Radar device, radar control method, radar control program

Abstract

To provide a radar device, etc. that are able to determine, according to a situation, an algorithm followed by a process of suppressing a side lobe signal component.SOLUTION: A control unit of a radar device includes an acquisition unit that acquires a mixed reception signal received by a specific reception antenna. The control unit includes a definition unit that defines a plurality of decoded signals obtained by decoding the mixed reception signal for each code corresponding to each transmission signal. The control unit includes a suppression unit. The suppression unit performs a suppression process for suppressing, in another decoded signal or a related signal related to the decoded signal, a side lobe signal component detected in another decoded signal in correlation with a target signal component corresponding to a transmission signal as a target in a specific decoded signal. The suppression unit executes the suppression process in accordance with one of a plurality of algorithms. According to a characteristic parameter correlated with the performance of each algorithm, the suppression unit selects the algorithm to be followed by the suppression process.SELECTED DRAWING: Figure 4

Description

[Technical field]

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

[0002] Patent Document 1 discloses a MIMO radar using a pseudorandom phase modulation method. Such a MIMO radar transmits transmission signals modulated by different CDM codes from each transmitting antenna. The MIMO radar generates a decoded signal spectrum by decoding the received signal according to each CDM code, and estimates a side lobe signal component from each decoded signal spectrum. The MIMO radar obtains a decoded signal spectrum in which the side lobe signal component is suppressed by subtracting each estimated side lobe signal component from the decoded signal spectrum corresponding to the target transmitting antenna. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] U.S. Patent No. 9,952,319 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, a number of algorithms have been proposed for use in suppressing side lobe signal components. The performance of each algorithm changes depending on the situation. However, Patent Document 1 does not disclose how to determine an algorithm depending on the situation.

[0005] An object of the present disclosure is to provide a radar device capable of determining an algorithm to be followed in the suppression process of a side lobe signal component according to the situation.Another object of the present disclosure is to provide a radar control method capable of determining an algorithm to be followed in the suppression process of a side lobe signal component according to the situation.Yet another object of the present disclosure is to provide a radar control program capable of determining an algorithm to be followed in the suppression process of a side lobe signal component according to the situation. [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 corresponding relationship 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 wireless communication system comprising: one or more transmit antennas (TX); A transmission signal generating unit (2) for generating a plurality of types of transmission signals modulated by different codes to be transmitted from a transmission antenna; A receiving antenna (RX) for receiving a mixed received signal obtained by mixing the respective transmission signals reflected by a reflecting object; a control unit (100) for processing the mixed received signal; Equipped with The control unit An acquisition unit (110) that acquires a mixed reception signal received by a specific reception antenna; A definition unit (120) that defines a plurality of decoded signals obtained by decoding the mixed received signal for each code corresponding to each transmitted signal; a suppression unit (130) that executes a suppression process in accordance with one of a plurality of algorithms to suppress a side lobe signal component detected in another decoded signal in correlation with a target signal component, which is a received signal component corresponding to a transmission signal targeted in a specific decoded signal, in the other decoded signal or a related signal related to the decoded signal; having The suppression section is The radar device selects the algorithm that the suppression process follows depending on a characteristic parameter that correlates with the performance of each algorithm.

[0008] A second aspect of the present disclosure is a radar control method executed by a processor (102) to control a radar device (1) including one or more transmitting antennas (TX), a transmitting signal generating unit (2) that generates a plurality of types of transmitting signals modulated by different codes and transmitted from the transmitting antennas, and a receiving antenna (RX) that receives a mixed receiving signal in which the transmitting signals are mixed together after being reflected by a reflecting object, the method comprising: Obtaining a mixed received signal received at a particular receiving antenna; Defining a plurality of decoded signals obtained by decoding the mixed received signal for each code corresponding to each transmitted signal; Executing a suppression process in accordance with any one of a plurality of algorithms, the suppression process suppressing a side lobe signal component detected in another decoded signal in correlation with a target signal component, which is a received signal component corresponding to a transmission signal targeted in a specific decoded signal, in the other decoded signal or a related signal related to the decoded signal; Including, To carry out the suppression process, This involves selecting the algorithms that the suppression process follows depending on characteristic parameters that correlate with the performance of each algorithm.

[0009] A third aspect of the present disclosure is a radar control program stored in a storage medium (101) for controlling a radar device (1) including one or more transmitting antennas (TX), a transmitting signal generating unit (2) that generates a plurality of types of transmitting signals modulated by different codes and transmitted from the transmitting antennas, and a receiving antenna (RX) that receives a mixed receiving signal in which the transmitting signals reflected by a reflecting object are mixed, the radar control program including instructions to be executed by a processor (102), The command is, Obtaining a mixed received signal received at a specific receiving antenna; defining a plurality of decoded signals obtained by decoding the mixed received signal for each code corresponding to each transmitted signal; executing a suppression process in accordance with one of a plurality of algorithms to suppress a side lobe signal component detected in another decoded signal in correlation with a target signal component, which is a received signal component corresponding to a transmission signal targeted in a specific decoded signal, in the other decoded signal or a related signal related to the decoded signal; Including, To execute the suppression process, This involves selecting the algorithm that the suppression process follows depending on a characteristic parameter that correlates with the performance of each algorithm.

