Radar device, radar control method, and radar control program

Abstract

A control unit of a radar device has an acquisition unit that acquires a mixed reception signal received by a specific reception antenna. The control unit has a definition unit that defines a plurality of decoded signals in which the mixed reception signal is decoded by each code corresponding to each transmission signal. The control unit has a removal unit capable of repeatedly executing removal processing. In the removal process, the removal unit estimates a sidelobe signal component detected in the other decoded signal in relation to a target signal component corresponding to a target transmission signal in the specific decoded signal, and removes the sidelobe signal component from the other decoded signal or a related signal related to the decoded signal. The removal unit performs at least a number of times of removal processing related to the ratio of the intensity of the peak value to the intensity of the thermal noise in the specific decoded signal.

Description

[0001] Cross-reference of related applications

[0002] This application is based on Japanese Patent Application No. 2023-161605, filed on September 25, 2023, the contents of which are incorporated herein by reference in their entirety. Technical Field

[0003] This disclosure relates to a technique for controlling a radar device. Background Technology

[0004] Patent Document 1 discloses a MIMO radar using a pseudo-random phase modulation method. Such a MIMO radar transmits signals modulated by different CDM codes from each transmitting antenna. The MIMO radar generates a decoded signal spectrum based on each CDM code for the received signal and infers sidelobe signal components from each decoded signal spectrum. The MIMO radar obtains a decoded signal spectrum with suppressed sidelobe signal components by subtracting the inferred sidelobe signal components from the decoded signal spectrum corresponding to the target transmitting antenna. To further improve the suppression of sidelobe signal components, the MIMO radar further infers sidelobe signal components from the decoded signal spectrum with suppressed sidelobe signal components and performs sidelobe signal component suppression processing multiple times by subtracting them again from the decoded signal spectrum.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: US Patent No. 9952319

[0008] The technical problem that the invention aims to solve

[0009] In Patent Document 1, the method for determining the number of times the sidelobe signal component suppression process is executed is not described. Therefore, in the technology of Patent Document 1, it is impossible to determine the number of times the suppression process is executed based on the situation. Summary of the Invention

[0010] The present disclosure addresses the challenge of providing a radar apparatus capable of performing a corresponding number of sidelobe signal component suppression processes depending on the situation. Another challenge is providing a radar control method capable of performing a corresponding number of sidelobe signal component suppression processes depending on the situation. Yet another challenge is providing a radar control program capable of performing a corresponding number of sidelobe signal component suppression processes depending on the situation.

[0011] The technical means disclosed herein for solving the problem will be described below. Furthermore, the symbols in parentheses within the scope of the patent claim correspond to the specific means described in the detailed embodiments below, and do not limit the technical scope of this disclosure.

[0012] The first aspect of this disclosure is a radar device, comprising:

[0013] More than one transmitting antenna;

[0014] A transmission signal generation unit generates multiple types of transmission signals modulated by different codes transmitted from the transmission antenna;

[0015] A receiving antenna that receives a mixed received signal, which is a combination of the transmitted signals reflected by the reflector; and

[0016] The control unit processes the mixed received signals.

[0017] The control unit has:

[0018] The acquisition unit acquires the mixed received signal received by a specific receiving antenna;

[0019] A definition section defines a plurality of decoded signals, which are obtained by decoding the mixed received signal with each code corresponding to each transmitted signal; and

[0020] The removal unit is capable of repeatedly performing a removal process by setting the relevant object of the sidelobe signal component as the object signal component of a specific decoded signal after the previous removal process. This removal process estimates the sidelobe signal component and removes it from other decoded signals or associated signals. The sidelobe signal component is a received signal component detected in other decoded signals in relation to the object signal component, which is the received signal component corresponding to the transmitted signal that is the object in the specific decoded signal.

[0021] The removal unit performs at least a number of removal processes related to the ratio of the peak intensity to the intensity of thermal noise in a particular decoded signal.

[0022] The second aspect of this disclosure is a radar control method executed by a processor to control a radar device, the radar device including one or more transmitting antennas, a transmitting signal generation unit, and a receiving antenna. The transmitting signal generation unit generates multiple types of transmitting signals modulated by different codes transmitted from the transmitting antennas, and the receiving antenna receives a mixed receiving signal composed of the various transmitting signals reflected by reflectors, including:

[0023] Acquire the mixed received signal received by a specific receiving antenna;

[0024] Define multiple decoded signals, which are obtained by decoding the mixed received signal with each code corresponding to each transmitted signal; and

[0025] A removal process is performed that estimates sidelobe signal components and removes these components from other decoded signals or associated signals, whereby the sidelobe signal components are received signal components detected in other decoded signals in relation to the target signal component, which is the received signal component corresponding to the transmitted signal that is the target in a particular decoded signal.

[0026] The removal process can be repeated by setting the relevant object of the sidelobe signal component to the object signal component of the specific decoded signal after the previous removal process.

[0027] The removal process includes performing at least a number of removal operations related to the ratio of the peak intensity to the intensity of thermal noise in a particular decoded signal.

[0028] The third aspect of this disclosure is a radar control program stored in a storage medium, containing commands that cause a processor (102) to execute to control a radar device, the radar device including one or more transmitting antennas, a transmitting signal generation unit, and a receiving antenna, the transmitting signal generation unit generating multiple types of transmitting signals modulated by different codes transmitted from the transmitting antennas, and the receiving antenna receiving a mixed receiving signal composed of the various transmitting signals reflected by reflectors, characterized in that...

