Radar device

Abstract

Provided is a radar device in which a trigger signal distribution circuit (30) distributes a trigger signal from a transmission / reception module (10M) of a master module system (100) to the transmission / reception module (10M) of the master module system (100) and a transmission / reception module (20M) of a plurality of sub-module systems (200) via respectively different trigger signal cables (41), (42), and outputs a reference signal from the transmission / reception module (10M) of the master module system (100) to the transmission / reception module (20M) of the plurality of sub-module systems (200). In the transmission / reception module (20M) of the plurality of sub-module systems (200), target parameters, which are obtained by performing FFT processing on a beat signal obtained from a high-frequency chirp signal of a transmitted RF signal in a correspondence relationship with a high-frequency chirp signal of a received RF signal due to a reflected wave received by a receiving antenna (20R), are corrected by a timing deviation obtained from the beat frequency of a received beat signal, which is obtained by performing complex FFT processing on a beat signal that has been I / Q separated using the received RF signal.

Description

radar equipment

[0001] The present disclosure relates to a radar device including a master module system and a plurality of slave module systems.

[0002] In recent years, development of radar devices mounted on automobiles to detect targets has progressed. One type of radar device is FM-CW radar, which uses frequency modulated continuous waves (hereinafter abbreviated as "FM-CW"). In FM-CW radar, high-resolution target detection requires high accuracy.

[0003] To achieve high resolution, it is effective to distribute the transceiver modules equipped with multiple transceiver circuits that make up the FM-CW radar and virtually expand the antenna aperture. One known technology for achieving high resolution is the "MIMO FM-CW radar," which adopts a multi-input, multi-output (MIMO) system that makes the transceiver circuits multi-channel, aiming to equivalently expand the antenna aperture. In other words, the MIMO system is a system that virtually expands the antenna aperture using multiple transceiver circuits.

[0004] The transmitter / receiver circuits that make up FM-CW radar are typically configured with an RF (Radio Frequency) signal source and employ phase-locked loop (PLL) control. PLL control in MIMO FM-CW radar requires that the chirp start timing be synchronized between each channel.

[0005] When a MIMO FM-CW radar is installed in a vehicle, the routing or length of the connection cables connecting multiple transmitter / receiver circuits is likely to vary depending on the vehicle model. Furthermore, the impedance between channels changes depending on the degree of bending of the connection cables or the fit between the connection cable connector and the transmitter / receiver module. These factors can change the delay of the trigger signal used to synchronize the chirp start timing of each channel, resulting in insufficient synchronization between the transmitter and receiver channels and potentially reducing the detection accuracy of the radar device.

[0006] In a radar device in which multiple modules are arranged separately, a technique for adjusting a processing difference due to a difference in operation timing between the multiple modules is disclosed in Patent Document 1. The radar device disclosed in Patent Document 1 detects the phase of a reference signal transmitted from a first module to a second module, and performs control to delay the reference signal based on the detected phase, thereby ensuring synchronization between the first module and the second module.

[0007] Japanese Patent Application Laid-Open No. 2021-25834

[0008] In the radar device disclosed in Patent Document 1, when transmitting a reference signal to multiple modules, variations in the length of the connecting cables can cause the received beat frequency to fold back from the negative frequency range, which can make it difficult to accurately detect the chirp start timing difference.

[0009] The present disclosure has been made in consideration of the above points, and aims to provide a radar device that can suppress a decrease in detection accuracy even if there is variation in the length of the signal distribution cable for the master module system and multiple slave module systems.

[0010] A radar device according to the present disclosure includes a master module system, a plurality of slave module systems, and a trigger signal distribution circuit, wherein the master module system includes a transceiver module, a transmitting antenna, and a receiving antenna, and wherein each of the plurality of slave module systems includes a transceiver module, a transmitting antenna, and a receiving antenna, and the trigger signal distribution circuit distributes a trigger signal from the transceiver module of the master module system and outputs it to the transceiver module of the master module system and to the transceiver module of each of the plurality of slave module systems via different trigger signal cables, and the transceiver module of the master module system outputs a trigger signal to the trigger signal distribution circuit and outputs a reference signal to the transceiver module of each of the plurality of slave module systems, and starts generating a high frequency chirp signal based on the reference signal using the trigger signal distributed from the trigger signal distribution circuit, and outputs a transmission RF signal in which the generated high frequency chirp signal is repeated to the transmitting antenna of the master module system. and obtains target specifications by FFT-processing a beat signal obtained from a high frequency chirp signal of a transmitted RF signal that corresponds to a high frequency chirp signal of a received RF signal due to a reflected wave received by the receiving antenna of the master module system, and the transmitting / receiving module of each of the plurality of slave module systems begins generating a high frequency chirp signal based on the reference signal from the transmitting / receiving module of the master module system in response to a trigger signal distributed from the trigger signal distribution circuit, and outputs a transmitted RF signal in which the generated high frequency chirp signal is repeated to the transmitting antenna of the slave module system, and corrects the target specifications obtained by FFT-processing the beat signal obtained from the high frequency chirp signal of the transmitted RF signal that corresponds to the high frequency chirp signal of a received RF signal due to a reflected wave received by the receiving antenna of the slave module system using a timing offset obtained from the beat frequency of the received beat signal obtained by complex FFT-processing of the beat signal that has been I / Q-separated using the received RF signal.

[0011] According to the present disclosure, a decrease in detection accuracy can be suppressed by detecting and correcting a timing deviation of a trigger signal for synchronizing each module from a master module system.

[0012] FIG. 1 is a block diagram showing a radar device according to a first embodiment; FIG. 2 is a block diagram showing a signal processing unit in the radar device according to the first embodiment; FIG. 3 is a diagram showing a chirp waveform when the timing of trigger signals is shifted in two transmission / reception modules; FIG. 4 is a diagram showing the frequency of a received beat signal in each of a transmission / reception module in a master module system and a transmission / reception module in a slave module system; FIG. 5 is a block diagram showing a radar device according to a second embodiment; FIG. 6 is a diagram showing the influence of a frequency and a DC component of a received beat signal in each of a transmission / reception module in a master module system and a transmission / reception module in a slave module system; and FIG. 7 is a block diagram showing a radar device according to a third embodiment.

[0013] First Embodiment A radar device according to a first embodiment will be described with reference to Fig. 1 to Fig. 4. The radar device according to the first embodiment comprises a master module system 100 and a plurality of slave module systems 200. １ ~200 ｎ This is a MIMO type FM-CW radar with a virtually enlarged antenna aperture. １ ~200 ｎ The number n is the number required when a MIMO type FM-CW radar is mounted on a vehicle, and the number of modules is determined by a trade-off between performance and cost.

[0014] The radar device according to the first embodiment further includes a trigger signal distribution circuit 30 and trigger signal cables 40, 41, and 42. １ ~42 ｎ and a reference signal cable 50 １ ~50 ｎ Trigger signal cables 40, 41, and 42 １ ~42 ｎ and a reference signal cable 50 １ ~50 ｎ In the first embodiment, a coaxial cable is used.

[0015] A master module system 100 and a plurality of slave module systems 200 １ ~200 ｎThe modules are mounted on a vehicle such as an automobile with the distance between the modules fixed. However, although the distance between the modules is fixed, the trigger signal cables 40, 41, and 42 １ ~42 ｎ The lengths of the cables are not necessarily the same. １ ~50 ｎ The lengths of the master module system 100 and the multiple slave module systems 200 are not necessarily the same. １ ~200 ｎ The master module system 100 and the multiple slave module systems 200 share the trigger signal and the reference signal from the master module system 100. １ ~200 ｎ By sharing the trigger signal and reference signal, the frequency and operation timing are synchronized in all module systems.

