Rader device, rader control method, and rader control program

Abstract

To provide a radar device or the like capable of executing suppression processing of a side lobe signal component several times according to a situation.SOLUTION: A control unit in a radar device has an acquisition unit for acquiring mixed reception signals received at a particular receiving antenna. The control unit has a defining unit that defines a plurality of decoded signals in which the mixed received signals are decoded for each code corresponding to each transmitted signal. The control unit has a removal unit capable of repeatedly executing removal processing. In the removal processing, the removal unit estimates a sidelobe signal component detected in other decoded signals in correlation with a target signal component corresponding to the target transmitted signal in a specific decoded signal, and removes the sidelobe signal component from other decoded signals or related signals associated with the decoded signals. The removal unit executes the removal processing for the number of times at least correlated to a ratio of the intensity of the peak to the intensity of a thermal noise in the specific decoded signal.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 a transmission signal modulated by a different CDM code from each transmitting antenna. The MIMO radar generates a decoded signal spectrum decoded according to each CDM code for the received signal, and estimates a side lobe signal component from each decoded signal spectrum. The MIMO radar can obtain 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. In order to increase the degree of suppression of the side lobe signal component, the MIMO radar further estimates the side lobe signal component from the decoded signal spectrum in which the side lobe signal component is suppressed, and subtracts it again from the decoded signal spectrum, thereby performing a side lobe signal component suppression process multiple times. [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] Patent Document 1 does not disclose how to determine the number of times the suppression process of the side lobe signal components is to be performed. Therefore, the technique of Patent Document 1 does not allow the number of times the suppression process is to be performed to be determined according to the situation.

[0005] An object of the present disclosure is to provide a radar device capable of executing a process for suppressing a side lobe signal component a number of times according to a situation.Another object of the present disclosure is to provide a radar control method capable of executing a process for suppressing a side lobe signal component a number of times according to a situation.A further object of the present disclosure is to provide a radar control program capable of executing a process for suppressing a side lobe signal component a number of times according to a 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 removal unit (130) capable of estimating a side lobe signal component, which is a received 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, and repeatedly performing a removal process of removing the side lobe signal component from the other decoded signal or a related signal related to the decoded signal by setting the correlation target of the side lobe signal component to the target signal component of the specific decoded signal after the previous removal process; having The removal section is The radar device executes the removal process a number of times that is at least correlated with the ratio of the peak intensity to the thermal noise intensity in a specific decoded signal.

[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; A side lobe signal component is estimated as a received 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, and a removal process is performed to remove the side lobe signal component from the other decoded signal or a related signal related to the decoded signal; Including, The removal process can be repeatedly performed by setting the correlation target of the side lobe signal component to a target signal component of a specific decoded signal after the previous removal process, Performing the cancellation process includes performing the cancellation process a number of times that is at least correlated to a ratio of an intensity of the peak to an intensity of thermal noise in the particular decoded signal.

[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; A side lobe signal component is estimated as a received signal component detected in another decoded signal in correlation with a target signal component that is a received signal component corresponding to a transmission signal targeted in a specific decoded signal, and a removal process is executed to remove the side lobe signal component from the other decoded signal or a related signal related to the decoded signal; Including, The removal process can be repeatedly performed by setting the correlation target of the side lobe signal component to a target signal component of a specific decoded signal after the previous removal process, Running the cancellation process includes running the cancellation process a number of times that is at least correlated to a ratio of an intensity of the peak to an intensity of thermal noise in a particular decoded signal.