[0029] The command includes:

[0030] Acquire the mixed received signal received by a specific receiving antenna;

[0031] Define multiple decoded signals, which are obtained by decoding the mixed received signal with each code corresponding to each transmitted signal; and

[0032] A removal process is performed that estimates sidelobe signal components and removes these components from other decoded signals or associated signals, whereby the sidelobe signal components are received signal components detected in other decoded signals in relation to the target signal component, which is the received signal component corresponding to the transmitted signal that is the target in a particular decoded signal.

[0033] The removal process can be repeated by setting the relevant object of the sidelobe signal component to the object signal component of the specific decoded signal after the previous removal process.

[0034] The removal process includes performing at least a number of removal operations related to the ratio of the peak intensity to the intensity of thermal noise in a particular decoded signal.

[0035] According to these first to third methods, at least a number of removal processes are performed, corresponding to 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 is related to the magnitude of the sidelobe signal components, by removing the sidelobe signal components a number of times corresponding to this ratio, the sidelobe signal components can be sufficiently suppressed. Therefore, it is possible to perform a corresponding number of sidelobe signal component suppression processes depending on the situation. Attached Figure Description

[0036] Figure 1 This is a block diagram showing the overall structure of the radar device according to the first embodiment.

[0037] Figure 2 This is a block diagram illustrating the functional structure of the control unit in the first embodiment.

[0038] Figure 3 This is a diagram illustrating an example of the transmission signal in the first embodiment.

[0039] Figure 4 This is a flowchart illustrating the radar control method in the first embodiment.

[0040] Figure 5 This is a schematic diagram representing the general overview of signal processing for generating the frequency spectrum of the decoded signal from the distance unit signal.

[0041] Figure 6 This is an example of a frequency spectrum used to represent the definition of the SN ratio.

[0042] Figure 7 This is a chart representing an example of the number of iterations associated with the SN ratio.

[0043] Figure 8 It is a schematic diagram representing an overview of the iterative process.

[0044] Figure 9 This is a schematic diagram showing the difference between cases where sidelobe signal components were suppressed and cases where they were not.

[0045] Figure 10 This is a graph illustrating an example of the number of iterations related to the SN ratio and peak count in the second embodiment.

[0046] Figure 11 This is a graph used to illustrate the peak positions related to the number of iterations in the third embodiment.

[0047] Figure 12 This is a flowchart illustrating the radar control method in the fourth embodiment.

[0048] Figure 13 This is a flowchart illustrating the radar control method in the fifth embodiment.

[0049] Figure 14 This is a chart showing an example of the burial peak value determined in the radar control method of the fifth embodiment. Detailed Implementation

[0050] Hereinafter, several embodiments of the present disclosure will be described based on the accompanying drawings. Furthermore, in each embodiment, repeated descriptions may be omitted by using the same symbols to denote corresponding structural elements. Additionally, where only a portion of the structure is described in each embodiment, the structures of other previously described embodiments can be applied to the other parts of that structure. Furthermore, not only combinations of structures explicitly shown in the descriptions of each embodiment are permitted, but structures from multiple embodiments can be partially combined with each other, even if not explicitly shown, provided there are no particular obstacles to such combinations.

[0051] (First Implementation)

[0052] use Figures 1-9 The first embodiment of this disclosure will be described. The 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 target information such as the distance to the target (which is the object that reflected the transmission signal), the relative speed with the target, and the target's orientation.

[0053] Target information output from radar device 1 is input to the vehicle ECU (Electronic Control Unit) via vehicle networks such as CAN (Control Area Network) and Ethernet. Based on the acquired target information, the vehicle ECU performs various processes for autonomous driving and advanced driver assistance.

[0054] As a type of target information-based processing, there are collision avoidance processing and warning processing. Collision avoidance processing is a vehicle control process that uses the braking system, steering system, etc., to avoid collisions with targets based on target information. Warning processing is a process that warns the driver of the possibility of a collision with a target based on target information.

[0055] like Figure 1As shown, the radar device 1 of this embodiment includes a transmission signal generation 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) radar that virtually increases the number of receiving antennas RX to more than the actual number by transmitting transmission signals from multiple transmission antennas TX.

[0056] The signal generation unit 2 receives a control signal from the control unit 100 and generates a modulated signal based on the control signal. This generated signal is, for example, a so-called chirp signal whose frequency varies with time (see reference). Figure 3 The generated signal is distributed and output to each channel of the transmitting circuit 3 and the receiving circuit 4. For each transmitting channel corresponding to each transmitting antenna TX, the transmitting signal generation unit 2 outputs a generated signal with pseudo-random phase modulation using different codes as the transmitting signal. This modulation method is also called code division multiplexing (CDM). Furthermore, as... Figure 3 As shown, in this embodiment, it is assumed that the transmission time, center frequency, and frequency band of the chirped signals transmitted from different transmit antennas TX are substantially the same. Furthermore, in Figure 3 In the diagram, examples of transmitted signals from two different transmitting antennas TX are represented by different line types, namely solid lines and dashed lines.

[0057] In this embodiment, a transmission signal with phase modulation by a different code is transmitted from each of the plurality of transmitting antennas TX to the outside world. Furthermore, the signal output to the receiving circuit 4 from the generated signal is referred to as the local signal below.

[0058] The transmitting circuit 3 and the receiving circuit 4 are both primarily composed of semiconductor integrated circuit devices such as MMICs (Monolithic Microwave Integrated Circuits). The transmitting circuit 3 is connected to the transmitting antenna TX and outputs a transmitted signal to the transmitting antenna TX. The transmitting circuit 3 has the same number of amplifiers 30 as the connected transmitting antenna TX. The amplifiers 30 amplify the transmitted signal output from the transmitting signal generation unit 2 and output it to the corresponding transmitting antenna TX.

