Multi-channel pulsed doppler signal receiving method, apparatus, device and medium

Abstract

This invention discloses a method, apparatus, device, and medium for receiving multi-channel pulse Doppler signals. The method first performs channelization processing based on polyphase filtering on the received signals of each receiving channel. Then, it performs sliding cross-correlation accumulation processing on each channel. Next, it extracts the results of the sliding cross-correlation accumulation processing, further performs FFT processing on the extracted results, and performs signal detection based on the FFT results. Based on the detection results, the pulse repetition frequency parameter of the PD signal is estimated. This invention belongs to the field of signal reception and processing, and can improve the detection sensitivity of PD signals while saving processing resources.

Description

Technical Field

[0001] This invention belongs to the field of signal receiving and processing technology, and particularly relates to a method, apparatus, device and medium for receiving multi-channel pulse Doppler signals. Background Technology

[0002] Pulse Doppler (PD) radar is the main radar system used in modern airborne radar and is also an important processing target for current spectrum sensing. Improving the sensitivity of PD signals is of great significance.

[0003] Regarding the sensitivity of PD signals, traditional digital channelization processing is limited by the limited processing resources, making it difficult to achieve long-term accumulation, thus resulting in very limited sensitivity. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art by providing a multi-channel pulse Doppler signal receiving method, apparatus, device, and medium. The method involves performing channelization processing based on polyphase filtering on the received signals of each receiving channel, then performing sliding cross-correlation accumulation processing on each channel, and finally extracting the results of the sliding cross-correlation accumulation processing to reduce computational load. Furthermore, the extracted results are subjected to FFT processing, and signal detection is performed based on the FFT processing results, thereby improving the detection sensitivity of the PD signal.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] A multi-channel pulse Doppler signal receiving method, the method comprising:

[0007] The intermediate frequency signal of each independent receiving channel is channelized separately to obtain the channelization result of each channel, including the channel number and time sampling point;

[0008] The channelization results are accumulated by sliding cross-correlation to obtain the weighted cross-correlation processing result;

[0009] Reduce the data rate of the weighted cross-correlation processing results;

[0010] The cross-correlation spectrum of each channel is obtained by performing a fast Fourier transform on the weighted cross-correlation processing results after reducing the data rate.

[0011] The amplitude of the cross-correlation spectrum is taken and a maximum threshold detection is performed. The time sampling points corresponding to all maximum values ​​that are greater than the detection threshold are recorded.

[0012] The pulse repetition frequency of the pulse Doppler signal is estimated based on the time sampling points corresponding to the maximum values ​​greater than the detection threshold.

[0013] Furthermore, the sliding cross-correlation accumulation of the channelization result includes:

[0014]

[0015] Where s1(m,n) and s2(m,n) are the channelization results, n is the time sampling point after channelization processing, m represents the channel number, R(m,n) is the weighted cross-correlation processing result, * represents conjugate, and N is the length of coherent accumulation.

[0016] Furthermore, reducing the data rate of the weighted cross-correlation processing result includes:

[0017] The data rate is reduced by N-point extraction of the weighted cross-correlation results.

[0018] Furthermore, the reduction of the data rate specifically includes:

[0019] Reduce the data rate to f s The sampling rate for each channel.

[0020] Furthermore, the number of points processed by the Fast Fourier Transform is M, and the cross-correlation spectrum resolution unit is... Accumulation time is

[0021] Furthermore, the formula for determining the maximum value includes:

[0022]

[0023] Where |Spec(m,n1)| is the maximum value, and |Spec(m,n)| is the amplitude of the cross-correlation spectrum.

[0024] Furthermore, estimating the pulse repetition frequency of the pulse Doppler signal based on the time sampling points corresponding to the maximum values ​​greater than the detection threshold specifically includes:

[0025] Find the difference between adjacent time sampling points corresponding to the maxima that are greater than the detection threshold. The minimum value is the corresponding pulse repetition frequency. The calculation formula is:

[0026]

[0027] Here, min() means taking the minimum value, diff() means the difference operation between adjacent values, and NN is the number of maxima greater than the detection threshold.