[0010] According to the first to third aspects, the removal process is performed at least a number of times that correlates with the ratio of the peak intensity to the thermal noise intensity in a specific decoded signal. Since the ratio of the peak intensity to the thermal noise intensity correlates with the magnitude of the side lobe signal component, the side lobe signal component can be sufficiently suppressed by removing the side lobe signal component a number of times according to the ratio. Therefore, it may be possible to perform the suppression process of the side lobe signal component a number of times 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] 1 is an example of a frequency spectrum for illustrating the definition of a signal-to-noise ratio. [Figure 7] 1 is a graph showing an example of the number of iterations correlated with the signal-to-noise ratio; [Figure 8] FIG. 1 is a schematic diagram showing an overview of an iteration process. [Figure 9] 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. [Figure 10] FIG. 11 is a diagram showing an example of the number of iterations correlated with the S / N ratio and the number of peaks in the second embodiment. [Figure 11] 13 is a graph for explaining a peak position correlated with the number of iterations in the third embodiment. [Figure 12] 13 is a flowchart showing a radar control method according to a fourth embodiment. [Figure 13] 13 is a flowchart showing a radar control method in the fifth embodiment. [Figure 14] 13 is a graph showing an example of a buried peak determined in the radar control method of the fifth embodiment. 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. 9. A radar device 1 is mounted on a moving body 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, a distance to a target that is a reflector that reflected the transmission signal, a relative speed with respect to the target, an orientation 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 received 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 and the receiving circuit via at least one of a LAN (Local Area Network) line, a wire harness, an internal bus, a wireless communication line, etc. 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 a specific 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 removal 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 removal 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 digital 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 * is 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 signal 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 due to terms other than the above corresponds to the side lobe signal components.

[0036] In the next step S50, the elimination block 130 detects peaks from the frequency spectrum. In peak detection, the elimination block 130 may identify, for example, a frequency bin where the intensity is a maximum value as the peak position. The elimination block 130 detects the peak by, for example, executing a Constant False Alarm Rate (CFAR) process. The elimination block 130 acquires at least the identified 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 nThe 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 cancellation block 130 determines the number of iterations. Here, the iteration means estimating a new side lobe signal component in another decoded signal from the peak of the decoded signal that has been subjected to the cancellation process, and canceling the new side lobe signal component from the decoded signal. That is, the iteration corresponds to a process of estimating a side lobe signal component correlated with the peak by setting the correlation target of the side lobe signal component to a specific decoded signal peak after the previous cancellation process, and further repeating the cancellation process with the side lobe signal component.

[0038] The cancellation block 130 cancels the signal-to-noise ratio χ tgt The number of iterations N that is at least correlated with itr Determine the signal-to-noise ratio χ tgt is the ratio from the peak intensity in the decoded signal to the noise floor (magnitude) of the thermal noise, that is, the ratio of the peak intensity to the noise floor of the thermal noise. The elimination block 130 may acquire the thermal noise as a parameter that is theoretically estimable and correlated with, for example, the circuit configuration and the ambient temperature in the radar device 1. Alternatively, the elimination block 130 may acquire the thermal noise as a parameter that is correlated with the received signal strength in a region in the RV map where no target exists. When acquiring the thermal noise as a parameter that is correlated with the received signal strength, the elimination block 130 may acquire the thermal noise according to the average value or median value of the received signal strength in the above-mentioned region. Alternatively, the elimination block 130 may acquire the thermal noise according to the mode value of the received signal strength in the above-mentioned region.

[0039] If there are multiple peaks in the frequency spectrum, the removal block 130 selects the signal-to-noise ratio χ tgtAlternatively, the removal block 130 may be correlated with the number of iterations N itr , the signal-to-noise ratio of each peak, χ tgt Alternatively, the removal block 130 may be correlated to the sum of N itr , the signal-to-noise ratio of each peak, χ tgt It may be correlated to the average of

[0040] The removal block 130 may be configured to reduce the signal-to-noise ratio χ tgt The larger the iteration count N itr The signal-to-noise ratio χ tgt and the number of iterations N itr The relationship information on the relationship between the signal-to-noise ratio χ and the noise ratio χ is stored in the memory 101 in the form of a function or table. The elimination block 130 calculates the relationship between the stored relationship information and the obtained signal-to-noise ratio χ tgt Depending on the number of iterations, N itr Determine.

