A channel separation method, terminal and medium based on frequency accumulation

Abstract

The present application discloses a channel separation method, terminal and medium based on frequency accumulation, the method comprising the following steps: performing non-coherent accumulation on radar echo sampling signals, and performing secondary frequency accumulation on the basis of the non-coherent accumulation; performing target detection according to the result of the secondary frequency accumulation to obtain the detection result; extracting the corresponding data of the non-coherent accumulation according to the detection result; calculating the mean of the obtained data as the detection threshold, performing threshold detection on the obtained data, and taking the first data higher than the detection threshold as the result of the first transmitting antenna to realize channel separation. The advantage of the present application is that the channel separation of radar signals is realized by a simple algorithm, which is easy to realize and has good timeliness, and lays the foundation for the subsequent velocity deambiguation, Doppler phase compensation and target angle measurement.

Description

Technical Field

[0001] The present application relates to the field of radar technology, and in particular to a channel separation method, terminal and medium based on frequency accumulation. Background Art

[0002] Compared with traditional infrared, laser, ultrasonic and other sensors, millimeter-wave radar is less affected by the environment and has high resolution in ranging, speed and angle measurement. It has unique use value and broad application prospects in target detection.

[0003] The main purpose of using MIMO technology in automotive millimeter-wave radar is to increase virtual channels in order to use fewer transmitting and receiving antennas to achieve a larger antenna aperture, thereby obtaining higher angular resolution.

[0004] There are many MIMO transmission modes, currently mainly including TDMA (Time Division Multiple Access) and DDMA (Doppler Diversity multiple access).

[0005] The advantage of TDMA transmission is that channel separation is very simple and easy to implement at the chip level. However, its disadvantages are also obvious, and as the number of transmitting antennas increases, these disadvantages will be multiplied and even lose their usability. They mainly include the following aspects:

[0006] 1. The transmission resources are not fully utilized. 2. The memory resources required by the backend are proportional to the transmitting antenna. 3. The reduction of PRF leads to a decrease in the maximum unambiguous speed measurement range. 4. Phase compensation is required before angle measurement.

[0007] Many factors make TDMA difficult to apply in 4D millimeter-wave radar.

[0008] The advantages of DDMA transmission mode mainly include the following aspects:

[0009] 1. Compared with TDMA, it utilizes all transmission resources and improves transmission gain; 2. The hardware requirements for its transmission are low (only one frequency source and a phase shifter are required at the transmitting end); 3. The channel separation method is simple.

[0010] In the millimeter wave radar signal processing module, the Doppler multiple access transmission method is often used. Since the transmitting antennas transmit at the same time, the amount of data storage can be greatly reduced, and the hardware requirements for its transmission are low; therefore, this transmission method is more favored by 4D millimeter wave radars, but one of the important difficulties is that the transmitting antennas transmit at the same time, so the channels need to be separated. In the prior art, most of the methods for channel separation of radar signals have a large amount of calculation and poor timeliness. For example, in the patent with publication number CN114624694A, it is proposed to use multiple combinations between sub-bands for target detection, thereby separating the channels, which has a large amount of calculation and poor timeliness. Summary of the invention

[0011] The present application provides a channel separation method, terminal and medium based on frequency accumulation, which has the advantage of realizing channel separation of radar signals through a simple algorithm, which is easy to implement and has good timeliness, and lays the foundation for subsequent velocity deambiguation, Doppler phase compensation and target angle measurement.

[0012] The technical solution of this application is as follows:

[0013] On the one hand, the present application provides a channel separation method based on frequency accumulation detection, comprising the following steps:

[0014] Step 1: Perform non-coherent accumulation on the radar echo sampling signal after two-dimensional fast Fourier transform, and perform secondary frequency accumulation based on the non-coherent accumulation;

[0015] Step 2: Perform target detection based on the result of frequency secondary accumulation to obtain the detection result;

[0016] Step 3: extracting non-coherent accumulation corresponding data according to the detection results in step 2;

[0017] Step 4: Calculate the mean of the data obtained in step 3 as the detection threshold, perform threshold detection on the data obtained in step 3, and use the first data above the detection threshold as the result of the first transmitting antenna to achieve channel separation.

[0018] Furthermore, in step 1, the radar echo sampling signal is transformed into the data after the distance fast Fourier transform FFT and the velocity fast Fourier transform FFT: , the data dimension is ,in N Indicates the number of antenna receiving channels. L Indicates the number of distance FFT points, M Indicates the number of Doppler FFT points; non-coherent accumulation data is , the data dimension is ; The result of the secondary frequency accumulation is , the data dimension is , , , Indicates rounding up. J is the number of transmitting antennas, K represents the exponential power of 2 that is greater than and closest to it, P Indicates the Doppler length after frequency integration.

