Radar system, control device, control method, control program

Abstract

To provide a radar system or the like capable of effectively utilizing a time domain with improved accuracy in transmission timing.SOLUTION: A radar system comprises a transmission / reception system including a plurality of transmission antennas that transmits a chirp signal having a temporally changing frequency and a plurality of reception antennas that receives the chirp signal that has been reflected in an environment as a reception signal. The radar system comprises a control device including a processor and controlling the transmission of the chirp signal from the transmission antennas. The processor is configured to execute acquisition of reception timing information related to reception timing of the reception signal by each reception antenna from the transmission / reception system. The processor is configured to execute control of transmission timing for each chirp signal from each transmission antenna such that the transmission time zone at least partially overlaps that of the chirp signal from a different transmission antenna and the frequency is shifted from that of the overlapping other chirp signal in the overlapping time zone.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] This disclosure relates to radar control technology.

Background Art

[0002] Patent Document 1 discloses a technique for controlling the radio wave transmission time of a radar device. In this technique, a control circuit connected to a plurality of radar devices receives a common time signal such as a time signal from a radio clock or a time signal from GPS (Global Positioning System). Based on the time signal, the control circuit allocates a radio wave emission time zone to each radar device. The control circuit prohibits the emission of radio waves from other radar devices during the time zone when a specific radar device emits radio waves.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In Patent Document 1, each radar device is controlled so that the radio wave emission time zones do not overlap. Therefore, the technology of Patent Document 1 does not effectively utilize the time domain. And the technology of Patent Document 1 does not disclose more precise control of transmission timing for effectively utilizing the time domain.

[0005] The objective of this disclosure is to provide a radar system that can effectively utilize the time domain by improving the accuracy of transmission timing. Another objective of this disclosure is to provide a control device that can effectively utilize the time domain by improving the accuracy of transmission timing. Yet another objective of this disclosure is to provide a control method that can effectively utilize the time domain by improving the accuracy of transmission timing. Yet another objective of this disclosure is to provide a control program that can effectively utilize the time domain by improving the accuracy of transmission timing. [Means for solving the problem]

[0006] The following describes the technical means of solving the problem described in this disclosure. Note that the claims and the reference numerals in parentheses in this section indicate the correspondence with the specific means described in the embodiments detailed later, and do not limit the technical scope of this disclosure.

[0007] A first aspect of this disclosure is a transmitting and receiving system (2) including a plurality of transmitting antennas (22; 22a, 22b) that transmit a chirp signal whose frequency changes over time, and a plurality of receiving antennas (23) that receive the chirp signal reflected from the outside as a received signal. A control device (3) having a processor (3b) and controlling the transmission of chirp signals from the transmitting antenna, Equipped with, The processor is The system obtains reception timing information regarding the reception timing of chirp signals at each receiving antenna, For each chirp signal from each transmitting antenna, the transmission timing is controlled according to the reception timing such that at least a portion of the transmission time overlaps with chirp signals from different transmitting antennas, and during the overlapping time, the frequency is shifted relative to other overlapping chirp signals. It is configured to perform, The processor is To control the transmission timing, This involves transmitting an inverted signal from a specific transmitting antenna, in which the direction of frequency time variation is reversed relative to the chirp signal from another transmitting antenna. The timing information that determines the transmission timing for each transmitting antenna is synchronized according to the timing when the frequencies of the chirp signal and the inverted signal overlap, Includes, Synchronizing the transmission timing is This includes synchronizing time information according to the interference timing between the chirp signal and the inverted signal in the data related to the received signal. fruit, The chirp signals from each transmitting antenna are, Different frequency change bandwidths It is a radar system.

[0008] A second aspect of the present disclosure is a control device for controlling a transceiver system (2) which includes a processor (3b) and a plurality of transmitting antennas (22; 22a, 22b) that transmit a time-varying chirp signal, and a plurality of receiving antennas (23) that receive the chirp signal reflected from the outside as a received signal, The processor is The system obtains reception timing information regarding the reception timing of chirp signals at each receiving antenna, For each chirp signal from each transmitting antenna, the transmission timing is controlled according to the reception timing such that at least a portion of the transmission time overlaps with chirp signals from different transmitting antennas, and during the overlapping time, the frequency is shifted relative to other overlapping chirp signals. It is configured to perform, The processor is To control the transmission timing, This involves transmitting an inverted signal from a specific transmitting antenna, in which the direction of frequency time variation is reversed relative to the chirp signal from another transmitting antenna. The timing information that determines the transmission timing for each transmitting antenna is synchronized according to the timing when the frequencies of the chirp signal and the inverted signal overlap, Includes, Synchronizing the transmission timing includes synchronizing time information according to the interference timing between the chirp signal and the inverted signal in the data regarding the received signal. fruit, The chirp signals from each transmitting antenna are, Different frequency change bandwidths