[0041] In the next step S70, the elimination block 130 executes the elimination process. In the side lobe suppression process, the elimination block 130 removes the decoded signal RC txn Further, the removal block 130 removes the side lobe signal components from the determined number of iterations N itr Then, an iteration process is performed in which this side lobe suppression process is repeated for each minute.

[0042] In the side lobe suppression process, the elimination block 130 estimates a side lobe signal component contained in a decoded signal decoded by a code corresponding to a certain transmitted signal, which is correlated with a peak of the decoded signal decoded by a code corresponding to another transmitted signal. For simplicity, as shown in FIG. 8, tx1 ,C tx2 The side lobe suppression process will be described using a range bin signal R based on a received signal that is a result of a transmission signal modulated by each of the modulated signals R and R being reflected by a target. In this case, the cancellation block 130 converts the decoded signal R tx1 * and the decoded signal RC tx2* For each of the peaks P1 and P2, estimate the side lobe signal components in the other frequency spectrum that correlate to the target peaks P1 and P2 in the frequency spectrum.

[0043] Specifically, the cancellation block 130 subtracts the decoded signal RC tx1 * From the peak P1^ in the frequency spectrum of the decoded signal RC tx2 * Side lobe signal component C in the frequency spectrum of tx2 * C tx1 Similarly, the cancellation block 130 calculates the decoded signal RC tx2 * From the peak P2^ in the frequency spectrum of the decoded signal RC tx1 * Side lobe signal component C in the frequency spectrum of tx1 * C tx2 Calculate P2^.

[0044] The cancellation block 130 then subtracts the estimated side lobe signal component C tx1 * C tx2 P2^ is the decoded signal RC tx1 * From the side lobe signal component C tx2 * C tx1 P1^ is the decoded signal RC tx2 * Each side lobe signal component is removed by subtracting it from. In the following, the signal obtained by removing the side lobe signal components from the decoded signal is referred to as a "decoded signal with side lobe components removed."

[0045] Furthermore, the removal block 130 removes the determined number of iterations N itr The iteration process is a process of re-estimating the side lobe signal components in the other decoded signals from the peaks in the decoded signal from which the side lobe signals have already been removed, and removing the estimated side lobe signal components from the other decoded signals.

[0046] In the example shown in FIG. 8, the cancellation block 130 cancels the decoded signal RC tx1 * Peak P in the cancelled decoded signal from 1_1 ^From the decoded signal RC tx2 * New side lobe signal component C in tx2 * C tx1 P 1_1 Then, the cancellation block 130 calculates the new side lobe signal component C tx2 * C tx1 P 1_1 ^ is the decoded signal RC tx2 * This allows the cancellation block 130 to subtract the side lobe signal component C tx2 * C tx1 P 1_1 Similarly, the cancellation block 130 obtains a further cancelled decoded signal in which the peak P 2_1 ^ to the new side lobe signal component C tx1 * C tx2 P 2_1 ^ is calculated and used as the decoded signal RC tx1 * , to obtain a further cancelled decoded signal.

[0047] The removal block 130 removes the determined number of iterations N itr 8, for the sake of simplicity, an example in which the iteration process is performed once is shown. However, the removal block 130 repeats the iteration process for the peak P 2_2 ^,P 1_2 The side lobe signal components are further estimated from each of ^, and the decoded signal RC tx1 * ,RC tx2 *It is possible to perform the second iteration process by subtracting from . Similarly, by repeating the estimation and removal of the side lobe signal component, the removal block 130 performs the iteration process for the determined number of iterations Nitr. Even if three or more types of codes are used in the modulation, the removal block 130 performs the side lobe suppression process in the same manner. For example, the same applies even if the transmission signals of the 12 transmitting antennas TX are modulated with different codes. In this case, the removal 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.

[0048] 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. The output block 140 estimates the direction, for example, by a DoA (Direction of Arrival) method. In the following S130, the output block 140 outputs the target information to the outside.

