 , step S180 is explained.

[0215] In step S180 , the speed calculation unit 253 calculates the relative speed of the object based on the beat signal S9 .

[0216] based on Fig. 20 The procedure of the speed calculation process ( S180 ) will be described.

[0217] In step S181, the speed calculation unit 253 extracts a beat signal of one sampling time from the beat signal S9. The sampling time is a predetermined time, and the beat signal of one sampling time is a beat signal of one time band.

[0218] The extracted beat signal is referred to as an “extracted beat signal”.

[0219] In step S182, the speed calculation unit 253 performs Doppler FFT on the extracted beat signal. Doppler FFT is an FFT used to obtain Doppler (speed) by performing FFT on the beat signal in the waveform direction. Through Doppler FFT, the phase change of each chirp can be known, and the speed can be obtained. That is, if there is a relative speed, the beat signal shifts little by little, so the Doppler FFT observes the shift as a phase change of a sine wave.

[0220] Then, the velocity calculation unit 253 calculates the power for each Doppler bin with respect to the data obtained by the Doppler FFT, and generates a power spectrum of the Doppler bin.

[0221] exist Fig.21 , a schematic diagram of the beat signal S9 is shown.

[0222] The beat signal S9 includes a plurality of beat signals with different waveforms and has a fixed time length.

[0223] The speed calculation unit 253 extracts a beat signal from the beat signal S9 at every sampling time ( S181 ), and performs Doppler FFT on the beat signal at every sampling time ( S182 ).

[0224] Back to Fig. 20 , and the description continues from step S183.

[0225] In step S183, the speed calculation unit 253 compares the power spectra of two consecutive time bands, calculates the difference between the power spectra of the two consecutive time bands, and stores the calculated difference. In this way, it is possible to separate the peak caused by the attack whose speed changes sharply with time and the peak of the detection object whose speed does not change much.

[0226] Specifically, the speed calculation unit 253 calculates the difference between the power spectrum generated this time in step S182 and the power spectrum generated last time in step S182 .

[0227] In addition, since there is no comparison object in step S183 of the first round, it is not necessary to execute step S183 of the first round.

[0228] exist Fig. 22 , a power spectrum 320 at the x-th sampling time and a power spectrum 320 at the (x+1)-th sampling time are shown. These two power spectra 320 are specific examples of power spectra of Doppler bins in two consecutive time bands.

[0229] The power spectrum 320 shows the power of each Doppler bin. The local peak (A) is a local peak corresponding to the coverage chirp interference, and the local peaks (T1) and (T2) are local peaks corresponding to the object.

[0230] The conditions represented by each power spectrum 320 are similar to those of the RD diagram 300 (see Figure 8 and Fig. 9 ) is the same as the situation shown in FIG. That is, there are two objects, and one of the objects is performing covering chirp interference. Moreover, the power of the covering chirp interference is dominant, and the local peak (T2) corresponding to the one object is buried.

[0231] The speed calculation unit 253 compares the two power spectra 320 and calculates a difference.

[0232] exist Fig.23 3 shows a difference graph 321. The difference graph 321 shows the difference between the power spectrum 320 at the x-th sampling time and the power spectrum 320 at the (x+1)-th sampling time.

[0233] In the difference graph 321 , the power of the Doppler bins corresponding to the local peaks of the two power spectra 320 is small.

[0234] The power (T1)(T2) is the difference in power of the local peak corresponding to the object, and the Doppler bin corresponding to the power (T1)(T2) does not change in any two consecutive time bands.

[0235] The power (A) is the difference of the power of the local peak corresponding to the coverage chirp interference, and the Doppler bin corresponding to the power (A) changes in two consecutive time bands. This is because the frequency gradually shifts in the coverage chirp interference.

[0236] Back to Fig. 20 , and the description continues from step S184.

[0237] In step S184 , the speed calculation unit 253 determines whether there is a beat signal in an unselected time zone.

[0238] When there is a beat signal in a time band that is not selected, the process proceeds to step S181.

[0239] When there is no beat signal in the unselected time band, the process proceeds to step S185.

[0240] In step S185 , the velocity calculation unit 253 calculates a deviation of the difference for each Doppler bin with respect to the difference stored in step S183 .

[0241] Specifically, the velocity calculation unit 253 calculates the standard deviation or variance of the difference for each Doppler bin.