[0009] A third aspect of the present disclosure is a control method executed by a processor (3b) for controlling a transmission / reception system (2) including a plurality of transmission antennas (22; 22a, 22b) that transmit chirp signals whose frequencies change over time, and a plurality of reception antennas (23) that receive the chirp signals reflected in the external environment as received signals, acquiring reception timing information regarding the reception timing of the chirp signal at each reception antenna from the transmission / reception system, for each chirp signal from each transmission antenna, controlling the transmission timing according to the reception timing such that at least a part of the transmission time bands overlaps for the chirp signals from different transmission antennas, and the frequencies are shifted with respect to other overlapping chirp signals in the overlapping time band, including Controlling the transmission timing includes causing a specific transmission antenna to transmit an inverted signal whose direction of frequency change over time is inverted with respect to the chirp signals from other transmission antennas, synchronizing the time information for determining the transmission timing for each transmission antenna according to the timing when the frequencies of the chirp signal and the inverted signal overlap, including Synchronizing the transmission timing includes synchronizing time information according to the interference timing between the chirp signal and the inverted signal in the data regarding the received signal. fruit, The chirp signals from each transmitting antenna are, Different frequency change bandwidths

[0010] ​​A fourth aspect of the present disclosure is a control program stored in a storage medium (3a) and executed by a processor (3b) for controlling a transmission / reception system (2) including a plurality of transmission antennas (22; 22a, 22b) that transmit chirp signals whose frequencies change over time and a plurality of reception antennas (23) that receive the chirp signals reflected by the outside world as reception signals, The instructions cause the transmission / reception system to acquire reception timing information regarding the reception timing of the chirp signal at each reception antenna, for each chirp signal from each transmission antenna, control the transmission timing according to the reception timing such that at least a part of the transmission time bands of the chirp signals from different transmission antennas overlap, and the frequencies are shifted with respect to other overlapping chirp signals in the overlapping time bands, including Controlling the transmission timing causes a specific transmission antenna to transmit an inverted signal in which the direction of the frequency change over time is inverted with respect to the chirp signals from other transmission antennas, synchronize the time information for determining the transmission timing for each transmission antenna according to the timing when the frequencies of the chirp signal and the inverted signal overlap, including Synchronizing the transmission timing includes synchronizing the time information according to the interference timing between the chirp signal and the inverted signal in the data regarding the reception signal fruit, The chirp signals from each transmitting antenna are, Different frequency change bandwidths .

[0011] According to these first to fourth embodiments, the transmission timing of the chirp signal is controlled such that, depending on the reception timing at which the transmitted chirp signal is received, at least a portion of the transmission time period overlaps with chirp signals from different transmitting antennas, and the frequency of the chirp signal is shifted relative to other overlapping chirp signals during the overlapping time period. Therefore, the transmission timing can be controlled while confirming the actual situation of the reception timing which is affected by the transmission timing. In other words, the transmission timing can be controlled while taking into account the deviation in transmission timing due to jitter etc. until the transmitted signal is transmitted. Furthermore, since the transmission time periods of chirp signals can be made to overlap at least a portion through such high-precision transmission timing control, the time domain is effectively utilized by improving the accuracy of the transmission timing. [Brief explanation of the drawing]

[0012] [Figure 1] This is a block diagram showing the overall configuration of the first embodiment. [Figure 2] This is a block diagram showing the functional configuration of a radar system according to the first embodiment. [Figure 3] This is a schematic diagram illustrating the operation of the transmission / reception system in normal mode in the first embodiment. [Figure 4] This is a schematic diagram illustrating the operation of the transmission / reception system in timing adjustment mode in the first embodiment. [Figure 5] This is a schematic diagram illustrating the operation of the transmission / reception system in time correction mode in the first embodiment. [Figure 6] This is a flowchart showing the control flow according to the first embodiment. [Figure 7] This is a schematic diagram illustrating the operation of the transmission / reception system in normal mode in the second embodiment. [Figure 8] This is a schematic diagram illustrating the operation of the transmission / reception system in time correction mode in the second embodiment. [Figure 9] This is a block diagram showing the functional configuration of a radar system according to a third embodiment. [Figure 10]This is a schematic diagram illustrating the operation of the transmission / reception system in timing adjustment mode in the third embodiment. [Modes for carrying out the invention]

[0013] Hereinafter, several embodiments of this disclosure will be described with reference to the drawings. In each embodiment, the same reference numerals will be used for corresponding components, and redundant explanations may be omitted. Furthermore, if only a part of the configuration is described in each embodiment, the configuration of other embodiments described earlier may be applied to the other parts of that configuration. Moreover, not only the combinations of configurations explicitly stated in the description of each embodiment, but also the configurations of multiple embodiments may be partially combined even if not explicitly stated, as long as there are no particular problems with the combination.

[0014] (First Embodiment) A first embodiment of this disclosure will be described with reference to Figures 1 to 6. The radar system 1 is mounted on a moving object such as a vehicle. The radar system 1 transmits a transmission signal St to the outside world, receives the transmission signal St reflected by an object as a reception signal Sr, and detects the distance to the target (which is the object that reflected the transmission signal St), the relative velocity to the target, and the orientation of the target as target information.

[0015] Target information output from radar system 1 is input to the in-vehicle ECU (Electronic control unit) via an in-vehicle network such as CAN (Control Area Network®) and Ethernet®. Based on the target information of each acquired target, the in-vehicle ECU performs various processes for autonomous driving and advanced driver assistance of the vehicle.

