Radar system, radar control device, radar control method, and radar control program

Abstract

To provide a radar system and the like capable of suppressing false detections.SOLUTION: A plurality of transmitting antennas in a radar system is arranged in groups corresponding to a plurality of height ranges, such that at least one group becomes an equal-number group having the same number as a group of another height range. A processor of the radar system is configured to transmit a transmission signal from each transmitting antenna with a shift amount whose difference pattern among the transmitting antennas within a group becomes non-overlapping between equal-number groups. The processor is configured to output sensing data corresponding to a received signal, in which a correspondence relationship between a plurality of peaks in a corresponding velocity spectrum and the plurality of transmitting antennas is identified by matching of an interval pattern among peaks and the difference pattern.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present disclosure relates to a radar control technique for controlling a radar system. [Background technology]

[0002] Patent Document 1 discloses a radar device that performs phase shift keying (PSK) on multiple transmission signals input to multiple transmitting antennas, rotating the phases of each signal by different amounts of phase rotation for each repetition period. The radar device sets the number of phases used for PSK to be greater than the number of transmitting antennas. As a result, the radar device unevenly arranges peaks based on the transmission signals on a Doppler spectrum obtained by analyzing the received signals. The radar device identifies the correspondence between the multiple peaks and the multiple transmitting antennas by using the locations where the peaks are unevenly arranged on the Doppler spectrum as clues. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6881177 Summary of the Invention [Problem to be solved by the invention]

[0004] However, height patterns can occur in which interference occurs between a direct signal, in which a transmitted signal reflected from a target reaches a receiving antenna, and a reflected signal, in which the transmitted signal is reflected from a reflecting object other than the target, such as the ground. In this case, the reception level of a received signal corresponding to a transmitting antenna within a specific height range may decrease. In this state, a peak corresponding to the received signal may not be detected in the Doppler spectrum. This may make it difficult to accurately identify the correspondence between the peak and the transmitting antenna. In this case, an incorrect correspondence may be selected, resulting in erroneous detection.

[0005] An object of the present disclosure is to provide a radar system capable of suppressing false detection. Another object of the present disclosure is to provide a radar control device capable of suppressing false detection. Yet another object of the present disclosure is to provide a radar control method capable of suppressing false detection. Yet another object of the present disclosure is to provide a radar control program capable of suppressing false detection. [Means for solving the problem]

[0006] The technical means of the present disclosure for solving the problems will be described below. Note that the claims and the reference characters in parentheses in this section indicate the correspondence with the specific means described in the embodiments described later in detail, and do not limit the technical scope of the present disclosure.

[0007] A first aspect of the present disclosure is a radar system having a plurality of transmit antennas (TX), at least one receive antenna (RX), and a processor (7b), The transmitting antenna is In the groups (Ga, Gb, Gc) for each of the plurality of height ranges, at least one group is arranged so that the number of groups is the same as the number of groups for the other height ranges; The processor transmitting, from each transmitting antenna, a transmission signal whose frequency changes over time in a repetition period and whose phase is shifted over time for each repetition period by a different amount between the transmitting antennas; outputting sensing data correlating transmitted signals from a plurality of transmitting antennas with received signals received by a receiving antenna; configured to run To transmit a transmission signal is a difference pattern of the shift amounts between the transmitting antennas in a group includes transmitting a transmission signal from each transmitting antenna with a shift amount that does not overlap between groups of the same number; Outputting sensing data is The correspondence between the multiple peaks in the corresponding velocity spectrum and the multiple transmitting antennas includes outputting sensing data correlated with the received signal identified by matching the interval pattern and difference pattern between the peaks.

[0008] A second aspect of the present disclosure is a radar control device that includes a processor (7b) and controls a radar system (1) that includes a plurality of transmitting antennas (TX) and at least one receiving antenna (RX) arranged in groups (Ga, Gb, Gc) for a plurality of height ranges, with at least one group having the same number of groups as the other height range groups, and The processor transmitting, from each transmitting antenna, a transmission signal whose frequency changes over time in a repetition period and whose phase is shifted over time for each repetition period by a different amount between the transmitting antennas; outputting sensing data correlating transmitted signals from a plurality of transmitting antennas with received signals received by a receiving antenna; configured to run To transmit a transmission signal is a difference pattern of the shift amounts between the transmitting antennas in a group includes transmitting a transmission signal from each transmitting antenna with a shift amount that does not overlap between groups of the same number; Outputting sensing data is The correspondence between the multiple peaks in the corresponding velocity spectrum and the multiple transmitting antennas includes outputting sensing data correlated with the received signal identified by matching the interval pattern and difference pattern between the peaks.

[0009] A third aspect of the present disclosure is a radar control method executed by a processor (7b) for controlling a radar system (1) having a plurality of transmitting antennas (TX) and at least one receiving antenna (RX) arranged in a plurality of groups (Ga, Gb, Gc) for each height range, with at least one group having the same number of groups as other height range groups, the method comprising: transmitting, from each transmitting antenna, a transmission signal whose frequency changes over time in a repetition period and whose phase is shifted over time for each repetition period by a different amount between the transmitting antennas; outputting sensing data correlating transmitted signals from a plurality of transmitting antennas with received signals received by a receiving antenna; Including, To transmit a transmission signal is a difference pattern of the shift amounts between the transmitting antennas in a group includes transmitting a transmission signal from each transmitting antenna with a shift amount that does not overlap between groups of the same number; Outputting sensing data is The correspondence between the multiple peaks in the corresponding velocity spectrum and the multiple transmitting antennas includes outputting sensing data correlated with the received signal identified by matching the interval pattern and difference pattern between the peaks.

