A digital dechirp implementation method, device and equipment

Abstract

The application relates to a digital Dechirp engineering implementation method, device and equipment. The method comprises the following steps: obtaining a radar echo signal, performing digital mixing on the radar echo signal and a reference signal to obtain a difference frequency signal sequence. The maximum bandwidth of the difference frequency signal sequence is used to determine a data decimation multiple of the difference frequency signal sequence, and an anti-aliasing low-pass filter is constructed by selecting an integer multiple of the data decimation multiple. The difference frequency signal sequence is segmented in layers according to the number of segments generated according to the data decimation multiple to obtain a layered segmented signal sequence. The layered segmented signal sequence is subjected to windowing recombination and FFT operation processing of the anti-aliasing low-pass filter to obtain an equivalent filtering sequence. The equivalent filtering sequence is decimated according to the order of the anti-aliasing low-pass filter and the data decimation multiple to obtain an equivalent filtering decimation sequence, and the equivalent filtering decimation sequence is recombined and subjected to FFT operation to generate a digital Dechirp processing sequence. The method can effectively reduce the hardware resource consumption of digital Dechirp in engineering implementation.

Description

Technical Field

[0001] This application relates to the field of radar signal processing technology, and in particular to a digital Decirp engineering implementation method, apparatus and equipment. Background Technology

[0002] With the deepening research into broadband and ultra-wideband radar, digital Decirp technology has emerged. In radar systems employing LFM signals, Decirp processing is widely used in time delay measurement, anti-jamming processing, parameter estimation, and broadband signal pulse compression, effectively reducing the signal sampling rate of radar receivers and the data rate of back-end signal processing. However, in broadband high-resolution radar, analog-domain Decirp processing methods introduce problems such as system distortion shifts, difficulty in generating high-precision, large-bandwidth linear frequency modulated reference signals, and the degradation of echo processing into non-coherent signals, thus limiting the performance and application of Decirp processing. Digital-domain Decirp processing methods perform difference frequency processing on the target echo signal directly sampled from the intermediate frequency and the digitized reference signal, followed by anti-aliasing low-pass filtering and data decimation to finally obtain the Decirp processing result.

[0003] The digital domain Decirp method effectively solves the problems existing in the analog domain Decirp and has been widely used. However, with large decimation factors, especially when the decimation factor cannot be decomposed into the product of two or more positive integers, the anti-aliasing low-pass filter for digital Decirp processing using data filtering will consume a lot of hardware resources, which will raise the threshold for the engineering application of digital Decirp. Summary of the Invention

[0004] Therefore, it is necessary to provide a digital Decirp engineering implementation method, apparatus, and equipment that can effectively reduce hardware resource consumption and improve radar signal processing efficiency to address the above-mentioned technical problems.

[0005] A method for implementing digital Decirp engineering, the method comprising:

[0006] The radar echo signal is acquired, and the radar echo signal is digitally mixed with the reference signal to obtain the difference frequency signal sequence.

[0007] The data decimation factor of the difference frequency signal sequence is determined based on the maximum bandwidth of the difference frequency signal sequence, and an anti-aliasing low-pass filter is constructed by selecting an integer multiple of the data decimation factor.

[0008] The difference frequency signal sequence is segmented by stacking based on the number of segments generated by the data extraction factor, resulting in a stacked segmented signal sequence.

[0009] The stacked segmented signal sequence is windowed and reassembled by an anti-aliasing low-pass filter and processed by FFT operation to obtain an equivalent filtered sequence.

[0010] The equivalent filter sequence is decimated based on the order of the anti-aliasing low-pass filter and the data decimation factor to obtain the equivalent filter decimation sequence. The equivalent filter decimation sequence is then reconstructed and subjected to FFT operation to generate the digital Decirp processing sequence.

[0011] In one embodiment, the method further includes: acquiring radar echo signals through a radar receiver, generating a reference signal based on radar transmitted waveform parameters, and digitally mixing the radar echo signals and the reference signal to obtain a difference frequency signal sequence.

[0012] In one embodiment, the method further includes: determining the data decimation factor D of the difference frequency signal sequence and the passband and stopband characteristics requirements of the anti-aliasing low-pass filter based on the maximum bandwidth of the difference frequency signal sequence; determining the order K-1 of the anti-aliasing low-pass filter by selecting an integer multiple of the data decimation factor D; and constructing the K-1 order anti-aliasing low-pass filter using the window function method.

[0013] In one embodiment, the method further includes: generating a number of segments based on the data extraction factor D and the length of the difference frequency signal sequence, and performing stacked segmentation on the difference frequency signal sequence to obtain stacked segmented subsequences. If the length of the last stacked segmented subsequence is greater than the length of the remaining data in the difference frequency signal sequence segment, the data portion of the stacked segmented subsequence exceeding the difference frequency signal sequence is padded with zeros. The stacked segmented subsequences are then reassembled to obtain a stacked segmented signal sequence.