[0016] Examples of processing based on target information include collision avoidance processing and warning processing. Collision avoidance processing is the process of controlling the vehicle to avoid collision with a target by controlling the braking system, steering system, etc., based on the target information of each target. Warning processing is the process of warning the driver of the possibility of collision with a target based on the target information of each target.

[0017] As shown in Figures 1 and 2, the radar system 1 of this embodiment includes a transmitting / receiving system 2 and a control unit 3. The transmitting / receiving system 2 and the control unit 3 are connected to each other via at least one of the following: a LAN (Local Area Network) line, a wire harness, an internal bus, and a wireless communication line.

[0018] The transmitting / receiving system 2 includes a plurality of transmitting / receiving units 20. Each transmitting / receiving unit 20 is a processing unit that performs signal transmission and reception processing. Each transmitting / receiving unit 20 comprises a transmitting signal generation unit 21, a transmitting antenna 22, a receiving antenna 23, a signal mixing unit 24, an A / D converter 25, a counter 26, and a transmitting / receiving control unit 27. At least a portion of each transmitting / receiving unit 20 is composed of a radio frequency integrated circuit such as an RFIC (Radio Frequency Integrated Circuit).

[0019] The transmission signal generation unit 21 receives an instruction signal from the transmission / reception control unit 27 (described later) and generates a millimeter-wave transmission signal St corresponding to the instruction signal. The transmission signal generation unit 21 is composed of, for example, a D / A converter and a voltage-controlled oscillator. For example, when the transmission signal generation unit 21 receives a digital signal whose frequency changes with time, which is output as an instruction signal, it converts it into an analog signal using a D / A converter. Then, the transmission signal generation unit 21 generates a high-frequency signal in the millimeter-wave band from the analog signal using a voltage-controlled oscillator and outputs it to the transmission antenna 22 as a transmission signal St. The transmission signal generation unit 21 also distributes a portion of the output transmission signal St from the original signal at a predetermined ratio and outputs it to the signal mixing unit 24. In the following, the signal output to the signal mixing unit 24 will be referred to as the local signal Sl.

[0020] The transmitting antenna 22 transmits the transmission signal St generated by the transmission signal generation unit 21 to the outside world. Specifically, the transmitting antenna 22 outputs the transmission signal St as a transmission wave exhibiting a chirp whose frequency changes over time in the millimeter-wave band. The receiving antenna 23 receives the reflected wave, which is the transmitted wave reflected by the target, as the received wave. The receiving antenna 23 outputs the received wave as a received signal Sr to the signal mixing unit 24. In this embodiment, an example is described in which each transmitting / receiving unit 20 is provided with one transmitting antenna 22 and one receiving antenna 23.

[0021] The signal mixing unit 24 generates a beat signal Sb by mixing the local signal Sl from the transmission signal generation unit 21 and the received signal Sr from the receiving antenna 23, and outputs it to the A / D converter 25. The generated beat signal Sb is an interference signal representing the frequency difference between the received signal Sr and the local signal Sl. The beat signal Sb is output to the A / D converter 25 after high-frequency components that deviate from the frequency difference between the received signal Sr and the local signal Sl are filtered out by a low-pass filter (not shown). In addition, received signals Sr originating from transmitted waves from other transmitting / receiving units 20 are also filtered by this low-pass filter if the time difference in the transmission timing between the transmitting / receiving units 20 is appropriately set. Note that a band-pass filter may be provided instead of a low-pass filter.

[0022] The A / D converter 25 samples the beat signal Sb at predetermined time intervals and converts it into digitized beat signal Sb data. This beat signal Sb data is output to the control unit 3 as reception result data for the received signal Sr. The reception result data may also include specific information added by the transmit / receive control unit 27, which will be described later.

[0023] The counter 26 counts the elapsed time during the operation of the transmit / receive unit 20. The counter 26 performs the counting, for example, by timing the clock of a clock oscillator. The counter 26 can output the current elapsed time as time information to the transmit / receive control unit 27. Note that the counter 26 may be part of the transmit / receive control unit 27.

[0024] The transmit / receive control unit 27 is mainly composed of at least one dedicated computer having a processor 3b. In addition to the processor, the transmit / receive control unit 27 includes memory, input / output interfaces, and buses connecting them.

[0025] The transmit / receive control unit 27 executes the transmit / receive processing in the transmit / receive unit 20. In the transmit / receive processing, the transmit / receive control unit 27 instructs the transmit signal generation unit 21 to generate a transmit signal St in accordance with the control command from the control unit 3, thereby realizing the output of the transmit signal St at a specific transmission timing. The transmit / receive control unit 27 generates multiple chirp signals as transmit signals St for each frame. The transmission timing of these transmit signals St is set to the start timing of the output of the first chirp signal in one frame.

[0026] For example, the transmit / receive control unit 27 refers to time information from the counter 26 and, upon obtaining time information corresponding to the transmission timing, outputs an instruction signal to the transmit signal generation unit 21. The instruction signal is a chirp signal whose frequency gradually decreases or increases with time. Accordingly, the transmit signal generation unit 21 generates a transmit signal St as a chirp signal. In addition, during the transmit / receive process, the transmit / receive control unit 27 outputs the received result data to the control unit 3.

