Parallel interference cancellation method for radar, radar, device and readable storage medium

Abstract

The application discloses a radar parallel interference cancellation method, a radar, a device and a readable storage medium, and relates to the technical field of radars.The method comprises the following steps: receiving an original radar signal, decomposing the original radar signal to obtain a plurality of decomposed channel radar signals, wherein the original radar signal comprises a time division multiplexing signal, and the channel radar signals at least comprise a first channel radar signal and a second channel radar signal; determining a first motion matrix corresponding to the first channel radar signal and a second motion matrix corresponding to the second channel radar signal; calculating an intersection motion matrix based on the first motion matrix and the second motion matrix, wherein the intersection motion matrix comprises the intersection of the first motion matrix and the second motion matrix; and outputting the intersection motion matrix as an interference cancellation result.The application reduces the cost of radar parallel interference cancellation.

Description

Technical Field

[0001] This application relates to the field of radar technology, and in particular to a parallel interference cancellation method, radar, device, and readable storage medium for radar. Background Technology

[0002] Millimeter-wave radar is widely used in fields such as autonomous driving due to its high range resolution and robustness to lighting conditions and harsh weather. However, this waveform is susceptible to parallel interference between radars. Parallel interference refers to the frequency slope of the parallel interference being consistent with the frequency slope of the type of signal transmitted by the radar itself. In this case, the radar will treat the parallel interference as a received signal and generate ghost objects. These ghost objects do not exist in the real world and are generated by parallel interference, but the radar will think that the ghost objects are real, thus causing the radar to be unable to accurately identify real objects.

[0003] Therefore, in order for radar to accurately identify real objects, it is necessary to eliminate parallel interference between radars. However, currently, the main way to avoid parallel interference between radars is to deploy additional central coordinators to instruct each radar to adjust its own radar parameters. However, the method of pre-setting a central coordinator to guide each radar to adjust its parameters to eliminate parallel interference requires the deployment of multiple central coordinators in actual application scenarios. This is difficult and costly, resulting in high costs for eliminating parallel interference between radars.

[0004] In summary, how to reduce the cost of eliminating parallel interference between radars is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0005] The main objective of this application is to provide a method, apparatus, and computer-readable storage medium for canceling parallel interference between radars, aiming to solve the technical problem of how to reduce the cost of canceling parallel interference between radars.

[0006] To achieve the above objectives, this application provides a method for parallel interference cancellation of radar, comprising the following steps:

[0007] The original radar signal is received and decomposed to obtain multiple channel radar signals. The channel radar signals include at least a first channel radar signal and a second channel radar signal, and the added phase difference between the first channel radar signal and the second channel radar signal is different.

[0008] Determine the first motion matrix corresponding to the first channel radar signal, and determine the second motion matrix corresponding to the second channel radar signal;

[0009] The intersection motion matrix is ​​calculated based on the first motion matrix and the second motion matrix, wherein the intersection motion matrix includes the intersection of the first motion matrix and the second motion matrix;

[0010] The intersection motion matrix is ​​output as the interference cancellation result to identify the motion trajectory of the real object based on the intersection motion matrix.

[0011] Optionally, the steps of determining the first motion matrix corresponding to the first channel radar signal and determining the second motion matrix corresponding to the second channel radar signal include:

[0012] The first channel radar signal is phase-calibrated to obtain the calibrated first channel radar signal;

[0013] The second channel radar signal is phase-calibrated to obtain the calibrated second channel radar signal.

[0014] Obtain the type of parallel radar interference to be eliminated in the original radar signal;

[0015] If the type of parallel radar interference to be eliminated includes unstable interference, perform a Fourier transform on the calibrated first channel radar signal to obtain the transformed first range matrix.

[0016] Perform a Fourier transform on the calibrated second-channel radar signal to obtain the transformed second range matrix;

[0017] The first distance matrix is ​​used as the first motion matrix corresponding to the first channel radar signal, and the second distance matrix is ​​used as the second motion matrix corresponding to the second channel radar signal.

[0018] Optionally, the step of calculating the intersection motion matrix based on the first motion matrix and the second motion matrix includes:

[0019] The difference between the first motion matrix and the second motion matrix is ​​calculated to obtain the difference matrix.

[0020] The difference matrix is ​​used to detect whether an object exists based on a preset algorithm, which includes a continuous false alarm rate algorithm.

[0021] If the detection result of the preset algorithm is that an object exists, then the intersection motion matrix is ​​calculated based on the difference matrix, the first motion matrix, and the second motion matrix.

[0022] Optionally, the step of calculating the intersection motion matrix based on the difference matrix, the first motion matrix, and the second motion matrix includes:

[0023] Copy the first motion matrix to obtain a first initial motion matrix, and copy the second motion matrix to obtain a second initial motion matrix;

[0024] Iterate through each element of the difference matrix in sequence and check whether the value of the traversed element is greater than a preset threshold.

[0025] If the value of the element being iterated is greater than a preset threshold, determine the position of the element being iterated.

[0026] Determine the first motion value at the element position in the first motion matrix, and determine the second motion value at the element position in the second cloud motion matrix;

[0027] The minimum value between the first motion value and the second motion value is determined. The element value at the element position in the first initial motion matrix is ​​set to be the same as the minimum value. The element value at the element position in the second initial motion matrix is ​​set to be the same as the minimum value. This process continues until all elements in the difference matrix have been traversed, resulting in the processed first initial motion matrix and the processed second initial motion matrix.

[0028] The intersection operation is performed on the processed first initial motion matrix and the processed second initial motion matrix to obtain the intersection motion matrix.

[0029] Optionally, after the step of obtaining the type of parallel radar interference to be eliminated in the original radar signal, the method further includes:

[0030] If the type of parallel radar interference to be eliminated includes stable interference, perform a Fourier transform on the processed first initial motion matrix to obtain the first velocity matrix.