[0049] The difference in dynamic range PSR between when 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 removal process is not performed, this dynamic range PSR satisfies the relationship shown in the following formula (3), where Nc is the total number of chirps of the transmission signal and Ntx is the number of transmission antennas modulated with CDM code.

number

[0050] 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 (4).

number

[0051] 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.

[0052] According to the first embodiment described above, the side lobe signal is removed at least a number of times that correlates with the ratio of the peak intensity of the received signal component corresponding to the target transmitted signal to the thermal noise. Since the ratio correlates with the magnitude of the side lobe signal component, the side lobe signal component can be sufficiently suppressed by removing the side lobe signal component a number of times according to the ratio. Therefore, it may be possible to perform the suppression process of the side lobe signal component a number of times according to the situation.

[0053] Second Embodiment As shown in FIG. 10, the second embodiment is a modification of the first embodiment.

[0054] In the second embodiment, the removal block 130 in S60 reduces the signal-to-noise ratio χ tgt In addition, the number of peaks N tgt Iteration count N correlated to itr Specifically, the removal block 130 determines the number of peaks N tgt The more, the more iterations N itr That is, the signal-to-noise ratio χ tgt Even if the signals are the same, the number of peaks N tgt If is large, the number of iterations for the signal is N itr The signal-to-noise ratio χ tgt and the number of peaks N tgt and the number of iterations, N itr The relationship information between the signal-to-noise ratio (SNR) and the noise ratio (SNR) is stored in the memory 101 in the form of a function or table. The removal block 130 performs a subtraction on the stored relationship information and the obtained SNR (SNR) χ tgt and the number of peaks N tgt Depending on, the number of iterations is N itr Determine.

[0055] Third embodiment As shown in FIG. 11, the third embodiment is a modification of the first embodiment.

[0056] In the third embodiment, the cancellation block 130 in S60 cancels the signal-to-noise ratio χ tgt In addition, the number of iterations N correlates with the Doppler frequency difference between the peaks. itr The Doppler frequency difference between peaks is the difference in Doppler frequency at each peak, as shown in FIG. 11. When multiple peaks exist, the side lobe signal components resulting from each peak overlap, and the spectral shape of the entire side lobe signal components is determined. The number of iterations N itr The optimal number of iterations N varies depending on where each peak is located in the spectrum shape of the entire side lobe signal component. itr The optimal number of can be determined by the Doppler frequency difference between the peaks, i.e., the relative positions of the peaks in the Doppler frequency domain, the code used, and the number of transmit antennas TX.

[0057] Therefore, the cancellation block 130 performs an iteration number N that correlates with the Doppler frequency difference, the code used, and the number of transmit antennas TX. itr Determine the signal-to-noise ratio χ tgt , Doppler frequency difference, the number of codes and transmitting antennas TX, and the number of iterations N itr The relationship information between the signal-to-noise ratio (SNR) and the noise ratio (SNR) is stored in the memory 101 in the form of a function or table. The removal block 130 performs a subtraction on the stored relationship information and the obtained SNR (SNR) χ tgt Depending on the Doppler frequency difference, the code, and the number of transmitting antennas TX, the number of iterations N itr Determine.

[0058] (Fourth embodiment) As shown in FIG. 12, the fourth embodiment is a modification of the first embodiment.

[0059] In the fourth embodiment, as shown in Fig. 12, the flow proceeds to S51 after S50. In S51, the removal block 130 removes the side lobe signal components from the decoded signal a specified number of times (for example, once). That is, at the time of S51, the iteration process of estimating and removing the side lobe signal components from the removed decoded signal is not performed. After S51, the flow proceeds to S52.

[0060] In S52, the elimination block 130 obtains a side lobe level, which is the magnitude of the side lobe signal component after the side lobe suppression in S51. The elimination block 130 obtains the average or median value of the side lobe signal component in at least a part of the frequency spectrum as the side lobe level. After S52, the flow proceeds to S53.