[0059] The transmitting antenna TX converts the electrical signal supplied by the transmitting signal generation unit 2, which serves as the transmitting signal, into a radio wave signal and transmits it to the outside. In this embodiment, 12 transmitting antennas TX are provided. Furthermore, when distinguishing each transmitting antenna TX individually below, it will be referred to as transmitting antenna TXn (n is a natural number from 1 to 12). The transmitting antenna TX is configured to include at least one antenna element. For example, the transmitting antenna TX is a patch antenna having multiple antenna elements in a planar shape. The antenna elements are arranged opposite to the ground plane on the side of a dielectric substrate on one side of which the ground plane is provided. The multiple antenna elements are connected in series, for example, via power supply lines that supply electrical signals.

[0060] The receiving antenna RX receives a radio wave signal that includes the transmitted signal reflected by a target, which is a reflector in the outside world, as the received signal. Multiple receiving antennas RX respectively receive a signal that is a mixture of the received signals corresponding to the respective transmitted signals from multiple transmitting antennas TX. Hereinafter, this mixed signal received by each receiving antenna RX will be referred to as the mixed received signal. Furthermore, the components of the mixed received signal that correspond to the respective transmitted signals from the multiple transmitting antennas TX will be referred to as the received signal components.

[0061] The receiving antenna RX converts the received signal, which is a radio wave signal, into an electrical signal and outputs it to the corresponding receiving circuit 4. The receiving antenna RX, for example, is a patch antenna, similar to the transmitting antenna TX, consisting of at least one antenna element connected in series via a power supply line.

[0062] The receiving circuit 4 is connected to the receiving antenna RX and acquires the received signal received by the receiving antenna RX for each receiving channel corresponding to each receiving antenna RX. The receiving circuit 4 has the same number of amplifiers 40 and signal mixing units 41 as the connected receiving antennas RX.

[0063] Amplifier 40 amplifies the received signal received by the receiving antenna and outputs it to signal mixing unit 41. Signal mixing unit 41 generates a beat frequency signal that mixes the local signal from the transmit signal generation unit 2 and the received signal. The generated beat frequency signal becomes an interference signal representing the frequency difference between the received signal and the local signal. After the beat frequency signal is filtered out by a low-pass filter (not shown) to remove high-frequency components that deviate from the frequency difference between the received signal and the local signal, it is output to control unit 100.

[0064] The control unit 100 is connected to the signal generation unit and the receiving circuit via at least one of the following: a LAN (Local Area Network) line, a wiring harness, an internal bus, and a wireless communication line. The control unit 100 is configured to include at least one dedicated computer.

[0065] The dedicated computer constituting the control unit 100 may be a radar ECU (Electronic Control Unit) specifically for controlling a particular radar device 1. Alternatively, the dedicated computer constituting the control unit 100 may be a radar control ECU that coordinates the control of multiple radar devices 1 mounted on a mobile body. Finally, the dedicated computer constituting the control unit 100 may be a sensor control ECU that coordinates the control of multiple sensors, including the radar device 1 and other sensors such as LiDAR (Light Detection and Ranging / Laser Imaging Detection and Ranging).

[0066] Each dedicated computer constituting the control unit 100 has at least one memory 101 and a processor 102. The memory 101 is a non-transitory physical storage medium, such as semiconductor memory, magnetic media, and optical media, that non-transitorily stores programs and data that can be read by the computer. The storage here can be the accumulation of data that is maintained even when the vehicle is started and turned off, or it can be temporary storage where the data is erased after the vehicle is started and turned off. The processor 102 includes, for example, at least one of the following as its core: CPU (Central Processing Unit), GPU (Graphics Processing Unit), RISC (Reduced Instruction Set Computer) - CPU, DFP (Data Flow Processor), and GSP (Graphics Streaming Processor).

[0067] In the control unit 100, the processor 102 executes multiple commands contained in the radar control program stored in the memory 101, which serves as a storage medium, in order to control the radar device 1. Thus, the control unit 100 constructs multiple functional blocks for controlling the radar device 1. For example... Figure 2 As shown, the multiple 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. Furthermore, each of these functional blocks, as a functional unit, can also be referred to as an acquisition unit, a definition unit, a removal unit, and an output unit, respectively.

[0068] Through the coordination of these blocks 110, 120, 130, and 140, the control unit 100 controls the radar device 1 according to the radar control method. Figure 4The radar control flow shown is executed. This radar control flow is executed repeatedly during the startup of radar device 1. This radar control flow is executed, for example, for each receiving channel, and a cycle is defined as executing it once for all receiving channels. Furthermore, each "S" in this radar control flow represents a multiple step executed by multiple commands contained in the radar control program.

[0069] First, in S10, acquisition block 110 acquires the mixed received signal. The mixed received signal is a beat frequency signal that combines the local signal from the signal generation unit with the received signal from the receiving antenna RX. The beat frequency signal is an interference signal that represents the frequency difference between the received signal and the local signal. The mixed received signal is acquired as a digitized digital signal sampled by an A / D converter at specified time intervals.

[0070] In the subsequent S20, definition block 120 performs a Fast Fourier Transform (FFT) on the mixed received signal. As a result, definition block 120 obtains the range spectrum of each chirp in the mixed received signal. The obtained range spectrum is a frequency spectrum representing the peak value corresponding to the distance to the target, and is discrete range data containing signal strength information for each unit (range unit) corresponding to the distance. Thereafter, as... Figure 5 As shown, N will be processed by FFT. c N samples, each chirping. s The data was converted into distance data, and N values ​​of specific distance units were extracted. c The data of each sample is recorded as the range cell signal R. Here, the data derived from the transmitted signal from the transmitting antenna TXn, and the code C... txn The encoded received signal component is set to P. n The range unit signal R before decoding serves as the received signal component C from each transmitting antenna TX before decoding. txn P n The sum of these can be defined by the following mathematical formula (1).

