WO2021240810A1 - Radar device and radar signal processing method - Google Patents

Abstract

A radar device (1) comprises: a plurality of antennas (14, 21) including one or more transmission antennas (14) and a plurality of reception antennas (21); and a radar signal processing device (7). The radar signal processing device (7) comprises: an integration-unit calculation unit (35) that sets a plurality of integration groups by grouping the plurality of reception antennas (21); a first integration unit (36) that executes a first coherent integration on an integration group internal signal corresponding to each of the plurality of integration groups, so as to generate a plurality of first integration signals corresponding respectively to the plurality of first integration groups; a second integration unit (37) that executes a second coherent integration on the plurality of first integration signals so as to generate a second integration signal; and an angle calculation unit (38) that calculates an angle value corresponding to each individual target candidate using the second integration signal.

Description

Radar device and radar signal processing method

This disclosure relates to a radar device and a radar signal processing method.

Conventionally, radar devices using multiple antennas have been developed. For example, Patent Document 1 discloses a radar device using a plurality of transmitting antennas and a plurality of receiving antennas. In the radar device described in Patent Document 1, a plurality of transmitting antennas and a plurality of receiving antennas are arranged so as to be orthogonal to each other. As a result, the antenna opening is expanded in the horizontal direction and the antenna opening is expanded in the vertical direction.

International Publication No. 2018/1292926

By using a plurality of antennas, one antenna having a large aperture can be equivalently realized. Normally, the antenna aperture length in a radar device is proportional to the angular resolution of the radar device. Therefore, by using a plurality of antennas, the angular resolution of the radar device can be improved.

However, in this case, the angle value corresponding to the target differs for each antenna. That is, a state occurs in which the target is located in the near field with respect to a plurality of antennas. This makes it difficult to integrate for angle measurement, and there is a problem that the amount of calculation for angle measurement increases.

The present disclosure has been made to solve the above-mentioned problems, and an object of the present disclosure is to reduce the amount of calculation for angle measurement in a radar device using a plurality of antennas.

The radar device according to the present disclosure is a radar device including a plurality of antennas including one or more transmitting antennas and a plurality of receiving antennas, and a radar signal processing device, wherein the radar signal processing device is a plurality of radar devices. By executing the integral unit calculation unit that sets a plurality of integral groups by grouping the receiving antennas of the above, and the first coherent integral for the signals in the integral group corresponding to each of the plurality of integral groups. The first integral unit that generates a plurality of first integral signals corresponding to each of the integral groups of the above, and the second integral unit that generates the second integral signal by executing the second coherent integral for the plurality of first integral signals. It includes an integration unit and an angle calculation unit that calculates an angle value corresponding to each target candidate using a second integration signal.

According to the present disclosure, since it is configured as described above, the integration for angle measurement can be facilitated. As a result, the amount of calculation for angle measurement can be reduced.

It is a block diagram which shows the main part of the radar apparatus which concerns on Embodiment 1. FIG. It is a block diagram which shows the main part of the 1st antenna module in the radar apparatus which concerns on Embodiment 1. FIG. It is a block diagram which shows the main part of the 1st signal processor in the radar apparatus which concerns on Embodiment 1. FIG. It is a block diagram which shows the hardware composition of the main part of the 1st signal processor in the radar apparatus which concerns on Embodiment 1. FIG. It is a block diagram which shows the other hardware composition of the main part of the 1st signal processor in the radar apparatus which concerns on Embodiment 1. FIG. It is a block diagram which shows the other hardware composition of the main part of the 1st signal processor in the radar apparatus which concerns on Embodiment 1. FIG. It is a flowchart which shows the operation of the 1st signal processor in the radar apparatus which concerns on Embodiment 1. FIG. It is explanatory drawing which shows the example of the distance bin number corresponding to a plurality of distance speed signals, the distance bin number corresponding to each distance speed signal, and the speed bin number corresponding to each distance speed signal. It is explanatory drawing which shows the example of the incoherent integration signal, the distance bin number corresponding to an incoherent integration signal, and the velocity bin number corresponding to an incoherent integration signal. It is explanatory drawing which shows the example of the arrival distance difference and the azimuth when one target is located in the distant field with respect to a plurality of receiving antennas. It is explanatory drawing which shows the example of the arrival distance difference and the azimuth when one target is located in the near field with respect to a plurality of receiving antennas. It is explanatory drawing which shows the example of a plurality of integration groups. It is explanatory drawing which shows the example of one integral group among a plurality of integral groups. It is explanatory drawing which shows the example of the receiving antenna position corresponding to each integration group, the conversion start azimuth corresponding to each integration group, and conversion end azimuth corresponding to each integration group. It is explanatory drawing which shows the example of the azimuth angle bin number which shows the maximum power in the 1st integration signal corresponding to each integration group. It is explanatory drawing which shows the other example of the azimuth angle bin number which shows the maximum power in the 1st integral signal corresponding to each integral group. It is explanatory drawing which shows the example of the plurality of first integration signals corresponding to each of a plurality of integration groups, and the second integration signal corresponding to the plurality of first integration signals. It is a block diagram which shows the main part of the radar apparatus which concerns on Embodiment 2. FIG. It is a block diagram which shows the main part of the 2nd antenna module in the radar apparatus which concerns on Embodiment 2. FIG. It is a block diagram which shows the main part of the 1st signal processor and the 2nd signal processor in the radar apparatus which concerns on Embodiment 2. FIG. It is explanatory drawing which shows the example of the plurality of integration groups corresponding one-to-one with a plurality of antenna modules. It is explanatory drawing which shows the example of the state in which a plurality of antennas are virtually arranged at equal intervals, while showing the example of the plurality of antenna arrangement intervals which are different from each other. It is explanatory drawing which shows the example of the state which the grating level exceeds a desired level. It is explanatory drawing which shows the example of the state which suppressed the grating level to a desired level or less. It is a block diagram which shows the hardware composition of the main part of the 2nd signal processor in the radar apparatus which concerns on Embodiment 2. FIG. It is a block diagram which shows the other hardware composition of the main part of the 2nd signal processor in the radar apparatus which concerns on Embodiment 2. FIG. It is a block diagram which shows the other hardware composition of the main part of the 2nd signal processor in the radar apparatus which concerns on Embodiment 2. FIG. It is a flowchart which shows the operation of the 2nd signal processor in the radar apparatus which concerns on Embodiment 2. FIG. It is a flowchart which shows the operation of the 1st signal processor in the radar apparatus which concerns on Embodiment 2. FIG.

Hereinafter, in order to explain this disclosure in more detail, a mode for carrying out this disclosure will be described with reference to the attached drawings.

Embodiment 1.
FIG. 1 is a block diagram showing a main part of the radar device according to the first embodiment. FIG. 2 is a block diagram showing a main part of the first antenna module in the radar device according to the first embodiment. FIG. 3 is a block diagram showing a main part of the first signal processor in the radar device according to the first embodiment. The radar device according to the first embodiment will be described with reference to FIGS. 1 to 3.

The radar device 1 includes a plurality of antenna groups. Each antenna group includes one or more antennas. More specifically, the plurality of antenna groups include one or more transmitting antenna groups and one or more receiving antenna groups. Each transmitting antenna group includes one or more transmitting antennas. Each receiving antenna group includes a plurality of receiving antennas.

Here, the radar device 1 includes one or more antenna modules. Each antenna group is provided in one of the corresponding antenna modules out of one or more antenna modules.

That is, each antenna module includes at least one transmitting antenna group and at least one receiving antenna group. Alternatively, each antenna module comprises at least one receiving antenna group. Alternatively, each antenna module comprises at least one transmit antenna group.

Hereinafter, an antenna module including at least one transmitting antenna group and at least one receiving antenna group may be referred to as a "first antenna module". Further, an antenna module including at least one receiving antenna group may be referred to as a "second antenna module". Further, an antenna module including at least one transmitting antenna group may be referred to as a "third antenna module".

The individual antenna modules are provided in the vehicle, for example. More specifically, the individual antenna modules are provided, for example, on the edge of the front window of the vehicle, the edge of the rear window of the vehicle, the pillars of the vehicle, the front bumper of the vehicle or the rear bumper of the vehicle. ing.

Hereinafter, in the first embodiment, an example in which one first antenna module is provided will be mainly described. Further, in the second embodiment, an example in which one first antenna module and a plurality of second antenna modules are provided will be mainly described.

As shown in FIG. 1, the radar device 1 includes a first antenna module 2_1, a first signal processor 3_1, and a display 4. The first antenna module 2_1 includes a transmitting unit 5 and a first receiving unit 6_1. The first signal processor 3_1 constitutes the main part of the radar signal processor 7.

As shown in FIG. 2, the transmission unit 5 includes a local oscillation signal generation unit 11, a code modulation unit 12, a plurality of transmitters 13, and a plurality of transmission antennas 14. The transmitting antenna group 15 is composed of a plurality of transmitting antennas 14. Further, the first receiving unit 6_1 includes a plurality of receiving antennas 21, a plurality of receivers 22, and a plurality of analog-to-digital converters (hereinafter referred to as “A / D converters”) 23. The receiving antenna group 24 is composed of a plurality of receiving antennas 21.

In the figure, _NTx indicates the number of transmission channels (hereinafter referred to as “the number of transmission channels”). The number of transmission channels _NTx corresponds to the number of transmission antennas 14. That is, the number of transmission channels _NTx corresponds to the number of transmitters 13. _{Hereinafter, the number n Tx} indicating each transmission channel may be referred to as a “transmission channel number”.