[0242] In step S186 , the velocity calculation unit 253 generates a difference histogram based on the deviation of each Doppler bin.

[0243] The difference statistics graph is a graph showing the statistics of the differences between Doppler bins. Specific examples of the statistics are standard deviation, smoothed standard deviation, variance, or smoothed variance.

[0244] Specifically, the velocity calculation unit 253 performs a smoothing process on the deviation of each Doppler bin. A specific example of the smoothing process is a process of obtaining a moving average (moving average process). Then, the velocity calculation unit 253 generates a graph showing the deviation of each Doppler bin after smoothing. The generated graph is a difference statistical graph.

[0245] In step S187, the velocity calculation unit 253 identifies a peak in the difference histogram. At this time, the velocity calculation unit 253 identifies a negative peak in order to detect an object with a small change in the Doppler bin.

[0246] Next, the velocity calculation unit 253 specifies the Doppler bin corresponding to the peak.

[0247] Then, the velocity calculation unit 253 calculates the relative velocity of the object based on the Doppler bin number corresponding to the peak.

[0248] exist Fig.24 The difference statistics graph 322 is shown in . The difference statistics graph 322 shows the moving average of the standard deviation of each Doppler bin.

[0249] By using the difference statistics graph 322 , it is possible to ignore the sharp phase shift caused by the chirp interference, focus on the gentle phase change, and determine the Doppler bin number corresponding to the object ( T1 ) ( T2 ).

[0250] ***Description of Embodiments***

[0251] In the distance calculation process ( Fig.14 In S170), steps S175 to S177 may be processed as follows.

[0252] The distance calculation unit 252 calculates the deviation of the number of times the distance bin is determined to correspond to the peak for each distance bin. Specific examples of the deviation are variance and standard deviation.

[0253] Next, the distance calculation unit 252 performs processing to obtain CFAR for the deviation of each distance bin.

[0254] Then, the distance calculation unit 252 specifies a distance bin having a change smaller than a threshold value among the data obtained by the processing, and calculates the relative distance based on the distance bin number of the specified distance bin.

[0255] CFAR is the abbreviation of Constant False Alarm Rate.

[0256] In the distance calculation process ( Fig.14 In S170), steps S171 to S174 may be processed as follows.

[0257] The distance calculation unit 252 performs Doppler FFT on the beat signal S9. Then, the distance calculation unit 252 performs range FFT for each Doppler bin on the data obtained by the Doppler FFT, thereby generating a power spectrum of the range bin for each Doppler bin.

[0258] That is, the processing after step S172 can also be applied to the RD map.

[0259] In the speed calculation process ( Fig. 20 In S180), steps S185 to S187 may also be processed as follows.

[0260] The velocity calculation unit 253 calculates the sum or arithmetic average of the differences for each Doppler bin.

[0261] Next, the velocity calculation unit 253 performs a process of calculating CFAR from the sum of each Doppler bin or the arithmetic mean of each Doppler bin.

[0262] Then, the speed calculation unit 253 specifies a Doppler bin having a change smaller than a threshold value in the data obtained by the processing, and calculates the relative speed based on the Doppler bin number of the specified Doppler bin.

[0263] In the speed calculation process ( Fig. 20 In S180), steps S181 to S184 may be processed as follows.

[0264] The velocity calculation unit 253 performs range FFT on the beat signal S9. Then, the velocity calculation unit 253 performs Doppler FFT for each range bin on the data obtained by the range FFT, thereby generating a power spectrum of the Doppler bin for each range bin.

[0265] That is, the processing after step S182 can also be applied to the RD map.

[0266] The processes of the distance calculation unit 252 and the speed calculation unit 253 may be replaced with each other.

[0267] That is, the distance calculation process ( Fig.14 The waveform of S170) is replaced by one sampling time, the range FFT is replaced by the Doppler FFT, and the range bin is replaced by the Doppler bin, thereby processing it as a speed calculation.

[0268] In addition, the speed calculation process ( Fig. 20 The one sampling time of S180) is replaced by one waveform, the Doppler FFT is replaced by the range FFT, the time band is replaced by the waveform, and the Doppler bin is replaced by the range bin, thereby performing distance calculation processing.

[0269] In this case, the distance calculation unit 252 uses the beat signal S9 to generate power spectra of distance bins in different time bands or different Doppler bins, generates a differential statistical graph of statistics representing the differences between the power spectra, and calculates the distance based on the distance bin number corresponding to the peak in the differential statistical graph as the relative distance of the object.