[0071] [Mathematical Expression 1]

[0072]

[0073] In S30, definition block 120 defines the decoded signal corresponding to the range element signal R. Specifically, for each code corresponding to each transmit antenna TX, definition block 120 generates a decoded signal after decoding the range element signal R using that code. Definition block 120 stores the decoded signal of each code in memory 101.

[0074] For example, suppose the transmitting antenna TX1 is the target transmitting antenna. In this case, the definition block 120 in S30 is for the code C corresponding to any one of the other transmitting antennas TX2 to TX12. tx2 ~C tx12 Decode any codes that have not been decoded up to the last loop. For example, in a loop where a specific code C is specified... txn In the case of decoding, the decoded signal uses code C. txn *And represented by the following mathematical formula (2), where the code C txn * is used for operations performed by C txn The code is decoded using phase modulation. Here, code C txn * is achieved by multiplying by C txn This changes all elements to the code 1.

[0075] [Mathematical Expression 2]

[0076]

[0077] In the subsequent S40, definition block 120 performs a Fast Fourier Transform (FFT) on the decoded signal. As a result, definition block 120 obtains the Doppler frequency spectrum of the mixed received signal. This frequency spectrum represents the velocity spectrum corresponding to the peak value of the target's velocity, and is discrete signal data containing signal strength information for each unit (velocity unit) corresponding to the velocity. Through this second FFT process, as... Figure 5 As shown, definition block 120 can acquire two-dimensional mapping data of distance and velocity. This two-dimensional mapping data can also be called RV mapping. Furthermore, in the Fast Fourier Transform (FFT) processing, definition block 120 multiplies the distance cell signal R by a window function. In this processing, the window function other than a rectangular function is, for example, a Hanning function, a Gaussian function, etc.

[0078] In the above mathematical formula (2), P is in the case of k=n. n The coefficient becomes 1. Therefore, as Figure 6 As shown, the velocity spectrum becomes the peak value P. n The sum of the spectrum of P and the spectrum diffused by other terms. n The spectrum generated by items other than these is equivalent to the sidelobe signal component.

[0079] In the subsequent S50, removal block 130 detects peaks from the frequency spectrum. In peak detection, removal block 130 can, for example, determine the frequency element with the maximum intensity as the peak location. Removal block 130 detects peaks, for example, by performing CFAR (Constant False Alarm Rate) processing. Removal block 130 at least acquires the determined peak location and its peak intensity as peak information associated with the detected peak. The peak information may include the phase at the peak, etc. In the decoded signal RC... txn In the case of *, peak detection is equivalent to detecting P in mathematical formula (2). n The peak value in the frequency spectrum of the decoded signal is an example of the "object signal component" that corresponds to the received signal component that is the object in the decoded signal.

[0080] Then, in S60, the removal block 130 determines the number of iterations. Here, iteration means: estimating new sidelobe signal components in other decoded signals from the peak value of the decoded signal after removal processing, and removing the new sidelobe signal components from the decoded signals. That is, iteration is equivalent to the following process: estimating the sidelobe signal components associated with the peak value of the specific decoded signal after the previous removal processing by setting the relevant object of the sidelobe signal components to the peak value of the previous removal processing, and further repeating the removal processing with the sidelobe signal components.

[0081] Remove block 130 determines at least the SN ratio χ in the frequency spectrum of the decoded signal corresponding to the transmitted signal as the object. tgt The relevant number of iterations N itr SN to χ tgt This is the ratio of the peak intensity in the decoded signal to the noise floor (size) of the thermal noise, i.e., the ratio of the peak intensity to the noise floor of the thermal noise. The removal block 130 may, for example, acquire thermal noise as a parameter that can be theoretically estimated as being related to the circuit structure and ambient temperature in the radar device 1. Alternatively, the removal block 130 may acquire thermal noise as a parameter related to the received signal strength in areas where the target does not exist in the RV mapping. Furthermore, when acquiring thermal noise as a parameter related to the received signal strength, the removal block 130 may acquire thermal noise corresponding to the average or median of the received signal strength in the aforementioned areas. Alternatively, the removal block 130 may acquire thermal noise corresponding to the mode of the received signal strength in the aforementioned areas.

[0082] When multiple peaks exist in the frequency spectrum, the removal block 130 can also be set to the ratio χ of the SN of the peak with the largest intensity. tgt Related. Alternatively, removing block 130 could also reduce the iteration count N. itr Let χ be the SN ratio of each peak value. tgtThe sum is related. Alternatively, removing block 130 can also reduce the iteration count N. itr Let χ be the SN ratio of each peak value. tgt The average correlation.

[0083] Remove block 130, for example Figure 7 As shown in the chart, SN is higher than χ. tgt The larger the value of N, the larger the iteration number N is considered to be. itr Regarding the ratio of SN to χ tgt With the number of iterations N itr The relational information is stored in memory 101 in the form of functions or tables. The removal block 130 compares the stored relational information with the acquired SN (Signal Number) using a ratio χ. tgt The number of iterations N is determined. itr .

[0084] In the following S70, removal block 130 performs the removal process. In the sidelobe suppression process, removal block 130 extracts data from the decoded signal RC... txn Remove sidelobe signal components. Further, remove the number of iterations N determined by repeatedly executing block 130. itr This is an iterative process of sidelobe suppression.