[0027] Each transmit / receive control unit 27 in the multiple transmit / receive units 20 receives individual control commands from the control unit 3. As a result, one of the following execution modes is performed for the transmit / receive processing by the multiple transmit / receive units 20 in cooperation with each other: normal mode, time correction mode, or timing adjustment mode.

[0028] In normal mode and timing adjustment mode, the transmit / receive control unit 27 outputs multiple chirp signals within one frame, each with a chirp slope unified to either an up-chirp or a down-chirp. In the example shown in Figure 3, the chirp slope is unified to a down-chirp. Furthermore, the multiple chirp signals within one frame have unified slope magnitude, center frequency, and transmission time width. The transmit / receive control unit 27 outputs a specified number of chirp signals in this manner at specified time intervals within one frame. In this embodiment, the time intervals between chirp signals are defined as substantially equal intervals. The transmit / receive control unit 27 continues the output processing of the transmitted signal St for a specified number of frames.

[0029] In this embodiment, each transmitted signal St from the multiple transmitting and receiving units 20 has substantially the same chirp slope, center frequency, and transmission time width. That is, the multiple transmitting and receiving units 20 transmit transmitted signals St with substantially the same frequency band, which is the bandwidth of the frequency change.

[0030] By adjusting the transmission timing for each transmitting / receiving unit 20, the transmission time periods of chirp signals transmitted from different transmitting antennas 22 overlap at least partially. For example, as shown in Figure 3, the transmission timing is adjusted so that chirp signals from separate transmitting antennas 22, indicated by different line types, are transmitted one by one in sequence. As a result, the transmission time periods of chirp signals from different transmitting antennas 22 that are adjacent in time partially overlap.

[0031] More specifically, as shown in Figure 3, the transmission start time Ts of a particular chirp signal from a particular transmitting antenna 22 is earlier than the transmission end time Tep of a temporally adjacent and preceding chirp signal (preceding signal) from another transmitting antenna 22. Furthermore, the transmission end time Te of this particular chirp signal is later than the transmission start time Tsf of a temporally adjacent and succeeding chirp signal (successor signal) from another transmitting antenna 22. Note that the particular chirp signal shown with transmission start time Ts and transmission end time Te in Figure 3 is an arbitrary chirp signal chosen for explanation purposes, and the above explanation can be applied even if other chirp signals are chosen as the particular chirp signal.

[0032] The time interval between chirp signals from different transmitting antennas 22 is determined according to the IF (Intermediate Frequency) band, which is the frequency band of the beat signal Sb, and the design of the low-pass filter. Here, the low-pass filter refers to the filter that filters the beat signal Sb output to the A / D converter 25. In other words, a time interval is specified that is sufficient to allow the chirp signals from other transmitting antennas 22 to be filtered by the low-pass filter.

[0033] In normal mode, the transmit / receive control unit 27 outputs the acquired reception result data to the control unit 3 simply as data relating to the beat signal Sb. In timing adjustment mode, the transmit / receive control unit 27 outputs the acquired reception result data to the control unit 3 with information regarding the reception timing of the received signal Sr included. For example, as shown in Figure 4, the transmit / receive control unit 27 adds the acquisition time data Dt of the data Dr, based on time information from the counter 26, to the beginning of the data frame of the digital data Dr relating to the beat signal Sb, as information regarding the reception timing.

[0034] In time correction mode, a specific transmitting / receiving unit 20 outputs a transmission signal St in a different manner than in normal mode. The transmission signal St of the other transmitting / receiving units 20 is the same as in normal mode. That is, each of the other transmitting / receiving units 20 transmits a transmission signal St in which the slope and magnitude of each chirp in one frame, the center frequency, and the transmission time width are unified. Furthermore, the above parameters are also unified among the transmitting / receiving units 20.

[0035] Then, the transmit / receive control unit 27 in a specific transmit / receive unit 20 instructs other transmit / receive units 20 to transmit an inverted signal in which the direction of frequency time change is reversed for at least one chirp signal in the transmit signal St of one frame. For example, as shown in Figure 5, if the transmit signal St from another transmit / receive unit 20 is a down chirp, then at least one chirp signal in the transmit signal St from the specific transmit / receive unit 20 is changed to an up chirp. Note that in Figure 5, only one chirp signal in one frame is inverted, but the slopes of two or more chirp signals may be reversed. All chirp signals from the specific transmit / receive unit 20 may also be inverted.

[0036] Furthermore, parameters other than the chirp slope for the transmitted signal St from a specific transmitting / receiving unit 20 are the same as the parameters in normal mode. In other words, in this embodiment, parameters other than the chirp slope for this transmitted signal St are the same as the parameters for transmitted signals St from other transmitting / receiving units 20.

[0037] As shown in Figure 5, the start time of transmission for these inverted signals is earlier than the end time of transmission for the preceding signal. Therefore, the frequencies of the preceding signal and the inverted signal interfere at a specific time. Also, the end time of transmission for the inverted signal is later than the start time of transmission for the following signal. Therefore, the frequencies of the inverted signal and the following signal also interfere at a specific time. The time at which these inverted signals and other chirp signals interfere will be referred to as the interference timing below.