[0270] Specifically, the distance calculation unit 252 extracts the beat signal of each time band from the beat signal S9, performs Fourier transform on the beat signal of each time band to generate power spectra of different time bands, compares the power spectra of each group of 2 consecutive time bands, calculates the difference in power of each distance bin, and generates a differential statistical chart based on the calculated difference.

[0271] Specifically, the distance calculation unit 252 uses the Doppler-range diagram obtained by Fourier transforming the beat signal S9 to generate power spectra of different Doppler bins, compares the power spectra of each group of two consecutive Doppler bins, calculates the difference in power of each distance bin, and generates a differential statistical chart based on the calculated difference.

[0272] Specifically, the distance calculation unit 252 calculates the standard deviation of the difference or the variance of the difference for each distance bin, performs smoothing processing on the standard deviation or the variance of each distance bin, and generates a difference statistical graph.

[0273] Furthermore, the velocity calculation unit 253 generates a histogram of Doppler bins using the beat signal S9 , and calculates a velocity based on a Doppler bin number corresponding to a peak in the histogram as the relative velocity of the object.

[0274] Specifically, the velocity calculator 253 performs Fourier transform on the beat signal for each waveform to generate a power spectrum of Doppler bins, identifies a Doppler bin corresponding to a peak in the power spectrum for each waveform, and generates a histogram based on the number of times each Doppler bin is identified.

[0275] Specifically, the speed calculation unit 253 uses the Doppler-range diagram obtained by Fourier transforming the beat signal S9 to generate a power spectrum of the Doppler bin for each range bin, determines the Doppler bin corresponding to the peak in the power spectrum for each range bin, and generates a histogram based on the number of times each Doppler bin is determined.

[0276] Specifically, the velocity calculation unit 253 calculates the number of times a Doppler bin is determined for each Doppler bin, generates a provisional histogram of the Doppler bin, and performs smoothing processing on the provisional histogram to generate a histogram.

[0277] The radar device 100 may also be a MIMO radar.

[0278] In this case, the radar device 100 includes a plurality of transmission antennas 113 and a plurality of reception antennas 114 . In addition, the radar device 100 includes the same number of low-pass filters 116 and ADCs 117 as the number of reception antennas 114 .

[0279] MIMO is the abbreviation of Multi-Input Multi-Output.

[0280] The radar device 100 may have a configuration that does not include either the distance calculation unit 252 or the speed calculation unit 253 .

[0281] **Effects of Implementation Method 1**

[0282] The radar device 100 achieves the following effects by designing signal processing for extracting information from the beat signal S9 within the framework of the conventional FMCW method.

[0283] The attack determination unit 251 performs attack determination based on the beat signal S8 in frame units, that is, the beat signal S9 , and obtains an attack determination result S10 .

[0284] Then, the information calculation unit 240 or the distance calculation unit 252 and the speed calculation unit 253 perform an operation according to the attack determination result S10.

[0285] Thereby, the relative distance of the object and the relative speed of the object are obtained.

[0286] The attack determination unit 251 can detect the coverage chirp interference by utilizing the fact that the coverage chirp interference generates power in a large area on the RD diagram.

[0287] Furthermore, even if the power of the object is buried by the high-power noise caused by the chirp interference, the distance calculation unit 252 can calculate the relative distance of the object, and the speed calculation unit 253 can calculate the relative speed of the object.

[0288] Implementation method 2.

[0289] Regarding a modification of the radar device 100, based on Figure 25 to Figure 28 The points different from the first embodiment will be mainly described.

[0290] ***About Modification 1***

[0291] ***Structure description***

[0292] based on Fig.25 , the structure of the radar device 100 is described.

[0293] The radar device 100 does not include the information calculation unit 240 and the attack determination unit 251 included in the configuration of the first embodiment.

[0294] ***Action description***

[0295] based on Fig.26 The following describes how to use radar.

[0296] Steps S110 to S130 are as described in the first embodiment.

[0297] After step S130, the process proceeds to step S170 and step S180.

[0298] In step S170, the distance calculation unit 252 calculates the relative distance of the object based on the beat signal S9. Step S170 is the same as that described in the first embodiment.