[0010] A fourth aspect of the present disclosure is a radar control program stored in a storage medium (7a) and including instructions to be executed by a processor (7b) that controls a radar system (1) having a plurality of transmitting antennas (TX) and at least one receiving antenna (RX) arranged in a plurality of groups (Ga, Gb, Gc) for each height range, the groups being equal in number for at least one group to the groups for the other height ranges, The command is, transmitting, from each transmitting antenna, a transmission signal whose frequency changes over time in a repetition period and whose phase is shifted over time for each repetition period by a different amount between the transmitting antennas; outputting sensing data correlating transmitted signals from a plurality of transmitting antennas with received signals received by a receiving antenna; Including, To transmit a transmission signal is a difference pattern of the shift amounts between the transmitting antennas in a group includes transmitting a transmission signal from each transmitting antenna with a shift amount that does not overlap between groups of the same number; To output sensing data, The correspondence between the multiple peaks in the corresponding velocity spectrum and the multiple transmitting antennas includes outputting sensing data correlated with the received signal identified by matching the interval pattern and difference pattern between the peaks.

[0011] According to these first to fourth aspects, transmission signals are transmitted from each transmitting antenna with a shift amount such that the difference patterns between the shift amounts between the transmitting antennas within a group are non-overlapping among groups with the same number of antennas. Here, the interval pattern between peaks in the velocity spectrum correlates with the difference pattern. Therefore, even if a peak is not detected by the height pattern for one of the groups with the same number of antennas, the difference pattern becomes non-overlapping, making the interval pattern non-overlapping, and it may be possible to distinguish which of the groups the remaining peak corresponds to. Therefore, by matching the difference pattern with the interval pattern, the correspondence between multiple peaks and multiple transmitting antennas can be accurately identified, and erroneous detection can be suppressed. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a schematic diagram showing the overall configuration of a radar system according to a first embodiment; [Figure 2] 3A and 3B are schematic diagrams for explaining phases assigned to transmission signals at each transmitting antenna. [Figure 3] 1 is a diagram illustrating an example of the arrangement of transmitting antennas and the amount of Doppler shift. [Figure 4] 10A and 10B are diagrams illustrating comparative examples of the arrangement of transmitting antennas and the amount of Doppler shift. [Figure 5] FIG. 2 is a block diagram showing the functional configuration of a control unit in the radar system. [Figure 6] 4 is a flowchart showing a radar control flow according to the first embodiment. [Figure 7] FIG. 10 is a diagram illustrating an example of a Doppler spectrum. [Figure 8] FIG. 10 is a diagram showing a comparative example of a Doppler spectrum. [Figure 9] 1 is a diagram illustrating an example of the arrangement of transmitting antennas and the amount of Doppler shift. [Figure 10] FIG. 10 is a diagram illustrating an example of a Doppler spectrum. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, multiple embodiments of the present disclosure will be described with reference to the drawings. Note that corresponding components in each embodiment are designated by the same reference numerals, and redundant description may be omitted. Furthermore, when only a portion of the configuration is described in each embodiment, the configuration of another previously described embodiment may be applied to the remaining portions of the configuration. Furthermore, in addition to the combinations of configurations explicitly stated in the description of each embodiment, configurations of multiple embodiments may be partially combined together even if not explicitly stated, provided that there is no particular problem with the combination.

[0014] (First embodiment) A first embodiment of the present disclosure will be described with reference to FIGS. 1 to 8. The radar device 1 shown in FIG. 1 is mounted on a moving object such as a vehicle. The radar device 1 transmits a transmission signal to the outside world and receives the transmission signal reflected by a target as a received signal. The radar device 1 acquires and outputs sensing data related to the target that reflected the transmission signal by analyzing the received signal. The radar device 1 is a so-called MIMO (Multiple-Input-Multiple-Output) radar that transmits transmission signals from multiple transmission antennas TX to artificially increase the number of receiving antennas RX beyond the actual number. The radar device 1 is an example of a "radar system."

[0015] The sensing data output from the radar device 1 is input to an in-vehicle ECU (Electronic Control Unit) via an in-vehicle network such as a Control Area Network (CAN) (registered trademark) or Ethernet (registered trademark). The in-vehicle ECU executes various processes for automatic driving of the vehicle and advanced driving assistance based on the acquired sensing data of each target.

[0016] The processes based on the sensing data include, for example, collision avoidance processing, warning processing, etc. The collision avoidance processing is a process of controlling the vehicle to avoid collision with the target by controlling the brake system, steering system, etc. based on the sensing data of each target. The warning processing is a process of warning the driver of the possibility of collision with the target based on the sensing data of each target.

[0017] 1, the radar device 1 of this embodiment includes a transceiver unit 2, a control unit 7, and a storage unit 8. The transceiver unit 2 is a processing unit that performs transmission processing of transmission signals and reception processing of reception signals. The transceiver unit 2 includes a clock oscillator 3, a signal generator 4, multiple transmission circuits 5, multiple transmission antennas TX, multiple reception antennas RX, and multiple reception circuits 6.

[0018] The clock oscillator 3 generates a periodic clock signal. The clock oscillator 3 transmits the clock signal to the signal generator 4 and each receiving circuit 6. The signal generator 4 generates a chirp signal modulated so that the frequency changes over time, for each chirp period Tc corresponding to the clock signal. The signal generator 4 generates a specified number of chirp signals for each measurement period Tf. The generated multiple chirp signals are distributed and output to each channel of the transmitting circuit 5 and the receiving circuit 6. Note that in FIG. 2, the chirp signal is shown as a so-called up-chirp signal, whose frequency increases over time. However, the chirp signal may also be a so-called down-chirp signal, whose frequency decreases over time.

[0019] In the following, the multiple chirp signals output from the signal generator 4 to the transmitter circuit 5 and transmitted from the transmitter antenna TX may be referred to as transmission signals. Furthermore, the multiple chirp signals output to the receiver circuit 6 in response to the transmission signals may be referred to as local signals.

[0020] The transmitting circuit 5 and the receiving circuit 6 are each mainly composed of a semiconductor integrated circuit device such as an MMIC (Monolithic Microwave Integrated Circuit). The transmitting circuit 5 is connected to a transmitting antenna TX and outputs a transmission signal to the transmitting antenna TX. The transmitting circuit 5 includes the same number of phase shifters 51 and amplifiers 52 as the number of connected transmitting antennas TX.