[0016] The master module system 100 includes a transceiver module 10M, a transmitting antenna 10T, and a receiving antenna 10R. １ ~200 ｎ are the transmitting and receiving modules 20M １ ~20M ｎ and transmitting antenna 20T １ ~20T ｎ and receiving antenna 20R １ ~20R ｎ In addition, the slave module system 200 １ ~200 ｎ have the same configuration, and therefore, in the following explanation, one slave module system 200 will be described as a representative, and the subscripts will be omitted to avoid complication, unless it is necessary to distinguish between them.

[0017] The transmitter / receiver module 10M in the master module system 100 includes a reference signal source 110, a transmitter / receiver circuit 120, a signal processing unit 130, and an ambient temperature monitor 140. The transmitter / receiver module 10M has a transmission signal output terminal 10a, a reception signal input terminal 10b, a trigger output terminal 10c, a trigger input terminal 10d, a reference signal output terminal 10e, and a target parameter output terminal 10g. The trigger input terminal 10d and the reference signal output terminal 10e are cable connectors.

[0018] The transmitting / receiving module 20M in the slave module system 200 includes a transmitting / receiving circuit 220, a signal processing unit 230, and an ambient temperature monitor 240. The transmitting / receiving module 20M has a transmitting signal output terminal 20a, a receiving signal input terminal 20b, a trigger input terminal 20d, a reference signal input terminal 20f, a reference signal output terminal 20e, and a target specification output terminal 20g. The trigger input terminal 20d, the reference signal input terminal 20f, and the reference signal output terminal 20e are cable connectors.

[0019] The transmission / reception module 10M outputs a transmission RF signal from the transmission signal output terminal 10a to the transmission antenna 10T, receives a reception RF signal from the reception antenna 10R via the reception signal input terminal 10b, outputs a trigger signal (TRIG) from the trigger output terminal 10c to the trigger signal distribution circuit 30 via the trigger signal line 40, receives the trigger signal from the trigger signal distribution circuit 30 via the trigger signal cable 41 at the trigger input terminal 10d, and outputs a reference signal from the reference signal output terminal 10e to the transmission / reception module 20M in each of the multiple slave module systems 200.

[0020] In the first embodiment, the trigger signal output from the trigger output terminal 10c is a pulsed signal output at a cycle of, for example, 100 milliseconds. The trigger signal input from the trigger input terminal 10d is a reference signal that determines the start timing of a high-frequency chirp signal, which is a frequency-modulated signal whose frequency changes over time, and the sampling start timing of reception AD conversion units (Analog to Digital Converters: ADCs) 125I and 125Q, which will be described later.

[0021] The reference signal is a signal that serves as a reference clock for generating a high-frequency chirp signal. In the first embodiment, the high-frequency chirp signal is a signal whose frequency changes linearly from 76 GHz to 77 GHz over 100 microseconds, i.e., an up-chirp signal.

[0022] The transmitter / receiver module 10M starts generating a high-frequency chirp signal based on the reference signal, i.e., synchronized with the reference signal, in response to a trigger signal input to the trigger input terminal 10d, and outputs a transmission RF signal consisting of a repeated high-frequency chirp signal to the transmission antenna 10T via the transmission signal output terminal 10a. The transmission antenna 10T receives the transmission RF signal, converts it into a transmission wave consisting of repeated FM-CW, and radiates the transmission wave into space.

[0023] The receiving antenna 10R receives a reflected wave that is the result of the transmission wave emitted by the transmitting antenna 10T being reflected by a target. The receiving antenna 10R converts the received reflected wave into a received RF signal that is a repeated high-frequency chirp signal, and outputs the received RF signal to the transmitting / receiving module 10M via the received signal input terminal 10b. The transmitting / receiving module 10M processes the input received RF signal to calculate the target specifications (including distance, speed, and direction, hereinafter referred to as target specifications).

[0024] The method of calculating the target specifications for the target by signal processing the received RF signal is performed by a commonly known method, for example, by FFT (Fast Fourier Transform) processing a beat signal (IF signal) having a frequency that is the difference between the frequencies of the high-frequency chirp signal of the corresponding transmitted RF signal (transmitted data) and the high-frequency chirp signal of the corresponding received RF signal (received data).

[0025] The transmitter / receiver module 10M separates the received RF signal into I / Q components, performs complex FFT processing using both the I and Q components, and obtains a received beat signal from the corresponding high-frequency chirp signals of the transmitted and received RF signals. This obtained received beat signal serves as a reference received beat signal for the transmitter / receiver module 20M in the slave module system to obtain the timing offset. This function is performed before the radar device is shipped.

[0026] The transmitter / receiver module 10M monitors the ambient temperature and corrects the frequency of the received beat signal in accordance with the monitored ambient temperature. The transmitter / receiver module 10M outputs the calculated target specifications to an ECU (Electronic Control Unit) installed in the vehicle.

[0027] 1, the transceiver module 10M has a reference signal source 110, a transceiver circuit 120, a signal processing unit 130, and an ambient temperature monitor 140. The reference signal source 110 outputs a reference signal to the transceiver circuit 120, and also outputs a reference signal from a reference signal output terminal 10e to provide the reference signal to the transceiver module 20M in each of the multiple slave module systems 200. The reference signal from the reference signal source 110 is a signal that serves as a reference clock for the transceiver circuit 120.

[0028] The transmission / reception circuit 120 receives a trigger signal input to trigger input terminal 10d and a reference signal from reference signal source 110, and starts generating a high-frequency chirp signal based on the reference signal in response to the trigger signal. The circuit outputs a transmit RF signal, which is a repeating high-frequency chirp signal, to transmitting antenna 10T via transmit signal output terminal 10a. The transmission / reception circuit 120 receives a received RF signal resulting from a reflected wave received by receiving antenna 10R via received signal input terminal 10b, generates a beat signal having a frequency that is the difference between the frequencies of the corresponding high-frequency chirp signals of the transmit RF signal and the received RF signal, and outputs the I and Q signals of the I / Q separated beat signal to signal processing unit 130.

[0029] 1, the transmission / reception circuit 120 includes an RF signal source 121, an amplifier 122, a complex quadrature mixer 123, high-pass filters (HPFs) 124I and 124Q, and reception AD conversion units 125I and 125Q. The RF signal source 121 uses a reference signal as a reference clock and starts generating a high-frequency chirp signal, which is a transmission RF signal, in response to a trigger signal input from the trigger input terminal 10d. The amplifier 122 amplifies the transmission RF signal generated by the RF signal source 121 and outputs it to the transmission antenna 10T.

[0030] The quadrature mixer 123 receives the transmission RF signal from the RF signal source 121 and the reception RF signal from the reception antenna 10R and converts the reception RF signal into an I-axis reception beat signal and a Q-axis reception beat signal, which are orthogonal to each other in the I / Q system. The HPF 124I suppresses the low-frequency components of the I-axis reception beat signal. The reception AD conversion unit 125I uses the trigger signal input from the trigger input terminal 10d as the sampling start timing, and digitally converts the I-axis reception beat signal from the HPF 124I and outputs the digital signal to the signal processing unit 130.

[0031] The HPF 124Q suppresses the low-frequency components of the received beat signal for the Q axis. The receiving AD conversion unit 125Q uses the trigger signal input from the trigger input terminal 10d as the sampling start timing, and digitally converts the received beat signal for the Q axis from the HPF 124Q and outputs the digital signal to the signal processing unit 130.

[0032] The signal processing unit 130 outputs a trigger signal from the trigger output terminal 10c to the distribution circuit 30. The signal processing unit 130 obtains target parameters by FFT processing of a beat signal obtained by digitally converting a beat signal obtained from a high-frequency chirp signal of a transmission RF signal that corresponds to the high-frequency chirp signal of the reception RF signal generated by the quadrature mixer 123. The calculation of the target parameters is performed by a generally known method.