[0028] On the other hand, the present invention also provides a multi-channel pulse Doppler signal receiving device, the device comprising:

[0029] The channelization processing module performs channelization processing on the intermediate frequency signal of each independent receiving channel to obtain the channelization result of each channel, including the channel number and time sampling point.

[0030] A cross-correlation accumulation module performs sliding cross-correlation accumulation on the channelization result to obtain a weighted cross-correlation processing result.

[0031] A data rate reduction module reduces the data rate of the weighted cross-correlation processing result.

[0032] The cross-correlation spectrum calculation module performs a fast Fourier transform on the weighted cross-correlation processing result after reducing the data rate to obtain the cross-correlation spectrum of each channel.

[0033] The maximum value detection module takes the amplitude of the cross-correlation spectrum and performs maximum value threshold detection, and records the time sampling points corresponding to all maximum values ​​that are greater than the detection threshold.

[0034] The pulse repetition frequency calculation module estimates the pulse repetition frequency of the pulse Doppler signal based on the time sampling points corresponding to the maximum values ​​greater than the detection threshold.

[0035] On the other hand, the present invention also provides a computer device, which includes a processor and a memory, wherein the memory stores a computer program, which is loaded and executed by the processor to implement the above-described arbitrary multi-channel pulse Doppler signal receiving method.

[0036] On the other hand, the present invention also provides a computer-readable storage medium storing a computer program, which is loaded and executed by a processor to implement the above-described arbitrary multi-channel pulse Doppler signal receiving method.

[0037] The beneficial effects of this invention are as follows:

[0038] This invention proposes a method for receiving weak PD signals in multiple channels based on channelized multi-pulse accumulation. First, the received signals of each receiving channel are processed by channelization based on polyphase filtering. Then, sliding cross-correlation accumulation is performed on each channel. The result of the sliding cross-correlation accumulation is then extracted to reduce the amount of computation and save processing resources. Furthermore, the extracted result is processed by FFT, and signal detection is performed based on the FFT result to improve the detection sensitivity of the PD signal. Finally, the pulse repetition frequency parameter of the PD signal is estimated based on the detection result. Attached Figure Description

[0039] Figure 1This is a schematic flowchart of the multi-channel pulse Doppler signal receiving method according to an embodiment of the present invention;

[0040] Figure 2 This is a structural block diagram of the multi-channel pulse Doppler signal receiving device according to an embodiment of the present invention. Detailed Implementation

[0041] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, unless otherwise specified, the following embodiments and features described therein can be combined with each other.

[0042] Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0043] Regarding the sensitivity of PD signals, traditional digital channelization processing is limited by the limited processing resources, making it difficult to achieve long-term accumulation, thus resulting in very limited sensitivity.

[0044] To address the aforementioned technical problems, the following embodiments of the multi-channel pulse Doppler signal receiving method, apparatus, device, and medium of the present invention are proposed.

[0045] Example 1

[0046] Reference Figure 1 ,like Figure 1 The diagram shown is a flowchart of the multi-channel pulse Doppler signal receiving method of this embodiment. The method specifically includes the following steps:

[0047] Step 1: Channelize the intermediate frequency signals from the two independent receiving channels respectively, assuming the results are s1(m,n) and s2(m,n), where m represents the channel number, and m = 1, 2, ..., M (M is the total number of channels), and n is the time sampling point after channelization, which is a positive integer. It is also assumed that the sampling rate of each channel is f. s =50MHz.

[0048] Step 2: Apply cross-correlation accumulation to the channelization results s1(m,n) and s2(m,n) of the two channels to obtain the weighted cross-correlation result R(m,n). The specific calculation formula is as follows:

[0049]

[0050] Where N = 16 is the length of the coherent accumulation.

[0051] Step 3: Extract N=16 points from R(m,n) to obtain R. * (m,n), thereby reducing the data rate of subsequent processing, the corresponding data rate is (m,n).

[0052] Step 4: For R * Each channel in (m,n) is processed by FFT to obtain the autocorrelation spectrum Spec(m,n) of each channel, thus accumulating the long-term energy of multiple pulses. Assuming the number of FFT points is M = 4096, the resolution unit of the autocorrelation spectrum is 762.94 Hz, and the accumulation time is 1.31 ms.