[0014] In one embodiment, the method further includes: windowing and reassembling each subsequence of the stacked segmented signal sequence using an anti-aliasing low-pass filter to obtain a windowed reassembled data sequence. An equivalent filtered sequence is obtained by performing an FFT operation on the windowed reassembled data sequence based on the data decimation factor D.

[0015] In one embodiment, the method further includes: decimating the equivalent filter sequence according to the ratio of the anti-aliasing low-pass filter order K to the data decimation factor D, and combining the first value of each segment of the equivalent filter sequence to obtain an equivalent filter decimation sequence. The equivalent filter decimation sequence is then processed by FFT to obtain a digital Decirp processing sequence.

[0016] In one embodiment, the data sampling point N of the radar echo signal is an integer multiple of the data decimation factor D.

[0017] In one embodiment, the radar system uses Decirp intermediate frequency direct sampling to obtain the radar echo signal in the digital domain.

[0018] A digital Decirp engineering implementation apparatus, the apparatus comprising:

[0019] The difference frequency signal generation module is used to digitally mix the radar echo signal with the reference signal to obtain the difference frequency signal sequence.

[0020] The low-pass filter construction module is used to determine the data decimation factor of the difference frequency signal sequence based on the maximum bandwidth of the difference frequency signal sequence, and to construct an anti-aliasing low-pass filter by selecting an integer multiple of the data decimation factor.

[0021] The stacked segmentation module is used to stack and segment the difference frequency signal sequence according to the number of segments generated by the data extraction factor, so as to obtain a stacked segmented signal sequence.

[0022] The equivalent filtering module is used to process the stacked segmented signal sequence through windowing reconstruction and FFT operation using an anti-aliasing low-pass filter to obtain an equivalent filtered sequence.

[0023] The digital Decirp processing sequence generation module is used to extract the equivalent filter sequence according to the order of the anti-aliasing low-pass filter and the data decimation factor to obtain the equivalent filter decimation sequence, reassemble the equivalent filter decimation sequence and perform FFT operation to generate the digital Decirp processing sequence.

[0024] A computer device includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program performing the following steps:

[0025] The radar echo signal is acquired, and the radar echo signal is digitally mixed with the reference signal to obtain the difference frequency signal sequence.

[0026] The data decimation factor of the difference frequency signal sequence is determined based on the maximum bandwidth of the difference frequency signal sequence, and an anti-aliasing low-pass filter is constructed by selecting an integer multiple of the data decimation factor.

[0027] The difference frequency signal sequence is segmented by stacking based on the number of segments generated by the data extraction factor, resulting in a stacked segmented signal sequence.

[0028] The stacked segmented signal sequence is windowed and reassembled by an anti-aliasing low-pass filter and processed by FFT operation to obtain an equivalent filtered sequence.

[0029] The equivalent filter sequence is decimated based on the order of the anti-aliasing low-pass filter and the data decimation factor to obtain the equivalent filter decimation sequence. The equivalent filter decimation sequence is then reconstructed and subjected to FFT operation to generate the digital Decirp processing sequence.

[0030] The aforementioned digital Decirp engineering implementation method, apparatus, and equipment firstly generate a difference frequency signal sequence from the acquired radar echo signal through digital mixing. Based on the bandwidth of the difference frequency signal sequence, an appropriate data decimation factor is flexibly selected. Then, considering the passband and stopband characteristics of the low-pass filter, the order of the low-pass filter is determined. This is used to segment the difference frequency signal sequence, resulting in a stacked segmented signal sequence. Each segment of this sequence is then windowed, reassembled, and subjected to FFT operations. By adding a small number of addition operations, the passband and stopband performance of the radar filter can be improved. Finally, high-performance data filtering and decimation are achieved using a small number of FFT operations. This approach simplifies the data processing sequence, reduces the order of the anti-aliasing low-pass filter, increases the multiplexing rate of the low-pass filter, and thus reduces the hardware resource consumption for Decirp processing engineering implementation. Attached Figure Description

[0031] Figure 1 This is a flowchart illustrating a digital Decirp engineering implementation method in one embodiment;

[0032] Figure 2 This is a flowchart illustrating the data layering and segmentation process in one embodiment;

[0033] Figure 3 This is a flowchart illustrating the sequence stacking segmented FFT operation in one embodiment;

[0034] Figure 4 This is a schematic diagram of a one-dimensional range image processed by matched filtering and stacked piecewise FFT operations in one embodiment;

[0035] Figure 5 This is a structural block diagram of a digital Decirp engineering implementation device in one embodiment;

[0036] Figure 6 This is an internal structural diagram of a computer device in one embodiment. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0038] like Figure 1 As shown, this application provides a digital Decirp engineering implementation method, including the following steps:

[0039] Step 102: Acquire the radar echo signal, and digitally mix the radar echo signal with the reference signal to obtain the difference frequency signal sequence.