[0010] According to the first to third aspects, an algorithm to be followed in the suppression process of the side lobe signal components is selected according to a characteristic parameter on which the performance of each algorithm depends. Since the characteristic parameter is in the decoded signal or the related signal, the algorithm can be selected according to the reception situation of the mixed reception signal. Therefore, it may be possible to determine the algorithm to be followed in the suppression process of the side lobe signal components according to the situation. [Brief description of the drawings]

[0011] [Figure 1] 1 is a block diagram showing an overall configuration of a radar device according to a first embodiment; [Diagram 2] FIG. 2 is a block diagram showing a functional configuration of a control unit according to the first embodiment. [Diagram 3] 4 is a graph showing an example of a transmission signal according to the first embodiment. [Figure 4] 4 is a flowchart illustrating a radar control method in the first embodiment. [Diagram 5] FIG. 2 is a schematic diagram showing an overview of signal processing to generate a frequency spectrum of a decoded signal from range bin signals; [Figure 6] FIG. 13 is a schematic diagram showing an overview of a side lobe suppression process. [Figure 7] FIG. 1 is a diagram showing an example of a frequency spectrum for explaining the definition of an S / N ratio. [Figure 8] FIG. 11 is a schematic diagram for explaining an example of an algorithm. [Figure 9]FIG. 11 is a schematic diagram for explaining another example of an algorithm. [Figure 10] FIG. 10 is a schematic diagram showing the difference between a case where side lobe signal components are suppressed and a case where side lobe signal components are not suppressed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, multiple embodiments of the present disclosure will be described with reference to the drawings. In addition, by assigning the same reference numerals to corresponding components in each embodiment, duplicated descriptions may be omitted. In addition, when only a part of the configuration is described in each embodiment, the configuration of the other embodiment described above can be applied to the other parts of the configuration. Furthermore, in addition to the combination of configurations explicitly stated in the description of each embodiment, configurations of multiple embodiments can be partially combined together even if not explicitly stated, as long as there is no particular problem with the combination.

[0013] First embodiment A first embodiment of the present disclosure will be described with reference to Fig. 1 to Fig. 10. The radar device 1 is mounted on a moving object such as a vehicle. The radar device 1 transmits a transmission signal to the outside world, receives the transmission signal reflected by an object as a received signal, and detects, as target information, the distance to a target that is the reflector that reflected the transmission signal, the relative speed with respect to the target, the direction of the target, and the like.

[0014] The target information 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 target information of each target.

[0015] The processes based on the target information include, for example, collision avoidance process, warning process, etc. The collision avoidance process is a process of performing vehicle control to avoid collision with the target by controlling the brake system, steering system, etc. based on the target information of each target. The warning process is a process of warning the driver of the possibility of collision with the target based on the target information of each target.

[0016] 1, the radar device 1 of this embodiment includes a transmission signal generating unit 2, multiple transmission circuits 3, multiple transmission antennas TX, multiple receiving antennas RX, multiple receiving circuits 4, and a control unit 100. The radar device 1 is a so-called MIMO (Multiple-Input-Multiple-Output) type radar that transmits transmission signals from multiple transmission antennas TX to artificially increase the number of receiving antennas RX beyond the actual number.

[0017] The transmission signal generating unit 2 receives a control signal from the control unit 100 and generates a modulated signal according to the control signal. The generated signal is, for example, a so-called chirp signal whose frequency changes over time (see FIG. 3). The generated signal is distributed to each channel of the transmission circuit 3 and the reception circuit 4 and output. The transmission signal generating unit 2 outputs, as a transmission signal, a generated signal to which a pseudo-random phase modulation with a different code is applied for each transmission channel corresponding to each transmission antenna TX. Such a modulation method is also called code division multiplexing (CDM). As shown in FIG. 3, in this embodiment, the transmission signals transmitted from different transmission antennas TX have substantially the same chirp transmission time, center frequency, and frequency band. In FIG. 3, the transmission signals transmitted from different transmission antennas TX are represented by different line types, i.e., solid lines and dashed lines.

[0018] That is, in this embodiment, a transmission signal to which phase modulation with different codes is applied is transmitted to the outside world from each of the multiple transmission antennas TX. Note that, in relation to the transmission signal, a signal output to the receiving circuit 4 among the generated signals is hereinafter referred to as a local signal.

[0019] The transmitting circuit 3 and the receiving circuit 4 are each mainly composed of a semiconductor integrated circuit device such as an MMIC (Monolithic Microwave Integrated Circuit). The transmitting circuit 3 is connected to a transmitting antenna TX and outputs a transmitting signal to the transmitting antenna TX. The transmitting circuit 3 includes amplifiers 30 in the same number as the connected transmitting antennas TX. The amplifiers 30 amplify the transmitting signals output from the transmitting signal generating unit 2 and output them to the corresponding transmitting antennas TX.