[0031] The processed second initial motion matrix is ​​subjected to Fourier transform to obtain the second velocity matrix;

[0032] The first velocity matrix is ​​used as the first motion matrix corresponding to the first channel radar signal, and the second velocity matrix is ​​used as the second motion matrix corresponding to the second channel radar signal. The step of calculating the intersection motion matrix based on the first motion matrix and the second motion matrix is ​​then performed.

[0033] Optionally, the step of performing phase calibration on the first channel radar signal to obtain the calibrated first channel radar signal includes:

[0034] The first added phase difference of the radar signal of the first channel is obtained, and the first added phase difference is input into the preset phase calibration sequence generation model so that the preset calibration sequence generation model can output the first phase calibration sequence.

[0035] The first channel radar signal is phase-calibrated using the first phase calibration sequence to obtain the calibrated first channel radar signal.

[0036] Optionally, the step of decomposing the original radar signal to obtain the decomposed multi-channel radar signal includes:

[0037] The radar signal multiplexing method for obtaining the original radar signal;

[0038] If the radar signal multiplexing method includes time-division multiplexing, the original radar signal is decomposed based on the time domain to obtain multiple channels of radar signal after decomposition.

[0039] In addition, to achieve the above objectives, this application also provides a radar, which includes a receiver and a transmitter. The transmitter is used to perform phase modulation on multi-channel radar signals and transmit the multi-channel phase-modulated radar signals as the original radar signals based on signal multiplexing. Each channel radar signal corresponds to an added phase difference.

[0040] The receiving end performs interference cancellation on the received radar signal using the steps of the parallel interference cancellation method for radar described above.

[0041] In addition, to achieve the above objectives, this application also provides a terminal device, including: a memory, a processor, and a parallel interference cancellation program for radar stored in the memory and executable on the processor. When the parallel interference cancellation program for radar is executed by the processor, it implements the steps of the parallel interference cancellation method for radar as described above.

[0042] In addition, to achieve the above objectives, this application also provides a computer-readable storage medium storing a parallel interference cancellation program for radar, which, when executed by a processor, implements the steps of the parallel interference cancellation method for radar as described above.

[0043] In this application, a raw radar signal is received and decomposed to obtain multiple channel radar signals. Each channel radar signal includes at least a first channel radar signal and a second channel radar signal, with different added phase differences. A first motion matrix corresponding to the first channel radar signal is determined, and a second motion matrix corresponding to the second channel radar signal is determined. An intersection motion matrix is ​​calculated based on the first and second motion matrices, where the intersection motion matrix includes the intersection of the first and second motion matrices. The intersection motion matrix is ​​output as the interference cancellation result to identify the motion trajectory of a real object based on the intersection motion matrix. Thus, compared with the existing technology that requires the additional deployment of a central coordinator to guide each radar to adjust its parameters to eliminate parallel interference, the embodiments of this application decompose the original radar signals of the signal multiplexing to obtain the first channel radar signal and the second channel radar signal, and then find the intersection based on the motion matrices corresponding to the first channel radar signal and the second channel radar signal, that is, to obtain the intersection motion matrix after parallel interference elimination. There is no need to deploy an additional central coordinator. The parallel interference between radars is eliminated by relying on the radar's own signal processing, thereby reducing the cost of eliminating parallel interference between radars. Attached Figure Description

[0044] The purpose, features, and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings.

[0045] Figure 1 This is a schematic diagram of the terminal / radar structure of the hardware operating environment involved in the embodiments of this application;

[0046] Figure 2 This is a flowchart illustrating the first embodiment of the parallel interference cancellation method for radar according to this application;

[0047] Figure 3 This is an illustrative diagram illustrating unstable interference.

[0048] Figure 4 An illustrative diagram for stabilizing interference;

[0049] Figure 5 An illustrative diagram illustrating ghost points (phantom objects) caused by unstable interference;

[0050] Figure 6 An illustrative diagram illustrating ghost points (phantom objects) caused by stabilizing interference;

[0051] Figure 7 This is a schematic diagram of the Chirp sequence transmitted in the first signal channel;

[0052] Figure 8A schematic diagram of the Chirp sequence transmitted in the second signal channel;

[0053] Figure 9 This is a schematic diagram of the system architecture of the parallel interference cancellation method for radar in this application;

[0054] Figure 10 A schematic diagram of the signal processing flow for commercial radar;

[0055] Figure 11 This is a schematic diagram of the distance Fourier transform results for the first signal channel;

[0056] Figure 12 This is a schematic diagram of the distance Fourier transform results for the second signal channel;

[0057] Figure 13 A schematic diagram of the Doppler Fourier transform results for the first signal channel;

[0058] Figure 14 A schematic diagram of the Doppler Fourier transform results for the second signal channel;

[0059] Figure 15 A schematic diagram of the Doppler Fourier transform results after phase calibration of the first signal channel;

[0060] Figure 16 A schematic diagram of the Doppler Fourier transform results after phase calibration of the second signal channel; Detailed Implementation

[0061] It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit this application.

[0062] Reference Figure 1 , Figure 1 This is a schematic diagram of the terminal device structure of the hardware operating environment involved in the embodiments of this application.

[0063] like Figure 1As shown, the terminal device may include: a processor 1001, such as a central processing unit (CPU), a communication bus 1002, a user interface 1003, a network interface 1004, and a memory 1005. The communication bus 1002 is used to enable communication between these components. The user interface 1003 may include a display screen and an input unit such as a keyboard; optionally, the user interface 1003 may also include a standard wired interface or a wireless interface. The network interface 1004 may optionally include a standard wired interface or a wireless interface (such as a Wi-Fi interface). The memory 1005 may be a high-speed random access memory (RAM) or a stable non-volatile memory (NVM), such as a disk drive. Optionally, the memory 1005 may also be a storage radar independent of the aforementioned processor 1001.

[0064] Those skilled in the art will understand that Figure 1 The structure shown does not constitute a limitation on the terminal device and may include more or fewer components than shown, or combine certain components, or have different component arrangements.

[0065] like Figure 1 As shown, the memory 1005, which serves as a storage medium, may include an operating radar, a data storage module, a network communication module, a user interface module, and a parallel interference cancellation program for the radar.