[0021] The phase shifter 51 imparts a specific phase shift to the input transmit signal. Specifically, the phase shifter 51 imparts at least a phase shift of a substantially constant amount per chirp period Tc to multiple chirp signals aligned in time. For example, as shown in FIG. 2, assume that a shift amount ω1 is imparted to multiple chirp signals as transmit signals transmitted from a specific transmit antenna TX1 among multiple transmit antennas TX. In this case, the phase of the kth chirp signal is rotated by the chirp number multiplied by the shift amount ω1 relative to its phase before input to the phase shifter 51. As a result, the phases of the multiple chirp signals aligned in time that pass through the phase shifter 51 change linearly per chirp period Tc. This linear phase change imparts a pseudo-Doppler velocity to the chirp signals according to the shift amount. The shift amount that imparts the phase change described above may be referred to as the Doppler shift amount below. Note that in FIG. 2, the chirp number k ranges from "1" to "N," which is the maximum number of chirp signals in the measurement period Tf. However, the chirp number k may be set to start from any number, such as "0." The chirp period Tc is an example of a "repetition period."

[0022] Each of the multiple phase shifters 51 imparts a different Doppler shift amount. That is, in FIG. 2, a shift amount ω2 different from the shift amount ω1 is imparted to multiple chirp signals transmitted from a transmitting antenna TX2 different from the transmitting antenna TX1. Similarly, for the transmitting antenna TXm, a shift amount ω2 different from the shift amounts ω1, ω2, etc. is imparted to multiple chirp signals transmitted. m As a result, the multiple transmission signals transmitted from the multiple transmission antennas TX are subjected to so-called Doppler Division Multiplexing (DDM).

[0023] The phase shifter 51 may impart a preset Doppler shift amount to the chirp signal. Alternatively, the phase shifter 51 may impart a different Doppler shift amount between measurement periods Tf in response to a control command from the control unit 7. The amplifier 52 amplifies the transmission signal output from the phase shifter 51 and outputs the amplified signal to the corresponding transmitting antenna TX.

[0024] The transmitting antenna TX converts the transmission signal supplied from the transmitting circuit 5 from an electrical signal to a radio wave signal and transmits it to the outside. A single transmitting antenna TX is configured to include at least one antenna element. For example, the transmitting antenna TX is a patch antenna equipped with multiple flat antenna elements. The antenna elements are arranged on the opposite side of a dielectric substrate having a ground plane on one side, facing the ground plane. The multiple antenna elements are connected, for example, in series, by a feeder line that supplies the electrical signal. Each transmission signal transmitted from the multiple transmitting antennas TX is given a different Doppler shift amount for each transmitting antenna TX by the corresponding phase shifter 51.

[0025] A plurality of transmitting antennas TX are provided for each of a plurality of height ranges in the vertical direction. Hereinafter, a set of a plurality of transmitting antennas TX provided in one height range will be referred to as a group of transmitting antennas TX.

[0026] For example, as shown in FIG. 3, assume that 12 transmitting antennas TX are provided. In the following description, the 12 transmitting antennas TX may be distinguished by adding an integer from 1 to 12 to the end of the symbol "TX." The transmitting antennas TX are provided in groups of four at substantially the same height. Specifically, transmitting antennas TX1, TX2, TX3, and TX4 are grouped as Ga, which are at substantially the same height. Transmitting antennas TX5, TX6, TX7, and TX8 are grouped as Gb, which are at substantially the same height. Furthermore, transmitting antennas TX9, TX10, TX11, and TX12 are grouped as Gc, which are at substantially the same height. In this example, the three groups Ga, Gb, and Gc are equal-number groups, each with the same number of transmitting antennas TX. In FIG. 3, the horizontal direction is designated as the X direction, and the height direction (vertical direction) is designated as the H direction.

[0027] The height positions of transmitting antennas TX within the same group may be offset from one another within a predetermined height range. The height range is determined according to the expected height pattern. The period of the height pattern correlates with the height of the transmitting antenna TX, the frequency of the transmitted signal, the distance to the target, the height of the target, the height of the receiving antenna RX, and the like. The height range is, for example, the range in which the strength of the received signal is equal to or less than a threshold value in the expected height pattern.

[0028] In the example shown in Fig. 3, the transmitting antennas TX are arranged at equal intervals in the X direction in each of the groups Ga, Gb, and Gc. The transmitting antennas TX are arranged in groups of three at the same position in the X direction. However, the positions of the transmitting antennas TX in the X direction are not limited to this. For example, the spatial intervals of the transmitting antennas TX in each of the groups Ga, Gb, and Gc may be unequal. Furthermore, the positions of the transmitting antennas TX in the X direction may not be the same among the groups Ga, Gb, and Gc.

[0029] The phase shifter 51 assigns a Doppler shift amount to each transmit signal so that the difference patterns of the Doppler shift amount between the transmitting antennas TX in each group Ga, Gb, and Gc do not overlap among groups with the same number of antennas. Furthermore, the phase shifter 51 assigns a Doppler shift amount that changes equally across all transmitting antennas TX. For example, the phase shifter 51 assigns a Doppler shift amount that increases in increments of π / 8 to the transmitting antennas TX1 to TX12. However, the phase shifter 51 prohibits the assignment of Doppler shift amounts of 0, π / 8, 2π / 8, and 3π / 8 to the transmitting antennas TX. In other words, the phase shifter 51 assigns a Doppler shift amount so that a section in which no target-derived peaks are detected is formed on the low-velocity side of the Doppler spectrum described below.

[0030] Here, the difference pattern is a change pattern of the difference between adjacent Doppler shift amounts. The difference pattern will be explained below by comparing Fig. 3, which illustrates an example of a non-overlapping case, with Fig. 4, which illustrates a comparative example of a difference pattern when overlapping.