[0020] The transmitting antenna TX converts an electric signal, which is a transmission signal provided from the transmission signal generating unit 2, into a radio wave signal and transmits the signal to the outside world. In this embodiment, it is assumed that 12 transmitting antennas TX are provided. In the following, when each transmitting antenna TX is to be individually distinguished, it is expressed as a transmitting antenna TXn (n is a natural number from 1 to 12). The transmitting antenna TX includes at least one antenna element. For example, the transmitting antenna TX is a patch antenna including a plurality of flat antenna elements. The antenna element is disposed on the surface of a dielectric substrate having a ground plane provided on one surface thereof, opposite the ground plane, so as to face the ground plane. The plurality of antenna elements are connected, for example, in series, by a power supply line that supplies an electric signal.

[0021] The receiving antenna RX receives, as a received signal, a radio signal including a transmission signal reflected from a target as a reflector in the outside world. Each of the multiple receiving antennas RX receives a signal in a state in which the reception signals corresponding to the respective transmission signals from the multiple transmitting antennas TX are mixed. Hereinafter, this mixed signal received by each receiving antenna RX is referred to as a mixed reception signal. Then, the components of each reception signal corresponding to each transmission signal from the multiple transmitting antennas TX mixed in the mixed reception signal are referred to as reception signal components.

[0022] The receiving antenna RX converts the received signal as a radio wave signal into an electric signal and outputs it to the corresponding receiving circuit 4. The receiving antenna RX is, for example, a patch antenna in which at least one antenna element is connected in series by a feeder line, similar to the transmitting antenna TX.

[0023] The receiving circuit 4 is connected to the receiving antennas RX, and acquires the signals received by the receiving antennas RX for each receiving channel corresponding to each receiving antenna RX. The receiving circuit 4 includes amplifiers 40 and signal mixers 41 in the same number as the connected receiving antennas RX.

[0024] The amplifier 40 amplifies the reception signal received by the reception antenna and outputs it to the signal mixer 41. The signal mixer 41 generates a beat signal by mixing the local signal from the transmission signal generation unit 2 and the reception signal. The generated beat signal is an interference signal that represents the frequency difference between the reception signal and the local signal. The beat signal is output to the control unit 100 in a state in which high-frequency components that deviate from the frequency difference between the reception signal and the local signal have been filtered out by a low-pass filter (not shown).

[0025] The control unit 100 is connected to the signal generating unit 2 and the receiving circuit 4 via at least one of a LAN (Local Area Network) line, a wire harness, an internal bus, and a wireless communication line, for example. The control unit 100 includes at least one dedicated computer.

[0026] The dedicated computer constituting the control unit 100 may be a radar ECU (Electronic Control Unit) specialized for controlling the radar device 1. The dedicated computer constituting the control unit 100 may be a radar management ECU that centrally controls a plurality of radar devices 1 mounted on a moving object. The dedicated computer constituting the control unit 100 may be a sensor management ECU that centrally controls a plurality of sensors including the radar device 1 and other sensors such as LiDAR (Light Detection and Ranging / Laser Imaging Detection and Ranging).

[0027] The dedicated computer constituting the control unit 100 has at least one memory 101 and one processor 102. The memory 101 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 mean accumulation in which data is retained even when the vehicle is turned off, or temporary storage in which data is erased when the vehicle is turned off. The processor 102 includes at least one type of core, such as a central processing unit (CPU), a graphics processing unit (GPU), a reduced instruction set computer (RISC)-CPU, a data flow processor (DFP), or a graph streaming processor (GSP).

[0028] In the control unit 100, the processor 102 executes a plurality of instructions included in a radar control program stored in the memory 101 in order to control the radar device 1. In this way, the control unit 100 constructs a plurality of functional blocks for controlling the radar device 1. The functional blocks constructed in the control unit 100 include an acquisition block 110, a definition block 120, a suppression block 130, and an output block 140, as shown in Fig. 2. Note that each of the above-mentioned functional blocks can also be referred to as a functional section, an acquisition section, a definition section, a suppression section, and an output section, respectively.

[0029] A radar control method in which the control unit 100 controls the radar device 1 through cooperation of these blocks 110, 120, 130, and 140 is executed according to the radar control flow shown in Fig. 4. This radar control flow is executed repeatedly while the radar device 1 is running. This radar control flow is executed, for example, for each reception channel, and one cycle is defined as the time when the flow is executed for all reception channels. Note that each "S" in this radar control flow represents multiple steps executed by multiple commands included in the radar control program.

[0030] First, in S10, the acquisition block 110 acquires a mixed reception signal. The mixed reception signal is a beat signal obtained by mixing a local signal from the signal generating unit and a reception signal from the receiving antenna RX. The beat signal is an interference signal that represents a frequency difference between the reception signal and the local signal. The mixed reception signal is acquired as a digitized time signal sampled at a predetermined time interval by an A / D converter.