[0299] In step S180, the speed calculation unit 253 calculates the relative speed of the object based on the beat signal S9. Step S180 is the same as that described in the first embodiment.

[0300] ***Effects of Modification 1***

[0301] The radar device 100 can calculate the relative distance to an object and the relative speed of the object with a smaller structure.

[0302] **Supplement to Example 1**

[0303] The radar device 100 may have a configuration that does not include either the distance calculation unit 252 or the speed calculation unit 253 .

[0304] ***About Modification 2***

[0305] ***Structure description***

[0306] based on Fig. 27 The configuration of the radar device 100 will be described.

[0307] The radar device 100 further includes an information selection unit 260 in addition to the configuration of the first embodiment.

[0308] ***Action description***

[0309] based on Fig.28 The following describes how to use radar.

[0310] Steps S110 to S130 are as described in the first embodiment.

[0311] After step S130 , the process proceeds to step S140 , step S150 , and step S160 .

[0312] In step S140, the attack determination unit 251 determines whether or not there is coverage chirp interference based on the beat signal S9. Step S140 is the same as that described in the first embodiment.

[0313] In step S150 , the information calculation unit 240 calculates the relative distance to the object and the relative speed of the object based on the beat signal S9 . Step S150 is the same as that described in the first embodiment.

[0314] The relative distance and relative speed calculated in step S150 are referred to as object information S11 .

[0315] In step S160 , the distance calculation unit 252 calculates the relative distance of the object based on the beat signal S9 , and the speed calculation unit 253 calculates the relative speed of the object based on the beat signal S9 . Step S160 is the same as that described in the first embodiment.

[0316] The relative distance calculated in step S160 is referred to as a relative distance S12 , and the relative speed calculated in step S160 is referred to as a relative speed S13 .

[0317] After step S140 , step S150 , and step S160 , the process proceeds to step S191 .

[0318] In step S191, the information selection unit 260 refers to the attack determination result S10 to check whether there is coverage chirp interference.

[0319] In the absence of coverage chirp interference, the process proceeds to step S192.

[0320] In the presence of coverage chirp interference, the process proceeds to step S193.

[0321] In step S192 , the information selection unit 260 selects and outputs the object information S11 .

[0322] In step S193 , the information selection unit 260 selects and outputs the relative distance S12 and the relative speed S13 .

[0323] ***Effects of Modification 2***

[0324] The radar device 100 is similar to the first embodiment and can calculate the relative distance to the object and the relative speed of the object.

[0325] **Supplementary information on implementation methods**

[0326] based on Fig.29 The hardware configuration of the signal processing device 200 will be described.

[0327] The signal processing device 200 includes a processing circuit 209 .

[0328] The processing circuit 209 is hardware that realizes the waveform control unit 210 , the waveform shaping unit 220 , the waveform storage unit 230 , the information calculation unit 240 , the attack countermeasure unit 250 , and the information selection unit 260 .

[0329] The processing circuit 209 may be dedicated hardware, or may be the processor 201 that executes a program stored in the memory 202 .

[0330] In the case where the processing circuit 209 is dedicated hardware, the processing circuit 209 is, for example, a single circuit, a complex circuit, a programmed processor, a parallel programmed processor, an ASIC, an FPGA, or a combination thereof.

[0331] ASIC is the abbreviation of Application Specific Integrated Circuit.

[0332] FPGA is the abbreviation of Field Programmable Gate Array.

[0333] The signal processing device 200 may include a plurality of processing circuits instead of the processing circuit 209 .

[0334] In the processing circuit 209 , part of the functions may be implemented by dedicated hardware, and the remaining functions may be implemented by software or firmware.

[0335] In this way, the functions of the signal processing device 200 can be implemented by hardware, software, firmware or a combination thereof.

[0336] Each embodiment is an illustration of a preferred mode and is not intended to limit the technical scope of the present disclosure. Each embodiment may be implemented partially or in combination with other modes. The steps described using flowcharts and the like may also be appropriately changed.

[0337] The “unit” as an element of the signal processing device 200 may be replaced with “processing”, “step”, “circuit” or “line”.