In the figure, _NRx indicates the number of receiving channels (hereinafter referred to as “number of receiving channels”). The number of receiving channels N _Rx corresponds to the number of receiving antennas 21. That is, the number of receiving channels N _Rx corresponds to the number of receivers 22 and corresponds to the number of A / D converters 23. _{Hereinafter, the number n Rx} indicating each receiving channel may be referred to as a “receiving channel number”.

Hereinafter, the RF (Radio Frequency) signal transmitted by the individual transmitting antenna 14 or the RF signal transmitted by the individual transmitting antenna 14 is collectively referred to as “transmission RF signal” or “transmission signal”. Further, the RF signal received by each receiving antenna 21 is referred to as a “reflected RF signal”. Further, the RF signal received by each receiving antenna 21 is referred to as a “received RF signal”.

The local oscillation signal generation unit 11 generates a local oscillation signal. The local oscillation signal generation unit 11 outputs the generated local oscillation signal to the code modulation unit 12. Further, the local oscillation signal generation unit 11 outputs the generated local oscillation signal to each receiver 22. The local oscillation signal generation unit 11 is configured by, for example, a dedicated circuit.

The code modulation unit 12 acquires the local oscillation signal output by the local oscillation signal generation unit 11. The code modulation unit 12 executes code modulation for the acquired locally oscillated signal. This produces a transmit RF signal corresponding to each transmit channel. The code modulation unit 12 outputs the generated transmission RF signal to the corresponding transmitter 13. The code modulation unit 12 is composed of, for example, a dedicated circuit.

The individual transmitter 13 acquires the transmission RF signal output by the code modulation unit 12. The individual transmitter 13 outputs the acquired transmission RF signal to the corresponding transmission antenna 14.

The individual transmitting antenna 14 receives the input of the transmitting RF signal output by the corresponding transmitter 13. Each transmitting antenna 14 radiates the input transmitted RF signal into space.

The transmitted RF signal radiated by the individual transmitting antennas 14 is reflected by the target. This produces a reflected RF signal. The generated reflected RF signal is incident on each receiving antenna 21. The individual receiving antennas 21 output the received RF signal corresponding to the incident reflected RF signal to the corresponding receiver 22.

Each receiver 22 acquires the local oscillation signal output by the local oscillation signal generation unit 11. Further, each receiver 22 acquires the received RF signal output by the corresponding receiving antenna 21. Each receiver 22 uses the acquired local oscillation signal and the acquired received RF signal to generate a beat signal corresponding to the corresponding receiving channel. Each receiver 22 outputs the generated beat signal to the corresponding A / D converter 23.

That _is, the _{N Rx} number of receivers _{22, N Rx} number of beat signals corresponding to _{N Rx} number of receiving channels is intended to be produced, respectively. The beat signal corresponding to each receive channel includes _{a component corresponding to NTx} transmission channels (that is, a component corresponding to _NTx transmission RF signals). Hereinafter, the beat signal corresponding to each received channel is referred to as a “received beat signal”. Further, the received RF signal or the received beat signal may be collectively referred to as a “received signal”.

The individual A / D converter 23 acquires the received beat signal output by the corresponding receiver 22. The individual A / D converter 23 converts the acquired received beat signal from an analog signal to a digital signal. Each A / D converter 23 outputs the converted received beat signal to the first signal processor 3_1.

As shown in FIG. 3, the first signal processor 3_1 includes a separation unit 31, a signal generation unit 32, an incoherent integration unit 33, a target candidate detection unit 34, an integration unit calculation unit 35, a first integration unit 36, and a second integration unit. It has a unit 37 and an angle calculation unit 38. The integration unit calculation unit 35, the first integration unit 36, and the second integration unit 37 constitute the main part of the coherent integration unit 39.

The separation unit 31 acquires the received beat signal output by each A / D converter 23. The separation unit 31 demodulates the acquired received beat signal. The demodulated received beat signal is separated into signals corresponding to individual transmission channels and separated into signals corresponding to individual reception channels. The separation unit 31 outputs the demodulated received beat signal to the signal generation unit 32.

The signal generation unit 32 acquires the received beat signal output by the separation unit 31. The signal generation unit 32 executes a discrete Fourier transform on the acquired received beat signal. As a result, a signal corresponding to the distance of each target candidate and the speed of each target candidate (hereinafter referred to as “distance speed signal”) is generated for each transmission channel and each reception channel. The signal generation unit 32 outputs the generated distance velocity signal to the incoherent integration unit 33.

The incoherent integration unit 33 acquires the distance velocity signal output by the signal generation unit 32. The incoherent integration unit 33 executes incoherent integration on the acquired distance velocity signal. The incoherent integration unit 33 outputs a signal generated by executing such incoherent integration (hereinafter referred to as “incoherent integration signal”) to the target candidate detection unit 34.

The target candidate detection unit 34 acquires the incoherent integration signal output by the incoherent integration unit 33. The target candidate detection unit 34 uses the acquired incoherent integration signal to calculate the distance value corresponding to each target candidate and the speed value corresponding to each target candidate. As a result, individual target candidates are detected.

Further, the target candidate detection unit 34 specifies a distance speed signal corresponding to each target candidate, a speed bin number corresponding to each target candidate, and a distance bin number corresponding to each target candidate. Here, the speed bin number indicates a sampling number in the speed direction. Further, the distance bin number indicates a sampling number in the distance direction. The target candidate detection unit 34 outputs the specified distance velocity signal, the specified velocity bin number, and the specified distance bin number to the coherent integration unit 39.

The integration unit calculation unit 35 sets a plurality of groups for integration (hereinafter referred to as "integration group" or "integration unit") by grouping a plurality of receiving antennas 21. At this time, the integration unit calculation unit 35 sets a plurality of integration groups so that each target candidate is approximated to be located in a distant field with respect to each integration group.

The first integration unit 36 executes coherent integration (hereinafter referred to as “first coherent integration”) for a signal corresponding to each integration group (hereinafter referred to as “integration group signal”) for each target candidate. Is. Here, as described above, a plurality of integration groups are set so that each target candidate is approximated to be located in the distant field with respect to each integration group. Therefore, the first coherent integral is based on the far field even when the corresponding target candidate is located in the near field with respect to the receiving antenna group 24.

The first integration unit 36 outputs a signal generated by executing the first coherent integration (hereinafter referred to as “first integration signal”) to the second integration unit 37. That is, the first integration unit 36 outputs the first integration signal corresponding to each integration group to the second integration unit 37.

The second integration unit 37 acquires the first integration signal output by the first integration unit 36. The second integration unit 37 executes coherent integration (hereinafter referred to as “second coherent integration”) with respect to the acquired second integration signal for each target candidate. The second integration unit 37 outputs a signal (hereinafter referred to as “second integration signal”) generated by executing the second coherent integration to the angle calculation unit 38.

The angle calculation unit 38 acquires the second integration signal output by the second integration unit 37. The angle calculation unit 38 calculates the angle value corresponding to each target candidate by using the acquired second integral signal. Each angle value indicates the azimuth angle of the corresponding target candidate.

The display 4 acquires the distance value calculated by the target candidate detection unit 34, the speed value calculated by the target candidate detection unit 34, and the angle value calculated by the angle calculation unit 38. The display 4 displays these values.

Hereinafter, the processes executed by the separation unit 31 may be collectively referred to as "separation processing". Further, the processing executed by the signal generation unit 32 may be generically referred to as "signal generation processing". Further, the processing executed by the incoherent integration unit 33 may be collectively referred to as "incoherent integration processing". Further, the processes executed by the target candidate detection unit 34 may be collectively referred to as “target candidate detection process”. Further, the processes executed by the integral unit calculation unit 35 may be collectively referred to as "integral unit calculation process". Further, the processes executed by the first integral unit 36 may be collectively referred to as "first integral process". Further, the processes executed by the second integral unit 37 may be collectively referred to as "second integral process". Further, the processes executed by the angle calculation unit 38 may be collectively referred to as "angle calculation process".

Hereinafter, the functions of the separation unit 31 may be collectively referred to as "separation function". Further, the functions of the signal generation unit 32 may be collectively referred to as a "signal generation function". Further, the functions of the incoherent integration unit 33 may be collectively referred to as "incoherent integration function". Further, the functions of the target candidate detection unit 34 may be collectively referred to as "target candidate detection function". Further, the functions of the integration unit calculation unit 35 may be collectively referred to as "integration unit calculation function". Further, the functions of the first integration unit 36 may be collectively referred to as the "first integration function". Further, the functions of the second integration unit 37 may be collectively referred to as "second integration function". Further, the functions of the angle calculation unit 38 may be collectively referred to as an "angle calculation function".

Hereinafter, the code of "F1" may be used for the separation function. Further, the code of "F2" may be used for the signal generation function. In addition, the code of "F3" may be used for the incoherent integration function. In addition, the code of "F4" may be used for the target candidate detection function. Further, the code of "F5" may be used for the integration unit calculation function. Further, the code of "F6" may be used for the first integration function. In addition, the code of "F7" may be used for the second integration function. Further, the code of "F8" may be used for the angle calculation function.

Next, the hardware configuration of the main part of the first signal processor 3_1 will be described with reference to FIGS. 4 to 6.

As shown in FIG. 4, the first signal processor 3_1 has a processor 41 and a memory 42. The memory 42 includes a plurality of functions (including a separation function, a signal generation function, an incoherent integration function, a target candidate detection function, an integration unit calculation function, a first integration function, a second integration function, and an angle calculation function) F1. The program corresponding to ~ F8 is stored. The processor 41 reads and executes the program stored in the memory 42. As a result, a plurality of functions F1 to F8 are realized.