[0031] In the next step S20, definition block 120 performs a Fast Fourier Transform (FFT) process on the mixed received signal. As a result, definition block 120 acquires a distance spectrum of each chirp in the mixed received signal. The acquired distance spectrum is a frequency spectrum showing a peak according to the distance to the target, and is discrete distance data including signal strength information for each bin (distance bin) corresponding to the distance as distance information. Hereinafter, as shown in FIG. 5, Ns samples of each of Nc chirps are converted into distance data by FFT processing, and data obtained by extracting Nc samples of a specific distance bin is referred to as a distance bin signal R. Here, the symbol C txn The received signal component encoded by n The range bin signal R before decoding is the received signal component C before decoding from each transmit antenna TX. txn P n It can be defined as the sum of the following equation (1).

number

[0032] In S30, the definition block 120 defines a decoded signal corresponding to the range bin signal R. Specifically, the definition block 120 generates a decoded signal by decoding the range bin signal R with each code corresponding to each transmitting antenna TX. The definition block 120 stores the decoded signal for each code in the memory 101.

[0033] For example, suppose that the transmitting antenna TX1 is the target transmitting antenna. In this case, the definition block 120 in S30 defines a code C tx2 ~C tx12 For the codes that have not been decoded in the previous loop, decode is performed. For example, a specific code C txn When decoding is performed for C txn Code C for decoding phase modulation by txn *Here, the symbol C is expressed by the following formula (2). txn * Each element has the code C txn For example, C txn It is a code whose elements all become 1 when multiplied by .

number

[0034] In the next step S40, the definition block 120 performs a fast Fourier transform (FFT) process on the decoded signal. As a result, the definition block 120 acquires a Doppler frequency spectrum of the mixed received signal. This frequency spectrum is a velocity spectrum showing a peak according to the velocity of the target, and is discrete velocity data including signal strength information for each bin (velocity bin) corresponding to the velocity. By this second FFT process, the definition block 120 can acquire two-dimensional map data of distance and velocity as shown in FIG. 5. This two-dimensional map data can also be called an RV map. In the fast Fourier transform process, the definition block 120 multiplies the distance bin signal R by a window function. In this process, the window function other than the rectangular function is, for example, a Hanning function or a Gaussian function.

[0035] In the above formula (2), when k=n, P n The coefficient of is 1. Therefore, as shown in Figure 6, the velocity spectrum has a peak P n The spectrum of P is the sum of the spectrum of P and the spectrum spread by other terms. n The spectrum of the terms other than the above corresponds to the side lobe signal component. For simplicity, in the example shown in FIG. 6, the code C tx1 ,C tx2 10 shows a range bin signal R based on the received signal reflected by the target and the modulated transmitted signal.

[0036] In the next step S50, the suppression block 130 detects a peak from the frequency spectrum. In the peak detection, the suppression block 130 may specify, for example, a frequency bin where the intensity is a maximum value as the peak position. The suppression block 130 detects the peak by, for example, executing CFAR (Constant False Alarm Rate) processing. The suppression block 130 acquires at least the specified peak position and its peak intensity as peak information related to the detected peak. The peak information may include the phase of the peak, etc. The decoded signal RC txn * In this case, peak detection is performed by P n The peak in the frequency spectrum of the decoded signal is an example of a "target signal component" which is a received signal component that corresponds to the target transmitted signal in the decoded signal.

[0037] Then, in S60, the suppression block 130 selects an algorithm for the side lobe suppression process. The suppression block 130 selects from a plurality of algorithms stored in advance in the memory 101, etc., in accordance with characteristic parameters that correlate with the performance of each algorithm.

[0038] For example, the characteristic parameters are parameters that correlate with the amount of calculation for each algorithm. The suppression block 130 acquires the amount of calculation for each algorithm that correlates with the characteristic parameters. The suppression block 130 selects an algorithm with the smallest amount of calculation as an algorithm to be used for the side lobe suppression process. Particularly in this embodiment, the suppression block 130 selects an algorithm related to the estimation process of the side lobe signal component in the side lobe suppression process.

[0039] For example, the characteristic parameters are the number of target peaks, N pk , target peak frequency f pk , chirp number N c , sign C txn , CDM multiplex number N cdm , SNR χ tgtThe characteristic parameters are at least one of the following: The characteristic parameters are defined for each algorithm. For example, the characteristic parameters include parameters that are common to each algorithm.

[0040] Here, the number of target peaks N pk is the number of peaks in the decoded signal spectrum detected in S50, and the target peak frequency f pk is the frequency of each peak. Chirp number N c is the number of chirps per transmission period in the transmission signal. cdm is the symbol C txn The number of multiplexed transmission signals, i.e., the code C used txn is the number of.

[0041] S / N ratio χ tgt is the ratio from the peak intensity in the decoded signal to the noise floor (magnitude) of the thermal noise, i.e., the ratio of the peak intensity to the noise floor of the thermal noise (see FIG. 7). The thermal noise may be thermal noise as a theoretically estimable parameter correlated with the circuit configuration and the ambient temperature in the radar device 1. Alternatively, the thermal noise may be thermal noise as a parameter correlated with the received signal strength in a target-free area in the RV map. Note that the thermal noise as a parameter correlated with the received signal strength may be thermal noise corresponding to the average, median, or mode of the received signal strength in the above-mentioned area.

[0042] The algorithm selected by the suppression block 130 will be described below assuming that two algorithms A1 and A2 are executable.

