A multi-user millimeter-wave radar anti-interference method based on waveform integrated design

Abstract

The present invention discloses a multi-user millimeter wave radar anti-interference method based on waveform integrated design, comprising: (1) each millimeter wave radar reads its own working parameters and compiles them into pilot information; (2) the pilot information is divided into first pilot information and second pilot information, and the first pilot information is superimposed on the millimeter wave radar signal through frequency division design and then transmitted; the second pilot information and the millimeter wave radar signal are respectively transmitted through beam division design; (3) the signals transmitted by other millimeter wave radars are received and the pilot information is separated; (4) a time-frequency diagram is obtained through short-time Fourier transform, and whether there is interference between the radars is determined according to the time-frequency diagram. If there is interference, the parameters of the waveform are optimized according to the cost function; (5) the working parameters of each millimeter wave radar are updated and new pilot information is generated with time T as a period, and steps (2)-(4) are repeated. The present invention improves the anti-interference capability of the millimeter wave radar system.

Description

Technical Field

[0001] The present invention relates to the technical field of radar anti-interference, and in particular to a multi-user millimeter wave radar anti-interference method based on waveform integrated design. Background Art

[0002] Millimeter-wave radar is less affected by the natural environment, can work all day and all weather, and has a moderate detection distance. Therefore, millimeter-wave radar technology is often used in autonomous driving to achieve functions such as front vehicle collision warning, lane change assistance, adaptive cruise control, and blind spot monitoring. However, with the widespread use of 77GHz automotive millimeter-wave radars, the problem of mutual interference between radars has ensued.

[0003] The patent with application number "202111372757.X" discloses a method for multi-user anti-interference of the millimeter-wave radar, including: obtaining a waveform with pilot information emitted by the radar; judging whether there is interference between the radars according to the pilot information in the waveform; when there is interference, optimizing the parameters of the waveform according to the cost function to obtain the optimized waveform; each millimeter-wave radar broadcasts the pilot information with its own working parameters, and other nearby millimeter-wave radars avoid the same working parameters after receiving the pilot information, thus solving the problem of mutual interference between multiple millimeter-wave radars due to the same working parameters in autonomous driving and smart transportation. However, this method does not consider the problem of mutual interference between the pilot information and the millimeter-wave radar during the transmission process due to mixing in the waveform with pilot information emitted by the radar. Summary of the invention

[0004] Purpose of the invention: In view of the above shortcomings, the present invention discloses a multi-user millimeter-wave radar anti-interference method based on waveform integrated design, which transmits pilot information and millimeter-wave radar pulse signals through waveform integrated design, avoids mutual interference caused by mixing the pilot information and the millimeter-wave radar pulse signals, and improves the anti-interference problem of the millimeter-wave radar system.

[0005] Technical solution: To solve the above problems, the present invention provides a millimeter wave radar anti-interference method based on waveform integrated design, which specifically includes the following steps:

[0006] (1) Each millimeter-wave radar reads its own operating parameters and compiles the parameter information into pilot information; the pilot information of each millimeter-wave radar is encoded;

[0007] (2) Divide the pilot information encoded by each millimeter-wave radar into first pilot information and second pilot information, superimpose the first pilot information on the millimeter-wave radar signal through frequency division design and then transmit it out; and transmit the second pilot information and the millimeter-wave radar signal separately through beam division design;

[0008] The first pilot information includes radar ID, working bandwidth, and working frequency; the second pilot information includes radar ID, transmission frequency, modulation waveform pulse width, beam shape, gain, and scanning mode; the millimeter wave radar signal is a pulse signal generated by each millimeter wave radar itself;

[0009] (3) After each millimeter-wave radar receives the pilot information and millimeter-wave radar signals transmitted by other millimeter-wave radars, the pilot information received by each millimeter-wave radar is separated from the millimeter-wave radar signal by filtering;

[0010] (4) decoding the pilot information separated in step (3) respectively and then performing short-time Fourier transform respectively to obtain a time-frequency diagram of the separated pilot information; judging whether there is interference between each millimeter-wave radar itself and other millimeter-wave radars according to the working parameters contained in the time-frequency diagram; when interference exists, optimizing the parameters of the waveform of each millimeter-wave radar itself according to the cost function to obtain an optimized waveform;

[0011] (5) With time T as a period, update the operating parameters of each millimeter-wave radar and generate new pilot information, and repeat steps (2) to (4).

[0012] Furthermore, step (4) also includes data caching, MTD processing, amplitude calculation, non-coherent accumulation, and original point trace extraction for the millimeter-wave radar signal corresponding to each separated millimeter-wave radar. The distance measurement, angle measurement, and speed measurement are finally realized through the extracted data.