[0066] exist Figure 1 In the terminal device shown, the network interface 1004 is mainly used for data communication with other devices; the user interface 1003 is mainly used for data interaction with the user; the processor 1001 and the memory 1005 in the terminal device of this application can be set in the terminal device. The terminal device calls the parallel interference cancellation program of the radar stored in the memory 1005 through the processor 1001 and executes the parallel interference cancellation method of the radar provided in the embodiment of this application.

[0067] Millimeter-wave radar is widely used in autonomous vehicles due to its high range resolution and robustness to lighting conditions and adverse weather. The commonly used millimeter-wave radar waveform is a frequency-modulated continuous wave, but this waveform is susceptible to inter-radar interference.

[0068] Inter-radar interference includes scanning interference and parallel interference: Scanning interference occurs when the frequency slope of the transmitted signal differs from that of the interfering signal. In this case, mutual interference increases effective noise and reduces receiver sensitivity. Parallel interference occurs when the frequency slope of the transmitted signal is the same as that of the interfering signal. In this case, mutual interference can produce ghost objects, which the radar itself cannot directly distinguish from real objects. Therefore, for millimeter-wave radar, parallel interference is a more serious security threat.

[0069] Existing scanning interference cancellation methods include zero-point methods, autoregressive models, short-time Fourier transforms and L-statistics, as well as iterative methods and adaptive thresholding. These methods remove interference components and reconstruct the signal. However, these methods are all based on the assumption that scanning interference only affects a portion of the chirp sequence, while parallel interference can affect the entire chirp sequence. Therefore, the application of these methods in scanning interference cancellation is not applicable to the cancellation of parallel interference.

[0070] To eliminate parallel interference between radars, existing methods have proposed stochastic parameter tuning and radar coordination approaches. These methods either randomly tune radar parameters or tune them according to instructions from a central coordinator. However, stochastic parameter tuning is difficult to implement in hardware and time-consuming in large-scale radar networks; therefore, both methods use simulations to evaluate algorithm performance. Furthermore, radar coordination systems typically require additional communication channels or a central coordinator, making implementation costly.

[0071] Based on the above issues, please refer to Figure 2 , Figure 2 This is a flowchart illustrating the first embodiment of the parallel interference cancellation method for radar according to this application. It should be noted that although the logical order is shown in the flowchart, in some cases, the steps shown or described may be performed in a different order than that shown here.

[0072] In this embodiment, the parallel interference cancellation method of the radar of this application is applied to the aforementioned terminal device. It should be understood that, based on different design needs of actual applications, the parallel interference cancellation method of the radar of this application can of course also be specifically applied to other terminal devices in different feasible implementations. For ease of understanding and explanation, the radar receiver is taken as the direct execution subject in this embodiment.

[0073] like Figure 2 As shown, in this embodiment, the parallel interference cancellation method for the radar includes the following steps:

[0074] Step S10: Receive the original radar signal, decompose the original radar signal to obtain multiple channel radar signals after decomposition, wherein the channel radar signals include at least a first channel radar signal and a second channel radar signal, and the added phase difference between the first channel radar signal and the second channel radar signal is different;

[0075] Parallel interference includes stable interference and unstable interference, such as Figure 3 As shown, unstable interference will occur when the frequency sweep period of the interference signal is different from that of the transmitted signal, such as... Figure 4 As shown, stable interference is caused by interference signals with the same frequency sweep period as the transmitted signal. It is distinguished by the difference in the chirp signal period. Radar measures distance using time of flight, which is calculated from the phase difference between the transmitted and received signals. However, radar can mix interference signals with the received signal, creating ghost objects, or ghost spots. Figure 5 As shown, unstable interference will generate ghost points at different distances (subcarriers) in time. Figure 6 As shown, a stable disturbance will produce a stable ghost point in time.

[0076] For unstable interference, the ghost object will move to different positions in adjacent chirps, and unstable interference can be eliminated by comparing distance (time).

[0077] For stable interference, it creates a stable ghost object in time. To eliminate stable interference, the transmitted signal (i.e., the signal transmitted by the radar transmitter) can be modulated to differentiate it from the interference signal, thus separating them. Preferably, the transmitted signal can be modulated in phase to distinguish the real object from the ghost object in the Doppler field.

[0078] To eliminate unstable interference, the distances between adjacent chirps can be compared. This transforms the comparison problem into an intersection calculation problem. Alternatively, the intersection of the distances between two signal channels can be chosen to eliminate unstable interference, since the chirps of these two signal channels are sent alternately, and ghost objects differ in distance at the chirp level.

[0079] For eliminating stable interference, the chirp timing is on the order of microseconds, and the position and velocity of the real object in the two signal channels remain unchanged. The motion of the real object is restricted by alternately transmitting the chirps through these two channels.

[0080] To eliminate parallel interference, the radar's transmitted signal needs to be different from the interfering signal. Existing radars measure velocity by measuring the phase difference of chirp sequences. Based on this, the transmitted signal can be modulated using the phase difference (adding a phase difference) to "add a velocity" to all detected targets. In this example, the radar transmitter is designed with two signal channels, each transmitting a radar signal with a different added phase difference. Optionally, the radar transmitter can use signal multiplexing to transmit these two signals, such as alternating transmission of the two channels using time-division multiplexing. To make these two channels distinguishable among detected targets, such as... Figure 7-8 As shown, different phase differences Δφ1 and Δφ2 were added to the two signals respectively. That is, the transmitted signal S1(t) of signal channel 1 and the transmitted signal S2(t) of signal channel 2 are respectively:

[0081]

[0082]

[0083] Where A1 and A2 are the amplitudes of the transmitted signals in signal channel 1 and signal channel 2, respectively; N is the total number of chirps in each signal channel; j is the imaginary unit; Δφ1 is the added phase difference of signal channel 1 (i.e., the first signal channel); Δφ2 is the added phase difference of signal channel 2 (i.e., the second signal channel); f t f is the frequency of the transmitted signal. t =S*t+f0, where S is the signal frequency slope and f0 is the signal starting frequency.