[0338] Description of Reference Numerals

[0339] 100 radar device, 110 analog front end, 111 waveform generator, 112 VCO, 113 transmitting antenna, 114 receiving antenna, 115 mixer, 116 low pass filter, 117 ADC, 200 signal processing device, 201 processor, 202 memory, 203 input and output interface, 209 processing circuit, 210 waveform control unit, 220 waveform shaping unit, 230 waveform storage unit, 240 information calculation unit, 250 attack countermeasure unit, 251 attack determination unit, 252 distance calculation unit, 253 speed Degree calculation unit, 260 information selection unit, 300 RD graph, 301 scanning window, 302 median processing result, 310 power spectrum, 311 distance peak graph, 312 histogram, 320 power spectrum, 321 difference graph, 322 difference statistics graph, S1 control signal, S2 ramp signal, S3 local wave, S4 received wave, S5 mixed signal, S6 filtered signal, S7 beat signal, S8 beat signal, S9 beat signal, S10 attack judgment result, S11 object information, S12 relative distance, S13 relative speed.

Claims

1. A signal processing device, wherein: The signal processing device comprises: a waveform accumulation unit that accumulates a beat signal in frame units, the beat signal being a digital signal obtained from a mixed signal obtained by mixing a local wave transmitted for detecting an object and a received wave received as a reflected wave corresponding to the local wave; a distance calculation unit that generates a histogram of range bins using a beat signal in frame units, and calculates a distance based on a range bin number corresponding to a peak in the histogram as a relative distance to the object; as well as A speed calculation unit generates power spectra of Doppler bins of different time bands or different distance bins using a beat signal of a frame unit, generates a difference statistical graph of a statistic representing a difference between the power spectra, and calculates a speed based on a Doppler bin number corresponding to a peak in the difference statistical graph as a relative speed of the object.

2. The signal processing device according to claim 1, wherein: The beat signal of the frame unit includes multiple beat signals with different waveforms. The distance calculation unit performs Fourier transform on the beat signal for each waveform to generate a power spectrum of range bins, determines a range bin corresponding to a peak in the power spectrum for each waveform, and generates the histogram based on the number of times each range bin is determined.

3. The signal processing device according to claim 1, wherein: The distance calculation unit uses the range-Doppler map obtained by Fourier transforming the beat signal of the frame unit, generates a power spectrum of the range bin according to each Doppler bin, determines the range bin corresponding to the peak in the power spectrum according to each Doppler bin, and generates the histogram based on the number of times each range bin is determined.

4. The signal processing device according to claim 2 or 3, wherein: The distance calculation unit calculates the number of times a distance bin is determined for each distance bin, generates a provisional histogram of the distance bin, and performs a smoothing process on the provisional histogram to generate the histogram.

5. The signal processing device according to any one of claims 1 to 4, wherein: The speed calculation unit extracts the beat signal of each time band from the beat signal of the frame unit, performs Fourier transform on the beat signal of each time band to generate the power spectrum of different time bands, compares the power spectra of each group of 2 consecutive time bands, calculates the difference in power of each Doppler bin, and generates the difference statistical chart based on the calculated difference.

6. The signal processing device according to any one of claims 1 to 4, wherein: The speed calculation unit uses the range-Doppler diagram obtained by Fourier transforming the beat signal of the frame unit to generate the power spectrum of the different range bins, compares the power spectra of each group of 2 consecutive range bins, calculates the difference in power of each Doppler bin, and generates the difference statistical chart based on the calculated difference.

7. The signal processing device according to claim 5 or 6, wherein: The velocity calculation unit calculates a standard deviation of the difference or a variance of the difference for each Doppler bin, performs a smoothing process on the standard deviation of each Doppler bin or the variance of each Doppler bin, and generates the difference statistical graph.

8. The signal processing device according to any one of claims 1 to 7, wherein: The signal processing device includes an attack determination unit that generates a range-Doppler map by performing Fourier transform on a beat signal in frame units, and determines the presence or absence of coverage chirp interference based on the range-Doppler map.

9. The signal processing device according to claim 8, wherein: The attack determination unit performs smoothing processing for each region in the range-Doppler map, calculates a representative value for each region in the range-Doppler map, and determines whether there is coverage chirp interference based on the representative value of each region.

10. The signal processing device according to claim 8 or 9, wherein: The signal processing device includes an information calculation unit that performs Fourier transform on the beat signal in frame units to calculate the relative distance to the object and the relative speed of the object.