[0013] Furthermore, in step (4), the parameters of the waveform of each millimeter-wave radar are optimized according to the cost function, and the optimized waveform specifically includes:

[0014] The cost function formula is:

[0015] ,

[0016] ,

[0017] '

[0018] In the formula, It is the sum of the autocorrelation sidelobe energy of each millimeter-wave radar and the cross-correlation energy between different coded signals; is the weighting coefficient; For the transmitting unit; is the coded signal; is the radar pulse width; For coded signal The autocorrelation function of is a coded signal and The cross-correlation function of

[0019] A genetic algorithm is used to find the optimal millimeter-wave radar, and the cost function is used as the fitness of the genetic algorithm. When the cost function is less than the preset value, the optimization is terminated to obtain the optimal millimeter-wave radar. The waveform parameters of the system are adjusted based on the working parameters of the optimal millimeter-wave radar to obtain the optimized waveform.

[0020] Furthermore, the short-time Fourier transform formula in step (4) is:

[0021] ,

[0022] In the formula, For leading information; is the window function.

[0023] Furthermore, the filtering method in step (3) is Kalman filtering.

[0024] In addition, the present invention also provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of any of the above methods when executing the computer program. A computer-readable storage medium stores a computer program, wherein the computer program implements the steps of any of the above methods when executed by the processor.

[0025] Beneficial effects: Compared with the prior art, the multi-user millimeter-wave radar anti-interference method based on waveform integrated design provided by the present invention has the following advantages: 1. By combining the frequency division transmission of millimeter-wave radar pilot information with the beam division transmission of pilot information, the speed of information transmission and the channel capacity are greatly improved, while avoiding the mutual interference problem caused by mixing the pilot information with the millimeter-wave radar pulse signal; 2. The pilot information and the millimeter-wave radar pulse can share the same set of hardware facilities, which greatly saves hardware resources and space. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Shown is a flow chart of the method of the present invention.

[0027] Figure 2 Shown is the structure diagram of the transmitting and receiving modules after the radar and pilot information waveform are integrated according to the present invention.

[0028] Figure 3 Shown is a schematic diagram of the principle structure of the frequency division design for transmitting the pilot information in the method of the present invention.

[0029] Figure 4 The figure shows the principle structure diagram of transmitting pilot information by sub-beam in the method of the present invention.

[0030] Figure 5 The figure shows the flow chart of the leading information encoding and decoding according to the present invention. DETAILED DESCRIPTION

[0031] The technical solution of the present invention is further described below in conjunction with the accompanying drawings.

[0032] like Figure 1 The present invention provides a multi-user millimeter wave radar anti-interference method based on waveform integrated design, which specifically includes the following steps:

[0033] Step 1: Each millimeter-wave radar reads its own operating parameters, and compiles the operating parameters to form pilot information corresponding to each millimeter-wave radar.

[0034] Step 2: Figure 2 and Figure 5 As shown, information encoding and channel encoding are performed for the pilot information of each millimeter-wave radar, and then the encoded pilot information and the millimeter-wave radar signal are waveform-integrated and transmitted through the millimeter-wave radar transmitting antenna;

[0035] Specifically, the encoded pilot information of each millimeter-wave radar is divided into first pilot information and second pilot information. The first pilot information includes radar identity ID, working bandwidth, and working frequency; the second pilot information includes radar identity ID, transmission frequency, modulation waveform pulse width, beam shape, gain, and scanning mode.

[0036] like Figure 3 As shown, the first pilot information is directly superimposed on the millimeter-wave radar signal through a frequency division design; the superimposed millimeter-wave radar signal is transmitted to the millimeter-wave radar transmitter and then transmitted through the millimeter-wave radar antenna; the working frequency of the millimeter-wave radar signal after the frequency division design is higher, and the frequency of the pilot information is lower. Since the millimeter radar signal has undergone pulse compression, the time for transmitting the pilot information is limited. If the pilot information is transmitted only through the frequency division design, the pilot information will be incompletely transmitted. Therefore, the frequency division design is used to transmit the first pilot information, and the beam division design is used to transmit the second pilot information.

[0037] like Figure 4 As described above, the beam splitting transmission is to transmit the millimeter wave radar pulse signal and the second pilot information through different antennas of the millimeter wave radar antenna array.

[0038] Step 3: Figure 2 and Figure 3As shown, each millimeter-wave radar transmits its own pilot information and radar pulse signal through its own transmitting antenna array, while each millimeter-wave radar receives the signals transmitted by other millimeter-wave radars through its own receiving antenna array; after receiving the signals transmitted by other millimeter-wave radars, the pilot information corresponding to each millimeter-wave radar is separated from the millimeter-wave radar signal through Kalman filtering.

[0039] Step 4: Figure 1 and Figure 5 As shown, the separated pilot information is decoded according to the frequency modulation; the decoded pilot information is subjected to short-time Fourier transform (STFT) to obtain the time-frequency diagram corresponding to the pilot information of other millimeter-wave radars. The short-time Fourier transform formula is:

[0040] ,

[0041] In the formula, For leading information; is the window function, and the center of the window function is ; By continuously moving the window function to perform Fourier transform, we can eventually get the result of short-time Fourier transform.

[0042] According to the working parameters contained in the time-frequency diagram, it is judged whether there is interference between each millimeter-wave radar itself and other millimeter-wave radars; when interference exists, the parameters of the waveform of each millimeter-wave radar itself are optimized according to the cost function to obtain the optimized waveform.