Alternatively, as shown in FIG. 5, the first signal processor 3_1 has a processing circuit 43. The processing circuit 43 executes processing corresponding to a plurality of functions F1 to F8. As a result, a plurality of functions F1 to F8 are realized.

Alternatively, as shown in FIG. 6, the first signal processor 3_1 has a processor 41, a memory 42, and a processing circuit 43. A program corresponding to a part of the plurality of functions F1 to F8 is stored in the memory 42. The processor 41 reads and executes the program stored in the memory 42. As a result, some of these functions are realized. Further, the processing circuit 43 executes processing corresponding to the remaining functions of the plurality of functions F1 to F8. As a result, such residual functions are realized.

The processor 41 is composed of one or more processors. As the individual processor, for example, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), a microprocessor, a microprocessor, or a DSP (Digital Signal Processor) is used.

The memory 42 is composed of one or more non-volatile memories. Alternatively, the memory 42 is composed of one or more non-volatile memories and one or more volatile memories. That is, the memory 42 is composed of one or more memories. The individual memory uses, for example, a semiconductor memory, a magnetic disk, an optical disk, a magneto-optical disk, a magnetic tape, or a magnetic drum. More specifically, each volatile memory uses, for example, a RAM (Random Access Memory). The individual non-volatile memories include, for example, a ROM (Read Only Memory), a flash memory, an EPROM (Erasable Programmable Read Only Memory), an EEPROM (Electricularly Erasable Digital Memory), a flexible drive disk, a drive disk A compact disc, a DVD (Digital Versaille Disc), a Blu-ray disc, or a mini disc is used.

The processing circuit 43 is composed of one or more digital circuits. Alternatively, the processing circuit 43 is composed of one or more digital circuits and one or more analog circuits. That is, the processing circuit 43 is composed of one or more processing circuits. The individual processing circuits are, for example, ASIC (Application Specific Integrated Circuit), PLD (Programmable Logic Device), FPGA (Field Programmable Gate Array), System LSI (Sy), and System (Sy). Is.

Here, when the processor 41 is composed of a plurality of processors, the correspondence between the plurality of functions F1 to F8 and the plurality of processors is arbitrary. That is, each of the plurality of processors may read and execute a program corresponding to one or more corresponding functions among the plurality of functions F1 to F8. The processor 41 may include a dedicated processor corresponding to each of the plurality of functions F1 to F8.

Further, when the memory 42 is composed of a plurality of memories, the correspondence between the plurality of functions F1 to F8 and the plurality of memories is arbitrary. That is, each of the plurality of memories may store a program corresponding to one or more corresponding functions among the plurality of functions F1 to F8. The memory 42 may include a dedicated memory corresponding to each of the plurality of functions F1 to F8.

Further, when the processing circuit 43 is composed of a plurality of processing circuits, the correspondence between the plurality of functions F1 to F8 and the plurality of processing circuits is arbitrary. That is, each of the plurality of processing circuits may execute processing corresponding to one or more corresponding functions among the plurality of functions F1 to F8. The processing circuit 43 may include a dedicated processing circuit corresponding to each of the plurality of functions F1 to F8.

Next, the operation of the first signal processor 3_1 will be described with reference to the flowchart shown in FIG.

First, the separation unit 31 executes the separation process (step ST1). Next, the signal generation unit 32 executes the signal generation process (step ST2). Next, the incoherent integration unit 33 executes the incoherent integration process (step ST3). Next, the target candidate detection unit 34 executes the target candidate detection process (step ST4). Next, the integration unit calculation unit 35 executes the integration unit calculation process (step ST5). Next, the first integration unit 36 executes the first integration process (step ST6). Next, the second integration unit 37 executes the second integration process (step ST7). Next, the angle calculation unit 38 executes the angle calculation process (step ST8).

Next, the detailed operation of the first antenna module 2_1 will be described.

Hereinafter, when any element in an arbitrary formula is described in a sentence, the element is described in a non-italic type regardless of whether the typeface of the element in the formula is italic. Further, regardless of whether or not the typeface of the element in the mathematical formula is bold, the element is described in non-bold type. This is mainly due to the request for electronic filing. For the typeface of each element, the typeface in the mathematical formula is correct.

<Local oscillation signal generation unit 11>
The local oscillation signal generation unit 11 generates the local oscillation signal L ₁ (h, t). The local oscillation signal generation unit 11 outputs the generated local oscillation signal L ₁ (h, t) to the code modulation unit 12, and receives the generated local oscillation signal L ₁ (h, t) individually. Output to the machine 22. The local oscillation signal L ₁ (h, t) is expressed by the following equation (1).

In equation (1), j is an imaginary unit. phi ₀ is an initial phase of the local oscillation signal. h is a hit number. H is the number of hits. _AL is the amplitude of the locally oscillated signal. f ₀ is the transmission frequency of the transmission RF signal. B ₀ is a modulation band of the transmission RF signal. T ₀ is the modulation time. t is time. T _chp is a transmission repetition cycle of the transmission RF signal corresponding to the transmission channel number n _Tx. T _chp is expressed by the following equation (2).

In the equation (2), _TTx is a transmission repetition period. _TTx is expressed by the following equation (3).

In equation (3), T ₁ is the time until the next modulation is executed.

<Code modulation unit 12>
_{The code modulation unit 12 acquires the local oscillation signal L 1} (h, t) output by the local oscillation signal generation unit 11. The code modulation unit 12 _{executes code modulation for the acquired local oscillation signal L 1} (h, t). At this time, the code modulation unit 12 _{adds a modulation code to the acquired local oscillation signal L 1} (h, t), whereby the transmission RF signal Tx (n _Tx , h, t) corresponding to each transmission channel is added. ) Is generated.

In other words, the local oscillation signal L ₁ (h, t) corresponding to each transmission channel is code-modulated. This makes it possible to improve the orthogonality of the radio waves transmitted by the individual transmitting antennas 14. As a result, it is possible to facilitate the separation of the signals corresponding to the individual transmission channels. In addition, it is possible to suppress the occurrence of interference between transmission channels and the occurrence of interference with the radar device 1 due to external radio waves.

Here, a specific example of code modulation will be described. The following specific example uses a cyclic code which is a pseudo-random number.

First, the code modulation unit 12 _{cyclically shifts the cyclic code C 0} (h) with the cyclic shift amount Δh (n _Tx ) according to the following equation (4). The cyclic code C ₀ (h) is preset. The cyclic shift amount Δh (n _Tx ) is set for each transmission channel.

By executing such a cyclic shift, the modulation code Code ₁ (n _Tx , h) corresponding to each transmission channel is generated. As the cyclic code C ₀ (h), an M sequence (Maximal Sequence Sequence), a Gold sequence, or a scissors sequence may be used.

Next, the code modulation unit 12 uses the local oscillation signal L ₁ (h, t) and the modulation code Code ₁ (n _Tx , h) according to the following equation (5) to correspond to the transmission RF corresponding to each transmission channel. Generate a signal Tx (n _Tx , h, t).

Next, the code modulation unit 12 outputs the generated transmission RF signal Tx (n _Tx , h, t) to the corresponding transmitter 13.

<Transmitter 13>
Each transmitter 13 acquires the transmission RF signal Tx (n _Tx , h, t) output by the code modulation unit 12. Each transmitter 13 outputs the acquired transmission RF signal Tx (n _Tx , h, t) to the corresponding transmission antenna 14.

<Transmitting antenna 14>
Each transmitting antenna 14 receives an input of a transmitting RF signal Tx (n _Tx , h, t) output by the corresponding transmitter 13. Each transmitting antenna 14 radiates the input transmission RF signal Tx (n _Tx , h, t) into space.

<Receiving antenna 21>
The transmit RF signal Tx (n _Tx , h, t) radiated by the individual transmit antennas 14 is reflected by the target. This produces a reflected RF signal. The generated reflected RF signal is incident on each receiving antenna 21. Each receiving antenna 21 outputs the received RF signal Rx ₁ (n _Rx , h, t) corresponding to the incident reflected RF signal to the corresponding receiver 22. The received RF signal Rx ₁ (n _Rx , h, t) is expressed by the following equation (6).

As shown in the equation (6), the received RF signal Rx ₁ (n _Rx , h, t) _{corresponding to each receiving channel is N Tx} reflected RF signals Rx ₀ (n _Tx , n _Rx , h, t). It is represented by the sum of. The N _Tx reflected RF signals Rx ₀ (n _Tx , n _Rx , h, t) _{correspond to the N Tx} transmission channels, respectively. _{The reflected RF signal Rx 0} (n _Tx , n _Rx , h, t) corresponding to each transmission channel is expressed by the following equation (7).

In the formula (7), _{A R} is the amplitude of the received RF signal. R _Tx (n _Tx , h, t) is the distance between each transmit channel and the target. R _Rx (n _Rx , h, t) is the distance between each receive channel and the target. c is the speed of light. t'is the time within one hit.

<Receiver 22>
_{Each receiver 22 acquires the local oscillation signal L 1} (h, t) output by the local oscillation signal generation unit 11. _{Further, each receiver 22 acquires the received RF signal Rx 1} (n _Rx , h, t) output by the corresponding receiving antenna 21.

Each receiver 22 down-converts the acquired received RF signal Rx ₁ (n _Rx , h, t) using the acquired local oscillation signal L _{1 (h, t).} The individual receivers 22 then use a band filter to filter the down-converted signal. The individual receivers 22 then amplify the strength of the filtered signal. The individual receivers 22 then use the amplified signal to perform phase detection.