[0043] The algorithm A1 is an algorithm for estimating a side lobe signal component by convolution of a target peak and a Fourier transformed code. In detail, when the algorithm A1 is executed, the suppression block 130 estimates the code component C txn * C txkBy Fourier transforming, the code component C txn * C txk The suppression block 130 generates a spectrum of the code component C txn * C txk The spectrum of the side lobe signal component is obtained by convolving the spectrum of the target peak with the peak spectrum of the target peak. The peak spectrum is a spectrum obtained by replacing the signal intensity of the decoded signal spectrum with zero except for the peak. In FIG. 8, the symbol C tx1 For the peak spectrum of the decoded signal, the Fourier transformed code component C tx2 * C tx1 In this case, in FIG. 8, the code C tx1 The side lobe signal components in the decoded signal spectrum obtained by decoding the codes other than are estimated.

[0044] Algorithm A2 is an algorithm for estimating a side lobe signal component by Fourier transforming the result of multiplying the inverse Fourier transform of the target peak by the sign component. To be more specific with reference to FIG. 9, when this algorithm A2 is executed, the suppression block 130 performs an inverse Fourier transform process on the peak spectrum. As a result, the suppression block 130 obtains the time signal of the peak component. The suppression block 130 adds the sign component C txn * C txk The suppression block 130 multiplies the code component C txn * C txk The estimated spectrum of the side lobe signal component is obtained by Fourier transforming the time signal multiplied by. tx1 For the time signal of the peak spectrum in the decoded signal decoded for tx2 * C tx1 For this reason, in FIG. 9, the code C tx1The side lobe signal components in the decoded signal spectrum obtained by decoding the codes other than are estimated.

[0045] The suppression block 130 selects the one of the above algorithms A1 and A2, which has the smaller amount of calculation f1, f2 correlated with the characteristic parameter. The amount of calculation f1, f2 of each algorithm A1, A2 is defined as a value correlated with the number of data multiplications from the peak spectrum to obtaining the estimated spectrum of the side lobe signal component, for example. The amount of calculation f1 of algorithm A1 is determined by the number of CDM multiplexes N as a characteristic parameter. cdm , the number of target peaks N pk , and the chirp number N c Specifically, the relationship expressed by the following formula (3) holds between the amount of calculation f1 and the above-mentioned three characteristic parameters.

number

[0046] On the other hand, the computational complexity f2 of algorithm A2 depends on the number of CDM multiplexes N as a characteristic parameter. cdm , and the chirp number N c Specifically, the relationship expressed by the following formula (4) holds between the amount of calculation f2 and the above-mentioned two characteristic parameters.

number

[0047] The suppression block 130 determines which of the algorithms A1 and A2 has the smaller amount of calculation f1 and f2 based on the above relationship. The suppression block 130 determines the algorithm A1 and A2 with the smaller amount of calculation f1 and f2 as the algorithm A1 and A2 to be actually executed in a later step.

[0048] In the next step S70, the suppression block 130 executes a side lobe suppression process. Specifically, the suppression block 130 executes an estimation process of the side lobe signal component using the selected algorithms A1 and A2. Then, the suppression block 130 executes a removal process to remove the estimated side lobe signal component from the spectrum of the decoded signal. Through the side lobe suppression process including the above estimation process and removal process, the suppression block 130 acquires a spectrum in which the side lobe signal component is suppressed from the decoded signal spectrum (suppressed spectrum).

[0049] The suppression block 130 performs side lobe suppression processing for each of the multiple decoded signals decoded by each code. For example, as shown in FIG. tx1 ,C tx2 In this case, the suppression block 130 performs side lobe suppression processing on the range bin signal R reflected by the target. tx1 * Based on the peak spectrum P1^ detected from the spectrum of tx2 * Side lobe signal component C in the spectrum of tx2 * C tx1 P1̂. The suppression block 130 then estimates this side lobe signal component C tx2 * C tx1 P1^ is the decoded signal RC tx2 * Similarly, the suppression block 130 removes from the spectrum of the decoded signal RC tx2 * Based on the peak spectrum P2^ detected from the spectrum of tx1 * Side lobe signal component C in the spectrum of tx1 * C tx2 P2̂. The suppression block 130 then estimates this side lobe signal component C tx1 * C tx2 P2^ is the decoded signal RC tx1* is removed from the spectrum.

[0050] For simplicity, Fig. 6 shows the side lobe suppression process when the transmission signal is modulated with two types of codes, but the suppression block 130 can perform the side lobe suppression process in the same way even when three or more types of codes are used in the modulation. For example, the same applies even when the transmission signals of the 12 transmission antennas TX are modulated with different codes. In this case, the suppression block 130 estimates the side lobe signal components in the other decoded signals from the peaks of the 12 types of decoded signals decoded for each code, and removes each side lobe signal component from each decoded signal.

[0051] The suppression block 130 may perform iterations of the side lobe suppression process. The iterations are processes for re-estimating the side lobe signal components in other decoded signal spectra based on a peak spectrum extracted from a decoded signal spectrum in which the side lobe signal components have been suppressed, and removing the re-estimated side lobe signal components from the other decoded signal spectra. The suppression block 130 can suppress the side lobe signal components to a greater extent by performing an appropriate number of iterations.