[0033] At this time, the target specifications may be corrected based on the ambient temperature monitored by the ambient temperature monitor 140. The target specifications are output to the ECU from a target specification output terminal 10g. The signal processing unit 130 may obtain the target specifications by performing complex FFT processing on the I-axis received beat signal from the reception AD conversion unit 125I and the Q-axis received beat signal from the reception AD conversion unit 125Q.

[0034] The signal processing unit 130 performs complex FFT processing on the I-axis beat signal from the reception AD conversion unit 125I and the Q-axis beat signal from the reception AD conversion unit 125Q to obtain a reception beat signal that serves as a reference for determining the timing offset of the trigger signal in the slave module system. The signal processing unit 130 corrects the frequency of the reception beat signal in accordance with the ambient temperature monitored by the ambient temperature monitor 140. This function is executed before the radar device is shipped. The ambient temperature monitor 140 measures the ambient temperature around the transmission / reception module 10M and outputs the measurement result to the signal processing unit 130.

[0035] 2, the signal processing unit 130 is composed of a processor 131, a memory 132, an input device 133, and an output device 134. The processor 131 is a central processing unit (CPU), a digital signal processor (DSP), or a field programmable gate array (FPGA). The memory 132 is a read only memory (ROM) and a random access memory (RAM).

[0036] The I-axis received beat signal from the reception AD conversion unit 125I and the Q-axis received beat signal from the reception AD conversion unit 125Q are sent to the processor 131 via the input device 133. The processor 131 reads and executes a signal processing program (including a complex FFT of the received data (beat signal)) stored in the memory 132, thereby performing processes to calculate target specifications, obtain a received beat signal for obtaining the amount of timing offset, and output the target specifications to the ECU via the output device 134. The processor 131 also performs a process to output a trigger signal to the trigger signal distribution circuit 30 via the output device 134.

[0037] The signal processing programs stored in the ROM of the memory 132 include a program for calculating target specifications, a program for obtaining a received beat signal, a program for outputting the target specifications, and a program for generating and outputting a trigger signal. The processor 131 temporarily loads the programs stored in the ROM into the RAM and executes them.

[0038] The transmitting / receiving module 20M in the slave module system 200 outputs a transmitting RF signal from the transmitting signal output terminal 20a to the transmitting antenna 20T, a receiving RF signal from the receiving antenna 20R is input via the receiving signal input terminal 20b, a trigger signal from the trigger signal distribution circuit 30 is input via the trigger signal cable 42 to the trigger input terminal 20d, and a reference signal from the transmitting / receiving module 10M in the master module system 100 is input via the reference signal input terminal 20f.

[0039] Slave module system 200 １ Transmitting and receiving module 20M in １ Reference signal input terminal 20f １ The reference signal cable 50 is connected to the reference signal output terminal 10e of the transmitting / receiving module 10M in the master module system 100. １ The transmitter / receiver module 20M is connected via the ２ ~20M ｎ Reference signal input terminal 20f ２ ~20f ｎ Each of the transmitting and receiving modules 20M has a smaller number.１ ~20M ｎ－１ Reference signal output terminal 20e １ ~20e ｎ－１ Reference signal cable 50 ２ ~50 ｎ The reference signal cable 50 is connected via the １ ~50 ｎ is a connecting cable having a pair of connectors.

[0040] The reference signal from the transmitting / receiving module 10M in the master module system 100 is transmitted to the plurality of slave module systems 200. １ ~200 ｎ Transmitting and receiving module 20M in １ ~20M ｎ The transmission / reception module 10M in the master module system 100 and the plurality of slave module systems 200 １ ~200 ｎ Transmitting and receiving module 20M in １ ~20M ｎ operates from a common reference signal.

[0041] The reference signal is transmitted to the transmitting / receiving module 10M in the master module system 100 and the plurality of slave module systems 200. １ ~200 ｎ Transmitting and receiving module 20M in １ ~20M ｎ Since the purpose is to synchronize the frequency of the transmission / reception module 20M, the frequency of the reference signal does not change even when it is transmitted. １ ~20M ｎ The operation of the reference signal cable 50 １ ~50 ｎ and the transmitting / receiving module 20M １ ~20M ｎ It is not affected by delays caused by internal transmission lines.

[0042] The transmit / receive module 20M has the same configuration and operates in the same manner as the transmit / receive module 10M in the master module system 100. That is, the transmit / receive module 20M starts generating a high-frequency chirp signal in synchronization with the reference signal input to the reference signal input terminal 20 in response to a trigger signal input to the trigger input terminal 20d, and outputs a transmit RF signal consisting of a repeated high-frequency chirp signal to the transmit antenna 20T via the transmit signal output terminal 20a. The transmit / receive module 20M processes the received RF signal input from the receive antenna 20R via the receive signal input terminal 20b to calculate target specifications for the target.

[0043] The transmitter / receiver module 20M separates the received RF signal into I / Q components, performs complex FFT processing using both the I and Q components, and obtains a received beat signal from the corresponding high-frequency chirp signal of the transmitted RF signal and the high-frequency chirp signal of the received RF signal. The transmitter / receiver module 20M obtains the timing offset of the trigger signal from the beat frequency of the obtained received beat signal and stores the timing offset. The timing offset is stored in correspondence with the monitored ambient temperature. This function is performed before the radar device is shipped.

[0044] Specifically, the timing offset of the trigger signal is obtained from the frequency difference between the beat frequency of the received beat signal obtained in the transmitting / receiving module 20M and the beat frequency of the received beat signal obtained at the same timing in the transmitting / receiving module 10M of the master module system 100. Since the received beat signal is obtained by performing complex FFT processing using both the I signal and the Q signal, the beat frequency of the received beat signal present at a negative distance is not aliased around the distance 0 (DC), and therefore the timing offset can be accurately obtained.

[0045] When the radar device is in operation, i.e., when target specifications are obtained, the transmission / reception module 20M reads out the stored timing offset, corrects the calculated target specifications in accordance with the timing offset, and outputs the corrected target specifications to the ECU. For example, the transmission / reception module 20M corrects the calculated target specifications so that the frequency difference of the beat frequency indicated by the timing offset becomes zero, and outputs the corrected target specifications to the ECU. If the target specifications are distances, the transmission / reception module 20M corrects the calculated distance values ​​so that the frequency difference of the beat frequencies becomes zero, and outputs the corrected distance information to the ECU. The transmission / reception module 20M monitors the ambient temperature and reads out the stored timing offset in accordance with the monitored ambient temperature.

[0046] 1, the transceiver module 20M has a transceiver circuit 220, a signal processing unit 230, and an ambient temperature monitor 240. The transceiver circuit 220, the signal processing unit 230, and the ambient temperature monitor 240 basically have the same configurations as the transceiver circuit 120, the signal processing unit 130, and the ambient temperature monitor 140 in the transceiver module 10M in the master module system 100, and operate in the same manner.

[0047] That is, the transmission / reception circuit 220 includes an RF signal source 221, an amplifier 222, a complex quadrature mixer 223, HPFs 224I and 224Q, and reception AD conversion units 225I and 225Q, and outputs a transmission RF signal, which is a repeated high-frequency chirp signal, to the transmission antenna 20T via the transmission signal output terminal 20a, generates a reception beat signal from the reception RF signal from the reception antenna 20R and the transmission RF signal, I / Q separates the reception beat signal, converts it into digital signals, and outputs the I signal and Q signal to the signal processing unit 130.

[0048] The signal processing unit 230 is incorporated into a hardware configuration made up of a processor 131, a memory 132, an input device 133, and an output device 134, together with the signal processing unit 130 in the master module system 100. Note that the signal processing units 230 and the signal processing unit 130 may each have a separate hardware configuration. The signal processing unit 230 obtains target specifications by FFT processing the digitally converted beat signal from the transmission / reception circuit 220.