[0084] The radar transmitter sends radar signals with different phase differences through two signal channels via signal multiplexing. After receiving the original radar signal, the radar receiver decomposes the original radar channel radar signal accordingly.

[0085] In one embodiment, the step of decomposing the original radar signal to obtain decomposed multi-channel radar signals includes:

[0086] Step S101: Obtain the radar signal multiplexing method of the original radar signal;

[0087] Step S102: If the radar signal multiplexing method includes time division multiplexing, the original radar signal is decomposed based on the time domain to obtain multiple channels of radar signal after decomposition.

[0088] After receiving the original radar signal, the radar receiver decomposes it in reverse using a signal multiplexing method, resulting in multiple radar channels. At least two signals are multiplexed; correspondingly, the decomposed channel radar signals include at least a first channel radar signal and a second channel radar signal. The original radar signal is the radar signal transmitted by the radar transmitter, such as an electromagnetic wave signal. For example, ... Figure 9 As shown, when the radar transmitter transmits signals from two signal channels using time-division multiplexing, the radar receiver decomposes the received signals using time-division multiplexing to obtain two signals, namely the first channel radar signal and the second channel radar signal.

[0089] Let τ be the time delay caused by the real object. i The time delay caused by the interference signal is denoted as τ. m Furthermore, the phase difference Δφ in the interference signal a and Δφ b These represent the phase difference between the two signal channels. The received raw radar signal r(t) can be expressed as:

[0090]

[0091] It should be noted that the phase offsets Δφ1 and Δφ2 are added before transmission. For example... Figure 10 As shown, the phase difference of the signal synthesized by the radar's transmitting antenna through a signal synthesizer is... The synthesized signal S(t) is obtained and transmitted. The radar's receiving antenna mixes the received signal with the transmitted signal without phase shift, and then samples the signal after low-pass filtering.

[0092] Step S20: Determine the first motion matrix corresponding to the first channel radar signal, and determine the second motion matrix corresponding to the second channel radar signal;

[0093] Unstable interference occurs when the sweep period of the interfering signal differs from that of the transmitted signal. The receiver (i.e., the receiving end) will incorrectly interpret the interfering signal as part of the received signal, and the different time delays of the received signal (such as...) will cause problems. Figure 3 Time delays (τ1, τ2, τ3, etc.) can generate ghost objects at different distances. Based on this, unstable interference can be eliminated by comparing the time-distance matrix and the motion matrix within the range domain.

[0094] Stable interference is caused by an interfering signal with the same frequency sweep period as the transmitted signal. The receiver can detect a stable time delay τ. Unlike unstable interference, stable interference cannot be distinguished or removed from ghost objects within the range domain through these two signal channels because its distance does not change with frequency sweep. To eliminate stable interference, "velocity" can be added to all detected objects, thus allowing the ghost objects to move in the Doppler domain of the time-velocity matrix relative to the detected real objects, thereby eliminating stable interference.

[0095] The first motion matrix can be a time-distance matrix or a time-velocity matrix. When eliminating unstable interference, the first motion matrix is ​​set to the time-distance matrix corresponding to the first channel radar signal. When eliminating temperature interference, the first motion matrix is ​​set to the time-velocity matrix corresponding to the first channel radar signal. Similarly, corresponding to the type of interference to be eliminated, the second motion matrix can also be a time-distance matrix or a time-velocity matrix. Optionally, the motion matrix can be obtained by performing a Fourier transform on the channel radar signal, such as performing an FFT (fast Fourier transform) on the channel radar signal. Specifically, a one-dimensional FFT transform on the channel radar signal yields the time-distance matrix, and a two-dimensional FFT transform on the channel radar signal yields the time-velocity matrix.

[0096] Understandably, after one type of interference is eliminated, another type of interference can be eliminated based on the result, thus achieving the elimination of both unstable and stable interference. Preferably, a one-dimensional FFT transform can be performed on the channel radar signal to obtain a time-range matrix. This time-range matrix can then be used as the motion matrix to eliminate unstable interference. Next, an FFT transform can be performed again on the motion matrix after eliminating unstable interference to obtain a time-velocity matrix, which is then used as the motion matrix to eliminate stable interference.

[0097] Step S30: Calculate the intersection motion matrix based on the first motion matrix and the second motion matrix, wherein the intersection motion matrix includes the intersection of the first motion matrix and the second motion matrix;

[0098] The intersection motion matrix can be the intersection of the first motion matrix and the second motion matrix. However, considering that the two signals have a certain time difference, the first motion matrix and the second motion matrix may not be completely consistent. In order to improve the accuracy of the intersection motion matrix, this embodiment provides a cross algorithm to calculate the intersection motion matrix. The cross algorithm calculates the intersection motion matrix by executing steps A10 to A30.

[0099] In one embodiment, the step of calculating the intersection motion matrix based on the first motion matrix and the second motion matrix includes:

[0100] Step A10: Subtract the first motion matrix from the second motion matrix to obtain the difference matrix;

[0101] Step A20: Detect whether there is an object in the difference matrix based on a preset algorithm, wherein the preset algorithm includes a continuous false alarm rate algorithm;

[0102] Step A30: If the detection result of the preset algorithm is that an object exists, then calculate the intersection motion matrix based on the difference matrix, the first motion matrix and the second motion matrix.

[0103] The difference matrix D can be the absolute difference between the first motion matrix and the second motion matrix. A preset algorithm is used to detect whether an object exists in the difference matrix. This preset algorithm includes a continuous false alarm rate (CFAR) algorithm, which detects whether a target exists. If no object exists, and there is no need to eliminate interference, no processing is required. If an object exists, steps B10 to B30 are then executed to calculate the intersection motion matrix, thereby eliminating the motion data of the ghost object (such as distance, speed, etc.) and retaining the motion data of the real object.