[0052] Then, in S80, the output block 140 acquires target information from the frequency spectrum. The target information includes at least one of the distance, speed, and direction of the target. If the target information includes the direction, the output block 140 estimates the direction from the frequency spectrum, for example, by a Direction of Arrival (DoA) method. The output block 140 may output the target information to an on-board ECU outside the radar device 1. Alternatively, the output block 140 may output the target information to a center outside the vehicle.

[0053] The difference in dynamic range PSR between when the above side lobe suppression is performed and when it is not performed will be described with reference to Fig. 9. When one target is assumed, the dynamic range PSR can be expressed as the ratio from the maximum value of the peak of the target to the side lobe. When the suppression process is not performed, this dynamic range PSR is expressed as the total number of chirps N of the transmission signal. c , the number of transmit antennas modulated with CDM code, N tx Therefore, the relationship shown in the following formula (5) is satisfied.

number

[0054] On the other hand, when the removal process shown in this embodiment is performed, the dynamic range PSR satisfies the relationship shown in the following formula (6).

number

[0055] That is, the radar device 1 that performs side lobe suppression has a larger dynamic range PSR than the radar device 1 that does not perform side lobe suppression.

[0056] According to the first embodiment described above, an algorithm to be followed in the estimation process of the side lobe signal components is selected according to the characteristic parameters on which the performance of each algorithm depends. Since the characteristic parameters are in the decoded signal or the related signal, the algorithm can be selected according to the reception conditions of the mixed reception signal. Therefore, it may be possible to determine the algorithm to be followed in the suppression process of the side lobe signal components according to the conditions.

[0057] Second Embodiment The second embodiment is a modification of the first embodiment.

[0058] In the second embodiment, the suppression block 130 estimates the side lobe signal component from a determinant that holds between the decoded signal spectrum and the true peak spectrum. For example, for simplicity, assume that there are two transmitting antennas TX1 and TX2, and the decoded signal RC tx1 * and R.C. tx2 * P 1dec and P 2dec In addition, the true peak signal component due to the transmission signal from the transmission antenna TX1 is P1, and the true peak signal component due to the transmission signal from the transmission antenna TX2 is P2. In this case, the decoded signal spectrum P 1dec ,P 2dec and the true peak spectra P1 and P2 are expressed by the determinant relationship shown in the following equation (7).

number

[0059] In addition, the matrix C in the first term on the right side 12 is C tx1 * C tx2 , C 21 is C tx2 * C tx1 Here, the matrix representing the left side of the formula (7), i.e., the decoded signal spectrum, is P, the matrix representing the first term on the right side is C+I (I is a unit matrix), and the matrix representing the true peak spectrum of the second term on the right side is P. t In this case, formula (7) can be replaced with the following formula (8).

number

[0060] In the above formula (8), the side lobe signal component is the first term on the right side, CP t Therefore, the matrix (C+I) is the code and the peak frequency f pk Since it is known from tBy estimating, the side lobe signal component can also be estimated. Here, Equation (8) can be transformed into the following Equation (9).

number

[0061] That is, the suppression block 130 converts the above equation (9) into P t Solving for P t By multiplying by C, the side lobe signal components can be estimated.

[0062] In S60 of this embodiment, the suppression block 130 is t The suppression block 130 selects a solution algorithm from among a number of algorithms. For example, the suppression block 130 selects a solution algorithm from among three algorithms. One solution algorithm is the Jacobi method. Another solution algorithm is the Gauss-Seidel method. Yet another solution algorithm is a method of multiplying P by the inverse or pseudo-inverse of the matrix (C+I).

[0063] The suppression block 130 is t In other words, the suppression block 130 selects an algorithm for which P t Select an algorithm that does not make the amount of calculations of P t The convergence of is determined by the properties of the matrix (C+I). Since the matrix (C+I) is determined according to the sign and peak frequency as described above, in this embodiment, the sign and peak frequency are characteristic parameters. Specifically, the suppression block 130 detects the maximum eigenvalue λ of the matrix C. 1max , and the matrix (I+C L ) -1 C U The maximum eigenvalue λ of 2max The algorithm is selected according to the absolute value of the matrix C L is the lower triangular matrix of matrix C, U is the upper triangular matrix of matrix C.

[0064] (Other embodiments) Although several 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 not departing from the gist of the present disclosure.

[0065] In a variant, suppression block 130 may remove side lobe signal components from the range bin signals instead of the decoded signal, in which case the range bin signals are an example of "related signals" related to the decoded signal.

[0066] In a modified example, the transmission signal generating unit 2 may impart modulation with a different code to each antenna set including a plurality of transmitting antennas TX. In this case, a different code is imparted to the transmission signal for each of a plurality of antenna sets including a predetermined number of transmitting antennas TX. In this case, the control unit 100 executes a removal process for each code of each antenna set. Note that the transmission signal corresponding to each transmitting antenna TX in the antenna set is imparted with phase shift keying or amplitude modulation, so that the corresponding received signal component can be separated for each transmission signal.