[0053] Step 5: Obtain |Spec(m,n)| by taking the amplitude of Spec(m,n), and perform extreme value threshold detection on |Spec(m,n)|. First, find the extreme value of |Spec(m,n)|. The specific judgment condition formula is: |Spec(m,n1)|≥|Spec(m,n1-1)|&|Spec(m,n1)|>|Spec(m,n1+1)|, then |Spec(m,n1)| is a maximum value. Assuming the detection threshold for the m-th channel is Thres(m), then determine whether |Spec(m,n1)| is greater than the detection threshold. If it is greater, then buffer n1. If multiple maxima are greater than the detection threshold, record them as n11, n12, ..., n1 respectively. NN , where NN represents the maximum number of caches.

[0054] Step 6: Based on n11, n12, ..., n1 NN Estimate the PRF (Pulse Repetition Frequency) of the PD signal and find n11, n12, ..., n1 NN The minimum difference between adjacent values ​​is the corresponding PRF. Combining this with the autocorrelation spectrum resolution unit from step 4 above, we get PRF = min[diff(n11,n12,…,n1…]. NN )]=762.94Hz. Where diff(·) represents the difference operation between adjacent values, and min(·) represents taking the minimum value.

[0055] This embodiment proposes a method for receiving weak PD signals in multiple channels based on channelized multi-pulse accumulation. First, the received signals of each receiving channel are processed by channelization based on polyphase filtering. Then, sliding cross-correlation accumulation is performed on each channel. The result of the sliding cross-correlation accumulation is then extracted to reduce the amount of computation and save processing resources. Furthermore, the extracted result is processed by FFT, and signal detection is performed based on the result of FFT, thereby improving the detection sensitivity of PD signals. Finally, the pulse repetition frequency parameter of the PD signal is estimated based on the detection result.

[0056] Example 2

[0057] Reference Figure 2 ,like Figure 2 The diagram shown is a structural block diagram of the multi-channel pulse Doppler signal receiving device of this embodiment. The device specifically includes the following structures:

[0058] The channelization processing module performs channelization processing on the intermediate frequency signal of each independent receiving channel to obtain the channelization result of each channel, including the channel number and time sampling point.

[0059] A cross-correlation accumulation module performs sliding cross-correlation accumulation on the channelization result to obtain a weighted cross-correlation processing result.

[0060] A data rate reduction module reduces the data rate of the weighted cross-correlation processing result.

[0061] The cross-correlation spectrum calculation module performs a fast Fourier transform on the weighted cross-correlation processing result after reducing the data rate to obtain the cross-correlation spectrum of each channel.

[0062] The maximum value detection module takes the amplitude of the cross-correlation spectrum and performs maximum value threshold detection, and records the time sampling points corresponding to all maximum values ​​that are greater than the detection threshold.

[0063] The pulse repetition frequency calculation module estimates the pulse repetition frequency of the pulse Doppler signal based on the time sampling points corresponding to the maximum values ​​greater than the detection threshold.

[0064] Example 3

[0065] This preferred embodiment provides a computer device that can implement the steps of any embodiment of the multi-channel pulse Doppler signal receiving method provided in this application. Therefore, it can achieve the beneficial effects of the multi-channel pulse Doppler signal receiving method provided in this application. For details, please refer to the previous embodiments, which will not be repeated here.

[0066] Example 4

[0067] Those skilled in the art will understand that all or part of the steps in the various methods of the above embodiments can be implemented by instructions, or by instructions controlling related hardware. These instructions can be stored in a computer-readable storage medium and loaded and executed by a processor. Therefore, embodiments of the present invention provide a storage medium storing multiple instructions that can be loaded by a processor to execute the steps of any embodiment of the multi-channel pulse Doppler signal receiving method provided by the present invention.

[0068] The storage medium may include: read-only memory (ROM), random access memory (RAM), disk or optical disk, etc.

[0069] Since the instructions stored in the storage medium can execute the steps in any of the multi-channel pulse Doppler signal receiving method embodiments provided in this invention, the beneficial effects that any of the multi-channel pulse Doppler signal receiving methods provided in this invention can achieve can be realized. For details, please refer to the previous embodiments, which will not be repeated here.