By these processing is executed in each receiver 22, the reception beat signal V _'1 corresponding to the receiving channel corresponding _{(n Rx, h, t)} is generated. That _is, in the _{N Rx} number of receivers _{22, N Rx} number of receiving the beat signal V _'1 corresponding to _{N Rx} number of receiving channels _(n Rx, h, t) is generated. Received beat signal _{V '1 (, n Rx,} h t) corresponding to each of the receiving channels is represented by the following equation (13).

In the formula (13), _{A V} is the amplitude of the received beat signal _{V '1 (n Rx, h} , t). As shown in equation (13), received corresponding to each reception channel beat signal _{V '1 (n Rx, h} , t) _{is, N Tx} number of receiving the beat signal _{V' 0 (n Tx, n} Rx, h, It is represented by the sum of t). N _Tx number of receiving the beat signal _{V '0 (n Tx, n} Rx, h, t) respectively _correspond to the _{N Tx} number of transmission channels. Received beat signal V _'0 corresponding to the individual transmission channels _{(n Tx, n Rx, h} , t) is expressed by the following equation (14).

Individual receiver 22 outputs thus received beat signal generated by _{V '1 (n Rx, h} , t) to the corresponding A / D converter 23 a.

<A / D converter 23>
Individual A / D converter 23, the corresponding received output by the receiver 22 beat signal _{V '1 (n Rx, h} , t) to obtain a. Individual A / D converter 23 converts the received beat signal is the acquired _{V '1 (n Rx, h} , t) to a digital signal from an analog signal. As a result, the received beat signal V ₁ (n _Rx , h, m) represented by the following equation (15) is generated.

_{The received beat signal V 1} (n _Rx , h, m) represented by the equation (15) corresponds to each received channel. Formula as shown in (15), receiving the beat signal corresponding to the individual receiving channel _{V 1 (n Rx, h,} m) _{is, N Tx} number of receiving the beat signal _{V 0 (n Tx, n Rx} , h, m) It is represented by the sum of. N _Tx of received beat signals V ₀ (n _Tx , n _Rx , h, m) _{correspond to N T} x of transmission channels, respectively. _{The received beat signal V 0} (n _Tx , n _Rx , h, m) corresponding to each transmission channel is expressed by the following equation (16).

In equation (16), Δt is the sampling interval within _{the modulation time T 0.} m is the sampling number of the received beat signal is sampled at the modulation time T within _0. M is the number of samples received beat signal within the modulation time T _0. In the equation (16), the ^{terms including Δt 2} and 1 / c ² are expressed approximately.

Each A / D converter 23 outputs the received beat signal V ₁ (n _Rx , h, m) thus generated to the first signal processor 3_1.

Next, the detailed operation of the first signal processor 3_1 will be described. That is, a detailed algorithm in each of steps ST1 to ST8 shown in FIG. 7 will be described.

<Separation unit 31 (step ST1)>
_{The separation unit 31 acquires the received beat signal V 1} (n _Rx , h, m) output by each A / D converter 23. The separation unit 31 demodulates the acquired received beat signal V ₁ (n _Rx , h, m) _{using the modulation code Code 1} (n _{Tx, h) corresponding to each transmission channel.} That is, the separation unit 31 _{demodulates the acquired received beat signal V 1} (n _Rx , h, m) by the following equation (17).

As a result, the received beat signals V _{1, C} (n _Tx , n _Rx , h, m) after demodulation are generated. The received beat signals V _{1, C} (n _Tx , n _Rx , h, m) after demodulation correspond to individual transmission channels and correspond to individual reception channels. In other words, the demodulated received beat signals V _{1, C} (n _Tx , n _Rx , h, m) are separated into signals corresponding to the individual transmission channels and correspond to the individual reception channels. Separated into signals.

However, for the received beat signals V _{1, C} (n _Tx , n _Rx , h, m) _{after demodulation, a signal that matches the corresponding modulation code Code 1} (n _Tx , h), that is, an autocorrelation signal V _{0. , C} (n _Tx , n _Rx , h, m) is expressed by the following equation (18). On the other hand, the received beat signals V _{1, C} (n _Tx , n _Rx , h, m) _{after demodulation do not match the corresponding modulation code Code 1} (n _Tx , h), that is, a signal V'that is cross-correlated. _{0, C} ( _n'Tx , n _Rx , h, m) is expressed by the following equation (19). Here, _n'Tx ≠ n _Tx .

The separation unit 31 outputs the demodulated received beat signals V _{1, C} (n _Tx , n _Rx , h, m) to the signal generation unit 32.

<Signal generation unit 32 (step ST2)>
The signal generation unit 32 _{acquires the received beat signals V 1, C} (n _Tx , n _Rx , h, m) after demodulation. The signal generation unit 32 executes a discrete Fourier transform on the _{acquired received beat signals V 1, C} (n _Tx , n _{Rx, h, m).} Specifically, for example, the signal generation unit 32 executes the discrete Fourier transform according to the following equation (20).

By executing such a discrete Fourier transform, a distance velocity signal f _{b, 1} (n _Tx , n _Rx , q, k) is generated. The distance velocity signals f _{b, 1} (n _Tx , n _Rx , q, k) correspond to individual transmission channels and correspond to individual reception channels. In other words, by executing such a discrete Fourier transform, a distance velocity signal f _{b, 1} (n _Tx , n _Rx , q, k) is generated for each transmission channel and each reception channel. Here, q is a speed bin number. k is a distance bin number.

At this time, the discrete Fourier transform is executed for each sampling number m and for each hit number h, so that the distance velocity signals f _{b, 1} (n _Tx , n _Rx , q, k) corresponding to the individual target candidates are executed. ) Is generated. As a result, the target candidate detection unit 34, which will be described later, can calculate the distance value corresponding to each target candidate and the speed value corresponding to each target candidate.

Further, in the radar device 1, the signal-to-noise ratio (Signal to Noise Ratio, SNR) is improved according to the _{10 log 10 (HM).} As a result, the target detection capability of the radar device 1 can be improved.

The signal generation unit 32 may use a fast Fourier transform (FFT) instead of the discrete Fourier transform. By using the fast Fourier transform, the amount of calculation in the signal generation unit 32 can be reduced. In addition, the processing speed of the signal generation unit 32 can be increased. As a result, the cost of the radar device 1 can be reduced, and the processing time of the radar signal processing device 7 can be shortened.

The signal generation unit 32 outputs the distance velocity signals f _{b, 1} (n _Tx , n _Rx , q, k) thus generated to the incoherent integration unit 33.

<Incoherent Integrator 33 (Step ST3)>
_{The incoherent integration unit 33 acquires the distance velocity signals f b, 1} (n _Tx , n _Rx , q, k) output by the signal generation unit 32. The incoherent integration unit 33 _{executes incoherent integration on the acquired distance velocity signals f b, 1} (n _Tx , n _Rx , q, k). Specifically, for example, the incoherent integration unit 33 executes the incoherent integration according to the following equation (21).

By executing such incoherent integration, incoherent integration signals f _{b, 1, inch} (q, k) are generated. The incoherent integration unit 33 outputs the generated incoherent integration signals f _{b, 1, inch} (q, k) to the target candidate detection unit 34.

FIG. 8 shows the distance velocity signal f _{b, 1} (n _Tx , n _Rx , q, k) and the distance velocity signal f _{b, 1} (n _Tx , n _Rx , q) for each transmission channel and each reception channel. , K) and an example of the speed bin number corresponding to the _{distance velocity signal f b, 1} (n _Tx , n _{Rx, q, k) are shown.} As shown in FIG. 8, a _{noise component is superimposed on the distance velocity signals f b, 1} (n _Tx , n _Rx , q, k).

On the other hand, FIG. 9 shows the incoherent integrated signal f _{b, 1, inch} (q, k), _{the distance bin number corresponding to the incoherent integrated signal f b, 1, inch} (q, k), and the incoherent. An example of the speed bin number corresponding to the integrated signal f _{b, 1, inch (q, k) is shown.}

By executing the incoherent integration shown in the equation (21), _{the electric power in the plurality of distance velocity signals f b, 1} (n _Tx , n _Rx , q, k) is integrated. That is, _{the signal strengths of N Tx} × N _Rx distance velocity signals f _{b, 1} (n _Tx , n _Rx , q, k) are integrated. As a result, the noise components are averaged (see FIGS. 8 and 9). As a result, the target detection capability of the radar device 1 can be improved.

<Target candidate detection unit 34 (step ST4)>
_{The target candidate detection unit 34 acquires the incoherent integration signals f b, 1, inch} (q, k) output by the incoherent integration unit 33. The target candidate detection unit 34 _{calculates the distance value corresponding to each target candidate based on the signal strength in the acquired incoherent integrated signal f b, 1, inch} (q, k), and also calculates the distance value corresponding to each target candidate, and the individual target candidate. Calculate the speed value corresponding to. As a result, individual target candidates are detected. For the detection of individual target candidates, for example, CA-CFAR (Cell Average Constant False Allarm Rate) processing is used. _{Hereinafter, the number n tgt} indicating each target candidate may be referred to as a “target candidate number”.