[0049] The signal processing unit 230 obtains an I / Q separated and digitally converted received beat signal from the transmission / reception circuit 220. The signal processing unit 230 obtains a timing offset amount in the trigger signal from the frequency difference between the beat frequency in the received beat signal obtained by the signal processing unit 130 in the transmission / reception module 10M of the master module system 100 at the same timing as the beat frequency in the received beat signal, and stores the timing offset amount in the memory 132. The signal processing unit 230 stores the timing offset amount associated with the ambient temperature in accordance with the ambient temperature monitored by the ambient temperature monitor 240 in the memory 132. This function is performed before the radar device is shipped.

[0050] When the radar device is in operation, that is, when the target specifications are to be obtained, the signal processing unit 230 reads from the memory 132 the timing offset amount of the trigger signal corresponding to the ambient temperature measured by the ambient temperature monitor 240, corrects the calculated target specifications so that the frequency difference of the beat frequency indicated by the read timing offset amount becomes zero, and outputs the corrected target specifications to the ECU from the target specification output terminal 20g.

[0051] The trigger signal distribution circuit 30 distributes the trigger signal from the transmitting / receiving module 10M of the master module system 100 to different trigger signal cables 41, 42. １ ~42 ｎ through the transmission / reception module 10M of the master module system 100 and the plurality of slave module systems 200 １ ~200 ｎ Each transceiver module 20M １ ~20M ｎ The transmitter / receiver module 10M of the master module system 100 and the slave module system 200 output the distributed trigger signal. １ ~200 ｎ receives the trigger signal distributed by the trigger signal distribution circuit 30, and operates by a common trigger signal.

[0052] The trigger signal distribution circuit 30 includes a trigger input terminal 30a to which a trigger signal is input from the trigger output terminal 10c of the transmitting / receiving module 10M of the master module system 100, a trigger output terminal 31 to which a trigger signal distributed to the trigger input terminal 10d of the transmitting / receiving module 10M of the master module system 100 is output, and a plurality of slave module systems 200 １ ~200 ｎ Each transceiver module 20M １ ~20M ｎ Trigger input terminal 20d at １ ~20d ｎ Trigger output terminals 32 that output the distributed trigger signals １ ~32 ｎ The trigger output terminal 31 and the trigger output terminal 32 １ ~32 ｎ is a cable connector.

[0053] a trigger signal cable 41 connecting the trigger output terminal 31 of the trigger signal distribution circuit 30 and the trigger input terminal 10d of the transmission / reception module 10M; and a trigger signal cable 42 connecting the trigger output terminal 32 of the trigger signal distribution circuit 30. １ ~32 ｎ Each of the transmitter and receiver modules 20M １ ~20M ｎ Trigger input terminal 20d at １ ~20d ｎ A trigger signal cable 42 connects the two １ ~42 ｎ are connecting cables of approximately the same length each having a pair of connectors.

[0054] Next, the operation of the radar device according to the first embodiment will be described. The reference signal output from the reference signal source 110 of the transmission / reception module 10M in the master module system 100 is supplied to the transmission / reception circuit 120 and is also transmitted to the plurality of slave module systems 200. １ ~200 ｎ Transmitting and receiving module 20M in １ ~20M ｎ Transmitting and receiving circuit 220 １ ~220 ｎReference signal cable 50 １ ~50 ｎ and is used as a reference clock.

[0055] The RF signal source 121 in the transmission / reception circuit 120 of the transmission / reception module 10M in the master module system 100 and the plurality of slave module systems 200 １ ~200 ｎ Transmitting and receiving module 20M in １ ~20M ｎ Transmitting and receiving circuit 220 １ ~220 ｎ RF signal source 221 at １ In order to generate a high frequency chirp signal based on a common reference clock generated by a reference signal, the transmitter / receiver circuit 120 and the transmitter / receiver circuit 220 １ ~220 ｎ The high frequency chirp signal generated by the

[0056] The trigger signal output from the signal processing unit 130 of the transmitting / receiving module 10M in the master module system 100 is a periodic pulse signal. The trigger signal output from the signal processing unit 130 is distributed by the trigger signal distribution circuit 30 and is transmitted to the transmitting / receiving module 10M in the master module system 100 and the plurality of slave module systems 200. １ ~200 ｎ Transmitting and receiving module 20M in １ ~20M ｎ Trigger signal cables 41 and 42 for all １ ~42 ｎ Supplied via.

[0057] The trigger signal distributed by the trigger signal distribution circuit 30 is transmitted to the RF signal source 121 in the transmission / reception circuit 120 of the transmission / reception module 10M and to the plurality of slave module systems 200. １ ~200 ｎ Transmitting and receiving circuit 220 １ ~220 ｎ RF signal source 221 at １1 to 221, the reception AD conversion units 125I and 125Q in the transmission / reception circuit 120, and the transmission / reception circuit 220 １ ~220 ｎ This is the reference for the sampling start timing of each of the reception AD conversion unit 225I and the reception AD conversion unit 225Q.

[0058] RF signal source 121 in the transmission / reception circuit 120 and the transmission / reception circuit 220 １ ~220 ｎ RF signal source 221 at １ When a trigger signal is input to each of the RF signal source 121 in the transmission / reception circuit 120 and the transmission / reception circuit 220 １ ~220 ｎ RF signal source 221 at １ The RF signal source 121 in the transmitting / receiving circuit 120 and the transmitting / receiving circuit 220 each start generating a high-frequency chirp signal. １ ~220 ｎ RF signal source 221 at １ Upon receiving a trigger signal, each of the amplifiers 122 to 221 generates a high frequency chirp signal based on a reference signal for frequency synchronization, and then the amplifiers 122 to 222 １ ~222 ｎ A transmit RF signal is sent to each of them.

[0059] Amplifier 122 and Amplifier 222 １ ~222 ｎ Each of them amplifies a high frequency chirp signal and transmits the signal to the transmitting antenna 10T and the transmitting antenna 20T. １ ~20T ｎ The signals are sent to the transmitting antenna 10T and the transmitting antenna 20T. １ ~20T ｎ Each of them radiates a high frequency chirp signal into space as a transmission wave, and the receiving antennas 10R and 20R １ ~20R ｎ The receiving antennas 10R and 20R receive reflected waves from the target. １ ~20R ｎ The quadrature mixers 123 and 223 convert the reflected waves into received RF signals. １~223 ｎ will be sent to each.

[0060] Complex quadrature mixer 123 and complex quadrature mixer 223 １ ~223 ｎ In each case, the received RF signal is transmitted to RF signal source 121 and RF signal source 221. １ ~221 ｎ The I / Q separated beat signals (IF signals) of the I signal and the Q signal are converted into beat signals (IF signals) of the Q signal by the transmission RF signals from the quadrature mixers 123 and 223. １ ~223 ｎ The baseband signals of the I signal beat signal and the Q signal beat signal from each are passed through the HPF 124I, the HPF 124Q, and the HPF 224I. １ ~224I ｎ and HPF224Q １ ~224Q ｎ Unnecessary low frequency components are suppressed by each of the reception AD conversion units 125I, 125Q, and 225I. １ ~225I ｎ and the receiving AD conversion unit 225Q １ ~225Q ｎ The signals are converted into digital signals by the signal processors 130 and 230. １ ~230 ｎ will be sent to each.

[0061] Signal processing unit 130 and signal processing unit 230 １ ~230 ｎ In order to detect a target, each module calculates target specifications by FFT processing of beat signals (IF signals) generated by the received RF signal and the transmitted RF signal. Here, a trigger signal is sent to the transmission / reception module 10M and the transmission / reception module 20M. １ ~20M ｎ Trigger signal cables 41 and 42 are supplied to the １ ~42 ｎ If there is a variation in the length of the transceiver module 10M and the transceiver module 20M １ ~20M ｎTrigger signal cables 41 and 42 are connected to each other. １ ~42 ｎ A difference occurs in the propagation time of the trigger signal from the trigger signal distribution circuit 30 depending on the length of the １ ~20M ｎ As a result, the chirp start timing of the slave module system 200 １ ~200 ｎ In this case, the frequency and phase of the received beat signal change depending on the amount of timing deviation, resulting in an error in the target specifications.