[0031] In the group Ga in the comparative example, the Doppler shift amount is set to 4π / 8 for the transmitting antenna TX1, 5π / 8 for the transmitting antenna TX2, 6π / 8 for the transmitting antenna TX3, and 7π / 8 for the transmitting antenna TX4. That is, the group Ga has a differential pattern in which the Doppler shift amount increases equally by π / 8 in ascending order.

[0032] In addition, in group Gb, Doppler shift amounts of 8π / 8, 9π / 8, 10π / 8, and 11π / 8 are set for transmitting antennas TX5, TX6, TX7, and TX8, in that order. Furthermore, in group Gc, Doppler shift amounts of 12π / 8, 13π / 8, 14π / 8, and 15π / 8 are set for transmitting antennas TX9, TX10, TX11, and TX12, in that order. That is, groups Ga and Gc also have differential patterns in which the Doppler shift amount increases equally in increments of π / 8 in ascending order. In summary, the differential patterns of groups Ga, Gb, and Gc are all [π / 8, π / 8, π / 8] from the side with the smallest Doppler shift amount. Therefore, groups Ga, Gb, and Gc are groups with the same number of overlapping differential patterns.

[0033] On the other hand, in this embodiment, the Doppler shift amounts are set to 4π / 8 for transmitting antenna TX1, 6π / 8 for transmitting antenna TX2, 7π / 8 for transmitting antenna TX3, and 8π / 8 for transmitting antenna TX4, as shown in Fig. 3. That is, group Ga has a differential pattern in which the Doppler shift amount increases by 2π / 8 between transmitting antennas TX1 and TX2, and increases by π / 8 between transmitting antennas TX2 and TX3 and between transmitting antennas TX3 and TX4, in ascending order.

[0034] In addition, for group Gb, Doppler shift amounts of 5π / 8, 9π / 8, 11π / 8, and 12π / 8 are set for transmitting antennas TX5, TX6, TX7, and TX8, in that order. That is, group Gb has a differential pattern in which, in ascending order of Doppler shift amount, the Doppler shift increases by 3π / 8 between transmitting antennas TX5 and TX6, by 2π / 8 between transmitting antennas TX6 and TX7, and by π / 8 between transmitting antennas TX7 and TX8.

[0035] Furthermore, in group Gc, Doppler shift amounts of 10π / 8, 13π / 8, 14π / 8, and 15π / 8 are set for transmitting antennas TX9, TX10, TX11, and TX12, in that order. That is, group Gc has a differential pattern in which, in ascending order of Doppler shift amount, the Doppler shift increases by 3π / 8 between transmitting antennas TX9 and TX10, by π / 8 between transmitting antennas TX10 and TX11, and by π / 8 between transmitting antennas TX7 and TX8.

[0036] In summary, the differential pattern of group Ga is [2π / 8,π / 8,π / 8], the differential pattern of group Gb is [3π / 8,2π / 8,π / 8], and the differential pattern of group Gc is [3π / 8,π / 8,π / 8]. Therefore, groups Ga, Gb, and Gc are equal-number groups with non-overlapping differential patterns.

[0037] The receiving antenna RX receives, as a received signal, a radio wave signal that includes a transmitted signal reflected from a target in the external world. Each of the multiple receiving antennas RX receives a signal that is a mixture of received signals corresponding to the transmitted signals from the multiple transmitting antennas TX. Hereinafter, this mixed signal received by each receiving antenna RX will be referred to as a mixed received signal. Furthermore, the components of the received signals that correspond to the transmitted signals from the multiple transmitting antennas TX and that are mixed in the mixed received signal will be referred to as received signal components.

[0038] The receiving antenna RX converts the received signal as a radio wave signal into an electrical signal and outputs it to the corresponding receiving circuit 6. The receiving antenna RX is, for example, a patch antenna, similar to the transmitting antenna TX, in which at least one antenna element is connected in series by a feeder line. Note that the transmitting antenna TX and the receiving antenna RX may also be monopole antennas, inverted-F antennas, loop antennas, or the like. Note that, hereinafter, multiple received signals received by multiple receiving antennas RX may be collectively referred to as a received signal group.

[0039] The receiving circuit 6 is connected to the receiving antenna RX and acquires the received signal received by the receiving antenna RX. The receiving circuit 6 includes amplifiers 61, signal mixers 62, and AD converters 63, the number of which is the same as the number of connected receiving antennas RX.

[0040] The amplifier 61 amplifies the received signal received by the receiving antenna RX and outputs it to the signal mixer 62. The signal mixer 62 generates a beat signal by mixing the local signal from the signal generator 4 with the received signal. The generated beat signal becomes an interference signal that represents the frequency difference between the received signal and the local signal. The beat signal generated by the signal mixer 62 may be filtered by a low-pass filter (not shown) to remove high-frequency components that deviate from the frequency difference between the received signal and the local signal. The beat signal is also called an IF signal.

[0041] The AD converter 63 converts the beat signal, which is an analog signal, into a digital signal. The AD converter 63 acquires the clock signal output from the clock oscillator 3, samples the beat signal at time intervals corresponding to the cycle of the clock signal, and digitizes it. The AD converter 63 sequentially outputs the digitized beat signal to the control unit 7.

[0042] The control unit 7 is connected to the transmitting / receiving unit 2 via at least one of, for example, a LAN (Local Area Network) line, a wire harness, an internal bus, a wireless communication line, etc. The configuration of the control unit 7 will be described later.

[0043] The accommodation unit 8 is a housing that accommodates the transceiver unit 2 and the control unit 7. The accommodation unit 8 includes a radome 81 and a case body 82. The radome 81 is mainly made of a transparent material that allows millimeter-wave band radio waves to pass through. The radome 81 is attached to the case body 82 so as to cover the antennas TX and RX. The radome 81 protects the antennas TX and RX while allowing radio waves to pass through, enabling signals to be transmitted and received by the antennas TX and RX. The case body 82, together with the radome 81, defines an accommodation space that accommodates the components of the radar device 1 described above.