The target candidate detection unit 34 identifies the _{distance velocity signals f b, 1} (n _Tx , n _Rx , q _ntgt , k _{ntgt) corresponding to each target candidate.} Further, the target candidate detection unit 34 identifies the _{speed bin number qntgt corresponding to each target candidate.} Further, the target candidate detection unit 34 identifies the _{distance bin number kntgt corresponding to each target candidate.} The target candidate detection unit 34 has the specified distance velocity signal f _{b, 1} (n _Tx , n _Rx , q _ntgt , k _ntgt ), the specified velocity bin number q _ntgt, and the specified distance bin number k. _{The ntgt} is output to the coherent integrating unit 39.

Here, before explaining the detailed operation of the coherent integration unit 39, the premise principle and the like will be described with reference to FIGS. 10 to 13.

As shown in FIG. 10, when one target is located in the far field with respect to a plurality of receiving antennas, the azimuth angles of the targets with respect to the individual receiving antennas can be regarded as the same. In this case, the arrival distance difference Δr _nRx corresponding to each receiving antenna is expressed by the following equation (22). Further, the target azimuth angles θ _{nRx and θ0} for each receiving antenna are expressed by the following equation (23).

Here, θ ₀ is the target azimuth angle with respect to the reference point. R _{Rx, 0} (n _Rx ) is the distance between each receiving antenna and the target. _R0 is the distance between the reference point and the target. Δr _{Far, nRx, and θ0} are the arrival distance differences corresponding to the individual receiving antennas when the target azimuth with respect to the reference point is θ _{0 and the target is located in the distant field.} d _nRx is the receiving antenna interval. d _nTx is the transmission antenna interval.

As shown in the equation (23), the target azimuths θ _{nRx and θ0 with} respect to the individual receiving antennas are approximated by the _{target azimuths θ 0} with respect to the reference point. That is, the target azimuth angles θ _{nRx and θ0} for each receiving antenna are approximated by the same value.

_{Hereinafter, for each target candidate, the signals f b, 1} (n _Tx , n _Rx , q _ntgt , k _ntgt ) corresponding to each transmission channel and corresponding to each reception channel are f _{b. , 1} (n _Tx , n _Rx ).

From the equations (22) and (23), the signals f _{b, 1} (n _Tx , n _Rx ) are represented by the following equation (24).

On the other hand, it is assumed that the discrete Fourier transform according to the following equation (25) is executed. Further, it is assumed that the condition shown in the following equation (26) is satisfied. In this case, the azimuth angle θ ₀ indicating the maximum power can be calculated.

Here, s ₀ is a signal including a phase represented by the distance difference between the reference point and the target. N _fft is the Fourier transform score. n _fft is the bin number after the Fourier transform.

Thus, in the distant world, the phase difference between the receiving antennas is an integer multiple of _{d Rx} sin θ _0. Therefore, a fast Fourier transform can be performed. As a result, coherent integration can be performed with a small amount of calculation for signals corresponding to a plurality of receiving antennas (that is, signals corresponding to all receiving antennas).

In the radar device, the angular resolution can be improved by increasing the antenna opening. Therefore, it is conceivable to increase the antenna opening by increasing the number of receiving antennas. However, due to the large antenna opening, one target may be located in the near field with respect to the plurality of receiving antennas, as shown in FIG. In this case, the target azimuths for each antenna will be different from each other.

In this case, the arrival distance difference Δr _nRx corresponding to each receiving antenna is expressed by the following equation (27). Further, the target azimuth angles θ _{nRx and θ0} for each receiving antenna are expressed by the following equation (28).

As shown in equation (28), the azimuth angle theta _nRx goals for the individual receiving _{antennas, .theta.0} becomes azimuth theta ₀ values different target relative to the reference point. That is, the target azimuth angles θ _{nRx and θ0} for each receiving antenna have different values.

As described above, in the near field, the target azimuth angles θ _{nRx and θ0} with respect to the individual receiving antennas are different from each other. Therefore, it is difficult to perform a fast Fourier transform on a signal corresponding to a plurality of receiving antennas (that is, a signal corresponding to all receiving antennas). Therefore, the conventional radar device performs coherent integration on the signal by using the discrete Fourier transform. As a result, there is a problem that the amount of calculation increases as compared with the case of using the fast Fourier transform.

On the other hand, in the radar device 1, a plurality of integration groups are set so that each target candidate is approximated to be located in a distant field with respect to each integration group. Then, a coherent integral (that is, a first coherent integral) is performed on the signal corresponding to each integral group (that is, the signal in the integral group). This ensures that the first coherent integral is based on the far field, even if the individual targets are located in the near field with respect to the receiving antenna group. Therefore, a fast Fourier transform or a chirp Z transform (Chirp Z-Transform, CZT) can be used for the first coherent integral. This is intended to reduce the amount of calculation.

FIG. 12 shows an example of a plurality of integration groups. FIG. 13 shows an example of one integral group among a plurality of integral groups. In the figure, _NG indicates the number of integration groups (hereinafter referred to as “the number of integration groups”). _{Hereinafter, the number n G} indicating each integral group may be referred to as an “integral group number”. In the figure, _{NRx and Far} indicate the number of receiving antennas included in each integration group (hereinafter referred to as “the number of receiving antennas”). _{Hereinafter, the numbers n Rx and Far} indicating individual receiving antennas in each integration group may be referred to as “receiving antenna numbers”.

Here, Δr _{Near, nG, and θ0} are arrival distance differences corresponding to the receiving antennas corresponding to the receiving antenna _{numbers n Rx, Far} = 0 in each integration group, and indicate the arrival distance difference in the near field. .. Further, Δr _{Far, nGNRx, Far + nRx, Far, and θ0} are arrival distance differences corresponding to individual receiving antennas in each integration group, and indicate the arrival distance difference in the distant field.

_{In the figure, θ'indicates the} target azimuth angle with respect to the receiving antenna corresponding to the receiving antenna number n Rx, Far = 0. Further, θ "indicates the target azimuth angle with respect to the receiving antenna corresponding to the receiving antenna numbers n _{Rx, Far} = N _{Rx, Far} -1. In each integration group, the azimuth angle θ'is the azimuth angle θ". It is set within a range that can be approximated to be the same value as.

That is, as shown in FIG. 12, the target is _{located in the near field with respect to NRx, Far} × _NG receiving antennas (that is, all receiving antennas). In other words, the target is located in the vicinity of the _{NG integral group.} However, as shown in FIG. 13, the target is approximated to be located in the distant field for each integral group.

Hereinafter, the detailed operation of the coherent integrator 39 will be described based on these principles and the like.

<Integral unit calculation unit 35 (step ST5)>
In the integration unit calculation unit 35, the number of integration groups _NG and the number of receiving antennas N _{Rx, Far} are preset. Alternatively, the integration unit calculation unit 35 calculates the number of integration groups _NG and the number of receiving antennas N _{Rx, Far} as follows.

_{That is, the integration unit calculation unit 35 calculates the opening D Far} in each integration group based on the _{azimuth angle difference Δθ Far} in each integration group according to the desired angular resolution and the desired integration performance. More specifically, the integration unit calculation unit 35 calculates the opening D _Far that satisfies the condition shown in the following equation (29). Here, K _Far is a preset coefficient. D _Near is an opening in the entire receiving antenna 21, that is, an opening in the receiving antenna group 24.

Next, the integration unit calculation unit 35 calculates the number of receiving antennas N _{Rx, Far} by the following equation (30). Further, the integration unit calculation unit 35 calculates the number of integration groups _NG by the following equation (31). Here, floor (x) indicates the largest integer among the integers smaller than the variable x.

A plurality of integration unit calculation units 35 are used based on the set number of integration groups _NG and the number of receiving antennas N _{Rx, Far} , or based on the above-calculated number of integration groups _NG and the number of receiving antennas N _{Rx, Far.} The receiving antennas 21 of the above are grouped. As a result, a plurality of integration groups are set.

<First integration unit 36 (step ST6)>
As shown in the following equation (32), the signals f _{b, 1} (n _Tx , n _Rx ) are represented by the signals _{f'b, 1} (n _Tx , n _G , n _{Rx, Far} ). The signals f _{b, 1} (n _Tx , n _Rx ) are signals corresponding to individual transmission channels and corresponding to individual reception channels for each target candidate. The signals f'b _{, 1} (n _Tx , n _G , n _{Rx, Far} ) are signals corresponding to individual transmission channels and individual integration groups for individual target candidates. ..

That is, the signals f'b _{, 1} (n _Tx , n _G , n _{Rx, Far} ) are represented by a distant field within the integration group. On the other hand, the signals f'b _{, 1} (n _Tx , n _G , n _{Rx, Far} ) are represented by the neighborhood field between the integration groups. The signals f'b _{, 1} (n _Tx , n _G , n _{Rx, Far} ) in the integration group are signals corresponding to the individual integration groups, that is, signals in the integration group.

Based on these characteristics, the first integration unit 36 performs a chirp Z-transform for the _{signals f'b, 1} (n _Tx , n _G , n _{Rx, Far) in the integration group for each target candidate.} Specifically, for example, the first integration unit 36 executes the chirp Z transform according to the following equation (33). As a result, the first integral signal f _CZT (n _Tx , n _G , n _czt ) corresponding to each integral group is generated.

Here, _AnG is a conversion start phase corresponding to each integration group. W _nG is the conversion phase interval corresponding to each integration group. d _{czt, nG} is the conversion distance interval corresponding to each integration group. θ _{s and nG} are conversion start azimuths corresponding to individual integration groups. θ _{e and nG} are conversion end azimuths corresponding to individual integration groups. N _czt is the CZT score corresponding to each integration group. n _czt is the azimuth bin number of the CZT corresponding to each integration group.

_AnG is expressed by the following equation (34). W _nG is expressed by the following equation (35).