[0070] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method of receiving a multi-channel pulsed Doppler signal, characterized by, The method includes: The intermediate frequency signal of each independent receiving channel is channelized separately to obtain the channelization result of each channel, including the channel number and time sampling point; The channelization results are accumulated by sliding cross-correlation to obtain the weighted cross-correlation processing result; The step of performing sliding cross-correlation accumulation on the channelization result includes: ； wherein, and is a channelization result, n is a time sampling point after channelization processing, m denotes a channel number, is a weighted cross-correlation processing result, denotes a conjugate, and N is a length of coherent accumulation; Reduce the data rate of the weighted cross-correlation processing results; The cross-correlation spectrum of each channel is obtained by performing a fast Fourier transform on the weighted cross-correlation processing results after reducing the data rate. The amplitude of the cross-correlation spectrum is taken and a maximum threshold detection is performed. The time sampling points corresponding to all maximum values ​​that are greater than the detection threshold are recorded. Find the difference between adjacent time sampling points corresponding to the maxima that are greater than the detection threshold. The minimum value is the corresponding pulse repetition frequency. The calculation formula is: ； Where min() means taking the minimum value, diff() means the difference operation between adjacent values, NN is the number of maxima greater than the detection threshold, M is the number of points processed by FFT, and N is the length of coherent accumulation.

2. The method of claim 1, wherein, The reduction of the data rate of the weighted cross-correlation processing result includes: The data rate is reduced by N-point extraction of the weighted cross-correlation results.

3. The method of claim 2, wherein the plurality of channels are determined by a plurality of pulse Doppler signals received from a plurality of transducers. The reduction of data rate specifically includes: reducing the data rate , is the sampling rate for each channel.

4. The multi-channel pulse Doppler signal receiving method as described in claim 3, characterized in that, The fast Fourier transform process has M points, and the cross-correlation spectrum resolution unit is... Accumulated time is .

5. The multi-channel pulse Doppler signal receiving method as described in claim 4, characterized in that, The formula for determining the maximum value includes: ； in, It is the maximum value. This represents the amplitude of the cross-correlation spectrum.

6. A multi-channel pulse Doppler signal receiving device, characterized in that, The apparatus is used to implement the method according to any one of claims 1-5, the apparatus comprising: The channelization processing module performs channelization processing on the intermediate frequency signal of each independent receiving channel to obtain the channelization result of each channel, including the channel number and time sampling point. A cross-correlation accumulation module performs sliding cross-correlation accumulation on the channelization result to obtain a weighted cross-correlation processing result. The step of performing sliding cross-correlation accumulation on the channelization result includes: ； in, and The result is the channelization output, where n represents the time sampling points after channelization. m Indicates the channel number. The result is a weighted cross-correlation processing result. This indicates conjugation, where N is the length of the coherent accumulation. A data rate reduction module reduces the data rate of the weighted cross-correlation processing result. The cross-correlation spectrum calculation module performs a fast Fourier transform on the weighted cross-correlation processing result after reducing the data rate to obtain the cross-correlation spectrum of each channel. The maximum value detection module takes the amplitude of the cross-correlation spectrum and performs maximum value threshold detection, and records the time sampling points corresponding to all maximum values ​​that are greater than the detection threshold. The pulse repetition frequency calculation module finds the difference between adjacent time sampling points corresponding to the maximum values ​​greater than the detection threshold, and the minimum value is the corresponding pulse repetition frequency. The calculation formula is as follows: ； Where min() means taking the minimum value, diff() means the difference operation between adjacent values, NN is the number of maxima greater than the detection threshold, M is the number of points processed by FFT, and N is the length of coherent accumulation.

7. A computer device, characterized in that, The computer device includes a processor and a memory, the memory storing a computer program, which is loaded and executed by the processor to implement the multi-channel pulse Doppler signal receiving method as described in any one of claims 1-5.

8. A computer-readable storage medium, characterized in that, The storage medium stores a computer program, which is loaded and executed by a processor to implement the multi-channel pulse Doppler signal receiving method as described in any one of claims 1-5.

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