[0044] The control unit 7 includes at least one dedicated computer. The dedicated computer constituting the control unit 7 may be a radar ECU (Electronic Control Unit) specialized for controlling a specific radar device 1. The dedicated computer constituting the control unit 7 may be a radar supervising ECU that comprehensively controls multiple radar devices 1 mounted on a moving object. The dedicated computer constituting the control unit 7 may be a sensor supervising ECU that comprehensively controls multiple sensors including the radar device 1 and other sensors such as LiDAR (Light Detection and Ranging / Laser Imaging Detection and Ranging).

[0045] The dedicated computer constituting the control unit 7 has at least one memory 7a and one processor 7b. The memory 7a is at least one type of non-transitory tangible storage medium, such as a semiconductor memory, a magnetic medium, or an optical medium, that non-temporarily stores computer-readable programs and data. Here, "storage" may refer to accumulation in which data is retained even when the radar device 1 is turned on or off, or may refer to temporary storage in which data is erased when the radar device 1 is turned off. The processor 7b includes at least one type of core selected from a central processing unit (CPU), a graphics processing unit (GPU), a reduced instruction set computer (RISC)-CPU, a data flow processor (DFP), and a graph streaming processor (GSP).

[0046] In the control unit 7, the processor 7b executes a plurality of instructions included in a radar control program stored in the memory 7a in order to control the radar device 1. In this way, the control unit 7 constructs a plurality of functional blocks for controlling the radar device 1. The functional blocks constructed in the control unit 7 include a transmission processing block 71 and a reception processing block 72, as shown in Fig. 5. The control unit 7 is an example of a "radar control device."

[0047] The radar control method in which the control unit 7 controls the radar device 1 through cooperation of these blocks 71 and 72 is executed in accordance with the radar control flow shown in Fig. 6. This radar control flow is executed repeatedly while the radar device 1 is running. Note that each "S" in this radar control flow represents a plurality of steps executed by a plurality of commands included in the radar control program.

[0048] First, in S10, the transmission processing block 71 outputs a command to start transmission processing to the transceiver unit 2, causing the transmission signals to be transmitted from the multiple transmission antennas TX. As described above, the chirp signals constituting the transmission signals are given different Doppler shift amounts for each transmission antenna TX by the action of the phase shifter 51. The Doppler shift amounts are given so that the difference patterns do not overlap between groups of the same number.

[0049] The transmission processing block 71 may transmit a command to start transmission processing, thereby causing the transceiver unit 2 to transmit a transmission signal with a preset amount of Doppler shift. Alternatively, the transmission processing block 71 may sequentially set the amount of Doppler shift for each measurement period Tf, and output information on the reset amount of Doppler shift to the transceiver unit 2.

[0050] Next, in S20, the reception processing block 72 acquires, from each reception circuit 6, each beat signal defined from each reception signal of the reception signal group. Then, in S30, the reception processing block 72 acquires a Doppler spectrum for the beat signal defined from the reception signal received by a single reception antenna RX. The reception processing block 72 may acquire a beat signal corresponding to a specific, predefined single reception antenna RX. Alternatively, the reception processing block 72 may change the single reception antenna RX corresponding to the acquired beat signal for each measurement period Tf.

[0051] To explain in more detail how the Doppler spectrum is acquired, the reception processing block 72 acquires the Doppler spectrum by performing a Fast Fourier Transform (FFT) twice on the beat signal. The reception processing block 72 acquires, for each chirp signal, a frequency spectrum (distance spectrum) that shows a peak at the frequency corresponding to the distance to the target through the first FFT. The distance spectrum data is a distance bin signal that includes information on the signal strength for each distance bin according to the distance resolution.

[0052] Furthermore, the reception processing block 72 performs a second FFT process on a waveform in which the phases at the range bins obtained in the first FFT process for the multiple chirp signals are arranged in time series. As a result of the FFT process, the reception processing block 72 obtains, for each range bin, a frequency spectrum (Doppler spectrum) that shows a peak at a position corresponding to the Doppler velocity (relative velocity) of the target. In this way, the reception processing block 72 obtains a two-dimensional spectrum of the range R and the Doppler velocity V. The Doppler spectrum is also called a velocity spectrum, and the two-dimensional spectrum is also called an RV map.

[0053] Next, in S40, the reception processing block 72 determines whether or not the Doppler spectrum has the same number of peaks as the number of transmitting antennas TX. If it is determined that the Doppler spectrum has the same number of peaks as the number of transmitting antennas TX, the flow proceeds to S50.

[0054] In S50, the reception processing block 72 matches the transmitting antenna TX with multiple peaks in the Doppler spectrum. For example, as shown in FIG. 7, the reception processing block 72 identifies a peak on the high-speed side adjacent to a speed section S where no peak exists as the peak corresponding to the transmitting antenna TX1. Then, the reception processing block 72 associates the transmitting antenna TX with the peak in descending order of the magnitude of the Doppler shift imparted to the transmission signal. In the following S60, the reception processing block 72 sets the maximum reliability (e.g., 100%) for the Doppler spectrum. After S60, the flow proceeds to S90.

[0055] On the other hand, if it is determined in S40 that the Doppler spectrum does not have the same number of peaks as the number of transmitting antennas TX, the flow proceeds to S70. In S70, the reception processing block 72 matches the interval pattern between the peaks with the difference pattern. Through matching, the reception processing block 72 identifies the correspondence between the multiple peaks in the Doppler spectrum and the multiple transmitting antennas TX.

[0056] More specifically, the phase shifter 51 assigns a pseudo Doppler velocity corresponding to the Doppler shift amount to each transmission signal transmitted from each transmitting antenna TX. Therefore, in the Doppler spectrum, a peak is detected in a velocity bin corresponding to the assigned Doppler velocity for each transmission signal. That is, the peak spacing pattern in the Doppler spectrum correlates with the differential pattern. The reception processing block 72 identifies the correspondence between multiple peaks and multiple transmitting antennas TX by searching for a differential pattern that matches the peak spacing pattern in the Doppler spectrum.