Hereinafter, the positions of the plurality of receiving antennas 21 included in the individual integration groups may be referred to as “reception antenna positions”. FIG. 14 shows an example of the receiving antenna position corresponding to each integration group, the conversion start azimuth θ _{s, nG} corresponding to each integration group, and the conversion end azimuth θ _{e, nG corresponding to each integration group.} ing.

As shown in FIG. 14, the conversion start azimuths θ _{s and nG} corresponding to the individual integration groups are the following azimuths. That is, the conversion start azimuth θ _{s, nG} is the direction when the target located at the _{conversion start azimuth θ 0, s} with respect to the reference point is viewed from the receiving antenna 21 corresponding _{to the receiving antenna number n Rx, Far = 0.} It is a horn.

Further, the conversion end azimuths θ _{e and nG} corresponding to each integration group are the following azimuth angles. That is, the conversion end azimuth θ _{e, nG} is the direction when the target located at the _{conversion end azimuth θ 0, e} with respect to the reference point is viewed from the receiving antenna 21 corresponding _{to the receiving antenna number n Rx, Far = 0.} It is a horn.

From the equation (33), when the condition shown in the following equation (36) is satisfied, the target located at the _{azimuth angle θ 0} with respect to the reference point is the azimuth with respect to the receiving antenna 21 corresponding to the receiving antenna _{number n Rx, Far = 0.} The maximum power is shown at angles θ _{nG and θ 0.}

That is, as shown in the following equation (37), the first integrated signal f _CZT (n _Tx , n _G , n _czt ) has the same azimuth bin number n'regardless of the receiving antenna position in the corresponding integration group. _The maximum power is shown in czt.

In such azimuth bin number n _'czt, far-field arrival distance difference _{Δr Far, nGNRx, Far + nRx} , Far, by integration by the phase based on _.theta.0 is made, the advent of near field distance difference [Delta] r _{Near, nG, .theta.0} It is in phase with respect to the phase based on. That is, it becomes coherent. This indicates the maximum power.

If a fast Fourier transform is performed instead of the chirp Z transform shown in equation (33), as shown in FIG. 15, the first integral signals corresponding to the individual integral groups have different azimuth bin numbers. It indicates the maximum power. As a result, processing for associating these azimuth bin numbers is required.

On the other hand, by executing the charp Z transform shown in Eq. (33), even if the target azimuth angles differ between the integration groups (see FIG. 14), _they are integrated into the same azimuth bin number n'cst. (See FIG. 16). Therefore, the first integral signal f _CZT (n _Tx , n _G , n _czt ) corresponding to each integral group shows the maximum power at the same azimuth bin number _n'cst. This makes it possible to eliminate the need for the process of associating the azimuth bin numbers. Therefore, the amount of calculation in the first integration unit 36 can be reduced. In addition, the integration loss in the first integration unit 36 can be reduced.

Further, the chirp Z transform shown in the equation (33) can be realized by using the fast Fourier transform. As a result, the amount of calculation in the first integration unit 36 can be reduced. Further, the processing time by the first integration unit 36 can be shortened.

Further, the first coherent integral can be executed in parallel for a plurality of integral groups. By using such parallel processing, the processing time by the first integration unit 36 can be shortened.

The first integration unit 36 outputs the first integration signal f _CZT (n _Tx , n _G , n _czt ) generated in this way to the second integration unit 37.

The first integration unit 36 may execute the fast Fourier transform shown in the following equation (38) instead of executing the chirp Z transform shown in the equation (33). As a result, the first integral signal _f'ft (n _Tx , n _G , n _fft ) corresponding to each integral group is generated.

From the equation (38), when the condition shown in the following equation (39) is satisfied, the target located at the _{azimuth angle θ 0} with respect to the reference point is the azimuth with respect to the receiving antenna 21 corresponding to the receiving antenna _{number n Rx, Far = 0.} The maximum power is shown at angles θ _{nG and θ 0.}

By using the fast Fourier transform shown in the equation (38), the amount of calculation in the first integrating unit 36 can be reduced as compared with the case of using the discrete Fourier transform (that is, compared with the conventional radar device). .. In addition, the integration loss in the first integration unit 36 can be reduced. However, as described above, processing for associating the angle bin number indicating the maximum power is required (see FIG. 15).

<Second integration unit 37 (step ST7)>
The second integration unit 37 acquires _{the first integration signal f CZT} (n _Tx , n _G , n _czt ) output by the first integration unit 36. The second integration unit 37 executes coherent integration with respect to the acquired first integration signal f _CZT (n _Tx , n _G , n _czt). That is, the second integration unit 37 executes the second coherent integration. As a result, the second integral signal f _DFT (n _czt ) is generated.

The second coherent integral is based on the near field. Specifically, for example, the second integration unit 37 executes the coherent integration according to the following equation (40).

Here, _R'0 is a relative distance to each target candidate. P _ncst is the target position in the azimuth bin number _{ncst of CZT.} P _nG is the position of the receiving antenna 21 corresponding to the receiving antenna _{numbers n Rx, Far} = 0 in each integration group.

P _nczt is expressed by the following equation (41). P _nG is expressed by the following equation (42).

_{From the equation (42), the azimuth angle θ 0} satisfying the condition shown in the following equation (43) indicates the maximum power. Hereinafter, the azimuth angle θ ₀ indicating the maximum power is referred to as “θ _{0, peak} ”. Further, the azimuth bin number n _ctz indicating the maximum power is described as "n _{ctz, peak} ".

The second integration unit 37 outputs the second integration signal f _DFT (n _czt ) generated in this way to the angle calculation unit 38.

FIG. 17 shows an example of a plurality of first integral signals f _CZT (n _Tx , n _G , n _{czt) corresponding to a plurality of integral groups.} That is, FIG. 17 shows an example of _{N G} number of first integration signal _f CZT corresponding to _{N G} number of integral group _{(n Tx, n G, n} czt). Further, FIG. 17 shows an example of the _{N G} number of first integration signal _{f CZT (n Tx, n G} , n czt) second integration signal corresponding to _f DFT _{(n czt).}

As shown in FIG. 17, a second integrated signal f _DFT (n _czt ) is generated by _{coherent integration with a plurality of first integrated signals f CZT} (n _Tx , n _G , n _czt). As a result, the antenna opening in the radar device 1 can be increased, so that the angular resolution of the radar device 1 can be improved. Further, since the power of the signal used for the angle measurement (that is, the second integral signal) can be increased, the angle measurement accuracy can be improved.

Further, in the radar device 1, not only the antenna opening can be increased by using a plurality of receiving antennas 21, but also a virtual array can be formed by using a plurality of transmitting antennas 14. This makes it possible to further increase the antenna opening. As a result, the angular resolution can be further improved.

Note that the modulation processing in the transmission RF signal corresponding to each transmission channel is not limited to the code modulation (that is, code division) by the code modulation unit 12. Such modulation processing may be performed as long as the separation unit 31 can realize the separation of the signals corresponding to the individual transmission channels. For example, such modulation processing may use time division, code division, frequency division, time division and code division, or frequency division and code division.

<Angle calculation unit 38 (step ST8)>
The angle calculation unit 38 acquires _{the second integration signal f DFT} (n _czt ) output by the second integration unit 37. The angle calculation unit 38 calculates an angle value corresponding to each target candidate by using the _{acquired second integral signal f DFT} (n _czt).

Specifically, for example, the angle calculation unit 38 calculates the azimuth angles θ _{0, peak corresponding to the corresponding azimuth bin numbers n ctz, peak} for each target candidate. The azimuth angle θ _{0, peak} is calculated by the following equation (44).

Here, n _{G, 0} is a receiving antenna number indicating a receiving antenna corresponding to the receiving antenna _{number n RX, Far} = 0 in the integration group corresponding to the reference point.

As described above, the radar device 1 according to the first embodiment includes a plurality of antennas (14, 21) including one or more transmitting antennas 14 and a plurality of receiving antennas 21, a radar signal processing device 7, and a radar signal processing device 7. In the radar device 1, the radar signal processing device 7 includes an integration unit calculation unit 35 that sets a plurality of integration groups by grouping a plurality of receiving antennas 21, and each of the plurality of integration groups. The first integral unit 36 that generates a plurality of first integral signals corresponding to a plurality of integral groups by executing the first coherent integral for the signals in the integral group corresponding to the above, and the plurality of first integrals. A second integration unit 37 that generates a second integration signal by executing a second coherent integration on the signal, and an angle calculation unit 38 that calculates an angle value corresponding to each target candidate using the second integration signal. , Equipped with. The angular resolution can be improved by increasing the antenna aperture by using a plurality of antennas (14, 21). Further, by setting a plurality of integration groups, coherent integration for angle measurement can be facilitated. As a result, the amount of calculation can be reduced.

Further, the radar signal processing method according to the first embodiment includes a plurality of antennas (14, 21) including one or more transmitting antennas 14 and a plurality of receiving antennas 21, and a radar signal processing device 7. In the radar signal processing method in the radar device 1, step ST5 in which the radar signal processing device 7 sets a plurality of integration groups by grouping a plurality of receiving antennas 21, and the radar signal processing device 7 Step ST6 to generate a plurality of first integrated signals corresponding to each of the plurality of integration groups by performing the first coherent integration for the signals in the integration group corresponding to each of the plurality of integration groups, and the radar signal. Step ST7, in which the processing device 7 generates the second integrated signal by performing the second coherent integration on the plurality of first integrated signals, and the radar signal processing device 7 individually use the second integrated signal. A step ST8 for calculating an angle value corresponding to a target candidate is provided. The angular resolution can be improved by increasing the antenna aperture by using a plurality of antennas (14, 21). Further, by setting a plurality of integration groups, coherent integration for angle measurement can be facilitated. As a result, the amount of calculation can be reduced.