[0067] In a modified example, the output block 140 of S80 may output the frequency spectrum as target information to the outside. For example, the output block 140 outputs the frequency spectrum to an on-board ECU outside the radar device 1. In this case, the on-board ECU to which the frequency spectrum is output acquires the position of the target, etc. from the peak of the target included in the frequency spectrum.

[0068] In a variant, the radar device 1 may include only a single transmitting antenna TX. In this case, the transmitting signal generating unit 2 generates a transmitting signal for one transmitting antenna, which is a mixture of a plurality of transmitting signals modulated by different codes.

[0069] In a variant, the suppression block 130 may select an algorithm depending only on characteristic parameters that are not common to each algorithm.

[0070] In a modified example, the dedicated computer constituting the control unit 100 may be an integration ECU that integrates the driving control of the vehicle. The dedicated computer constituting the control unit 100 may be a judgment ECU that judges a driving task in the driving control of the vehicle. The dedicated computer constituting the control unit 100 may be a monitoring ECU that monitors the driving control of the vehicle. The dedicated computer constituting the control unit 100 may be an evaluation ECU that evaluates the driving control of the vehicle.

[0071] In a modified example, the dedicated computer constituting the control unit 100 may be a navigation ECU that navigates the driving route of the vehicle. The dedicated computer constituting the control unit 100 may be a locator ECU that estimates the vehicle's own state quantity. The dedicated computer constituting the control unit 100 may be an actuator ECU that controls the driving actuator of the vehicle. The dedicated computer constituting the control unit 100 may be an HCU (Human Machine Interface (HMI) Control Unit) that controls the presentation of information in the vehicle. The dedicated computer constituting the control unit 100 may be a computer other than the vehicle that constitutes, for example, an external center or a mobile terminal capable of communicating with the vehicle.

[0072] In a modified example, the dedicated computer constituting the control unit 100 may have at least one of a digital circuit and an analog circuit as a processor. Here, the digital circuit is at least one of ASIC (Application Specific Integrated Circuit), FPGA (Field Programmable Gate Array), SOC (System on a Chip), PGA (Programmable Gate Array), CPLD (Complex Programmable Logic Device), etc. Furthermore, such a digital circuit may have a memory that stores a program.

[0073] In a modified example, the moving body to which the control unit 100 is applied may be, for example, an autonomous device (autonomous robot) capable of transporting luggage or collecting information by autonomous driving or remote driving. Furthermore, the autonomous device (autonomous robot) may be an autonomous driving robot including an autonomous driving vehicle.

[0074] In addition to the embodiments described above, the above-mentioned embodiments and modifications may be implemented as a control device that is configured to be mountable on a moving body and has at least one processor 102 and one memory 101. Specifically, the above-mentioned 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.).

[0075] (Disclosure of technical ideas) This specification discloses multiple technical ideas described in the following multiple dependent claims. Some of the claims may be described in a multiple dependent form, where the subsequent claim alternatively refers to the preceding claim. Furthermore, some of the claims may be described in a multiple dependent form, where the subsequent claim alternatively refers to the preceding claim. The claims described in these multiple dependent forms define multiple technical ideas.

[0076] (Technical thought 1) one or more transmit antennas (TX); a transmission signal generating unit (2) for generating a plurality of types of transmission signals modulated by different codes to be transmitted from the transmitting antenna; A receiving antenna (RX) for receiving a mixed received signal obtained by mixing the transmission signals reflected by a reflector; a control unit (100) for processing the mixed received signal; Equipped with The control unit An acquisition unit (110) that acquires the mixed reception signal received by a specific reception antenna; A definition unit (120) that defines a plurality of decoded signals obtained by decoding the mixed received signal for each of the codes corresponding to each of the transmitted signals; a suppression unit (130) that executes a suppression process in accordance with one of a plurality of algorithms to suppress a side lobe signal component detected in another decoded signal in correlation with a target signal component that is a received signal component corresponding to the transmission signal targeted in the specific decoded signal, in the other decoded signal or a related signal related to the decoded signal; having The suppression unit is A radar apparatus for selecting the algorithm according to which the suppression process is performed in response to a characteristic parameter correlated with the performance of each of the algorithms.

[0077] (Technical thought 2) The suppression unit is The radar device according to Technical Idea 1, wherein the suppression process executes an estimation process for estimating the side lobe signal component and a removal process for subtracting the estimated side lobe signal component from another decoded signal or the related signal, and the algorithm for the estimation process is selected in accordance with the characteristic parameters.

[0078] (Technical Thought 3) The suppression unit is The radar device according to Technical Idea 1 or 2, wherein the algorithm to be subjected to the suppression process is selected according to the characteristic parameters common to each of the algorithms to be selected.

[0079] (Technical Thought 4) The radar device according to any one of Technical Ideas 1 to 3, wherein the characteristic parameters include values ​​correlating with the amount of calculation of each of the algorithms.

[0080] (Technical Thought 5) The radar device according to Technical Idea 4, wherein the characteristic parameters include the number of peaks relating to the reflectors in the frequency spectrum of the decoded signal.

[0081] (Technical Thought 6) The radar device according to Technical Idea 4 or Technical Idea 5, wherein the characteristic parameter includes a frequency of a peak relating to the reflector in a frequency spectrum of the decoded signal.