[0057] A specific example of matching will now be described with reference to Fig. 7, which shows the Doppler spectrum corresponding to Fig. 3, and Fig. 8, which shows the Doppler spectrum corresponding to Fig. 4, which is a comparative example in which difference patterns overlap. For example, as shown in the graphs on the right side of Figs. 3 and 4, suppose that the intensity P of a received signal, which is a transmission signal from a transmitting antenna TX belonging to group Gb and reflected by a specific target, decreases due to the occurrence of a height pattern. Then, suppose that the peak corresponding to group Gb disappears from the peaks for that target in the Doppler spectrum.

[0058] In this case, in the comparative example in which the difference patterns of the same number of groups overlap, the peak corresponding to group Gb disappears, resulting in two sets of four peaks with equal peak intervals being detected. There is also a possibility that velocity aliasing occurs in the Doppler spectrum. Therefore, it is difficult to determine which of these two sets of peaks corresponds to group Ga or Gc.

[0059] On the other hand, in this embodiment, where the difference patterns of the same number of groups are non-overlapping, two sets of four peaks with different interval patterns are detected. For example, if the smallest peak interval is D, the interval pattern of the set on the low-speed side is [2D, D, D] in ascending order of speed. The interval pattern of the set on the high-speed side is [3D, D, D]. Therefore, the reception processing block 72 determines that the set of peaks with the interval pattern [2D, D, D] corresponds to group Ga, which has a difference pattern of [2π / 8, π / 8, π / 8]. The reception processing block 72 then determines that the set of peaks with the interval pattern [3D, D, D] corresponds to group Gc, which has a difference pattern of [3π / 8, π / 8, π / 8]. The interval pattern of the set of peaks assumed to be lost in this example is [4D, 2D, D].

[0060] In the next step S80, the reception processing block 72 sets a reliability level for the Doppler spectrum according to the number of matched groups. The reception processing block 72 sets a higher reliability level the more matched groups there are. For example, if the reception processing block 72 has successfully matched two of the three groups Ga, Gb, and Gc, it sets the reliability level to 70%. Also, if the reception processing block 72 has successfully matched one of the three groups Ga, Gb, and Gc, it sets the reliability level to 30%.

[0061] In S90 following S60 or S80, the reception processing block 72 acquires the Doppler spectrum that was not acquired in S30. As a result, the reception processing block 72 acquires the Doppler spectrum, and therefore the two-dimensional spectrum, corresponding to each of the received signals received by all of the receiving antennas RX.

[0062] Next, in S100, the reception processing block 72 performs angle measurement processing according to the matching result using the acquired multiple two-dimensional spectra. That is, the reception processing block 72 performs a third FFT process on a waveform obtained by arranging the phases of each peak in an integrated spectrum obtained by integrating multiple two-dimensional spectra. At this time, the reception processing block 72 defines the correspondence between each peak and each transmitting antenna TX according to the matching result, and then performs FFT processing. As a result, the reception processing block 72 obtains an angle spectrum showing a peak at a position corresponding to the relative angle with respect to the target. Note that the FFT process in S100 is performed using a group of beat signals corresponding to a group of received signals obtained by receiving transmission signals from multiple transmitting antennas TX at multiple receiving antennas RX. For this reason, this FFT process can also be referred to as MIMO angle measurement processing.

[0063] Furthermore, in S110, the reception processing block 72 outputs sensing data. The reception processing block 72 outputs at least the distance to the target, the relative velocity, and the relative angle as sensing data. The target distance information, relative velocity information, and relative angle information are information correlating with a group of received signals obtained by MIMO angle measurement processing, in which transmission signals from multiple transmitting antennas TX are received by each of multiple receiving antennas RX. The sensing data are data correlating with a group of received signals in which the correspondence between the transmitting antennas TX and the Doppler spectrum peaks has been identified by the above-mentioned matching. Furthermore, the reception processing block 72 tracks targets for each measurement period Tf based on the sensing data from the previous or previous measurement period Tf, and outputs the sensing data including an identification ID for each target. The reception processing block 72 determines whether to re-assign an identification ID in response to variations in the target's relative angle, depending on the reliability set in S60 or S80. For example, the higher the reliability, the more likely the reception processing block 72 is to allow continued tracking of a target with the same identification ID even when there is variation in the relative angle.

[0064] According to the first embodiment described above, transmission signals are transmitted from each transmitting antenna TX with Doppler shift amounts such that the difference patterns of the Doppler shift amounts between the transmitting antennas TX within a group are non-overlapping among groups with the same number of antennas. Here, the interval patterns between peaks in the Doppler spectrum correlate with the difference patterns. Therefore, even if a peak is not detected by the height pattern for one of the groups with the same number of antennas, the difference patterns become non-overlapping, and the interval patterns also become non-overlapping. This makes it possible to distinguish which of the groups the remaining peaks corresponds to. Therefore, by matching the difference patterns with the interval patterns, the correspondence between multiple peaks and multiple transmitting antennas TX can be accurately identified. This reduces erroneous detection of target sensing data.

[0065] Furthermore, according to the first embodiment, the transmission signal is transmitted with a Doppler shift amount that changes equally across all the transmission antennas TX, which makes it easy to impart a Doppler shift amount in terms of hardware.

[0066] Furthermore, according to the first embodiment, the fewer the number of transmitting antennas TX identified by the differential pattern matching, the lower the reliability set for the sensing data. Therefore, it may be possible to output sensing data according to the decrease in reliability due to the decrease in the number of peaks in the height pattern.

[0067] In addition, according to the first embodiment, when the same number of peaks as the total number of transmitting antennas TX are not detected, sensing data correlated with the received signal identified by matching the interval pattern with the difference pattern is output, so that matching can be reliably performed when a height pattern occurs.