[0085] In the sidelobe suppression process, block 130 removes sidelobe signal components that are presumed to be related to the peak value of the decoded signal decoded using a code corresponding to a certain transmitted signal and are contained in the decoded signal decoded using codes corresponding to other transmitted signals. Here, for simplicity, as Figure 8 As shown, based on the code C from the two transmitting antennas TX1 and TX2 respectively. tx1 C tx2 Taking the range cell signal R of the received signal after the modulated transmitted signal is reflected by the target as an example, the sidelobe suppression processing is explained. In this case, the removal block 130 targets the decoded signal RC. tx1 * and decoding signal RC tx2 Each of * is presumed to be a sidelobe signal component in the frequency spectrum of the other party, related to the peak values ​​P1 and P2 of the target in the frequency spectrum.

[0086] Specifically, block 130 is removed from the decoded signal RC. tx1 The peak value P1^ in the frequency spectrum of the decoded signal is used to calculate the RC value of the decoded signal. tx2 The sidelobe signal component C in the frequency spectrum of * tx2 *C tx1 P1^. Furthermore, similarly, block 130 is removed from the decoded signal RC. tx2 The peak value P2^ in the frequency spectrum of the decoded signal is used to calculate the RC value of the decoded signal. tx1 The sidelobe signal component C in the frequency spectrum of * tx1 *C tx2P2^.

[0087] Then, block 130 removes the estimated sidelobe signal component C by... tx1 *C tx2 P2^ from the decoded signal RC tx1 *Subtract from the middle, and remove the sidelobe signal component C tx2 *C tx1 P1^ from the decoded signal RC tx2 The sidelobe signal components are removed by subtracting from the decoded signal. Furthermore, in the following, the decoded signal from which the sidelobe signal components have been removed will be referred to as the decoded signal with all sidelobe components removed.

[0088] Furthermore, block 130 is removed and the determined number of iterations N is executed. itr The corresponding iterative process is as follows: Based on the peak values ​​removed from the decoded signal, the sidelobe signal components in other decoded signals are inferred again, and these inferred sidelobe signal components are removed from the other decoded signals.

[0089] exist Figure 8 In the example shown, block 130 is removed from the decoded signal RC. tx1 * Remove peak values ​​P from the decoded signal. 1_1 ^, calculate the RC signal of the decoded signal tx2 The new sidelobe signal component C in * tx2 *C tx1 P 1_1 Then, remove block 130 from the decoded signal RC. tx2 *Subtract the new sidelobe signal component C from the middle. tx2 *C tx1 P 1_1 ^. Therefore, removing block 130 yields the suppressed sidelobe signal component C. tx2 *C tx1 P 1_1 The decoded signal is further removed by ^. Similarly, removal block 130 removes the peak P. 2_1 ^Calculate the new sidelobe signal component C tx1 *C tx2 P 2_1 ^, and by taking it from the decoded signal RC tx1 Subtract from * to obtain the further decoded signal after removal.

[0090] The number of iterations N determined by removing the repetition of block 130 itr The process involves iterations. Furthermore, in... Figure 8 For simplicity, the example shown illustrates a single iteration. However, removing block 130 by removing the peak P... 2_2 ^、P 1_2Each of the ^ further estimates the sidelobe signal components, and from the decoded signal RC tx1 *、RC tx2 Subtracting from the * allows for the execution of a second iteration. Similarly, by repeatedly estimating and removing sidelobe signal components, removal block 130 performs the determined number of iterations N. itr The process involves iterative processing. Furthermore, even when more than three codes are used in the modulation, the removal block 130 performs sidelobe suppression processing in the same way. For example, this is also true even when the transmitted signals from each of the 12 transmit antennas TX are modulated with different codes. In this case, the removal block 130 estimates the sidelobe signal components in the other decoded signals from their respective peak values ​​for the 12 types of decoded signals decoded by each code, and removes each sidelobe signal component from each decoded signal.

[0091] Then, in S80, output block 140 acquires target information from the frequency spectrum. The target information includes at least one of the target's range, velocity, and bearing. Output block 140 estimates the bearing, for example, using the DoA (Direction of Arrival) method. In the subsequent S130, output block 140 outputs the target information to the outside.

[0092] Reference Figure 9 The difference in dynamic range PSR between implementing and not implementing the sidelobe suppression described above is explained. Assuming a target, the dynamic range PSR can be expressed as the ratio of the maximum value of the target's peak to the sidelobes. Without sidelobe suppression, this dynamic range PSR assumes a total chirp number of N in the transmitted signal. c Let N be the number of transmitting antennas modulated by CDM code. tx When, the following mathematical expression (3) represents the relationship.

[0093] [Mathematical Expression 3]

[0094]

[0095] On the other hand, when the removal process shown in this embodiment is performed, the dynamic range PSR satisfies the relationship expressed by the following mathematical formula (4).

[0096] [Mathematical Expression 4]

[0097]

[0098] That is, in radar device 1 that performs sidelobe suppression, the dynamic range PSR is larger compared to radar device 1 that does not perform it.

[0099] According to the first embodiment described above, sidelobe signal removal is performed at least a number of times, which is related to the ratio of the peak intensity of the received signal component corresponding to the transmitted signal to the thermal noise. Since the ratio is related to the magnitude of the sidelobe signal component, by removing sidelobe signal components a number of times corresponding to the ratio, the sidelobe signal component can be sufficiently suppressed. Therefore, it is possible to perform a corresponding number of sidelobe signal component suppression processes depending on the situation.

[0100] (Second Implementation)

[0101] like Figure 10 As shown, the second embodiment is a variation of the first embodiment.