Embodiment 2.
FIG. 18 is a block diagram showing a main part of the radar device according to the second embodiment. FIG. 19 is a block diagram showing a main part of the second antenna module in the radar device according to the second embodiment. FIG. 20 is a block diagram showing a main part of the first signal processor and the second signal processor in the radar device according to the second embodiment. The radar device according to the second embodiment will be described with reference to FIGS. 18 to 20.

In FIG. 18, the same blocks as those shown in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. Further, in FIG. 19, the same blocks as those shown in FIG. 2 are designated by the same reference numerals and the description thereof will be omitted. Further, in FIG. 20, the same blocks as those shown in FIG. 3 are designated by the same reference numerals and the description thereof will be omitted.

As shown in FIG. 18, the radar device 1a includes a first antenna module 2_1, a first signal processor 3_1, and a display 4. In addition to this, the radar device 1a includes a plurality of second antenna modules 2_2. Further, the radar device 1a includes a plurality of second antenna modules 2_2 and a plurality of second signal processors 3_2 corresponding to one-to-one. Each second signal processor 3_2 includes a second receiver 6_2. The first signal processor 3_1 and the plurality of second signal processors 3_2 constitute the main part of the radar signal processor 7a.

Note that, in FIG. 18, only one second antenna module 2_2 out of the plurality of second antenna modules 2_2 is shown. Further, in FIG. 18, only one second signal processor 3_2 out of the plurality of second signal processors 3_2 is shown.

As shown in FIG. 19, the second receiving unit 6_2 in each second antenna module 2_2 includes a local oscillation signal generation unit 11, a plurality of receiving antennas 21, a plurality of receivers 22, and a plurality of A / D converters. 23 is included. The receiving antenna group 24 is composed of a plurality of receiving antennas 21.

The local oscillation signal generation unit 11 in the second reception unit 6_2 is the same as the local oscillation signal generation unit 11 in the transmission unit 5. The plurality of receiving antennas 21, the plurality of receivers 22 and the plurality of A / D converters 23 in the second receiving unit 6_1 are the plurality of receiving antennas 21 and the plurality of receivers 22 in the first receiving unit 6_1. And a plurality of A / D converters 23. Therefore, detailed description thereof will be omitted.

Hereinafter, the number of antenna modules N _MDL in the radar device 1a may be referred to as “the number of modules”. _{Further, the number n MDL} indicating each antenna module in the radar device 1a may be referred to as a “module number”.

The radar device 1a includes a plurality of antenna modules (including one first antenna module 2_1 and _NMDL- 1 second antenna module 2_2). The plurality of antenna modules may be arranged at equal intervals or may be arranged at irregular intervals. Hereinafter, an example in which a plurality of antenna modules are arranged at unequal intervals will be mainly described.

Further, the individual antenna modules, is intended to include a plurality of antennas _(N including _Tx transmit antennas 14 and _{N Rx} receive antennas 21. Or _{comprises N Rx} receive antennas 21.). The plurality of antennas in the individual antenna modules may be arranged at equal intervals or may be arranged at irregular intervals. Hereinafter, an example in which a plurality of antennas in each antenna module are arranged at uneven intervals will be mainly described.

As shown in FIG. 20, each second signal processor 3_2 includes a separation unit 31 and a signal generation unit 32. The separation unit 31 and the signal generation unit 32 in the individual second signal processor 3_1 are the same as the separation unit 31 and the signal generation unit 32 in the first signal processor 3_1. Therefore, detailed description thereof will be omitted. Note that FIG. 20 illustrates only one second signal processor 3_2 out of the plurality of second signal processors 3_2.

As shown in FIG. 20, the first signal processor 3_1 in the radar device 1a includes a separation unit 31, a signal generation unit 32, an incoherent integration unit 33, a target candidate detection unit 34, an integration unit calculation unit 35, and a first integration unit 36. , The second integration unit 37 and the angle calculation unit 38 are included. In addition to this, the first signal processor 3_1 in the radar device 1a includes an arrangement equal spacing section 51. The integration unit calculation unit 35, the first integration unit 36, the second integration unit 37, and the arrangement equal spacing unit 51 constitute the main part of the coherent integration unit 39a.

The radar device 1a includes a receiving antenna group 24 of _NMDLs. That is, the radar device 1a includes N _Rx × N _MDL receiving antennas 21. The integration unit calculation unit 35 sets _{N MDL} integration groups _{by grouping N Rx} × N _MDL receiving antennas 21 for each antenna module.

That is, as shown in FIG. 21, a plurality of integration groups corresponding to a plurality of antenna modules on a one-to-one basis are set. In other words, _NG = N _MDL and n _G = n _MDL .

As described above, the plurality of antennas in each antenna module are arranged at unequal intervals. Therefore, in each antenna module, there are a plurality of antenna arrangement intervals d _{Rx, nRx, and Far} that are different from each other. In other words, in each integration group, there are a plurality of antenna arrangement intervals d _{Rx, nRx, Far} that are different from each other (see FIG. 22).

The arrangement equal spacing unit 51 calculates the greatest common divisor Δd _{Rx, Far} in a plurality of antenna arrangement intervals d _{Rx, nRx, Far for each integration group.} Specifically, for example, the arrangement equal spacing unit 51 calculates the _{greatest common divisor Δd Rx, Far by the following equation (45).} Here, GCD (x) indicates the greatest common divisor in the array x.

Further, the arrangement equal spacing unit 51 is based on the calculated greatest common divisor Δd _{Rx, Far} , and the following signals in the integration group _{f'b , 1} (n Tx, n _G , n _{Rx, Far, GCD).} ) Is generated. That is, the signal f'b _{, 1} (n _Tx , n _G , n _{Rx, Far, GCD} ) in the integration group is a signal corresponding to each transmission channel and is a signal corresponding to each integration group. .. Further, a plurality of signals f'b _{, 1} (n _Tx , n _G , n _{Rx, Far, GCD} ) in the integration group are included in the corresponding integration group based on the greatest common divisor Δd _{Rx, Far calculated above.} This is a signal in a state where the antennas of the above are virtually arranged at equal intervals. FIG. 22 shows an example of such a state.

Specifically, for example, the arrangement equal spacing unit 51 _{generates signals f'b, 1} (n _Tx , n _G , n _{Rx, Far, GCD} ) in the integration group by the following equation (46). Here, n _{Rx, Far, and GCD} are receiving antenna numbers in a state where a plurality of antennas in the corresponding integration group are virtually arranged at equal intervals.

When a plurality of receiving antennas 21 in each integration group are arranged at unequal intervals by using the _{signals f'b, 1} (n _Tx , n _G , n _{Rx, Far, GCD) in the integration group.} Even so, it is possible to use a fast Fourier transform or a charp Z transform for the first coherent integral. As a result, as described in the first embodiment, the amount of calculation can be reduced and the processing time can be shortened.

The arrangement equal spacing unit 51 outputs the signals f'b _{, 1} (n _Tx , n _G , n _{Rx, Far, GCD} ) in the integration group thus generated to the first integration unit 36. ..

The first integration unit 36 acquires _{signals f'b, 1} (n _Tx , n _G , n _{Rx, Far, GCD} ) in the integration group output by the arrangement equalization unit 51. When the first coherent integration is executed, the first integration unit 36 replaces the _{signals f'b, 1} (n _Tx , n _G , n _{Rx, Far) in the integration group described in the first embodiment.} The acquired signals in the integration group _{f'b , 1} (n Tx, n _G , n _{Rx, Far, GCD} ) are used. As a result, although the plurality of antennas included in the individual integration groups are arranged at equal intervals, the plurality of antennas are arranged at equal intervals in the first coherent integral. .. A fast Fourier transform or a chirp Z transform is used for the first coherent integral.

By executing the first coherent integration, the first integration signal f _CZT (n _Tx , n _G , n _czt ) is generated. The first integration unit 36 outputs the generated first integration signal f _CZT (n _Tx , n _G , n _czt ) to the second integration unit 37.

The operation of the second integrating unit 37 is the same as that described in the first embodiment. Further, the operation of the angle calculation unit 38 is the same as that described in the first embodiment. Therefore, detailed description thereof will be omitted.

Here, with reference to FIGS. 23 and 24, the effect of arranging a plurality of antenna modules at unequal intervals will be described. In addition, the effect of arranging a plurality of antennas in each antenna module at unequal intervals will be described.

When a plurality of antenna modules are arranged at equal intervals and the module arrangement intervals exceed the wavelength of the radio wave, the grating level becomes large (see FIG. 23). As a result, the grating level may exceed the desired level. This also applies when the antenna arrangement interval exceeds the wavelength of the radio wave (see FIG. 23).

On the other hand, the grating can be reduced by arranging a plurality of antenna modules at unequal intervals (see FIG. 24). Therefore, the total number of antenna modules in the radar device 1a (hereinafter referred to as "total number of modules") can be reduced in order to suppress the grating level to a desired level or lower. Further, by arranging a plurality of antennas in each antenna module at unequal intervals, the grating can be reduced (see FIG. 24). Therefore, in order to suppress the grating level to a desired level or less, the total number of antennas in each antenna module (hereinafter referred to as "total number of antennas") can be reduced.