11. The signal processing device according to claim 10, wherein: The distance calculation unit calculates the relative distance when it is determined that coverage chirp interference exists. The speed calculation unit calculates the relative speed when it is determined that coverage chirp interference exists. The information calculation unit calculates the relative distance and the relative speed when it is determined that there is no coverage chirp interference.

12. The signal processing device according to claim 10, wherein: The signal processing device includes an information selection unit, which selects the relative distance calculated by the distance calculation unit and the relative speed calculated by the speed calculation unit when it is determined that there is coverage chirp interference, and selects the relative distance calculated by the information calculation unit and the relative speed calculated by the information calculation unit when it is determined that there is no coverage chirp interference.

13. A signal processing device, wherein: The signal processing device comprises: a waveform accumulation unit that accumulates a beat signal in frame units, the beat signal being a digital signal obtained from a mixed signal obtained by mixing a local wave transmitted for detecting an object and a received wave received as a reflected wave corresponding to the local wave; and A speed calculation unit uses a beat signal of a frame unit to generate power spectra of Doppler bins of different time bands or different distance bins, generates a differential statistical chart of statistics representing differences between power spectra, and calculates a speed based on a Doppler bin number corresponding to a peak in the differential statistical chart as a relative speed of the object.

14. A radar device, wherein: The radar device comprises: an analog front end that transmits a local wave, receives a reflected wave corresponding to the local wave as a received wave, mixes the local wave with the received wave to generate a mixed signal, and generates a beat signal as a digital signal corresponding to the mixed signal; and The signal processing device according to any one of claims 1 to 13.

15. A radar application method, wherein: The waveform accumulation unit accumulates a beat signal in frame units, the beat signal being a digital signal obtained from a mixed signal obtained by mixing a local wave transmitted for detecting an object and a received wave received as a reflected wave corresponding to the local wave. The distance calculation unit generates a histogram of range bins using the beat signal in frame units, and calculates a distance based on a range bin number corresponding to a peak in the histogram as a relative distance to the object. The speed calculation unit generates power spectra of Doppler bins of different time bands or different distance bins using a beat signal of a frame unit, generates a differential statistical graph representing a statistical quantity of a difference between the power spectra, and calculates a speed based on a Doppler bin number corresponding to a peak in the differential statistical graph as a relative speed of the object.

16. A radar application method, wherein: The waveform accumulation unit accumulates a beat signal in frame units, the beat signal being a digital signal obtained from a mixed signal obtained by mixing a local wave transmitted for detecting an object and a received wave received as a reflected wave corresponding to the local wave. The speed calculation unit generates power spectra of Doppler bins of different time bands or different distance bins using a beat signal of a frame unit, generates a differential statistical graph representing a statistical quantity of a difference between the power spectra, and calculates a speed based on a Doppler bin number corresponding to a peak in the differential statistical graph as a relative speed of the object.

17. A computer-readable recording medium recording a radar operation program, wherein: The radar application program is used to enable the computer to execute the following processing: A waveform accumulation process for accumulating a beat signal in frame units, the beat signal being a digital signal obtained from a mixed signal obtained by mixing a local wave transmitted for detecting an object and a received wave received as a reflected wave corresponding to the local wave; A distance calculation process of generating a histogram of distance bins using a beat signal in a frame unit, and calculating a distance based on a distance bin number corresponding to a peak in the histogram as a relative distance of the object; as well as The speed calculation process uses the beat signal of the frame unit to generate the power spectrum of the Doppler bins in different time bands or different distance bins, generates a differential statistical chart representing the statistical quantity of the difference between the power spectra, and calculates the speed based on the Doppler bin number corresponding to the peak in the differential statistical chart as the relative speed of the object.

18. A computer-readable recording medium recording a radar operation program, wherein: The radar application program is used to enable the computer to execute the following processing: a waveform accumulation process of accumulating a beat signal in frame units, the beat signal being a digital signal obtained from a mixed signal obtained by mixing a local wave transmitted for detecting an object and a received wave received as a reflected wave corresponding to the local wave; and The speed calculation process uses the beat signal of the frame unit to generate the power spectrum of the Doppler bins in different time bands or different distance bins, generates a differential statistical chart representing the statistical quantity of the difference between the power spectra, and calculates the speed based on the Doppler bin number corresponding to the peak in the differential statistical chart as the relative speed of the object.