[0062] Therefore, the radar device according to the first embodiment includes the signal processing unit 230 １ ~230 ｎ Each of them is a receiving AD conversion unit 225I １ ~225I ｎ The I-axis beat signal (IF signal) converted into a digital signal from each of the AD converters 225Q １ ~225Q ｎ The timing deviation of the trigger signal, which is obtained from the beat frequency in the received beat signal obtained by complex FFT processing of the Q-axis beat signal (IF signal) converted into a digital signal from each of the signals, is read from the memory 132, and is input to the signal processing unit 230. １ ~230 ｎ The target specifications calculated by each unit are corrected according to the amount of timing deviation read out.

[0063] The radar device according to the first embodiment includes a signal processing unit 130 and a signal processing unit 230. １ ~230 ｎ In each case, an I / Q separated received beat signal is obtained, and a signal processing unit 230 １ ~230 ｎ Each of the trigger signal cables 41 and 42 corrects the target specifications using the timing deviation of the trigger signal obtained from the difference between the beat frequency of its own received beat signal and the beat frequency of the received beat signal of the signal processing unit 130 at the same timing. １ ~42 ｎThis corrects errors in the target specifications that occur due to changes in the frequency and phase of the received beat signal caused by variations in the length of the target, thereby preventing a decrease in detection accuracy.

[0064] signal processing unit 230 １ ~230 ｎ The timing deviation of the trigger signal used in each step is detected before the shipment of the radar device, and the detected timing deviation is stored in the signal processing unit 230 as a calibration table. １ ~230 ｎ The timing deviations are stored in respective memories, and when target specifications are obtained, the timing deviations are read out from the calibration tables stored in the memories to correct the target specifications.

[0065] Next, a calibration procedure for obtaining a calibration table will be described. First, as shown in FIG. 1, the receiving antenna 10R of the master module system 100 and the receiving antenna 10R of the slave module system 200 are connected to each other. １ ~200 ｎ Receiving antenna 20R １ ~20R ｎ A target Tg or a target simulator is prepared, which is placed at a position equidistant from the target Tg.

[0066] A transmission wave is emitted from the transmitting antenna 10T of the master module system 100 toward the target Tg, and a reflected wave of the transmission wave from the target Tg is received by the receiving antenna 10R of the master module system 100 and the slave module system 200. １ ~200 ｎ Receiving antenna 20R １ ~20R ｎ At this time, the slave module system 200 １ ~200 ｎ Transmitting antenna 20T １ ~20T ｎ It is assumed that no transmitted waves are emitted from the

[0067] The signal processing unit 130 of the transmitting / receiving module 10M in the master module system 100 and the slave module system 200 １ ~200 ｎ Transmitting and receiving module 20M in １ ~20M ｎsignal processing unit 230 １ ~230 ｎ Each of the signal processors 230 obtains an I / Q separated received beat signal. １ ~230 ｎ Each stores in memory 132 a frequency difference between the beat frequency of its own I / Q separated received beat signal and the beat frequency of the I / Q separated received beat signal from signal processing unit 130 obtained at the same timing as the beat frequency of the I / Q separated received beat signal from signal processing unit 130, as a timing deviation amount of the trigger signal, in association with the ambient temperature monitored by ambient temperature monitor 240.

[0068] signal processing unit 230 １ ~230 ｎ In the above, the calculation of the timing deviation of the trigger signal is the same, so hereinafter, the slave module system 200 １ The calculation of the timing deviation amount in the above case will be described below. In the explanation, subscripts will be omitted. Now, the trigger signal input to the transmission / reception circuit 220 in the slave module system 200 is delayed by a time τ error Assume that the input is delayed.

[0069] As a result, the chirp signal start timing of the RF signal source 221 in the slave module system 200 is delayed by a time τ error 3, the transmitted RF signal TR from the RF signal source 221 Ｓ is the transmitted RF signal TR from the RF signal source 121. Ｍ More time τ error Be late.

[0070] On the other hand, the received RF signal RE input to the quadrature mixer 123 in the master module system 100 Ｍ As shown in FIG. 3, the transmitted RF signal TR Ｍ More time τ １ The received RF signal RE input to the quadrature mixer 223 in the slave module system 200 is delayed. Ｓ is the received RF signal RE as shown in FIG. Ｍ and the transmission RF signal TR Ｍ More time τ１ Be late.

[0071] 3 shows the chirp waveforms of the master module system 100 and the slave module system 200. In FIG. 3, the horizontal axis represents time, the vertical axis represents frequency, and the TR Ｍ is the transmission RF signal of the transceiver module 10M in the master module system 100, RE Ｍ is the received RF signal of the transceiver module 10M in the master module system 100, and TR Ｓ is the transmission RF signal of the transceiver module 10M in the slave module system 200, RE Ｓ indicates the RF signal received by the transmitting / receiving module 10M in the slave module system 200.

[0072] The signal processing unit 130 receives the RF signal RE. Ｍ and the transmitted RF signal TR Ｍ A received beat signal BF is converted by performing complex FFT processing using the beat signal Ｍ The beat frequency f ｉｆ＿Ｍ and the signal processing unit 230 receives the RF signal RE. Ｓ and the transmitted RF signal TR Ｓ A received beat signal BF is converted by performing complex FFT processing using the beat signal Ｓ The beat frequency f ｉｆ＿Ｓ In FIG. 4, the horizontal axis represents the distance (beat frequency) and the vertical axis represents the level. Ｍ is the received beat signal calculated by the signal processing unit 130, BF Ｓ indicates the received beat signal calculated by the signal processing unit 230.

[0073] As shown in FIG. error is the time τ １ is greater than the time τ error Due to the influence of Ｓ is the transmitted RF signal TR Ｓ Even if the received RF signal RE is input to the quadrature mixer 223 at an earlier timing, the quadrature mixer 223 Ｓ and the transmitted RF signal TR ＳThe beat signal (IF signal) is separated into I / Q signals, and the signal processing unit 230 performs complex FFT processing using both the I signal and the Q signal. Ｓ is in the negative frequency region, the received beat signal BF is not aliased, as shown in FIG. Ｓ indicates the correct value.

[0074] The received beat signal BF obtained by the signal processing unit 130 Ｍ The beat frequency f ｉｆ＿Ｍ can be expressed by the following equation (1), and the received beat signal BF obtained by the signal processing unit 230 Ｓ The beat frequency f ｉｆ＿Ｓ can be expressed by the following formula (2): f ｉｆ＿Ｍ = (B / T ｃ )τ1...(1) f ｉｆ＿Ｓ = (B / T ｃ ) (τ １ -τ error ) ... (2) In the above equations (1) and (2), B is the chirp frequency bandwidth, T ｃ is the chirp time.

[0075] The timing shift f of the trigger signal in the slave module system 200 relative to the master module system 100 ｉｆ＿(S -M) is the received beat signal BF Ｍ The beat frequency f ｉｆ＿Ｍ Received beat signal BF Ｓ The beat frequency f ｉｆ＿Ｓ This corresponds to the frequency difference of f and can be expressed by the following equation (3): ｉｆ＿(S -M) = f ｉｆ＿Ｓ -f ｉｆ＿Ｍ　　　　 ... (3) Time τ error is the time τ １ Even if the received beat signal BF Ｓ The beat frequency f ｉｆ＿Ｓ Since the timing deviation f ｉｆ＿(S -M) also shows the correct value.