[0068] Second Embodiment As shown in FIGS. 9 and 10, the second embodiment is a modification of the first embodiment.

[0069] In the second embodiment, the phase shifter 51 imparts a Doppler shift amount that makes the difference patterns non-overlapping even between groups having different numbers of transmitting antennas TX.

[0070] In this embodiment, as shown in FIG. 9, the Doppler shift amount is set to 5π / 8 for transmitting antenna TX1, 6π / 8 for transmitting antenna TX2, 7π / 8 for transmitting antenna TX3, and 8π / 8 for transmitting antenna TX4.

[0071] In group Gb, the Doppler shift amounts are set to 4π / 8, 9π / 8, and 11π / 8 for the transmitting antennas TX5, TX6, and TX7, in that order. Furthermore, in group Gc, the Doppler shift amounts are set to 10π / 8, 12π / 8, and 13π / 8 for the transmitting antennas TX8, TX9, and TX10, in that order.

[0072] In summary, the differential pattern of group Ga is [π / 8, π / 8, π / 8, π / 8], the differential pattern of group Gb is [5π / 8, 2π / 8], and the differential pattern of group Gc is [2π / 8, π / 8]. Therefore, groups Gb and Gc are equal-number groups with non-overlapping differential patterns. Furthermore, group Ga, which has a larger number of transmitting antennas TX than groups Gb and Gc, has a differential pattern that does not include the differential patterns of groups Gb and Gc. In other words, the differential patterns of group Ga do not overlap with those of groups Gb and Gc. Therefore, in this embodiment, the differential patterns do not overlap even between groups with different numbers of transmitting antennas TX. In this case, the peaks corresponding to each transmitting antenna TX in the Doppler spectrum acquired in S30 are arranged as shown in FIG. 10.

[0073] (Other embodiments) Although multiple embodiments have been described above, the present disclosure should not be construed as being limited to those embodiments, and can be applied to various embodiments and combinations within the scope that does not deviate from the gist of the present disclosure.

[0074] In a modified example, the reception processing block 72 of S50 may perform matching processing for each single Doppler spectrum for the number of reception antennas RX. The reception processing block 72 may perform the processes of S40, S50, S60, S70, and S80 for each single Doppler spectrum, and combine the matching results for each single Doppler spectrum to define a correspondence relationship.

[0075] In a modified example, at least a part of the processing executed in blocks 71 and 72 may be executed by a processor external to the radar device 1. For example, at least a part of the processing may be executed by a processor of an on-board ECU mounted on a vehicle in which the radar device 1 is installed. For example, in Fig. 6, the processing from S30 onwards may be executed by the processor of the on-board ECU. In this case, the "radar system" includes the radar device 1 and the processor of the on-board ECU.

[0076] In a modified example, the radar device 1 may include only one receiving antenna RX. In this case, the receiving processing block 72 outputs sensing data correlated with the received signal received by the single receiving antenna RX.

[0077] In a modified example, the phase shifter 51 may assign a Doppler shift amount that does not form a section where no target-derived peak is detected on the low-velocity side of the Doppler spectrum. For example, when assigning Doppler shift amounts that increase in increments of π / 8 to the transmitting antennas TX1 to TX12, the phase shifter 51 may assign a range from 0 to 11π / 8 to each transmitting antenna TX.

[0078] In a modified example, the dedicated computer constituting the control unit 7 may have at least one of a digital circuit and an analog circuit as the processor 7b. Here, the digital circuit is at least one of an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), an SOC (System on a Chip), a PGA (Programmable Gate Array), and a CPLD (Complex Programmable Logic Device). Such a digital circuit may also have a memory 7a that stores a program.

[0079] In a modified example, the mobile body to which the radar device 1 is applied may be, for example, an autonomous robot that can transport luggage or collect information by autonomous traveling or remote traveling. Examples of the autonomous robot include an autonomous vehicle.

[0080] (Disclosure of technical ideas) This specification discloses multiple technical ideas described in the following multiple clauses. Some clauses may be written in a multiple dependent form, with the subsequent clause referring to the preceding clause as an alternative. Furthermore, some clauses may be written in a multiple dependent form, referring to another multiple dependent clause. These multiple dependent clauses define multiple technical ideas.

[0081] (Technical thought 1) A radar system having a plurality of transmitting antennas (TX), at least one receiving antenna (RX), and a processor (7b), The transmitting antenna is In the groups (Ga, Gb, Gc) for each of the plurality of height ranges, at least one of the groups is arranged to be an equal number of groups with the same number as the groups in the other height ranges, The processor: transmitting, from each of the transmitting antennas, a transmission signal whose frequency changes over time in a repetition period and whose phase is shifted over time by a different amount between the transmitting antennas in each of the repetition periods; outputting sensing data correlating the transmitted signals from the plurality of transmitting antennas with received signals received by the receiving antennas; configured to run The transmitting of the transmission signal includes: a difference pattern of the shift amounts between the transmitting antennas in the group includes transmitting the transmission signals from each of the transmitting antennas with the shift amounts that do not overlap among the groups of the same number; The outputting of the sensing data includes: A radar system including: outputting the sensing data correlated with the received signal, the correspondence between a plurality of peaks in a corresponding velocity spectrum and a plurality of the transmitting antennas being identified by matching the spacing pattern between the peaks with the difference pattern.

[0082] (Technical thought 2) The transmitting of the transmission signal includes: The radar system according to Technical Idea 1 includes transmitting the transmission signal with the shift amount varying equally across all of the transmitting antennas.

[0083] (Technical Thought 3) The transmitting of the transmission signal includes: A radar system according to Technical Idea 1 or Technical Idea 2, which includes transmitting the transmission signal from each of the transmitting antennas with the shift amount such that the differential patterns do not overlap, even between the groups with different numbers of transmitting antennas.

[0084] (Technical Thought 4) The outputting of the sensing data includes: A radar system according to any one of technical ideas 1 to 3, which includes setting a lower reliability for the sensing data as the number of transmitting antennas identified by matching the difference pattern decreases.