[0102] In the second embodiment, the removal block 130 in S60, except for SN ratio χ tgt In addition, it was decided to include the peak number N. tgt The relevant number of iterations N itr Specifically, for example, Figure 10 As shown, the number of peaks N tgt The more blocks 130 are removed, the more iterations N are required. itr That is, even if SN is greater than χ. tgt For the same signal, if the number of peaks N tgt If there are many iterations, then the number of iterations N for that signal is... itr Increased. Regarding the ratio of SN to χ. tgt and peak number N tgt With the number of iterations N itr The relational information is stored in memory 101 in the form of functions or tables. The removal block 130, based on the stored relational information and the obtained SN ratio χ... tgt and peak number N tgt The number of iterations N is determined. itr .

[0103] (Third implementation method)

[0104] like Figure 11 As shown, the third embodiment is a variation of the first embodiment.

[0105] In the third embodiment, when the removal block 130 in S60 has multiple peaks in the frequency spectrum, in addition to SN ratio χ, tgt In addition, the number of iterations N related to the Doppler frequency difference between the peaks is also determined. itr .like Figure 11 As shown, the Doppler frequency difference between peaks is the difference in Doppler frequencies within each peak. In the presence of multiple peaks, the overall spectral shape of the sidelobe signal components is determined by the overlap of the sidelobe signal components caused by each peak. (Iteration count N) itrThe optimal number varies depending on where each peak is located within the overall spectral shape of the sidelobe signal components. This involves the number of iterations, N. itr The optimal number can be determined by the Doppler frequency difference between the peaks, i.e., the positional relationship between the peaks in the Doppler frequency region, the code used, and the number of transmit antennas TX.

[0106] Therefore, the number of iterations N for removing block 130 is related to the Doppler frequency difference, the code used, and the number of transmitting antennas TX. itr Regarding the ratio of SN to χ tgt Doppler frequency difference, code, and the number of transmitting antennas TX and the number of iterations N itr The relational information is stored in memory 101 in the form of functions or tables. The removal block 130, based on the stored relational information and the obtained SN ratio χ... tgt The number of iterations N is determined by the Doppler frequency difference, the code, and the number of transmitting antennas TX. itr .

[0107] (Fourth Implementation)

[0108] like Figure 12 As shown, the fourth embodiment is a variation of the first embodiment.

[0109] In the fourth embodiment, such as Figure 12 As shown, the process transitions to S51 after S50. In S51, removal block 130 removes sidelobe signal components from the decoded signal only a predetermined number of times (e.g., once). That is, at the time point S51, the iterative process of estimating and removing sidelobe signal components from the decoded signal after removal is not performed again. After S51, the process transitions to S52.

[0110] In S52, removal block 130 obtains the sidelobe level as the magnitude (intensity) of the sidelobe signal components after sidelobe suppression in S51. Removal block 130 obtains the average or median of the sidelobe signal components in at least a portion of the frequency spectrum as the sidelobe level. After S52, the process proceeds to S53.

[0111] In S53, the removal block 130 determines whether iterative processing is needed based on the sidelobe level. For example, if the sidelobe level converges to the upper limit of the allowable level range, the removal block 130 determines that iterative processing is not needed; if it deviates from the upper limit of the allowable level range, it determines that iterative processing is needed. Here, the allowable level range is, for example, the range in which the sidelobe level is below or less than a threshold, and the upper limit is that threshold. The threshold is, for example, a value related to the magnitude of the noise floor of the thermal noise. The allowable level range is an example of an "allowable intensity range." Furthermore, determining in S53 that iterative processing is not needed can also be translated as determining the number of iterations N. itrIt was zero times.

[0112] If it is determined in S53 that iterative processing is not required, the process proceeds to S80. Conversely, if it is determined in S53 that iterative processing is required, the process proceeds to S60, and the number of iterations N is determined. itr Furthermore, even in cases where it is determined that iterative processing is required based on the sidelobe level, the SN ratio χ... tgt The size also has the number of iterations N in S60. itr The case where it is determined to be zero times.

[0113] After S60, the process proceeds to S71. In S71, block 130 is removed based on the determined number of iterations N. itr Then, iterative processing is performed. Even in S71, similar to S70 in the first embodiment, there may be a case where the iterative processing is performed zero times, that is, no iterative processing is performed. After S71, this process proceeds to S80.

[0114] (Fifth Implementation)

[0115] like Figure 13 , 14 As shown, the fifth embodiment is a variation of the first embodiment.

[0116] In the fifth embodiment, such as Figure 13 As shown, the process transitions to S53 after S50. In S53, block 130 determines whether there was a buried peak in the previous cycle. Here, as... Figure 14 As shown, the buried peak is the peak value in the frequency spectrum of the decoded signal before the sidelobe signal components are suppressed, which is hidden within the sidelobe signal components. In other words, the buried peak is a peak value with a lower intensity than the sidelobe signal components.

[0117] If a buried peak is detected, the process proceeds to S54. In S54, removal block 130 determines whether the current receiving antenna RX is the initial receiving antenna RX used for sidelobe suppression in this cycle. If it is determined to be the initial receiving antenna RX used for sidelobe suppression, the process proceeds to S60. On the other hand, if it is determined not to be the initial receiving antenna RX, the process proceeds to S55. In S55, removal block 130 determines whether there is a buried peak in the initial receiving antenna RX. If a buried peak is detected, the process proceeds to S60.

[0118] On the other hand, if it is determined in S53 that there was no buried peak in the previous cycle, i.e., no buried peak was detected, or if it is determined in S55 that there was no buried peak in the initial antenna, this process proceeds to S55. That is, if it is determined that there is no buried peak, the sidelobe suppression process is interrupted.