[0076] The signal processing unit 130 calculates the timing deviation f obtained by the above equation (3). ｉｆ＿(S-M) The temperature is stored in the memory 132 in association with the ambient temperature. １ ~200 ｎ Transmitting and receiving module 20M in １ ~20M ｎ While changing the ambient temperature of the slave module system 200 １ ~200 ｎ The timing deviation f ｉｆ＿(S -M) That is, the timing deviation amount f is calculated while changing the ambient temperature. ｉｆ＿(S -M) By calculating the timing deviation f ｉｆ＿(S -M) The temperature characteristics can be corrected.

[0077] Multiple slave module system 200 １ ~200 ｎ In each case, an ambient temperature monitor 240 １ ~240 ｎ The ambient temperature monitored by each and the timing deviation f calculated at the ambient temperature when monitored ｉｆ＿(S -M) A calibration table in which the values ​​are associated with each other is created in the memory 132, and the signal processing unit 230 １ ~230 ｎ In the master module system 100, the ambient temperature monitored by the ambient temperature monitor 140 and the received beat signal BF calculated at the ambient temperature at the time of monitoring are stored in the memory 132. Ｍ The beat frequency f ｉｆ＿Ｍ A calibration table in which the values ​​are associated with each other is created in the memory 132 and stored in the memory 132 for the signal processing unit 130.

[0078] In this way, the plurality of slave module systems 200 １ ~200 ｎ In each case, the ambient temperature and timing deviation f ｉｆ＿(S -M) The calibration table in which the１ ~230 ｎ By storing the data in the memory 132, the slave module system 200 can be used during operation of the radar device. １ ~200 ｎ Signal processing unit 230 in each １ ~230 ｎ Ambient temperature monitor 240 １ ~240 ｎ The timing deviation f is calculated from the calibration table according to the ambient temperature monitored by each of the ｉｆ＿(S -M) The timing deviation f ｉｆ＿(S -M) The target specifications are corrected using

[0079] As described above, in the radar device according to the first embodiment, the trigger signal from the transmission / reception module 10M of the master module system 100 is distributed by the trigger signal distribution circuit 30 and is provided to the transmission / reception module 10M of the master module system 100 and the transmission / reception modules 20M of the plurality of slave module systems 200 via the different trigger signal cables 41, 42, respectively, and the reference signal from the transmission / reception module 10M of the master module system 100 is output to the transmission / reception modules 20M of the plurality of slave module systems 200, and in the transmission / reception modules 20M of the plurality of slave module systems 200, the high-frequency chirp signal of the received RF signal due to the reflected wave received by the receiving antenna 20R is generated. The target parameters obtained by FFT processing the beat signal obtained from the high-frequency chirp signal of the transmitted RF signal that corresponds to the target signal are corrected using the timing offset amount obtained from the beat frequency of the received beat signal that has been I / Q separated using the received RF signal and then complex FFT processed. Therefore, even if the lengths of the trigger signal cables 41, 42 are different and a timing offset occurs between the trigger signals, the correctly obtained timing offset amount can be used, and the timing offset can be correctly corrected for the transmission / reception module 20M of the slave module system 200 relative to the transmission / reception module 10M of the master module system 100, thereby suppressing deterioration of radar performance.

[0080] Furthermore, the radar device according to the first embodiment stores the timing deviation amount in association with the ambient temperature in a calibration table, and can read out the timing deviation amount from the calibration table according to the ambient temperature, thereby correcting the target specifications with higher accuracy.

[0081] Second Embodiment A radar device according to a second embodiment will be described with reference to Fig. 5 and Fig. 6. The radar device according to the second embodiment is the same as the slave module system 200 in the radar device according to the first embodiment. １ ~200 ｎ Transmitting and receiving module 20M １ ~20M ｎ Further, a delay circuit 250 １ ~250 ｎ The difference is that it has the above, but other points are the same.

[0082] Therefore, the following description will be limited to the delay circuit 250 １ ~250 ｎ The following will be mainly explained. １ ~250 ｎ 5 and 6, the same reference numerals as those in FIGS. 1 to 4 indicate the same or corresponding parts.

[0083] The delay circuit 250 is connected between the trigger input terminal 20d and the transmission / reception circuit 220. The delay circuit 250 is a delay circuit that can change the amount of delay. The trigger signal delayed by the delay circuit 250 determines the start timing of the high-frequency chirp signal from the RF signal source 221 and the sampling start timing of the reception AD conversion units 225I and 225Q.

[0084] The delay circuit 250 delays the trigger signal input to the trigger input terminal 20d in order to prevent degradation of the signal-to-noise ratio (SNR) of the received beat signal due to the presence of a direct current (DC) component caused by the influence of a DC offset in the receiving circuit, which is a path that processes the transmission RF signal from the RF signal source 221 and the received RF signal from the receiving antenna 20R, i.e., the quadrature mixer 223, the HPFs 224I and 224Q, and the receiving AD conversion units 225I and 225Q.

[0085] By delaying the trigger signal using the delay circuit 250, the timing offset calculated by the signal processing unit 230 is offset, the frequency of the received beat signal can be obtained without being affected by the DC component, and the timing offset can be obtained with high accuracy. As a result, the target specifications can be obtained with high accuracy, and a decrease in detection accuracy can be suppressed.

[0086] Next, the setting of the delay amount (offset amount) in the delay circuit 250 will be described. The delay amount in the delay circuit 250 is set before shipping the radar device. First, as shown in FIG. 5, the receiving antenna 10R of the master module system 100 and the receiving antenna 10R of the slave module system 200 are set. １ ~200 ｎ Receiving antenna 20R １ ~20R ｎ A target Tg or a target simulator is prepared, which is placed at a position equidistant from the target Tg.

[0087] A transmission wave is emitted from the transmitting antenna 10T of the master module system 100 toward the target Tg, and a reflected wave of the transmission wave from the target Tg is received by the receiving antenna 10R of the master module system 100 and the slave module system 200. １ ~200 ｎ Receiving antenna 20R １ ~20R ｎ At this time, the slave module system 200 １ ~200 ｎ Transmitting antenna 20T １ ~20T ｎIt is assumed that no transmitted waves are emitted from the

[0088] At this time, there may be a DC component in the frequency band of the received RF signal of the transmission / reception module 20M in the slave module system 200. That is, when the signal processing unit 230 does not delay the trigger signal by the delay circuit 250, the transmitted RF signal TR Ｓ and the received RF signal RE Ｓ The received beat signal BF is converted by performing complex FFT processing using Ｓ０ The beat frequency f ｉｆ＿Ｓ０ 6, is in a region where a DC component of the transmission / reception circuit 220 in the transmission / reception module 20M exists. In the second embodiment, the trigger signal is delayed by a delay circuit, and the transmission RF signal TR is outside the beat frequency region where a DC component exists, as shown in FIG. Ｓ and the received RF signal RE Ｓ The received beat signal BF is converted by performing complex FFT processing using Ｓ０ The beat frequency f ｉｆ＿Ｓ０ Offset the

[0089] In FIG. 6, the horizontal axis indicates the distance (beat frequency) and the vertical axis indicates the level. Ｍ is the received beat signal calculated by the signal processing unit 130, BF Ｓ０ is the received beat signal calculated by the signal processing unit 230 when the trigger signal is not delayed, BF Ｓ indicates the received beat signal calculated by the signal processing unit 230 when the trigger signal is delayed, and DC indicates the direct current component generated by the transmission / reception circuit 220 in the transmission / reception module 20M.

[0090] The delay circuit 250 delays the trigger signal by a delay time τ ａ That is, the timing deviation is set to a delay time τ ａ When the offset is made by 1 / f, the received beat signal BF obtained by the signal processing unit 230 is Ｓ The beat frequency f ｉｆ＿Ｓ can be expressed by the following equation (4): ｉｆ＿Ｓ = (B / T ｃ ) (τ １ -τ error -τ ａ) (4) The received beat signal BF Ｍ The beat frequency f ｉｆ＿Ｍ can be expressed by the above equation (1), and the received beat signal BF Ｓ０ The beat frequency f ｉｆ＿Ｓ０ can be expressed by the above formula (2).