[0019] Furthermore, in step 2, the number of range gates and Doppler gates of the detection results are recorded as .

[0020] Furthermore, in step 3, the corresponding data of non-coherent accumulation is extracted according to the detection results in step 2 and recorded as :

[0021] .

[0022] Furthermore, in step 4, the mean of the data obtained in step 3 is calculated as the detection threshold :

[0023] ;

[0024] right Perform threshold detection. If it is greater than , marked as 1; otherwise marked as 0; the threshold detection result is recorded as :

[0025] ;

[0026] Will The position of the first 1 mark after consecutive 0 marks in is recorded as the result of the first transmitting antenna.

[0027] On the other hand, the present application provides a radar signal processing terminal, including a processor and a memory, wherein the memory stores a computer program, and when the computer program is called and executed by the processor, the channel separation method based on frequency accumulation detection as described above is implemented.

[0028] On the other hand, the present application provides a computer-readable medium, in which a computer program is stored. When the computer program is called and executed by a computer, the channel separation method based on frequency accumulation detection as described above is implemented.

[0029] In summary, the beneficial effects of the present application are as follows: utilizing the Doppler multiple access MIMO transmission mechanism, performing secondary frequency accumulation on the basis of non-coherent accumulation, and then performing target detection, which can greatly reduce the amount of detection calculations; extracting the corresponding data of the non-coherent accumulation according to the detection results, using the extracted data mean as the detection threshold, performing secondary detection, thereby separating the channel distance corresponding to the first transmitting antenna and realizing channel separation. The algorithm is simple and easy to implement, laying the foundation for subsequent velocity deambiguation, Doppler phase compensation and target angle measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is the principle diagram of Doppler multiple access;

[0031] Figure 2 is a schematic diagram of the non-coherent accumulation result of radar signals in a specific embodiment of the present application;

[0032] Figure 3 is a schematic diagram of radar signal frequency accumulation results in a specific embodiment of the present application;

[0033] Figure 4 is a schematic diagram of a threshold detection result in a specific embodiment of the present application;

[0034] Figure 5 It is a schematic diagram of channel separation results in a specific embodiment of the present application. DETAILED DESCRIPTION

[0035] The specific implementation of the present application is described in detail below with reference to the accompanying drawings.

[0036] A specific embodiment of the present application provides a channel separation method based on frequency accumulation detection, comprising the following steps:

[0037] Step 1: Perform non-coherent accumulation on the radar echo sampling signal after two-dimensional fast Fourier transform, and perform secondary frequency accumulation based on the non-coherent accumulation.

[0038] First, using the MIMO transmission mechanism of Doppler multiple access, under the condition of Doppler multiple access transmission, the transmitting antennas can transmit signals simultaneously. The frequency offset on different transmitting antennas is achieved by applying different phase rotations between chirps, while the phase of the signal within the chirp remains unchanged.

[0039] like Figure 1 As shown, assuming that there are a total of J transmit antennas, then for the transmit antenna j , the phase shift applied in adjacent chirps Determined by the following formula:

[0040]

[0041] in, , Indicates rounding up. K Indicates greater than J and closest to J The exponential power of 2.

[0042] The radar echo sampling signal is transformed by the distance fast Fourier transform (FFT) and the velocity fast Fourier transform (FFT) to obtain the data: , the data dimension is ,in N Indicates the number of antenna receiving channels. L Indicates the number of distance FFT points, M Indicates the number of Doppler FFT points; non-coherent accumulation data is , the data dimension is ; The result of the secondary frequency accumulation is , the data dimension is , , which represents the Doppler length after frequency accumulation.

[0043] Step 2: Target detection is performed based on the result of the secondary frequency accumulation to obtain the detection result; the detection result can be one or more. The number of range gates and Doppler gates of the detection result is recorded as .

[0044] Step 3: Extract the corresponding data of non-coherent accumulation according to the detection results in step 2 and record it as :

[0045] .

[0046] Step 4: Calculate the mean of the data obtained in step 3 as the detection threshold :

[0047] ;

[0048] Perform threshold detection on the data obtained in step 3, and use the first data above the detection threshold as the result of the first transmitting antenna to achieve channel separation. Specifically,

[0049] right Perform threshold detection. If it is greater than , marked as 1; otherwise marked as 0; the threshold detection result is recorded as :

[0050] ;

[0051] Will The position of the first 1 mark after consecutive 0 marks in is recorded as the result of the first transmitting antenna.

[0052] This method can effectively realize channel separation and lay the foundation for signal processing processes such as target speed measurement and angle measurement.