[0119] (Other implementation methods)

[0120] The above describes several implementation methods, but this disclosure is not to be construed as being limited to these implementation methods. It can be applied to various implementation methods and combinations without departing from the spirit of this disclosure.

[0121] In a variation, block 130 can be replaced by the decoded signal, and sidelobe signal components can be removed from the range cell signal. In this case, the range cell signal is an example of an "associated signal" related to the decoded signal.

[0122] In a modified example, the transmit signal generation unit 2 may apply modulation using a different code to each antenna group comprising multiple transmit antennas TX. In this case, a different code is applied to the transmit signal for each of the multiple antenna groups comprising a predetermined number of transmit antennas TX. In this case, the control unit 100 performs a removal process for each code of each antenna group. Furthermore, the transmit signal corresponding to each transmit antenna TX within the antenna group is subjected to phase-shift modulation or amplitude modulation, making it possible to separate the received signal component corresponding to each transmit signal.

[0123] In a modified example, the output block 140 of S80 may output the frequency spectrum to an external device as target information. For example, the output block 140 may output the frequency spectrum to an on-board ECU external to the radar device 1. In this case, the on-board ECU at the output destination may obtain the target's position, etc., from the peak values ​​of the target contained in the frequency spectrum.

[0124] In a variant, the radar device 1 may have only a single transmitting antenna TX. In this case, the transmitting signal generation unit 2 generates a transmitting signal for a single transmitting antenna, which is a mixture of multiple transmitting signals modulated by different codes.

[0125] In variations, the dedicated computer constituting the control unit 100 may be an integrated ECU that integrates the vehicle's driving control. Alternatively, the dedicated computer constituting the control unit 100 may be a judgment ECU that determines the driving task in the vehicle's driving control. Or, the dedicated computer constituting the control unit 100 may be a monitoring ECU that monitors the vehicle's driving control. Or, the dedicated computer constituting the control unit 100 may be an evaluation ECU that evaluates the vehicle's driving control.

[0126] In variations, the dedicated computer constituting the control unit 100 may be a navigation ECU that navigates the vehicle's driving path. Alternatively, the dedicated computer constituting the control unit 100 may be a locator ECU that estimates the vehicle's own state quantities. Or, the dedicated computer constituting the control unit 100 may be an actuator ECU that controls the vehicle's driving actuators. Or, the dedicated computer constituting the control unit 100 may be an HCU (Hman Machine Interface) Control Unit that controls information prompts within the vehicle. Alternatively, the dedicated computer constituting the control unit 100 may be a computer outside the vehicle, such as an external center or mobile terminal capable of communicating with the vehicle.

[0127] In a variation, the dedicated computer constituting the control unit 100 may have at least one of digital circuitry and analog circuitry as a processor. Here, the digital circuitry may be, for example, at least one of ASIC (Application Specific Integrated Circuit), FPGA (Field Programmable Gate Array), SOC (System on a Chip), PGA (Programmable Gate Array), and CPLD (Complex Programmable Logic Device). Furthermore, such digital circuitry may have a memory storing the program.

[0128] In a variation, the mobile body to which the control unit 100 is applied may be, for example, an autonomous robot capable of cargo handling or information collection via autonomous driving or remote operation. Furthermore, the autonomous robot may also be an autonomous driving robot including an autonomous vehicle.

[0129] In addition to the methods described above, the above-described embodiments and modifications can also be configured as control devices that can be mounted on a mobile body and have at least one processor 102 and one memory 101. Specifically, the above-described embodiments and modifications can also be implemented as processing circuits (e.g., processing ECUs) or semiconductor devices (e.g., semiconductor chips).

[0130] (The disclosure of technical ideas)

[0131] This specification discloses several technical ideas described in the following list of items. Several items are sometimes described in subsequent items in a multiple dependent form, selectively referencing an antecedent. Furthermore, several items are sometimes described in a multiple dependent form, referring to another multiple dependent form. These items described in multiple dependent forms define several technical ideas.

[0132] (Technical Idea 1)

[0133] A radar device, comprising:

[0134] More than one transmit antenna (TX);

[0135] Transmit signal generation unit (2) generates multiple types of transmit signals modulated by different codes transmitted from the transmit antenna;

[0136] A receiving antenna (RX) receives a mixed received signal, which is a combination of the transmitted signals after reflection from the reflector; and

[0137] Control unit (100) that processes the mixed received signal

[0138] The control unit has:

[0139] Acquisition unit (110) acquires the mixed received signal received by the specific receiving antenna;

[0140] Definition unit (120) defines a plurality of decoding signals, which are obtained by decoding the mixed received signal by each code corresponding to each of the transmitted signals; and

[0141] The removal unit (130) is capable of repeatedly performing a removal process by setting the related object of the sidelobe signal component as the object signal component of a specific decoded signal after the previous removal process. This removal process estimates the sidelobe signal component and removes it from other decoded signals or associated signals, where the sidelobe signal component is a received signal component detected in other decoded signals in relation to the object signal component. The object signal component is a received signal component corresponding to the transmitted signal that is the object in the specific decoded signal.

[0142] The removal unit performs the removal process at least a number of times, which is related to the ratio of the peak intensity to the intensity of thermal noise in the specific decoded signal.

[0143] (Technical Idea 2)

[0144] According to the radar device of technical concept 1, the removal unit performs the removal process at least a number of times related to the ratio and the number of peaks.

[0145] (Technical Idea 3)

[0146] According to the radar device of technical concept 1 or 2, the removal unit performs the removal process at least a number of times related to the ratio and the Doppler frequency difference between the plurality of peaks.