[0038] As described above, in the time correction mode, each transmit / receive unit 20 acquires a signal Sr as a received signal Sr, which includes interference noise that has frequency-interfered with chirp signals from other transmit / receive units 20, as shown in Figure 5. Figure 5 shows an example of raw waveform data including interference noise for each received signal Sr corresponding to each transmitted signal St shown by different line types in the upper graph. In Figure 5, in each raw waveform data, an intensity peak as interference noise appears at the time corresponding to the interference timing. The transmit / receive control unit 27 adds information about the reception timing to the beat signal Sb corresponding to this received signal Sr, i.e., the beat signal Sb including interference noise, in the same way as in the timing adjustment mode. The transmit / receive control unit 27 outputs the data of the beat signal Sb to which the reception timing information has been added as reception result data.

[0039] Control unit 3 is a control device that appropriately switches and controls each of the execution modes described above. Control unit 3 is configured to include at least one dedicated computer. The dedicated computer constituting control unit 3 may be a sensing ECU (Electronic Control Unit) specialized in controlling the transmission / reception system 2. The dedicated computer constituting control unit 3 may be a sensor integration ECU that comprehensively controls multiple types of sensors mounted on the vehicle. The dedicated computer constituting control unit 3 may be an integration ECU that integrates the driving control of the vehicle. The dedicated computer constituting control unit 3 may be a decision ECU that determines driving tasks in the driving control of the vehicle. The dedicated computer constituting control unit 3 may be a monitoring ECU that monitors the driving control of the vehicle. The dedicated computer constituting control unit 3 may be an evaluation ECU that evaluates the driving control of the vehicle.

[0040] The dedicated computer constituting the control unit 3 may be a navigation ECU that navigates the vehicle's driving path. The dedicated computer constituting the control unit 3 may be a locator ECU that estimates the vehicle's own state variables. The dedicated computer constituting the control unit 3 may be an actuator ECU that controls the vehicle's driving actuators. The dedicated computer constituting the control unit 3 may be an HCU (HMI (Human Machine Interface) Control Unit) that controls information presentation in the vehicle. The dedicated computer constituting the control unit 3 may be a computer other than the vehicle that, for example, constructs an external center or mobile terminal that can communicate with the vehicle.

[0041] The dedicated computer constituting the control unit 3 has at least one memory 3a and one processor 3b. The memory 3a is at least one type of non-transitory tangible storage medium, such as semiconductor memory, magnetic media, and optical media, which non-temporarily stores programs and data that can be read by the computer. Here, storage may be accumulation where data is retained even when the sensor system is turned off, or temporary storage where data is erased when the sensor system is turned off. The processor 3b includes at least one type as a core, such as a CPU (Central Processing Unit), GPU (Graphics Processing Unit), RISC (Reduced Instruction Set Computer)-CPU, DFP (Data Flow Processor), and GSP (Graph Streaming Processor).

[0042] In the control unit 3, the processor 3b executes multiple instructions contained in the control program stored in memory 3a to control the transmit / receive unit 20. This allows the control unit 3 to construct multiple functional blocks for controlling the transmit / receive unit 20. These functional blocks, as shown in Figure 2, include a control command block 31 and a data processing block 32.

[0043] Through the combined action of blocks 31 and 32, the control method by which the control unit 3 controls the radar system 1 is executed according to the control flow shown in Figure 3. This control flow is executed repeatedly during vehicle startup. In this control flow, each "S" represents multiple steps executed by multiple instructions included in the control program.

[0044] First, in S10, the control command block 31 determines whether the adjustment conditions for the transmitting / receiving unit 20 are met. The adjustment conditions are those that determine that at least one of time correction and timing adjustment is necessary. For example, the adjustment conditions are that a specified number of frames have been reached and that the transmitting / receiving unit 20 has performed target detection processing in normal mode. The adjustment conditions may also be that the vehicle is allowed to not use target information from the radar system 1 for a certain period of time. This period may be a vehicle stop period, such as a stop period corresponding to the status of traffic lights. The adjustment conditions may also be that at least one of the above conditions is met, or both are met, with each of the above conditions as subconditions.

[0045] If the adjustment conditions are not met, this flow proceeds to S90, which will be described later. On the other hand, if the adjustment conditions are met, this flow proceeds to S20. In S20, the control command block 31 commands the transmit / receive unit 20 to execute the time correction mode.

[0046] In S30, the data processing block 32 acquires the received data in time correction mode. Then, in S40, the control command block 31 performs time correction processing according to the received data. More specifically, the control command block 31 first acquires the interference timing at which interference noise is observed in each transmit / receive unit 20. The interference timing is acquired in correlation with the reception timing and the relative time difference of the interference noise to that reception timing.