[0104] In this embodiment, the difference between the first motion matrix and the second motion matrix is ​​calculated to obtain a difference matrix. Based on a preset algorithm, the presence of an object in the difference matrix is ​​detected. If the preset algorithm detects that an object exists, the intersection motion matrix is ​​calculated based on the difference matrix, the first motion matrix, and the second motion matrix. The intersection motion matrix is ​​calculated only when an object is detected, i.e., when ghost objects need to be eliminated. If there is no object, the intersection motion matrix does not need to be calculated, thus reducing the number of times the intersection motion matrix is ​​calculated.

[0105] In one embodiment, the step of calculating the intersection motion matrix based on the difference matrix, the first motion matrix, and the second motion matrix includes:

[0106] Step B10: Copy the first motion matrix to obtain the first initial motion matrix, and copy the second motion matrix to obtain the second initial motion matrix;

[0107] Step B20: Iterate through each element of the difference matrix in sequence and check whether the element value of the traversed element is greater than a preset threshold.

[0108] Step B30: If the element value of the traversed element is greater than a preset threshold, determine the element position of the traversed element.

[0109] This element is all the elements included in the difference matrix. For example, a two-row, two-column difference matrix contains four elements. The position of an element can be its row and column position in the difference matrix, such as row 1, column 1, row 1, column 2, etc.

[0110] Step B40: Determine the first motion value at the element position in the first motion matrix, and determine the second motion value at the element position in the second cloud motion matrix;

[0111] Step B50: Determine the minimum value between the first motion value and the second motion value, set the element value at the element position in the first initial motion matrix to be the same as the minimum value, set the element value at the element position in the second initial motion matrix to be the same as the minimum value, until all elements in the difference matrix have been traversed, and obtain the processed first initial motion matrix and the processed second initial motion matrix.

[0112] Step B60: Perform an intersection operation on the processed first initial motion matrix and the processed second initial motion matrix to obtain the intersection motion matrix.

[0113] Let the first motion matrix be denoted as X, the second motion matrix as Y, and the preset threshold as D. T Let the difference matrix be denoted as D, the first initial motion matrix after processing be denoted as M, and the second initial motion matrix after processing be denoted as N. The specific process of the crossover algorithm is as follows: First, initialize matrices M and N to X and Y, respectively. Then, calculate the difference matrix D, which is the absolute difference between X and Y: D = |XY|. Next, check for the existence of an object using the Continuous False Alarm Rate (CFAR) algorithm. If an object exists, iterate through the difference matrix D. If any element in D is greater than a threshold D... T If any element in D is greater than the threshold D, then... T Let the element position be denoted as s. Assign the minimum value at element position s in matrices X and Y to matrices M and N. Otherwise, retain the original values ​​of matrices M and N at element position s. Finally, return the interference-reduced matrices M and N, and calculate the intersection of M and N to obtain the intersection motion matrix.

[0114] Step S40: Output the intersection motion matrix as the interference cancellation result to identify the motion trajectory of the real object based on the intersection motion matrix.

[0115] The intersection motion matrix corresponds to the first motion matrix and the second motion matrix. When the first and second motion matrices are time-distance matrices, the intersection motion matrix is ​​the time-distance matrix after interference cancellation. When the first and second motion matrices are time-velocity matrices, the intersection motion matrix is ​​the time-velocity matrix after interference cancellation. Figure 9As shown, the intersection motion matrix after one-dimensional FFT processing of the channel radar signal and interference removal is the time-range matrix. The intersection motion matrix after two-dimensional FFT processing of the channel radar signal and interference removal is the time-velocity matrix. Both the time-range matrix and the time-velocity matrix can be output as interference removal results after interference removal.

[0116] In this embodiment, the original radar signal is received and decomposed to obtain multiple channel radar signals. Each channel radar signal includes at least a first channel radar signal and a second channel radar signal, with different added phase differences. A first motion matrix corresponding to the first channel radar signal is determined, and a second motion matrix corresponding to the second channel radar signal is determined. An intersection motion matrix is ​​calculated based on the first and second motion matrices, where the intersection motion matrix includes the intersection of the first and second motion matrices. The intersection motion matrix is ​​output as the interference cancellation result to identify the trajectory of a real object. Thus, compared to existing interference cancellation methods that require an additional central coordinator to guide each radar to adjust its parameters to eliminate parallel interference, this embodiment decomposes the original radar signal (which has been multiplexed) to obtain the first and second channel radar signals. Then, it calculates the intersection of the motion matrices corresponding to the first and second channel radar signals to obtain the intersection motion matrix after parallel interference cancellation. This eliminates the need for an additional central coordinator and relies on the radar's own signal processing to eliminate parallel interference between radars, thereby reducing the cost of eliminating parallel interference between radars.

[0117] Furthermore, based on the first embodiment of this application described above, a second embodiment of the parallel interference cancellation method for radar of this application is proposed. Contents identical or similar to those in the first embodiment can be referred to the above description and will not be repeated hereafter. In this embodiment, the step S20 of the above embodiment, which determines the first motion matrix corresponding to the first channel radar signal, and the step of determining the second motion matrix corresponding to the second channel radar signal, are refined, including:

[0118] Step C10: Perform phase calibration on the first channel radar signal to obtain the calibrated first channel radar signal;

[0119] Step C20: Perform phase calibration on the second channel radar signal to obtain the calibrated second channel radar signal;

[0120] To make these two signal channels distinguishable among detected targets, different phase differences φ1 and φ2 are added to the two signals, which also "adds a velocity" to all detected targets. To eliminate the velocity added to the target due to the added phase difference, the channel radar signals can be phase-calibrated to reduce the "velocity" added to the detected object.