[0061] In S53, the elimination block 130 determines whether or not iteration processing is required depending on the side lobe level. For example, if the side lobe level falls within the upper limit of the allowable level range, the elimination block 130 determines that iteration processing is unnecessary, and if it falls outside the upper limit of the allowable level difference range, it determines that iteration processing is necessary. Here, the allowable level range is, for example, a range in which the side lobe level is equal to or less than a threshold value, and the upper limit is the threshold value. The threshold value is, for example, a value that correlates with the magnitude of the noise floor of thermal noise. Note that determining that iteration processing is unnecessary in S53 is a process of determining whether or not iteration processing is unnecessary when the number of iterations N itr This can also be rephrased as determining that the number of times is zero.

[0062] If it is determined in S53 that the iteration process is not required, the flow proceeds to S80. On the other hand, if it is determined in S53 that the iteration process is required, the flow proceeds to S60, and the number of iterations N is set. itr Even if it is determined that iteration processing is required based on the side lobe level, the S / N ratio χ tgt Depending on the size of, the number of iterations in S60 is N itr may be determined to be zero.

[0063] After S60, the flow proceeds to S71. In S71, the removal block 130 executes the iteration process according to the determined number of iterations Nitr. In S71, as in S70 of the first embodiment, the iteration process may be executed zero times, that is, the iteration process may not be executed. After S71, the flow proceeds to S80.

[0064] Fifth embodiment As shown in FIGS. 13 and 14, the fifth embodiment is a modification of the first embodiment.

[0065] In the fifth embodiment, as shown in Fig. 13, the flow proceeds to S53 after S50. In S53, the removal block 130 determines whether or not there is a buried peak in the previous cycle. Here, the buried peak is a peak buried in the side lobe signal components in the frequency spectrum of the decoded signal before the side lobe signal components are suppressed, as shown in Fig. 14. In other words, the buried peak is a peak with a lower intensity than the side lobe signal components.

[0066] If it is determined that there is a buried peak, the flow proceeds to S54. In S54, the elimination block 130 determines whether the current receiving antenna RX is the first receiving antenna RX that performs side lobe suppression processing in the current cycle. If it is determined that the current receiving antenna RX is the first receiving antenna RX that performs side lobe suppression, the flow proceeds to S60. On the other hand, if it is determined that the current receiving antenna RX is not the first receiving antenna RX, the flow proceeds to S55. In S55, the elimination block 130 determines whether there is a buried peak in the first receiving antenna RX. If it is determined that there is a buried peak, the flow proceeds to S60.

[0067] On the other hand, if it is determined in S53 that there is no buried peak in the previous cycle, i.e., that no buried peak has been detected, or if it is determined in S55 that there is no buried peak at the first receiving antenna, the flow proceeds to S55. In other words, if it is determined that there is no buried peak, the side lobe suppression process is interrupted.

[0068] (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.

[0069] In a variant, cancellation block 130 may cancel side lobe signal components from the range bin signals instead of the decoded signal, where the range bin signals are an example of "related signals" related to the decoded signal.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] 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.

[0075] 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.

[0076] 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.

[0077] 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.).

[0078] (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.

[0079] (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 removal unit (130) capable of repeatedly executing a removal process of estimating a side lobe signal component, which is a received signal component detected in another decoded signal in correlation with a target signal component, which is a received signal component corresponding to the transmission signal targeted in a specific decoded signal, and removing the side lobe signal component from the other decoded signals or related signals related to the decoded signals, by setting a correlation target of the side lobe signal component to the target signal component of the specific decoded signal after the previous removal process; having The removal unit includes: A radar device that executes the removal process a number of times that is at least correlated with a ratio of a peak intensity to an intensity of thermal noise in a specific decoded signal.

[0080] (Technical thought 2) The radar device according to Technical Idea 1, wherein the removal unit executes the removal process at least a number of times that correlates with the ratio and the number of peaks.

[0081] (Technical Thought 3) The radar device according to Technical Idea 1 or 2, wherein the removal unit executes the removal process a number of times that is correlated with at least the ratio and the Doppler frequency differences between the multiple peaks.