[0053] The following is a detailed description of the steps of this method using a specific application scenario. In this scenario, there are 6 transmitting antennas, 8 receiving antennas, and the radar echo 2D FFT result is , the dimension is 8×512×128, that is, there are 8 receiving channels, the number of FFT points in the distance dimension is 512, and the number of points in the Doppler dimension is 128. Doppler multiple access The result of non-coherent accumulation is , the dimension is 512×128, the number of distance dimension points is 512, and the number of Doppler dimension points is 128. The result of the secondary frequency accumulation is , the dimension is 512×16, the number of FFT points in the distance dimension is 512, and the number of points in the Doppler dimension is 16.

[0054] The non-coherent accumulation results are as follows Figure 2 As shown, the result after frequency accumulation is as follows Figure 3 shown.

[0055] right Figure 3 The results are shown in the table below:

[0056] Table 1 Frequency accumulation test results

[0057] Distance Gate Doppler Gate Goal 1 136 1 Goal 2 211 3 Goal 3 301 16

[0058] Taking the first target as an example, the detection result is (136,1), and the algorithm is explained:

[0059] The range gate is 136, the Doppler gate is 1; the number of Doppler points is 128, which is divided into 8 parts, one part corresponds to 128 / 8 = 16;

[0060] Therefore, in the non-coherent results The extracted data is: .

[0061] The average amplitude of the eight points is used as the detection threshold for threshold detection. The result is as follows: Figure 4 As shown, it can be seen that the points of the 1st, 2nd, 5th, 6th, 7th and 8th channels are higher than the threshold, while the points of channels 3 and 4 are lower than the threshold. Channel 5 is used as the receiving data corresponding to the first transmitting antenna, thereby achieving channel separation.

[0062] The final separation results of the three target channels are as follows Figure 5 As shown, it can be seen that channel separation for all targets is achieved.

[0063] Another specific embodiment of the present application provides a radar signal processing terminal, including a processor and a memory, wherein the memory stores a computer program, and when the computer program is called and executed by the processor, the channel separation method based on frequency accumulation detection as described above is implemented.

[0064] Another specific embodiment of the present application provides a computer-readable medium, in which a computer program is stored. When the computer program is called and executed by a computer, the channel separation method based on frequency accumulation detection as described above is implemented.

[0065] The above is only a preferred implementation of the present application. It should be pointed out that a person skilled in the art can make several modifications and improvements without departing from the inventive concept of the present application, and these all fall within the scope of protection of the present application.

Claims

1. A channel separation method based on frequency accumulation detection, characterized in that: The following steps are involved: Step 1: Perform non-coherent accumulation on the radar echo sampling signal after two-dimensional fast Fourier transform, and perform secondary frequency accumulation based on the non-coherent accumulation; Step 2: Perform target detection based on the result of frequency secondary accumulation to obtain the detection result; Step 3: extracting non-coherent accumulation corresponding data according to the detection results in step 2; Step 4: Calculate the mean of the data obtained in step 3 as the detection threshold, perform threshold detection on the data obtained in step 3, and use the first data above the detection threshold as the result of the first transmitting antenna to achieve channel separation; In step 1, the radar echo sampling signal is transformed into the data after the range fast Fourier transform FFT and the velocity fast Fourier transform FFT. , the data dimension is ,in N Indicates the number of antenna receiving channels. L Indicates the number of distance FFT points, M Indicates the number of Doppler FFT points; The non-coherent accumulation data is , the data dimension is ; The result of the secondary frequency accumulation is , the data dimension is , , , Indicates rounding up. J is the number of transmitting antennas, K represents the exponential power of 2 that is greater than and closest to it, P It indicates the Doppler length after frequency accumulation; In step 2, the number of range gates and Doppler gates of the detection results are recorded as ; In step 3, the corresponding data of non-coherent accumulation is extracted according to the detection results in step 2 and recorded as : ； In step 4, the mean of the data obtained in step 3 is calculated as the detection threshold : ； right Perform threshold detection. If it is greater than , marked as 1; otherwise marked as 0; the threshold detection result is recorded as : ； Will The position of the first 1 mark after consecutive 0 marks in is recorded as the result of the first transmitting antenna.

2. A radar signal processing terminal, characterized in that: The invention comprises a processor and a memory, wherein the memory stores a computer program, and when the computer program is called and executed by the processor, the channel separation method based on frequency accumulation detection as claimed in claim 1 is implemented.

3. A computer-readable medium, characterized in that The computer readable medium stores a computer program, and when the computer program is called and executed by a computer, the channel separation method based on frequency accumulation detection as claimed in claim 1 is implemented.

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