19. A signal processing device, wherein: The signal processing device comprises: a waveform accumulation unit that accumulates a beat signal in frame units, the beat signal being a digital signal obtained from a mixed signal obtained by mixing a local wave transmitted for detecting an object and a received wave received as a reflected wave corresponding to the local wave; a velocity calculation unit that generates a histogram of Doppler bins using the beat signal in frame units, and calculates a velocity based on a Doppler bin number corresponding to a peak in the histogram as a relative velocity of the object; A distance calculation unit generates power spectra of distance bins of different time bands or different Doppler bins using a beat signal of a frame unit, generates a differential statistical graph of a statistical quantity representing a difference between the power spectra, and calculates a distance based on a distance bin number corresponding to a peak in the differential statistical graph as a relative distance of the object.

20. A signal processing device, wherein: The signal processing device comprises: a waveform accumulation unit that accumulates a beat signal in frame units, the beat signal being a digital signal obtained from a mixed signal obtained by mixing a local wave transmitted for detecting an object and a received wave received as a reflected wave corresponding to the local wave; and A distance calculation unit generates power spectra of distance bins of different time bands or different Doppler bins using a beat signal of a frame unit, generates a differential statistical graph of a statistical quantity representing a difference between the power spectra, and calculates a distance based on a distance bin number corresponding to a peak in the differential statistical graph as a relative distance of the object.

21. A radar device, wherein: The radar device comprises: an analog front end that transmits a local wave, receives a reflected wave corresponding to the local wave as a received wave, mixes the local wave with the received wave to generate a mixed signal, and generates a beat signal as a digital signal corresponding to the mixed signal; and The signal processing device according to claim 19 or 20.

22. A radar application method, wherein: The waveform accumulation unit accumulates a beat signal in frame units, the beat signal being a digital signal obtained from a mixed signal obtained by mixing a local wave transmitted for detecting an object and a received wave received as a reflected wave corresponding to the local wave. The velocity calculation unit generates a histogram of Doppler bins using the beat signal in frame units, and calculates a velocity based on a Doppler bin number corresponding to a peak in the histogram as a relative velocity of the object. The distance calculation unit generates power spectra of distance bins of different time bands or different Doppler bins using a beat signal of a frame unit, generates a differential statistical chart representing a statistical quantity of a difference between the power spectra, and calculates a distance based on a distance bin number corresponding to a peak in the differential statistical chart as a relative distance of the object.

23. A radar application method, wherein: The waveform accumulation unit accumulates a beat signal in frame units, the beat signal being a digital signal obtained from a mixed signal obtained by mixing a local wave transmitted for detecting an object and a received wave received as a reflected wave corresponding to the local wave. The distance calculation unit generates power spectra of distance bins of different time bands or different Doppler bins using a beat signal of a frame unit, generates a differential statistical chart representing a statistical quantity of a difference between the power spectra, and calculates a distance based on a distance bin number corresponding to a peak in the differential statistical chart as a relative distance of the object.

24. A computer-readable recording medium recording a radar operation program, wherein: The radar application program is used to enable the computer to execute the following processing: A waveform accumulation process for accumulating a beat signal in frame units, the beat signal being a digital signal obtained from a mixed signal obtained by mixing a local wave transmitted for detecting an object and a received wave received as a reflected wave corresponding to the local wave; a speed calculation process of generating a histogram of Doppler bins using the beat signal in frame units, and calculating a speed based on a Doppler bin number corresponding to a peak in the histogram as a relative speed of the object; and The distance calculation process uses the beat signal of the frame unit to generate the power spectrum of the distance bins of different time bands or different Doppler bins, generates a differential statistical chart representing the statistical quantity of the difference between the power spectra, and calculates the distance based on the distance bin number corresponding to the peak in the differential statistical chart as the relative distance of the object.

25. A computer-readable recording medium recording a radar operation program, wherein: The radar application program is used to enable the computer to execute the following processing: a waveform accumulation process of accumulating a beat signal in frame units, the beat signal being a digital signal obtained from a mixed signal obtained by mixing a local wave transmitted for detecting an object and a received wave received as a reflected wave corresponding to the local wave; and The distance calculation process uses the beat signal of the frame unit to generate the power spectrum of the distance bins of different time bands or different Doppler bins, generates a differential statistical chart representing the statistical quantity of the difference between the power spectra, and calculates the distance based on the distance bin number corresponding to the peak in the differential statistical chart as the relative distance of the object.

Images