[0091] Delay time τ in the delay circuit ａ is set by the signal processing unit 230. That is, the signal processing unit 230 outputs the received beat signal BF Ｓ The beat frequency f ｉｆ＿Ｓ The delay circuit 250 outputs a digital value indicating the offset amount corresponding to the delay time τ ａ The digital value indicating the offset amount is stored in the memory 132 for the signal processing unit 230. Ｓ０ The beat frequency f ｉｆ＿Ｓ０ is outside the beat frequency region where the direct current component DC exists, the delay amount (delay time τ ａ ) is 0.

[0092] The signal processing unit 230 has a delay time setting program stored in the memory 132 shown in FIG. 2. The delay time setting program is used to set the delay time based on the received beat signal BF obtained by the signal processing unit 230. Ｓ The beat frequency f ｉｆ＿Ｓ is compared with a set beat frequency which is a threshold value set outside the area where the direct current component DC exists, and if it is equal to or less than the set beat frequency, the received beat signal BF Ｓ and a digital value corresponding to the difference in beat frequency exceeding the set frequency, to the delay circuit 250.

[0093] As explained in the radar device according to the first embodiment, the signal processing unit 230 calculates the timing deviation f ｉｆ＿(S -M) is obtained and stored in the memory 132. At this time, the received beat signal BF Ｓ Since the frequency is set to a value that can avoid the influence of DC components that deteriorate the S / N ratio, the timing deviation amount can be obtained with high precision.

[0094] As described in the radar device according to the first embodiment, when the radar device is in operation, the signal processing unit 230 performs FFT processing on the beat signal obtained by converting the received RF signal to calculate target specifications, and reads from the memory 132 the timing deviation amount f associated with the ambient temperature monitored by the ambient temperature monitor 240. ｉｆ＿(S -M) , and the offset amount (delay time) are read from the memory 132, and the calculated target specifications are calculated by taking into consideration the read offset amount. ｉｆ＿(S -M) The offset value read out at this time is the received beat signal BF Ｓ The beat frequency f ｉｆ＿Ｓ However, as shown in the above formula (4), the delay time τ ａ As a result, the influence of the S / N ratio degradation can be avoided, and the timing deviation amount f ｉｆ＿(S -M) The accuracy is also high, and the degradation of radar performance can be suppressed.

[0095] signal processing unit 230 １ ~230 ｎ The offset amount (delay time) and timing deviation amount of the trigger signal used in each step are determined by setting the delay time τ ａ Determine the timing deviation amount, and calculate the delay time τ ａ The delay amount corresponding to the detected timing deviation amount is used as a calibration table in the signal processing unit 230. １ ~230 ｎ The data is stored in each memory as a calibration table.

[0096] As described above, the radar device according to the second embodiment has the same effects as the radar device according to the first embodiment. In addition, in each of the transmission / reception modules 20M in each of the slave module systems 200, the trigger signal that starts the generation of a high-frequency chirp signal is the trigger signal distributed from the trigger signal distribution circuit 30 via the delay circuit 250. Therefore, the beat frequency of the received beat signal obtained by I / Q separation of the received RF signal is always set outside the region where the direct-current component DC exists. This makes it possible to use a highly accurate timing offset amount, thereby further suppressing degradation of radar performance.

[0097] Third Embodiment A radar device according to a third embodiment will be described with reference to Fig. 7. The radar device according to the third embodiment is different from the radar device according to the second embodiment in that it does not include the timing offset amount and the delay amount (delay time τ ａ ) using a target Tg or a target simulator, whereas the transmission wave from the transmitting antenna 10T of the master module system 100 is used as a direct wave and is transmitted to the receiving antenna 10R of the master module system 100 and the slave module system 200. １ ~200 ｎ Receiving antenna 20R １ ~20R ｎ 7, the difference is that the timing offset and the delay amount in the delay circuit 250 are obtained by directly receiving the signal from the delay circuit 250, but other points are the same. In addition, in Fig. 7, the same reference numerals as those in Fig. 5 indicate the same or corresponding parts.

[0098] The configuration of the radar device according to the third embodiment is the same as that of the radar device according to the second embodiment. Therefore, the setting of the timing deviation amount and the delay time τ ａ The following mainly describes the setting of the timing deviation amount and the delay time τ in the delay circuit 250. ａ Unlike the first and second embodiments, the setting of the above is performed when the ambient temperature monitored by the ambient temperature monitor 240 changes by more than the set value compared to the previous setting during operation of the radar device, and also periodically and periodically.

[0099] Each time the setting is performed, the delay time τａ In other words, the offset amount and timing deviation amount are stored in a storage section of memory 132 corresponding to signal processing section 230, and when acquiring the target specifications, signal processing section 230 reads out the offset amount and timing deviation amount stored in memory 132, takes into account the calculated target specifications and the read offset amount, corrects the target specifications using the timing deviation amount, and outputs the corrected target specifications from target specification output terminal 20g to the ECU.

[0100] First, the setting of the timing offset will be described. The case where the delay amount of the delay circuit 250 is 0, that is, the case where the configuration is the same as that of the radar device according to the first embodiment, will be described. The radar device has a master module system 100 and a plurality of slave module systems 200. １ ~200 ｎ The arrangement of the master module system 100 and the transmitting antenna 10T of the slave module system 200 is fixed. １ ~200 ｎ Receiving antenna 20R １ ~20R ｎ The distance between each of the slave module systems 200 and the received RF signal input to the transmitting / receiving module 10M of the master module system 100 is fixed. １ ~200 ｎ Transmitting and receiving module 20M １ ~20M ｎ The relationship between each of the received RF signals input thereto is uniquely determined.

[0101] Therefore, as shown in FIG. 7, a transmission wave is radiated from a transmission antenna 10T of the master module system 100 into space, and a direct wave from the transmission antenna 10T is received by a reception antenna 10R of the master module system 100 and a reception antenna 10R of the slave module system 200. １ ~200 ｎ Receiving antenna 20R １ ~20R ｎ The slave module system 200 directly receives the RF signals from the master module system 100 and uses the received RF signals. １ ~200 ｎ The timing deviation of the trigger signals in each of the slave module systems 200 can be obtained.１ ~200 ｎ Transmitting antenna 20T １ ~20T ｎ No transmitting waves are emitted from

[0102] That is, the received beat signal BF obtained by the signal processing unit 130 Ｍ The beat frequency f ｉｆ＿Ｍ can be expressed by the above formula (1). １ is the transmitted RF signal TR Ｍ After the direct wave is received, the received RF signal RE Ｍ The time required for the signal processor 230 to obtain the received beat signal BF Ｓ The beat frequency f ｉｆ＿Ｓ In the above equation (2), the delay time τ １ τ ２ This can be expressed by replacing with τ ２ is the transmitted RF signal TR Ｍ After the direct wave is received, the received RF signal RE Ｓ is the time it takes to obtain １ +α. α is the transmission antenna 10T and the reception antenna 20R. １ ~20R ｎ The time is based on the distance to each other.

[0103] Therefore, the timing deviation f ｉｆ＿(S -M) can be calculated using the above formula (3). ｉｆ＿(S -M) is stored in the storage section of the memory 132 corresponding to the signal processing section 230 and is maintained until the next setting. ｉｆ＿(S -M) is stored in association with the ambient temperature monitored by the ambient temperature monitor 240 at the time of setting.

[0104] As explained in the first embodiment, the quadrature mixer 223 receives the received RF signal RE. Ｓ and the transmitted RF signal TR ＳThe beat signal (IF signal) obtained by the above is separated into I / Q signals, and the signal processing unit 230 performs complex FFT processing using both the I and Q signals to generate a received beat signal BF Ｓ Since the received beat signal BF Ｓ The correct value is obtained as the timing deviation f ｉｆ＿(S -M) As a result, when the target specifications are acquired, the timing deviation f ｉｆ＿(S -M) Since the target specifications are corrected using the above formula, it is possible to suppress the deterioration of detection performance.