[0047] The control command block 31 then generates time correction information to eliminate the timing discrepancies in interference between each transmitting / receiving unit 20. The time correction information includes, for example, information regarding the difference in interference timing in the target transmitting / receiving unit 20 with respect to the interference timing in a specific reference transmitting / receiving unit 20. The control command block 31 generates time correction information for each transmitting / receiving unit 20, excluding the reference transmitting / receiving unit 20. The control command block 31 outputs the time correction information to the corresponding transmitting / receiving unit 20. This causes the control command block 31 to perform time correction on each counter 26 in each transmitting / receiving unit 20.

[0048] Alternatively, the control command block 31 may store the generated time correction information in a storage medium such as memory 3a instead of outputting it to each transmitting / receiving unit 20. The stored time correction information is used to apply a time offset to the received result data acquired from each transmitting / receiving unit 20. In this case, generating and storing the time correction information corresponds to the time correction process.

[0049] Through the time correction process described above, the time information of the counter 26 that determines the transmission timing for each transmitting / receiving unit 20, i.e., each transmitting antenna 22, is synchronized across the entire transmitting / receiving system 2.

[0050] Next, in S50, the control command block 31 commands each transmit / receive unit 20 to execute the timing adjustment mode. Then, in S60, the data processing block 32 obtains reception result data containing information about the reception timing from each transmit / receive unit 20.

[0051] Then, in S70, the control command block 31 adjusts the transmission timing of the transmission signal St for each transmit / receive unit 20. The transmission timing is defined as time information correlated with, for example, a relative time difference Td with respect to a reference transmission timing in a specific reference transmit / receive unit 20. In the example shown in Figure 4, the reference transmission timing is substantially the same as the start time of the frame. The transmission timing is defined to correlate with the transmission order to other transmit / receive units 20 in one frame, which is set in advance for each transmit / receive unit 20. The control command block 31 outputs an adjustment command containing information about the defined transmission timing to the corresponding transmit / receive unit 20. Upon outputting this adjustment command, the control command block 31 causes each transmit / receive unit 20 to perform the adjustment of the transmission timing. The control command block 31 may also define each transmission timing by considering the distance information to the target for each transmit / receive unit 20, corresponding to the reception result data from each transmit / receive unit 20 in the previous normal mode. The control command block 31 may omit outputting the adjustment command for transmit / receive units 20 that do not require adjustment of the transmission timing.

[0052] In the subsequent S80, the control command block 31 performs a verification process to confirm whether the transmission process has been realized at the commanded transmission timing. In the verification process, the control unit 3 again commands the transmit / receive unit 20 to transmit the transmission signal St and output the reception result data, including the reception timing. In the verification process, if the received signal Sr has not been acquired at the reception timing corresponding to the commanded transmission timing, the control unit 3 again defines the transmission timing and outputs the command. Once the reception timing corresponding to the commanded transmission timing is realized, the control unit 3 completes the verification process and proceeds to S90.

[0053] In S90, the control command block 31 outputs an execution command for transmission and reception processing in normal mode. In S100, the data processing block 32 acquires the received result data and generates target information from the data. For example, the data processing block 32 obtains the target distance and relative velocity by performing 2D-FFT processing on the AD-converted beat signal Sb. The data processing block 32 outputs the generated target information and terminates this flow.

[0054] According to the first embodiment described above, the transmission timing of the chirp signal is controlled such that, depending on the reception timing at which the transmitted chirp signal is received, at least a portion of the transmission time period overlaps with chirp signals from different transmitting antennas 22, and the frequency of the chirp signal is shifted from other overlapping chirp signals during the overlapping time period. Therefore, the transmission timing can be controlled while confirming the actual situation of the reception timing which is affected by the transmission timing. In other words, the transmission timing can be controlled while taking into account the deviation in transmission timing due to jitter, etc., until the transmitted signal St is transmitted. Furthermore, since the transmission time periods of chirp signals can be made to overlap at least a portion by this highly accurate transmission timing control, the time domain is effectively utilized by improving the accuracy of the transmission timing.

[0055] In particular, since the transmission timing can be controlled using the counter 26 of the transmit / receive unit 20, which includes the RFIC, the transmission timing can be adjusted by the accuracy of the RFIC's internal clock. For example, adjustment may be possible on the order of a few nanoseconds to tens of nanoseconds.

[0056] Furthermore, according to the first embodiment, time information that determines the transmission timing for each transmitting antenna 22 is synchronized according to the timing at which the frequencies of the chirp signal and the inverted signal overlap. Therefore, the time information can be synchronized based on the timing at which the frequencies of the actually transmitted chirp signal and the inverted signal overlap. Consequently, the time information used for transmission timing control can be synchronized more reliably.

[0057] (Second embodiment) As shown in Figures 7 and 8, the second embodiment is a modification of the first embodiment.

[0058] In the second embodiment, the transmission signals from the multiple transmitting and receiving units 20 have different frequency bands, as shown in Figure 7. The frequency band of the transmission signal St in each transmitting and receiving unit 20 is predetermined, for example. The magnitude of the chirp slope and the transmission time width are substantially the same. Furthermore, the transmission timing of each transmission signal St is defined to be substantially the same. That is, a chirp signal with a different frequency band depending on the transmitting and receiving unit 20, and substantially the same transmission time from the transmission start time Ts to the transmission end time Te, is transmitted as the transmission signal St. Note that the chirp signals shown in Figure 7 with transmission start time Ts and transmission end time Te are arbitrary chirp signals chosen for explanation purposes, and the above explanation can be applied when other chirp signals are considered.