[0085] (Technical Thought 5) The outputting of the sensing data includes: The radar system according to any one of Technical Ideas 1 to 4 includes, when the same number of peaks as the total number of the transmitting antennas are not detected, outputting the sensing data correlated with the received signal identified by matching the interval pattern with the difference pattern.

[0086] The above technical ideas 1 to 5 may be implemented in the form of a radar control device, a radar control method, and a radar control program. [Explanation of symbols]

[0087] 1: radar device (radar system), 7: control unit (radar control device), 7a: memory (storage medium), 7b: processor, Ga, Gb, Gc: groups, TX: transmitting antenna, RX: receiving antenna

Claims

1. A radar system having a plurality of transmit antennas (TX), at least one receive antenna (RX), and a processor (7b), The transmitting antenna is In the groups (Ga, Gb, Gc) for each of a plurality of height ranges, at least one of the groups is arranged to be an equal number of groups with the same number as the groups for other height ranges, The processor: transmitting, from each of the transmitting antennas, a transmission signal whose frequency changes over time in a repetition period and whose phase is shifted over time for each of the repetition periods by a different amount between the transmitting antennas; outputting sensing data correlating the transmitted signals from the plurality of transmitting antennas with received signals received by the receiving antennas; configured to run The transmitting of the transmission signal includes: a difference pattern of the shift amounts between the transmitting antennas in the group includes transmitting the transmission signals from each of the transmitting antennas with the shift amounts that do not overlap among the groups of the same number, The outputting of the sensing data includes: A radar system including: outputting the sensing data correlated with the received signal, the correspondence between a plurality of peaks in a corresponding velocity spectrum and a plurality of the transmitting antennas being identified by matching the interval pattern between the peaks with the difference pattern.

2. The transmitting of the transmission signal includes:

2. The radar system according to claim 1, further comprising transmitting the transmission signal with the shift amount varying by an equal amount across all of the transmission antennas.

3. The transmitting of the transmission signal includes:

2. The radar system according to claim 1, further comprising transmitting the transmission signals from the transmitting antennas with the shift amount such that the differential patterns do not overlap even between the groups having different numbers of transmitting antennas.

4. The outputting of the sensing data includes: The radar system according to claim 1 , further comprising: setting a lower reliability for the sensing data as the number of the transmitting antennas identified by the matching of the difference pattern decreases.

5. The outputting of the sensing data includes:

2. The radar system according to claim 1, further comprising: outputting the sensing data correlated with the received signal identified by matching the interval pattern with the difference pattern when the number of peaks detected is not the same as the total number of the transmitting antennas.

6. A radar control device for controlling a radar system (1) having a processor (7b), the radar control device including a plurality of transmitting antennas (TX) and at least one receiving antenna (RX) arranged in groups (Ga, Gb, Gc) for a plurality of height ranges, the number of groups being equal for at least one of the groups being equal to the number of groups for other height ranges, The processor: transmitting, from each of the transmitting antennas, a transmission signal whose frequency changes over time in a repetition period and whose phase is shifted over time for each of the repetition periods by a different amount between the transmitting antennas; outputting sensing data correlating the transmitted signals from the plurality of transmitting antennas with received signals received by the receiving antennas; configured to run The transmitting of the transmission signal includes: a difference pattern of the shift amounts between the transmitting antennas in the group includes transmitting the transmission signals from each of the transmitting antennas with the shift amounts that do not overlap among the groups of the same number, The outputting of the sensing data includes: a radar control device that outputs the sensing data correlated with the received signal, the correspondence between a plurality of peaks in a corresponding velocity spectrum and a plurality of the transmitting antennas being identified by matching an interval pattern between the peaks with the difference pattern.

7. A radar control method executed by a processor (7b) for controlling a radar system (1) having a plurality of transmitting antennas (TX) and at least one receiving antenna (RX) arranged in a plurality of groups (Ga, Gb, Gc) for each height range, the number of groups being equal for at least one of the groups being equal to the number of groups for other height ranges, the method comprising: transmitting, from each of the transmitting antennas, a transmission signal whose frequency changes over time in a repetition period and whose phase is shifted over time for each of the repetition periods by a different amount between the transmitting antennas; outputting sensing data correlating the transmitted signals from the plurality of transmitting antennas with received signals received by the receiving antennas; Including, The transmitting of the transmission signal includes: a difference pattern of the shift amounts between the transmitting antennas in the group includes transmitting the transmission signals from each of the transmitting antennas with the shift amounts that do not overlap among the groups of the same number, The outputting of the sensing data includes: A radar control method including outputting the sensing data correlated with the received signal, the correspondence between a plurality of peaks in a corresponding velocity spectrum and a plurality of the transmitting antennas being identified by matching an interval pattern between the peaks with the difference pattern.

8. A radar control program stored in a storage medium (7a) and including instructions to be executed by a processor (7b) for controlling a radar system (1) having a plurality of transmitting antennas (TX) and at least one receiving antenna (RX) arranged in groups (Ga, Gb, Gc) for a plurality of height ranges, the number of groups being equal for at least one of the groups being equal to the number of groups for other height ranges, The instruction: transmitting, from each of the transmitting antennas, a transmission signal whose frequency changes over time in a repetition period and whose phase is shifted over time for each of the repetition periods by a different amount between the transmitting antennas; outputting sensing data correlating the transmitted signals from the plurality of transmitting antennas with received signals received by the receiving antennas; Including, The transmitting of the transmission signal includes: a difference pattern of the shift amounts between the transmitting antennas in the group includes transmitting the transmission signals from each of the transmitting antennas with the shift amounts that do not overlap among the groups of the same number, The outputting of the sensing data includes: a radar control program that outputs the sensing data that correlates with the received signal, the correspondence between a plurality of peaks in a corresponding velocity spectrum and a plurality of the transmitting antennas being identified by matching an interval pattern between the peaks with the difference pattern.

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