[0105] Moreover, when the ambient temperature monitored by the ambient temperature monitor 240 changes by more than the set value compared to the previous setting, the timing deviation amount f ｉｆ＿(S -M) Since the timing offset f is automatically reset, it is possible to suppress the deterioration of radar performance caused by the timing offset of the trigger signal due to the influence of the temperature characteristics of the trigger signal cable 42 caused by changes in the ambient temperature. ｉｆ＿(S -M) Since the trigger signal timing is automatically reset, it is possible to suppress the deterioration of radar performance caused by deviation in the timing of the trigger signal due to aging of the trigger signal cable 42 or the transmission / reception module 20M.

[0106] Next, the delay time τ in the delay circuit 250 ａ The setting of the delay time τ ａ The direct wave from the transmitting antenna 10T is transmitted to the receiving antenna 10R of the master module system 100 and the slave module system 200. １ ~200 ｎ Receiving antenna 20R １ ~20R ｎ are directly received, and the delay time τ in the delay circuit 250 is calculated by using the respective received RF signals. ａ At this time, the slave module system 200 １ ~200 ｎ Transmitting antenna 20T １ ~20T ｎNo transmitting waves are emitted from

[0107] The received beat signal BF obtained by the signal processing unit 230 Ｓ The beat frequency f ｉｆ＿Ｓ As explained in the timing deviation amount, as explained in the second embodiment, in the above equation (4), the delay time τ １ τ ２ As explained in the second embodiment, the delay time τ corresponding to the offset amount ａ is outside the beat frequency region where the DC component exists, Ｓ and the received RF signal RE Ｓ The received beat signal BF is converted by performing complex FFT processing using Ｓ The beat frequency f ｉｆ＿Ｓ is the value to be offset.

[0108] The signal processing unit 230 outputs the received beat signal BF Ｓ The beat frequency f ｉｆ＿Ｓ The delay circuit 250 outputs a digital value indicating the offset amount corresponding to the delay time τ ａ The digital value indicating the offset thus obtained is stored in the storage section of the memory 132 corresponding to the signal processing section 230 and is maintained until the next setting. At this time, the received beat signal BF Ｓ Since the frequency is set to a value that can avoid the influence of DC components that deteriorate the S / N ratio, the timing deviation amount can be obtained with high precision.

[0109] When acquiring the target specifications, the signal processing unit 230 reads the offset amount and timing deviation amount stored in the memory 132, corrects the calculated target specifications using the read timing deviation amount while taking into account the read offset amount, and outputs the corrected target specifications to the ECU from the target specification output terminal 20g.

[0110] As described above, the radar device according to the third embodiment has the same effects as the radar device according to the first or second embodiment, and also has the advantage of being able to set the timing deviation amount and the delay time τａ Since the setting is performed during operation of the radar device, the timing deviation amount can be set appropriately in response to changes in the ambient temperature and changes in the quality of the trigger signal cable 42, etc.

[0111] It should be noted that the embodiments may be freely combined, or any of the components in each embodiment may be modified, or any of the components in each embodiment may be omitted.

[0112] The radar device according to the present disclosure is suitable for use as a radar device mounted on an automobile to detect targets.

[0113] 100 Master module system, 10M Transmitting / receiving module, 110 Reference signal source, 120 Transmitting / receiving circuit, 130 Signal processing unit, 140 Ambient temperature monitor, 10T Transmitting antenna, 10R Receiving antenna, 200 １ ~200 ｎ Slave module system, 20M １ ~20M ｎ Transmitting and receiving module, 220 １ ~220 ｎ Transmitting and receiving circuit, 230 １ ~230 ｎ signal processing unit, 240 １ ~240 ｎ Ambient temperature monitor, 250 １ ~250 ｎ Delay circuit, 20T １ ~20T ｎ Transmitting antenna, 20R １ ~20R ｎ Receiving antenna, 30 distribution circuit for trigger signal.

Claims

1. A system comprising a master module system, a plurality of slave module systems, and a trigger signal distribution circuit, wherein the master module system comprises a transmitting / receiving module, a transmitting antenna, and a receiving antenna, and each of the plurality of slave module systems comprises a transmitting / receiving module, a transmitting antenna, and a receiving antenna, and the trigger signal distribution circuit distributes a trigger signal from the transmitting / receiving module of the master module system and outputs the trigger signal to the transmitting / receiving module of the master module system and to the transmitting / receiving module of each of the plurality of slave module systems via different trigger signal cables, the transmitting / receiving module of the master module system outputs the trigger signal to the trigger signal distribution circuit and outputs a reference signal to the transmitting / receiving module of each of the plurality of slave module systems, and starts generating a high frequency chirp signal based on the reference signal by the trigger signal distributed from the trigger signal distribution circuit, outputs a transmission RF signal in which the generated high frequency chirp signal is repeated to the transmitting antenna of the master module system, and obtains target specifications by performing FFT processing on a beat signal obtained from the high frequency chirp signal of the transmission RF signal which corresponds to the high frequency chirp signal of the reception RF signal due to a reflected wave received by the reception antenna of the master module system, a transmission / reception module of each of the plurality of slave module systems starts generating a high frequency chirp signal based on a reference signal from the transmission / reception module of the master module system in response to the trigger signal distributed from the trigger signal distribution circuit, outputs a transmission RF signal in which the generated high frequency chirp signal is repeated to a transmission antenna of the slave module system, and corrects target parameters obtained by FFT processing a beat signal obtained from the high frequency chirp signal of the transmission RF signal which corresponds to the high frequency chirp signal of a received RF signal due to a reflected wave received by a receiving antenna of the slave module system, by a timing offset amount obtained from the beat frequency of a received beat signal obtained by complex FFT processing of an I / Q separated beat signal using a received RF signal.

2. A radar device as described in claim 1, wherein in each of the transceiver modules of the plurality of slave module systems, a trigger signal that initiates generation of the high-frequency chirp signal is a trigger signal distributed from the trigger signal distribution circuit via a delay circuit.

3. A radar device as described in claim 2, wherein the delay amount in the delay circuit is a delay time that offsets the beat frequency of the received beat signal outside a beat frequency region in which a DC component generated by a path that processes the received RF signal in a transmission / reception module exists.

4. A radar device as claimed in any one of claims 1 to 3, wherein the amount of timing offset in the transmission / reception module of each of the multiple slave module systems is a frequency difference between a beat frequency in a received beat signal obtained by I / Q separation of the received RF signal of the own transmission / reception module and a beat frequency in a received beat signal obtained by I / Q separation of the received RF signal of the transmission / reception module of the master module system, and wherein correction of target parameters in the transmission / reception module of each of the multiple slave module systems is a correction to obtain target parameters such that the frequency difference in the beat frequencies becomes zero.

5. A radar device as claimed in any one of claims 1 to 3, wherein in each of the transmitting and receiving modules of the plurality of slave module systems, the timing offset amount is stored in a calibration table, and correction of target specifications is performed using the timing offset amount stored in the calibration table.

6. The radar device according to claim 4, wherein the timing offset amount stored in the calibration table in each of the plurality of slave module systems is obtained by using a received RF signal resulting from a reflected wave received by a receiving antenna in the master module system and a receiving antenna in each of the plurality of slave module systems, the receiving antennas being arranged at equal intervals with respect to the target, after a transmission wave radiated from a transmitting antenna in the master module system is reflected from the target.

7. A radar device as claimed in any one of claims 1 to 3, wherein in the transmitting / receiving module of each of the plurality of slave module systems, the timing offset amount is obtained using a received RF signal resulting from a receiving wave received by a receiving antenna in the master module system and a receiving antenna in each of the plurality of slave module systems, the receiving wave being a direct wave radiated from a transmitting antenna in the master module system.