[0059] In this case, when the time correction mode is commanded in S20, a specific transmitting / receiving unit 20 transmits an inverted signal with the direction of frequency change reversed, similar to the first embodiment (see Figure 8). Note that the frequency bandwidth of the inverted signal may be changed so as to interfere with all other chirp signals.

[0060] Furthermore, in this embodiment, the control command block 31 of the control unit 3 outputs an adjustment command to each transmit / receive unit 20 in S70 so as to synchronize the transmission timings according to the acquired reception timing.

[0061] (Third embodiment) As shown in Figures 9 and 10, the third embodiment is a modification of the first embodiment.

[0062] In the third embodiment, each transmitting / receiving unit 20 is capable of transmitting and receiving in the MIMO (Multiple-Input and Multiple-Output) manner. Each transmitting / receiving unit 20 is equipped with multiple transmitting antennas 22a, 22b and receiving antennas 23 to realize the MIMO method. The multiple transmitting antennas 22a, 22b in one transmitting / receiving unit 20 are arranged at a predetermined interval. The multiple receiving antennas 23 are also arranged at equal intervals that correlate with the arrangement interval of the transmitting antennas 22a, 22b. In the following, an example in which each transmitting / receiving unit 20 is provided with two transmitting antennas 22a, 22b and four receiving antennas 23 will be described, but the number of each antenna is not limited to this.

[0063] The transmitting / receiving unit 20 is configured to be able to mechanically or electrically switch between the transmitting antennas 22a and 22b from which the transmission signal St is transmitted. This allows the transmitting / receiving unit 20 to transmit the transmission signal Sta from transmitting antenna 22a and the transmission signal Stb from transmitting antenna 22b in a time-switched manner, as shown in Figure 10. In other words, the transmitting / receiving unit 20 can transmit the transmission signal St using a time-division multiplexing (TDM) method with multiple transmitting antennas 22a and 22b.

[0064] The receiving antennas 23 each receive the transmission signals Sta and Stb and convert them into the received signal Sr. In the transmitting / receiving unit 20, a beat signal Sb is generated for each receiving antenna 23 and output to the control unit 3 as reception result data as appropriate.

[0065] The beat signal Sb, based on the transmission signals Sta and Stb from multiple transmitting antennas 22a and 22b received by a single receiving antenna 23, can be processed virtually as a beat signal Sb from multiple receiving antennas based on a transmission signal from a single transmitting antenna. Therefore, especially in normal mode, the data processing in the control unit 3 allows the received result data to be handled as data acquired from a number of virtual receiving antennas equal to the number of transmitting antennas 22a and 22b multiplied by the number of receiving antennas 23.

[0066] As described above, even when multiple transmitting antennas 22a and 22b are provided for each transmitting / receiving unit 20, the control unit 3 can perform transmission timing adjustment processing based on the received data in timing adjustment mode, as shown in Figure 10.

[0067] In this case, since there are multiple receiving antennas 23 for each transmitting / receiving unit 20, multiple reception result data are generated for each receiving antenna 23 for one transmitting / receiving unit 20. Therefore, in S60, the data processing block 32 only needs to select and acquire specific reception result data for one transmitting / receiving unit 20.

[0068] (Other embodiments) Although several embodiments have been described above, this disclosure is not limited to those embodiments and can be applied to various embodiments and combinations without departing from the spirit of this disclosure.

[0069] In the modified example, the dedicated computer constituting the control unit 3 may have at least one of the digital circuit and analog circuit as a processor. Here, the digital circuit is at least one of the following, such as ASIC (Application Specific Integrated Circuit), FPGA (Field Programmable Gate Array), SOC (System on a Chip), PGA (Programmable Gate Array), and CPLD (Complex Programmable Logic Device). Furthermore, such a digital circuit may have memory for storing programs.

[0070] In the modified examples, the mobile body to which the radar system 1 is applied may be, for example, an autonomous mobile robot capable of transporting goods or collecting information by autonomous or remote driving. In addition to the embodiments described so far, the above embodiments and modifications may be implemented in the form of a processing circuit (e.g., a processing ECU, etc.) or a semiconductor device (e.g., a semiconductor chip, etc.) as a control device configured to be mounted on a host mobile body and having at least one processor 3b and one memory 3a. [Explanation of Symbols]

[0071] 1: Radar system, 2: Transmitting / receiving system, 22, 22a, 22b: Transmitting antenna, 23: Receiving antenna, 3: Control unit (control device), 3a: Memory (storage medium), 3b: Processor