[0121] After calibration, the phase difference between adjacent sweep sequences of the real object in these two signal channels is: The phase differences of the ghost objects are: Φ′ a =Δφ a -Δφ1Φ′ b =Δφ b -Δφ2, where Φ′1 is the phase difference between adjacent sweep sequences of the real object after phase calibration of the first channel radar signal, and Φ′2 is the phase difference between adjacent sweep sequences of the real object after phase calibration of the second channel radar signal. a Φ′ represents the phase difference between adjacent sweep sequences of the ghost object after phase calibration of the first channel radar signal. b The phase difference between adjacent sweep sequences of the ghost object after phase calibration of the second channel radar signal, v i f is the velocity of the object. t Let be the frequency of the transmitted signal, c be the speed of light, Δφ1 be the added phase difference of the transmitted signal in the first signal channel, and Δφ2 be the added phase difference of the transmitted signal in the second signal channel. a Let Δφ be the phase difference of the interference signal in the first signal channel. b f represents the phase difference of the interference signal in the second signal channel. t =S*t+f0, where S is the signal frequency slope and f0 is the signal starting frequency.

[0122] Step C30: Obtain the type of parallel radar interference to be eliminated in the original radar signal;

[0123] Step C40: If the type of parallel radar interference to be eliminated includes unstable interference, perform a Fourier transform on the calibrated first channel radar signal to obtain the transformed first range matrix.

[0124] Step C50: Perform a Fourier transform on the calibrated second channel radar signal to obtain the transformed second range matrix;

[0125] Step C60: Use the first distance matrix as the first motion matrix corresponding to the first channel radar signal, and use the second distance matrix as the second motion matrix corresponding to the two channel radar signal.

[0126] Unstable interference occurs when the sweep period of the interfering signal differs from that of the transmitted signal. Let the calibrated first-channel radar signal be denoted as y1(t), and the calibrated second-channel radar signal as y2(t). Perform Fourier transforms on y1(t) and y2(t), specifically, a range FFT can be performed on y1(t) and y2(t) in a fast time. Here, the fast time is the duration of one chirp of the signal period. (Refer to...) Figure 11-12 , Figure 11 This example demonstrates the range FFT results of the first channel radar signal, showing the range variation over time within the frame. Figure 12 An example of range FFT results showing the range variation over time in frames of the second-channel radar signal is presented.

[0127] Figure 11-12 The different positions of the ghost object in the first and second signal channels are shown. However, the trajectory of the real object is consistent across both channels. Therefore, the intersection of the distance matrices (i.e., the time distance matrices) of the two signal channels can be calculated in the distance domain, thereby eliminating unstable interference.

[0128] In this embodiment, during unstable interference cancellation, the results of the range Fourier transform of the first and second channel radar signals are used as the first motion matrix X and the second motion matrix Y, which are then input into the cross algorithm. If ghost objects caused by unstable interference exist, these ghost objects will appear at different range positions in each signal channel, thus the unstable interference can be effectively eliminated by taking the intersection of the range matrices. Furthermore, after decomposing the received original radar signal, this embodiment performs phase calibration on the first and second channel radar signals, thereby reducing the "velocity" added to the detected real object and ensuring the authenticity of the detected real object's velocity.

[0129] In one embodiment, after the step of obtaining the type of parallel radar interference to be eliminated in the original radar signal, the method further includes:

[0130] Step D10: If the type of parallel radar interference to be eliminated includes stable interference, perform a Fourier transform on the processed first initial motion matrix to obtain the first velocity matrix.

[0131] Step D20: Perform a Fourier transform on the processed second initial motion matrix to obtain the second velocity matrix;

[0132] Step D30: Use the first velocity matrix as the first motion matrix corresponding to the first channel radar signal, use the second velocity matrix as the second motion matrix corresponding to the second channel radar signal, and perform the step of calculating the intersection motion matrix based on the first motion matrix and the second motion matrix.

[0133] Stable interference is caused by an interference signal with the same frequency sweep period as the transmitted signal, and can be detected with a stable time delay τ. Unlike unstable interference, stable interference cannot be distinguished and removed from ghost objects caused by stable interference in the range domain through two signal channels because its distance does not change with frequency sweep.

[0134] To eliminate stabilizing interference, a velocity is "added" to all detected objects (by adding a phase difference), which allows ghost objects to be separated from the detected real objects in the Doppler domain. The radar estimates the velocity by measuring the phase difference in the frequency sweep sequence. Specifically, it is assumed that the real object is located at a distance d. i The movement speed is v i When the time delay is τ i =2(d i ±v i k) / c, where k is the chirp index (i.e., slow time) and c is the speed of light. The phase differences Φ1 and Φ2 in the sweep sequence calculated from the real object for two signal channels can be calculated using the following formula: Phase difference Φ of ghost objects a and Φ b They are respectively: Φ a =Δφ a , Φ b =Δφ b Assume the phase difference in the interference signal is static, i.e., Δφ. a =Δφ b Different velocities can be "added" to objects detected in the two channels by performing phase modulation on the transmitted signal. This is done by performing Doppler FFT, such as... Figure 13-14 Examples of 2D FFT results are shown at Δφ1=0 and Δφ2=-π / 2, where phase modulation exists only in the transmitted signal and the interfering signal has no phase modulation. Therefore, the detected real object will have different "velocities" in the two signal channels, while the ghost object's velocity remains constant (after phase calibration, the real object will have the same velocity in both signal channels, while the ghost object will have different velocities), thus allowing the real object to be distinguished from the ghost object by velocity, thereby eliminating stable interference.

[0135] like Figure 15-16As shown, after phase calibration of the radar channel signals, the ghost object will be modulated to a different location in the Doppler band. The stabilization interference cancellation problem is simplified to calculating the intersection between the 2D FFT results of the two signal channels. Stabilization interference cancellation is performed using cross-matrix. The phase-calibrated Doppler FFT results are used as input to the cross-matrix algorithm of the first motion matrix X and the second motion matrix Y, instead of inputting based on the FFT results. Because the ghost object has different velocities in the two signal channels, stabilization interference is eliminated by the intersection of the velocity matrices.