[0043] Specifically, the principle of multi-user millimeter-wave radar optimization is that in order to prevent mutual interference between millimeter-wave radars, the signals of each millimeter-wave radar are required to be orthogonal to each other; therefore, the cross-correlation value between each millimeter-wave radar should be as small as possible, so the sum of the autocorrelation sidelobe energy of each millimeter-wave radar and the cross-correlation energy between different coded signals is used as the optimization cost function. The cost function formula is:

[0044] ,

[0045] ,

[0046] '

[0047] In the formula, It is the sum of the autocorrelation sidelobe energy of each millimeter-wave radar and the cross-correlation energy between different coded signals; is the weighting coefficient; For the transmitting unit; is the coded signal; is the radar pulse width; For coded signal The autocorrelation function of is a coded signal and The cross-correlation function of

[0048] For multi-user radar, the autocorrelation coefficient of the frequency coded signal The sidelobes need to be as low as possible, and the cross-correlation function It should also be as small as possible; the anti-interference of multi-user radar is a combination problem to find the best. The optimal millimeter-wave radar is found through genetic algorithm, and the cost function is used as the fitness of the genetic algorithm. When the cost function is less than the preset value, the optimization is terminated to obtain the optimal millimeter-wave radar. The parameters of its own waveform are adjusted and optimized based on the working parameters of the optimal millimeter-wave radar, so that the optimized waveform signal is orthogonal to the signal of the optimal millimeter-wave radar.

[0049] like Figure 1 As shown, while processing the separated pilot information, data caching, MTD processing, amplitude calculation, non-coherent accumulation, and original point trace extraction are performed on the separated millimeter-wave radar signal (radar reflection signal), thereby realizing distance measurement, angle measurement, speed measurement, etc. The reading of the pilot information and the processing of the radar reflection signal do not interfere with each other.

[0050] Step 5: After T ms, each millimeter-wave radar updates its own working parameters and regenerates pilot information, repeating steps 2 to 4. Each millimeter-wave radar periodically sends its own pilot information, receives the pilot information of other millimeter-wave radars, and optimizes its own waveform parameters, so that the multi-user millimeter-wave radar maintains the optimal state and improves work efficiency.

Claims

1. A multi-user millimeter wave radar anti-interference method based on waveform integrated design, characterized in that: The specific steps include: (1) Each millimeter-wave radar reads its own operating parameters and compiles the parameter information into pilot information; the pilot information of each millimeter-wave radar is encoded; (2) Divide the pilot information encoded by each millimeter-wave radar into first pilot information and second pilot information, superimpose the first pilot information on the millimeter-wave radar signal through frequency division design and then transmit it out; and transmit the second pilot information and the millimeter-wave radar signal separately through beam division design; The first pilot information includes radar ID, working bandwidth, and working frequency; the second pilot information includes radar ID, transmission frequency, modulation waveform pulse width, beam shape, gain, and scanning mode; the millimeter wave radar signal is a pulse signal generated by each millimeter wave radar itself; (3) After each millimeter-wave radar receives the pilot information and millimeter-wave radar signals transmitted by other millimeter-wave radars, the pilot information received by each millimeter-wave radar is separated from the millimeter-wave radar signal by filtering; (4) After decoding the pilot information separated in step (3), short-time Fourier transform is performed respectively to obtain a time-frequency diagram of the separated pilot information; judging whether there is interference between each millimeter-wave radar itself and other millimeter-wave radars according to the working parameters contained in the time-frequency diagram; when interference exists, optimizing the parameters of the waveform of each millimeter-wave radar itself according to the cost function, and obtaining the optimized waveform specifically includes: The cost function formula is: ， ， ‘ In the formula, It is the sum of the autocorrelation sidelobe energy of each millimeter-wave radar and the cross-correlation energy between different coded signals; is the weighting coefficient; For the transmitting unit; is the coded signal; is the radar pulse width; For coded signal The autocorrelation function of is a coded signal and The cross-correlation function of A genetic algorithm is used to find the optimal millimeter-wave radar, and the cost function is used as the fitness of the genetic algorithm. When the cost function is less than a preset value, the optimization is terminated to obtain the optimal millimeter-wave radar. The waveform parameters of the radar are adjusted based on the working parameters of the optimal millimeter-wave radar to obtain the optimized waveform. (5) With time T as a period, update the operating parameters of each millimeter-wave radar and generate new pilot information, and repeat steps (2) to (4).

2. The multi-user millimeter wave radar anti-interference method based on waveform integrated design according to claim 1 is characterized in that: Step (4) also includes data caching, MTD processing, amplitude calculation, non-coherent accumulation, and original point trace extraction for the separated millimeter wave radar signal.

3. The multi-user millimeter wave radar anti-interference method based on waveform integrated design according to claim 1 is characterized in that: The short-time Fourier transform formula in step (4) is: ， In the formula, For leading information; is the window function.

4. The multi-user millimeter wave radar anti-interference method based on waveform integrated design according to claim 1 is characterized in that: The filtering method in step (3) is Kalman filtering.

5. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of any one of the methods of claim 1 to claim 4 when executing the computer program.

6. A computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of the method according to any one of claims 1 to 4.

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