Claims

1. A transmitting and receiving system (2) includes a plurality of transmitting antennas (22; 22a, 22b) that transmit a chirp signal whose frequency changes over time, and a plurality of receiving antennas (23) that receive the chirp signal reflected from the outside as a received signal. A control device (3) having a processor (3b) and controlling the transmission of the chirp signal from the transmitting antenna, Equipped with, The aforementioned processor, The transmission and reception system acquires reception timing information regarding the reception timing of the chirp signal at each receiving antenna, With respect to each chirp signal from each transmitting antenna, the transmission timing is controlled according to the reception timing such that at least a portion of the transmission time overlaps with that of a chirp signal from a different transmitting antenna, and that during the overlapping time, the frequency is shifted relative to other overlapping chirp signals. It is configured to perform, The aforementioned processor, To control the transmission timing, To cause a specific transmitting antenna to transmit an inverted signal in which the direction of frequency time variation is reversed relative to the chirp signal from another transmitting antenna, The timing information that determines the transmission timing for each transmitting antenna is synchronized according to the timing at which the frequencies of the chirp signal and the inverted signal overlap. Includes, Synchronizing the aforementioned transmission timing is This includes synchronizing the time information in accordance with the interference timing between the chirp signal and the inverted signal in the data relating to the received signal, The chirp signals from each of the transmitting antennas are Radar systems with different frequency bands.

2. The aforementioned transmission timing is controlled by, The radar system according to claim 1, further comprising controlling the transmission timing such that all of the aforementioned transmission time periods overlap.

3. The transmitting and receiving system generates reception result data in which the reception timing information is added to the data relating to the received signal. The radar system according to claim 1, wherein the processor includes acquiring information regarding the reception timing and acquiring the reception result data.

4. A control device for controlling a transmitting and receiving system (2) which includes a processor (3b) and a plurality of transmitting antennas (22; 22a, 22b) that transmit a chirp signal whose frequency changes over time, and a plurality of receiving antennas (23) that receive the chirp signal reflected from the outside as a received signal, The aforementioned processor, The transmission and reception system acquires reception timing information regarding the reception timing of the chirp signal at each receiving antenna, With respect to each chirp signal from each transmitting antenna, the transmission timing is controlled according to the reception timing such that at least a portion of the transmission time overlaps with that of a chirp signal from a different transmitting antenna, and that during the overlapping time, the frequency is shifted relative to other overlapping chirp signals. It is configured to perform, The aforementioned processor, To control the transmission timing, To cause a specific transmitting antenna to transmit an inverted signal in which the direction of frequency time variation is reversed relative to the chirp signal from another transmitting antenna, The timing information that determines the transmission timing for each transmitting antenna is synchronized according to the timing at which the frequencies of the chirp signal and the inverted signal overlap. Includes, Synchronizing the aforementioned transmission timing is This includes synchronizing the time information in accordance with the interference timing between the chirp signal and the inverted signal in the data relating to the received signal, The chirp signals from each of the transmitting antennas are Control devices with different frequency change bandwidths.

5. A control method performed by a processor (3b) to control a transmitting and receiving system (2) which includes a plurality of transmitting antennas (22; 22a, 22b) that transmit a chirp signal whose frequency changes over time, and a plurality of receiving antennas (23) that receive the chirp signal reflected from the outside as a received signal, wherein The transmission and reception system acquires reception timing information regarding the reception timing of the chirp signal at each receiving antenna, With respect to each chirp signal from each transmitting antenna, the transmission timing is controlled according to the reception timing such that at least a portion of the transmission time overlaps with that of a chirp signal from a different transmitting antenna, and that during the overlapping time, the frequency is shifted relative to other overlapping chirp signals. Includes, The aforementioned transmission timing is controlled by, To cause a specific transmitting antenna to transmit an inverted signal in which the direction of frequency time variation is reversed relative to the chirp signal from another transmitting antenna, The timing information that determines the transmission timing for each transmitting antenna is synchronized according to the timing at which the frequencies of the chirp signal and the inverted signal overlap. Includes, Synchronizing the aforementioned transmission timing is This includes synchronizing the time information in accordance with the interference timing between the chirp signal and the inverted signal in the data relating to the received signal, The chirp signals from each of the transmitting antennas are Control methods with different frequency change bandwidths.

6. A control program, which includes instructions to be executed by a processor (3b) and stored in a storage medium (3a) for controlling a transmitting and receiving system (2) that includes a plurality of transmitting antennas (22; 22a, 22b) that transmit a chirp signal whose frequency changes over time, and a plurality of receiving antennas (23) that receive the chirp signal reflected from the outside as a received signal, The aforementioned instruction is, The transmission and reception system is used to obtain reception timing information regarding the reception timing of the chirp signal at each receiving antenna. For each chirp signal from each transmitting antenna, the transmission timing is controlled according to the reception timing such that at least a portion of the transmission time overlaps with that of a chirp signal from a different transmitting antenna, and that during the overlapping time, the frequency is shifted compared to other overlapping chirp signals. Includes, Controlling the transmission timing means To cause a specific transmitting antenna to transmit an inverted signal in which the direction of frequency time variation is reversed relative to the chirp signal from another transmitting antenna, The timing information that determines the transmission timing for each transmitting antenna is synchronized according to the timing at which the frequencies of the chirp signal and the inverted signal overlap. Includes, Synchronizing the aforementioned transmission timing is This includes synchronizing the time information in accordance with the interference timing between the chirp signal and the inverted signal in the data relating to the received signal, The chirp signals from each of the transmitting antennas are Control programs with different frequency change bandwidths.

Images