Hereinafter, the processes executed by the arrangement equal spacing unit 51 may be collectively referred to as "arrangement equal spacing processing". Further, the functions of the arrangement equal spacing unit 51 may be collectively referred to as "arrangement equal spacing function". Further, the reference numeral of "F11" may be used for the arrangement equal spacing function.

The hardware configuration of the main part of the first signal processor 3_1 is the same as that described with reference to FIGS. 4 to 6 in the first embodiment. Therefore, detailed description thereof will be omitted.

That is, the first signal processor 3_1 has a plurality of functions (separation function, signal generation function, incoherent integration function, target candidate detection function, integration unit calculation function, arrangement equal spacing function, first integration function, second. It includes an integration function and an angle calculation function.) It has F1 to F8 and F11. Each of the plurality of functions F1 to F8 and F11 may be realized by the processor 41 and the memory 42, or may be realized by the processing circuit 43. Here, the processor 41 may include a dedicated processor corresponding to each of the plurality of functions F1 to F8 and F11. Further, the memory 42 may include a dedicated memory corresponding to each of the plurality of functions F1 to F8 and F11. Further, the processing circuit 43 may include a dedicated processing circuit corresponding to each of the plurality of functions F1 to F8 and F11.

The hardware configuration of the main part of the second signal processor 3_1 is the same as the hardware configuration of the main part of the first signal processor 3_1. Therefore, detailed description thereof will be omitted.

That is, the second signal processor 3_2 has a plurality of functions (including a separation function and a signal generation function) F1 and F2. Each of the plurality of functions F1 and F2 may be realized by the processor 41 and the memory 42, or may be realized by the processing circuit 43 (FIG. 25, FIG. 26 or FIG. 27). reference). Here, the processor 41 may include a dedicated processor corresponding to each of the plurality of functions F1 and F2. Further, the memory 42 may include a dedicated memory corresponding to each of the plurality of functions F1 and F2. Further, the processing circuit 43 may include a dedicated processing circuit corresponding to each of the plurality of functions F1 and F2.

Next, the operation of the second signal processor 3_2 will be described with reference to the flowchart shown in FIG. 28.

First, the separation unit 31 executes the separation process (step ST11). Next, the signal generation unit 32 executes the signal generation process (step ST12).

Next, the operation of the first signal processor 3_1 will be described with reference to the flowchart shown in FIG. In FIG. 29, the same steps as those shown in FIG. 7 are designated by the same reference numerals and the description thereof will be omitted.

First, the processes of steps ST1 to ST5 are executed. However, in step ST5, the integration unit calculation unit 35 sets a plurality of integration groups corresponding to a plurality of antenna modules on a one-to-one basis.

Next, the placement equal spacing unit 51 executes the placement equal spacing process (step ST21).

Next, the processes of steps ST6 to ST8 are executed. However, in step ST6, the first integration unit 36 _{replaces the signal f'b , 1} (n Tx, n _G , n _{Rx, Far} ) in the integration group with the signal _{f'b , 1} (n Tx) in the integration group. , N _G , n _{Rx, Far, GCD} ).

As described above, in the radar device 1a according to the second embodiment, the plurality of antenna modules (2_1, _1) are arranged at unequal intervals. As a result, the total number of modules can be reduced in achieving the desired grating level. As a result, the radar device 1a can be realized at low cost.

Further, a plurality of antennas (14, 21) are arranged at unequal intervals. As a result, the total number of antennas can be reduced in achieving the desired grating level. As a result, the radar device 1a can be realized at low cost.

Further, in the first integration unit 36, the plurality of antennas (14, 21) are evenly spaced based on the greatest common divisor in the plurality of arrangement intervals (antenna arrangement intervals) corresponding to the plurality of antennas (14, 21). The first coherent integral is performed assuming that it is arranged in, and the first coherent integral uses a fast Fourier transform. This makes it possible to facilitate the first coherent integration even when a plurality of antennas (14, 21) are arranged at unequal intervals. That is, the amount of calculation can be reduced and the processing time can be shortened.

Further, in the first integration unit 36, the plurality of antennas (14, 21) are evenly spaced based on the greatest common divisor in the plurality of arrangement intervals (antenna arrangement intervals) corresponding to the plurality of antennas (14, 21). The first coherent integral is performed assuming that it is arranged in, and the first coherent integral uses the charp Z-transform. This makes it possible to facilitate the first coherent integration even when a plurality of antennas (14, 21) are arranged at unequal intervals. That is, the amount of calculation can be reduced and the processing time can be shortened.

It should be noted that, within the scope of the disclosure of the present application, it is possible to freely combine each embodiment, modify any component of each embodiment, or omit any component in each embodiment. ..

The radar signal processing method according to the present disclosure can be used for a radar device. The radar device according to the present disclosure can be used, for example, in a vehicle.

1,1a Radar device, 2_1 1st antenna module, 2_1 2nd antenna module, 3_1 1st signal processor, 3_1 2nd signal processor, 4 display, 5 transmitter, 6_1 first receiver, 6_1 second receiver Unit, 7, 7a radar signal processing device, 11 local oscillation signal generator, 12 code modulator, 13 transmitter, 14 transmit antenna, 15 transmit antenna group, 21 receive antenna, 22 receiver, 23 A / D converter, 24 receiving antenna group, 31 separation unit, 32 signal generation unit, 33 incoherent integration unit, 34 target candidate detection unit, 35 integration unit calculation unit, 36 first integration unit, 37 second integration unit, 38 angle calculation unit, 39 , 39a Coherent integration unit, 41 processor, 42 memory, 43 processing circuit, 51 arrangement equal spacing unit.

Claims (18)

1. A radar device including a plurality of antennas including one or more transmitting antennas and a plurality of receiving antennas, and a radar signal processing device.
   The radar signal processing device is
   An integration unit calculation unit that sets a plurality of integration groups by grouping the plurality of receiving antennas.
   A first integration unit that generates a plurality of first integration signals corresponding to the plurality of integration groups by executing the first coherent integration for the signals in the integration group corresponding to each of the plurality of integration groups. When,
   A second integration unit that generates a second integration signal by executing a second coherent integration on the plurality of first integration signals.
   A radar device including an angle calculation unit that calculates an angle value corresponding to each target candidate using the second integration signal.
2. The radar device according to claim 1, wherein the first coherent integral is based on a distant field.
3. The radar device according to claim 1, wherein the first coherent integral is integrated so that the plurality of first integrated signals show the maximum power at the same angle bin number.
4. The radar device according to claim 1, wherein the first coherent integral uses a fast Fourier transform.
5. The radar device according to claim 3, wherein the first coherent integral uses a chirp Z-transform.
6. The radar device according to claim 1, wherein each of the plurality of antennas is provided in the corresponding antenna module among the plurality of antenna modules.
7. The radar device according to claim 6, wherein the plurality of antenna modules are arranged at unequal intervals.
8. The radar device according to claim 1 or 7, wherein the plurality of antennas are arranged at unequal intervals.
9. The first integration unit executes the first coherent integration on the assumption that the plurality of antennas are arranged at equal intervals based on the greatest common divisor at the plurality of arrangement intervals corresponding to the plurality of antennas. To do
   The radar device according to claim 8, wherein the first coherent integral uses a fast Fourier transform.
10. The first integration unit executes the first coherent integration on the assumption that the plurality of antennas are arranged at equal intervals based on the greatest common divisor at the plurality of arrangement intervals corresponding to the plurality of antennas. To do
    The radar device according to claim 8, wherein the first coherent integral uses a chirp Z-transform.
11. The radar signal processing device is
    A signal generation unit that generates a distance velocity signal corresponding to the individual target candidate by using the received signals received by the plurality of receiving antennas.
    It is characterized by including a target candidate detection unit that calculates a distance value corresponding to the individual target candidate and a speed value corresponding to the individual target candidate by using the incoherent integrated signal corresponding to the distance speed signal. The radar device according to claim 1.
12. The radar device according to claim 11, wherein the radar signal processing device includes an incoherent integrating unit that generates the incoherent integral signal by performing incoherent integration on the distance velocity signal.
13. The one or more transmitting antennas include a plurality of transmitting antennas.
    The radar device according to claim 1, wherein a modulation process for separation is executed for a transmission signal transmitted by each of the plurality of transmission antennas.
14. The radar device according to claim 13, wherein the modulation process uses time division, code division, frequency division, time division and code division, or frequency division and code division.
15. The radar device according to claim 13, wherein the modulation process uses a plurality of modulation codes corresponding to the plurality of transmitting antennas.
16. The radar device according to claim 1, wherein the plurality of antennas are provided in a vehicle.
17. Each of the plurality of antennas is provided on the edge of the front window of the vehicle, the edge of the rear window of the vehicle, the pillar of the vehicle, the front bumper of the vehicle, or the rear bumper of the vehicle. The radar device according to claim 16.
18. A radar signal processing method in a radar device including a plurality of antennas including one or more transmitting antennas and a plurality of receiving antennas, and a radar signal processing device.
    A step in which the radar signal processing device sets a plurality of integration groups by grouping the plurality of receiving antennas.
    The radar signal processing device performs the first coherent integration on the signals in the integration group corresponding to each of the plurality of integration groups, whereby the plurality of first integration signals corresponding to the plurality of integration groups are respectively. And the steps to generate
    A step in which the radar signal processing device generates a second integrated signal by performing a second coherent integral on the plurality of first integrated signals.
    A step in which the radar signal processing device calculates an angle value corresponding to each target candidate using the second integrated signal, and
    A radar signal processing method characterized by comprising.

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