[0136] Understandably, in order to eliminate both stable and unstable interference, a Fourier transform, such as FFT, can be performed on the range matrix after unstable interference is eliminated to obtain the velocity matrix (i.e., the time velocity matrix). This yields the first velocity matrix of the phase-calibrated first channel radar signal and the second velocity matrix of the phase-calibrated second channel radar signal. These two velocity matrices are then used as the first motion matrix X and the second motion matrix Y, respectively, and input into the crossover algorithm to obtain the intersection motion matrix where both stable and unstable interference are eliminated. Using this motion matrix to identify the trajectory of an object, the trajectory of the real object can be obtained without identifying ghost objects, ensuring that the radar can accurately identify the real object.

[0137] In one embodiment, the step of performing phase calibration on the first channel radar signal to obtain the calibrated first channel radar signal includes:

[0138] Step E10: Obtain the first added phase difference of the radar signal of the first channel, and input the first added phase difference into the preset phase calibration sequence generation model so that the preset calibration sequence generation model can output the first phase calibration sequence.

[0139] Step E20: Perform phase calibration on the first channel radar signal using the first phase calibration sequence to obtain the calibrated first channel radar signal.

[0140] The first added phase difference is the added phase difference of the first channel radar signal. The radar transmitter determines the added phase difference between the two signal channels when transmitting the signal. The radar receiver can obtain this phase difference determined by the transmitter. The preset phase calibration sequence generation model can be: By inputting the first added phase difference Δφ1 into the phase calibration sequence generation model, the first phase calibration sequence c1(k1) can be obtained. Multiplying the first phase calibration sequence by the first channel radar signal yields the calibrated first channel radar signal. Similarly, the phase calibration sequence of the second radar channel signal is denoted as c2(k2). Where Δφ2 is the second added phase difference of the second channel radar signal. Let the first channel radar signal be y1(t) and the second channel radar signal be y2(t), then c1(k1)*y1(t) is the calibrated first channel radar signal, and c2(k2)*y2(t) is the calibrated second channel radar signal.

[0141] To verify the effectiveness of the parallel interference cancellation method for radar proposed in this application, a real-world scenario experiment was conducted and the results were obtained. The scenario experiment and the results are described below.

[0142] A. Implementation and Setup

[0143] Hardware: A parallel interference cancellation system was implemented using the Texas Instruments AWR1843BOOST mmWave sensor and DCA1000EVM data acquisition adapter. The AWR1843BOOST operates in the 76-81 GHz band and is equipped with three transmit antennas and four receive antennas. In the experiments, one transmit antenna and one receive antenna were used to demonstrate the interference cancellation performance. Additionally, the AWR1843BOOST includes a phase shifting module before transmission, enabling phase modulation. Data processing and analysis were performed on a desktop computer equipped with an 8-core processor (AMD Ryzen 7 3700X) @ 3.60 GHz and 16 GB of memory.

[0144] Software: mmWave Studio was used to configure the mmWave sensor module and acquire data from the analog-to-digital converter (ADC). Additionally, MATLAB R2022(a) was used to read the data and implement the parallel interference cancellation method for the aforementioned radar.

[0145] B. Evaluation Indicators

[0146] Ghost object removal probability: This probability assesses the ability to remove ghost objects. Each frame with parallel interference is marked (e.g., frames without moving objects but detected using the CFAR algorithm). The number of frames N in which ghost objects appear is calculated. The parallel interference removal algorithm used, CFAR, is used to check whether these ghost objects have been removed, and the number M of frames where ghost objects were successfully removed is calculated. The ghost object removal probability is M / N.

[0147] Real Object Removal Probability: This probability assesses the false alarm rate. Specifically, in some experiments, a person walks around and their location is marked. The total number of real objects (e.g., the moving person) is calculated, denoted as K. A parallel interference removal algorithm is used, employing CFAR to check the number L of real objects present in these frames. The real object removal probability is (KL) / K, representing the probability that the algorithm incorrectly identifies a real object as a ghost object and removes it. A smaller value indicates better performance.

[0148] Interference Reduction Intensity: This metric assesses the reduction in the intensity of the ghost object. Specifically, before interference cancellation, the power intensity of the ghost object is P1. Using the interference cancellation system, the power intensity at that location will be reduced to P2. The power reduction of the ghost object is evaluated using P1-P2; this is a numerical result used to assess the effectiveness of parallel interference cancellation.

[0149] C. Overall Performance

[0150]

[0151]

[0152] In addition, this application also provides a radar, which includes a receiver and a transmitter. The transmitter is used to perform phase modulation on multi-channel radar signals and transmit the multi-channel phase-modulated radar signals as the original radar signals based on signal multiplexing. Each channel radar signal corresponds to an added phase difference.

[0153] Specifically, each channel radar signal can be a chirp signal. Phase modulation is applied to the multi-channel radar signals, that is, the phase difference between adjacent sweep sequences of each channel radar signal is modulated. Each channel radar signal adds a phase difference to the original chirp signal's phase difference (i.e., adds a phase difference). Signal multiplexing can be performed using time-division multiplexing to transmit the phase-modulated multi-channel radar signals.

[0154] The receiving end uses the aforementioned parallel interference cancellation method for radar to cancel interference in the received radar signal.

[0155] The specific implementation of the receiving end in this application is basically the same as the embodiments of the parallel interference cancellation method for radar described above, and will not be repeated here.

[0156] Furthermore, this application also proposes a terminal device, which includes a memory, a processor, and a parallel interference cancellation program for radar stored in the memory and executable on the processor. When the parallel interference cancellation program for radar is executed by the processor, it implements the steps of the parallel interference cancellation method for radar as described above.

[0157] The specific implementation of the terminal device in this application is basically the same as the embodiments of the parallel interference cancellation method for radar described above, and will not be repeated here.

[0158] In addition, to achieve the above objectives, this application also provides a readable storage medium storing a parallel interference cancellation program for radar, which, when executed by a processor, implements the steps of the parallel interference cancellation method for radar as described above.

[0159] The specific implementation of the readable storage medium in this application is basically the same as the embodiments of the parallel interference cancellation method for radar described above, and will not be repeated here.

[0160] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or radar that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or radar. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or radar that includes that element.