[0147] (Technical Idea 4)

[0148] According to any one of technical concepts 1 to 3, in the radar device, the removal unit interrupts the removal process when the intensity of the sidelobe signal component in a particular decoded signal converges to the upper limit of the allowable intensity range.

[0149] (Technical Idea 5)

[0150] According to the radar device described in technical concept 4, the removal unit stops the removal process when the intensity converges to the upper limit of the allowable intensity range after the removal process has been performed a predetermined number of times.

[0151] (Technical Idea 6)

[0152] According to any one of technical concepts 1 to 5, in the radar device, if no peak value with an intensity lower than that of the sidelobe signal component is detected in a specific decoded signal in the previous cycle, the removal unit stops the removal process.

[0153] (Technical Idea 7)

[0154] According to any one of technical concepts 1 to 6, in a radar device, if no peak value with an intensity lower than that of the sidelobe signal component is detected in a specific decoded signal after decoding the mixed received signal received from the other receiving antenna, the removal unit stops the removal process.

[0155] Furthermore, the technical ideas 1 to 7 mentioned above can also be implemented using radar control methods and radar control programs.

Claims

1. A radar device, characterized in that, include: More than one transmit antenna (TX); Transmit signal generation unit (2) generates multiple types of transmit signals modulated by different codes transmitted from the transmit antenna; A receiving antenna (RX) that receives a mixed received signal, which is a mixture of the transmitted signals after being reflected by a reflector; as well as Control unit (100), which processes the mixed received signal, The control unit has: Acquisition unit (110) acquires the mixed received signal received by the specific receiving antenna; A definition unit (120) defines a plurality of decoding signals, which are obtained by decoding the mixed received signal by each code corresponding to each of the transmitted signals; as well as The removal unit (130) is capable of repeatedly performing a removal process by setting the related object of the sidelobe signal component as the object signal component of a specific decoded signal after the previous removal process. This removal process estimates the sidelobe signal component and removes it from other decoded signals or associated signals, where the sidelobe signal component is a received signal component detected in other decoded signals in relation to the object signal component. The object signal component is a received signal component corresponding to the transmitted signal that is the object in the specific decoded signal. The removal unit performs the removal process at least a number of times, which is related to the ratio of the peak intensity to the intensity of thermal noise in the specific decoded signal.

2. The radar device according to claim 1, characterized in that, The removal unit performs the removal process at least a number of times related to the ratio and the number of peak values.

3. The radar device according to claim 1, characterized in that, The removal unit performs the removal process at least a number of times, which is related to the ratio and the Doppler frequency difference between the plurality of the peaks.

4. The radar device according to claim 1, characterized in that, When the intensity of the sidelobe signal component in a particular decoded signal converges to the upper limit of the allowable intensity range, the removal unit interrupts the removal process.

5. The radar device according to claim 4, characterized in that, If the intensity after performing the removal process a predetermined number of times converges to the upper limit of the allowable intensity range, the removal unit terminates the removal process.

6. The radar device according to claim 1, characterized in that, If no peak value with an intensity lower than that of the sidelobe signal component is detected in a specific decoded signal in the previous cycle, the removal unit stops the removal process.

7. The radar device according to claim 1, characterized in that, If no peak value with an intensity lower than that of the sidelobe signal component is detected in a specific decoded signal after decoding the mixed received signal received from the other receiving antenna, the removal unit stops the removal process.

8. A radar control method, executed by a processor (102), for controlling a radar device (1), the radar device comprising one or more transmitting antennas (TX), a transmitting signal generation unit (2), and a receiving antenna (RX), the transmitting signal generation unit generating multiple types of transmitting signals modulated by different codes transmitted from the transmitting antennas, the receiving antenna receiving a mixed receiving signal formed by mixing the transmitted signals after reflection from a reflector, characterized in that, include: Acquire the mixed received signal received by the specific receiving antenna; Multiple decoding signals are defined, which are obtained by decoding the mixed received signal by each of the codes corresponding to each of the transmitted signals; as well as A removal process is performed that estimates sidelobe signal components and removes these components from other decoded signals or associated signals, whereby the sidelobe signal components are received signal components detected in other decoded signals in relation to an object signal component, which is the received signal component corresponding to the transmitted signal that is the object in the specific decoded signal. The removal process can be repeated by setting the relevant object of the sidelobe signal component as the object signal component of the specific decoded signal after the previous removal process. Performing the removal process includes performing the removal process at least a number of times, which is related to the ratio of the peak intensity to the intensity of thermal noise in a particular decoded signal.

9. A radar control program, stored in a storage medium (101), comprising commands executed by a processor (102) to control a radar device (1), the radar device including one or more transmitting antennas (TX), a transmitting signal generation unit (2), and a receiving antenna (RX), the transmitting signal generation unit generating multiple types of transmitting signals modulated by different codes transmitted from the transmitting antennas, the receiving antenna receiving a mixed receiving signal formed by the mixing of the transmitted signals after reflection from a reflector, characterized in that, The command includes: Acquire the mixed received signal received by the specific receiving antenna; Multiple decoding signals are defined, which are obtained by decoding the mixed received signal by each of the codes corresponding to each of the transmitted signals; as well as A removal process is performed that estimates sidelobe signal components and removes these components from other decoded signals or associated signals, whereby the sidelobe signal components are received signal components detected in other decoded signals in relation to an object signal component, which is the received signal component corresponding to the transmitted signal that is the object in the specific decoded signal. The removal process can be repeated by setting the relevant object of the sidelobe signal component as the object signal component of the specific decoded signal after the previous removal process. Performing the removal process includes performing the removal process at least a number of times, which is related to the ratio of the peak intensity to the intensity of thermal noise in a particular decoded signal.

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