[0082] (Technical Thought 4) The radar device according to any one of Technical Ideas 1 to 3, wherein the removal unit interrupts the removal process when the intensity of the side lobe signal component in the specific decoded signal falls within an upper limit of an allowable intensity range.

[0083] (Technical Thought 5) The radar device according to Technical Idea 4, wherein the elimination unit stops the elimination process when the intensity after executing the elimination process a prescribed number of times falls within an upper limit of the allowable intensity range.

[0084] (Technical Thought 6) The radar device according to any one of Technical Ideas 1 to 5, wherein the removal unit discontinues the removal process if a peak having a lower intensity than the side lobe signal component has not been detected in the specific decoded signal in the previous cycle.

[0085] (Technical Thought 7) The radar device according to any one of Technical Ideas 1 to 6, wherein the removal unit discontinues the removal process when a peak having a lower intensity than the side lobe signal component is not detected in a specific decoded signal decoded from the mixed received signal received by another receiving antenna.

[0086] Incidentally, the above technical ideas 1 to 7 may be realized in the form of a radar control method and a radar control program. [Explanation of symbols]

[0087] 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: removal block (removal 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 removal unit (130) capable of repeatedly performing a removal process of estimating a side lobe signal component, which is a received signal component detected in another decoded signal in correlation with a target signal component, which is a received signal component corresponding to the transmission signal targeted in a specific decoded signal, and removing the side lobe signal component from the other decoded signals or related signals related to the decoded signals, by setting a correlation target of the side lobe signal component to the target signal component of the specific decoded signal after the previous removal process; having The removal unit includes: A radar device that executes the removal process a number of times that is at least correlated with a ratio of a peak intensity to a thermal noise intensity in a specific decoded signal.

2. The radar device according to claim 1 , wherein the removal unit executes the removal process at least a number of times that correlates with the ratio and the number of the peaks.

3. The radar device according to claim 1 , wherein the removal unit executes the removal process a number of times that is correlated with at least the ratio and a Doppler frequency difference between the plurality of peaks.

4. The radar device according to claim 1 , wherein the removal unit suspends the removal process when the strength of the side lobe signal component in a particular decoded signal falls within an upper limit of a tolerable strength range.

5. The radar device according to claim 4 , wherein the elimination unit stops the elimination process when the intensity after the elimination process is executed a prescribed number of times falls within an upper limit of the allowable intensity range.

6. The radar device according to claim 1 , wherein the removal unit stops the removal process when the peak having a lower intensity than the side lobe signal component has not been detected in the specific decoded signal in the previous cycle.

7. 2. The radar device according to claim 1, wherein the removal unit discontinues the removal process when the peak having a lower intensity than the side lobe signal component is not detected in the specific decoded signal decoded from the mixed received signal received by another receiving antenna.

8. 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; estimating a side lobe signal component, which is a received signal component detected in another decoded signal in correlation with a target signal component, which is a received signal component corresponding to the transmission signal targeted in a particular decoded signal, and performing a removal process of removing the side lobe signal component from the other decoded signal or a related signal related to the decoded signal; Including, The removal process can be repeatedly performed by setting a correlation target of the side lobe signal component to the target signal component of the specific decoded signal after the previous removal process, A radar control method, wherein performing the removal process includes performing the removal process a number of times that is at least correlated with a ratio of a peak intensity to a thermal noise intensity in a specific decoded signal.

9. 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; executing a removal process of estimating a side lobe signal component, which is a received signal component detected in another decoded signal in correlation with a target signal component, which is a received signal component corresponding to the transmission signal targeted in a specific decoded signal, and removing the side lobe signal component from the other decoded signal or a related signal related to the decoded signal; Including, The removal process can be repeatedly performed by setting a correlation target of the side lobe signal component to the target signal component of the specific decoded signal after the previous removal process, The radar control program, wherein executing the removal process includes executing the removal process a number of times that is at least correlated with a ratio of a peak intensity to a thermal noise intensity in a specific decoded signal.

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