[0161] The sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0162] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above, and includes several instructions to cause a terminal device (which may be a mobile phone, computer, server, air conditioner, or network device, etc.) to execute the methods described in the various embodiments of this application.

[0163] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A method for canceling parallel interference in radar, characterized in that, The parallel interference is inter-radar interference, which occurs when the frequency slope of the radar's transmitted signal is the same as the frequency slope of the interference signal from other radars. The radar mixes the interference signal with the received signal to generate ghost objects. The parallel interference cancellation method for the radar includes the following steps: The original radar signal is received and decomposed to obtain multiple channel radar signals. The channel radar signals include at least a first channel radar signal and a second channel radar signal, and the added phase difference between the first channel radar signal and the second channel radar signal is different. Determine the first motion matrix corresponding to the first channel radar signal, and determine the second motion matrix corresponding to the second channel radar signal; The intersection motion matrix is ​​calculated based on the first motion matrix and the second motion matrix, wherein the intersection motion matrix includes the intersection of the first motion matrix and the second motion matrix; The intersection motion matrix is ​​output as the interference cancellation result to identify the motion trajectory of the real object based on the intersection motion matrix; The step of decomposing the original radar signal to obtain decomposed multi-channel radar signals includes: The radar signal multiplexing method for obtaining the original radar signal; If the radar signal multiplexing method includes time-division multiplexing, the original radar signal is decomposed based on the time domain to obtain multiple channels of radar signal after decomposition.

2. The parallel interference cancellation method for radar as described in claim 1, characterized in that, The steps of determining the first motion matrix corresponding to the first channel radar signal and determining the second motion matrix corresponding to the second channel radar signal include: The first channel radar signal is phase-calibrated to obtain the calibrated first channel radar signal; The second channel radar signal is phase-calibrated to obtain the calibrated second channel radar signal. Obtain the type of parallel radar interference to be eliminated in the original radar signal; If the type of parallel radar interference to be eliminated includes unstable interference, perform a Fourier transform on the calibrated first channel radar signal to obtain the transformed first range matrix. Perform a Fourier transform on the calibrated second-channel radar signal to obtain the transformed second range matrix; The first distance matrix is ​​used as the first motion matrix corresponding to the first channel radar signal, and the second distance matrix is ​​used as the second motion matrix corresponding to the second channel radar signal.

3. The parallel interference cancellation method for radar as described in claim 1, characterized in that, The step of calculating the intersection motion matrix based on the first motion matrix and the second motion matrix includes: The difference between the first motion matrix and the second motion matrix is ​​calculated to obtain the difference matrix. The difference matrix is ​​used to detect whether an object exists based on a preset algorithm, which includes a continuous false alarm rate algorithm. If the detection result of the preset algorithm is that an object exists, then the intersection motion matrix is ​​calculated based on the difference matrix, the first motion matrix, and the second motion matrix.

4. The parallel interference cancellation method for radar as described in claim 3, characterized in that, The step of calculating the intersection motion matrix based on the difference matrix, the first motion matrix, and the second motion matrix includes: Copy the first motion matrix to obtain a first initial motion matrix, and copy the second motion matrix to obtain a second initial motion matrix; Iterate through each element of the difference matrix in sequence and check whether the value of the traversed element is greater than a preset threshold. If the value of the element being iterated is greater than a preset threshold, determine the position of the element being iterated. Determine a first motion value at the element position in the first motion matrix, and determine a second motion value at the element position in the second motion matrix; The minimum value between the first motion value and the second motion value is determined. The element value at the element position in the first initial motion matrix is ​​set to be the same as the minimum value. The element value at the element position in the second initial motion matrix is ​​set to be the same as the minimum value. This process continues until all elements in the difference matrix have been traversed, resulting in the processed first initial motion matrix and the processed second initial motion matrix. The intersection operation is performed on the processed first initial motion matrix and the processed second initial motion matrix to obtain the intersection motion matrix.

5. The parallel interference cancellation method for radar as described in claim 4, characterized in that, After the step of obtaining the type of parallel radar interference to be eliminated in the original radar signal, the method further includes: If the type of parallel radar interference to be eliminated includes stable interference, perform a Fourier transform on the processed first initial motion matrix to obtain the first velocity matrix. The processed second initial motion matrix is ​​subjected to Fourier transform to obtain the second velocity matrix; The first velocity matrix is ​​used as the first motion matrix corresponding to the first channel radar signal, and the second velocity matrix is ​​used as the second motion matrix corresponding to the second channel radar signal. The step of calculating the intersection motion matrix based on the first motion matrix and the second motion matrix is ​​then performed.

6. The parallel interference cancellation method for radar as described in claim 2, characterized in that, The step of performing phase calibration on the first channel radar signal to obtain the calibrated first channel radar signal includes: The first added phase difference of the radar signal of the first channel is obtained, and the first added phase difference is input into the preset phase calibration sequence generation model so that the preset calibration sequence generation model can output the first phase calibration sequence. The first channel radar signal is phase-calibrated using the first phase calibration sequence to obtain the calibrated first channel radar signal.

7. A radar, comprising a receiver and a transmitter, wherein the transmitter is used to perform phase modulation on multi-channel radar signals, and transmits the multi-channel phase-modulated radar signals as the original radar signal based on signal multiplexing, wherein... Each of the aforementioned channel radar signals corresponds to an added phase difference; The receiving end uses the parallel interference cancellation method of radar as described in any one of claims 1 to 6 to perform parallel interference cancellation on the received radar signal.

8. A terminal device, characterized in that, The terminal device includes: a memory, a processor, and a parallel interference cancellation program for radar stored in the memory and executable on the processor. When the parallel interference cancellation program for radar is executed by the processor, it implements the steps of the parallel interference cancellation method for radar as described in any one of claims 1 to 6.

9. A readable storage medium, characterized in that, The readable storage medium stores a parallel interference cancellation program for the radar, which, when executed by a processor, implements the steps of the parallel interference cancellation method for the radar as described in any one of claims 1 to 6.

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