[0082] (Technical Thought 7) The radar device according to any one of Technical Ideas 4 to 6, wherein the characteristic parameters include the number of types of the codes.

[0083] (Technical Thought 8) The radar device according to any one of Technical Ideas 4 to 7, wherein the characteristic parameter includes a ratio of a peak related to the reflector in a frequency spectrum of the decoded signal to thermal noise.

[0084] Incidentally, the above technical ideas 1 to 8 may be realized in the form of a radar control method and a radar control program. [Explanation of symbols]

[0085] 1: radar device, 2: transmission signal generating unit, 100: control unit, 101: memory (storage medium), 102: processor, 110: acquisition block (acquisition section), 120: definition block (definition section), 130: suppression block (suppression section), TX: transmission antenna, RX: reception antenna

Claims

1. one or more transmit antennas (TX); a transmission signal generating unit (2) for generating a plurality of types of transmission signals modulated by different codes to be transmitted from the transmitting antenna; A receiving antenna (RX) for receiving a mixed received signal obtained by mixing the respective transmission signals reflected by a reflector; a control unit (100) for processing the mixed received signal; Equipped with The control unit An acquisition unit (110) that acquires the mixed received signal received at a specific receiving antenna; A definition unit (120) that defines a plurality of decoded signals obtained by decoding the mixed received signal for each of the codes corresponding to each of the transmitted signals; a suppression unit (130) that executes a suppression process in accordance with one of a plurality of algorithms to suppress a side lobe signal component detected in another decoded signal in correlation with a target signal component that is a received signal component corresponding to the transmission signal targeted in the specific decoded signal, in the other decoded signal or a related signal related to the decoded signal; having The suppression unit is A radar apparatus for selecting the algorithm according to which the suppression process is performed in response to a characteristic parameter correlated with the performance of each of the algorithms.

2. The suppression unit is 2. The radar device according to claim 1, wherein the suppression process executes an estimation process for estimating the side lobe signal component and a removal process for subtracting the estimated side lobe signal component from another of the decoded signals or the related signals, and the algorithm for the estimation process is selected in accordance with the characteristic parameters.

3. The suppression unit is 2. The radar device according to claim 1, wherein the algorithm to be subjected to the suppression process is selected in accordance with the characteristic parameter common to each of the algorithms to be selected.

4. The radar device according to claim 1 , wherein the characteristic parameters include values ​​correlating with the amount of calculation of each of the algorithms.

5. The radar device according to claim 4 , wherein the characteristic parameters include a number of peaks relating to the reflector in a frequency spectrum of the decoded signal.

6. The radar device according to claim 4 , wherein the characteristic parameters include a frequency of a peak relating to the reflector in a frequency spectrum of the decoded signal.

7. The radar device according to claim 4 , wherein the characteristic parameters include the number of types of the codes.

8. The radar device according to claim 4 , wherein the characteristic parameter includes a ratio of a peak relating to the reflector to thermal noise in a frequency spectrum of the decoded signal.

9. A radar control method executed by a processor (102) for controlling a radar device (1) including one or more transmitting antennas (TX), a transmitting signal generating unit (2) for generating a plurality of types of transmitting signals modulated by different codes and transmitted from the transmitting antennas, and a receiving antenna (RX) for receiving a mixed receiving signal in which the transmitting signals reflected by a reflecting object are mixed, the method comprising: Obtaining the mixed received signal received at a particular receiving antenna; defining a plurality of decoded signals obtained by decoding the mixed received signal for each of the codes corresponding to each of the transmitted signals; Executing a suppression process in accordance with any one of a plurality of algorithms, the suppression process suppressing a side lobe signal component detected in another decoded signal in correlation with a target signal component that is a received signal component corresponding to the transmission signal targeted in the specific decoded signal, in the other decoded signal or a related signal related to the decoded signal; Including, The execution of the suppression process includes: A method of radar control comprising selecting the algorithms according to which the suppression process is to be performed in response to a characteristic parameter correlated with the performance of each of the algorithms.

10. A radar control program stored in a storage medium (101) for controlling a radar device (1) including one or more transmitting antennas (TX), a transmitting signal generating unit (2) that generates a plurality of types of transmitting signals modulated by different codes and transmitted from the transmitting antennas, and a receiving antenna (RX) that receives a mixed receiving signal in which the transmitting signals reflected by a reflecting object are mixed, the radar control program including instructions to be executed by a processor (102), The instruction: Obtaining the mixed received signal received at a specific receiving antenna; defining a plurality of decoded signals obtained by decoding the mixed received signal for each of the codes corresponding to each of the transmitted signals; execute a suppression process in accordance with one of a plurality of algorithms, the suppression process suppressing a side lobe signal component detected in another decoded signal in correlation with a target signal component that is a received signal component corresponding to the transmission signal targeted in the specific decoded signal, in the other decoded signal or a related signal related to the decoded signal; Including, Executing the suppression process includes: a radar control program for selecting the algorithm to be followed by the suppression process in response to a characteristic parameter correlated with the performance of each of the algorithms.

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