[0040] The radar system uses the Decirp intermediate frequency direct sampling method to obtain the radar intermediate frequency echo signal in the digital domain, which, after digital quadrature demodulation, is as follows:

[0041]

[0042] Where, x B (n) represents the baseband radar echo signal, T t f is the pulse duration. c Let be the center frequency, t be the time variable, and γ be the linear frequency modulation (LFM). Here, we assume the amplitude of the transmitted signal is 1. The distance from a target point to the radar is R. i c is the speed of light, and n is the number of digitized radar echo signal sampling points.

[0043] Specifically, the time width of the reference signal generated in the digital domain is consistent with the echo time width, while the frequency and frequency modulation are consistent with the radar echo signal x. B (n) Identical LFM signals, with a reference distance of R. ref The generated reference signal is then represented as:

[0044]

[0045] Where, x ref (n) is the reference signal, T r Let R be the time width of the receiving gate. Δ =R i -R ref The noise signal is denoted as N(n). Mixing the radar echo signal with the reference signal generates the following difference frequency signal sequence:

[0046]

[0047] Step 104: Determine the data decimation factor of the difference frequency signal sequence based on the maximum bandwidth of the difference frequency signal sequence, and construct an anti-aliasing low-pass filter by selecting an integer multiple of the data decimation factor.

[0048] Specifically, the data decimation factor D of the difference frequency signal sequence is determined based on the maximum bandwidth of the difference frequency signal sequence, so that the data sampling points N of the radar echo signal are integer multiples of the data decimation factor D. The passband and stopband characteristics of the anti-aliasing low-pass prototype filter are determined based on the data decimation factor D. A suitable filter order K-1 is further selected, so that K is an integer multiple of D. The K-1 order anti-aliasing low-pass filter is obtained by the window function method.

[0049] Step 106: Based on the number of segments generated by the data extraction multiple, the difference frequency signal sequence is stacked and segmented to obtain a stacked segmented signal sequence.

[0050] Specifically, based on the ratio I of the difference frequency signal sequence length N to the data decimation factor D, I = N / D is used as the number of segments in the difference frequency signal sequence. The difference frequency signal sequence is then stacked into segments to obtain stacked segmented subsequences. The length of each subsequence is equal to the order of the anti-aliasing low-pass filter. There is overlap between the data segments. The i-th data segment is x(iD+m), (m = 0, 1, ..., K-1). When the value of iD+m (i = 0, 1, ..., I-1; m = 0, 1, ..., K-1) exceeds the length N of the difference frequency signal sequence, the excess data is padded with zeros, and the stacked segmented subsequences are reconstructed to obtain the stacked segmented signal sequence.

[0051] Step 108: The stacked segmented signal sequence is processed by windowing and FFT operation of the anti-aliasing low-pass filter to obtain the equivalent filtered sequence.

[0052] Each segment of the stacked signal sequence is windowed using an anti-aliasing low-pass filter. The windowed data sequences are then recombined sequentially to obtain a windowed reconstructed data sequence. Finally, an FFT operation at point D is performed on the windowed reconstructed data sequence to obtain the equivalent wave sequence X for the i-th segment. i (k), (k = 0, 1, ..., D-1).

[0053] Step 110: Extract the equivalent filter sequence according to the order of the anti-aliasing low-pass filter and the data decimation factor to obtain the equivalent filter decimation sequence. Reassemble the equivalent filter decimation sequence and perform FFT operation to generate the digital Decirp processing sequence.

[0054] The equivalent filter sequence is decimated based on the ratio of the anti-aliasing low-pass filter order K to the data decimation factor D. The first value Xi(0), (i = 0, 1, ..., I-1) of each segment of the equivalent filter sequence is selected and combined to form the equivalent filter decimation sequence y(i), (i = 0, 1, ..., I-1). The equivalent filter decimation sequence is then processed by FFT to obtain the digital Decirp processed sequence. This method improves the passband and stopband performance of the radar low-pass filter by adding only a small number of addition operations without increasing the number of FFT operation points, thereby reducing the hardware resource overhead of digital Decirp processing.

[0055] The aforementioned digital Decirp engineering implementation method, apparatus, and equipment firstly generate a difference frequency signal sequence from the acquired radar echo signal through digital mixing. Based on the bandwidth of the difference frequency signal sequence, an appropriate data decimation factor is flexibly selected. Then, considering the passband and stopband characteristics of the low-pass filter, the order of the low-pass filter is determined. This is used to segment the difference frequency signal sequence, resulting in a stacked segmented signal sequence. Each segment of this sequence is then windowed, reassembled, and subjected to FFT operations. By adding a small number of addition operations, the passband and stopband performance of the radar filter can be improved. Finally, high-performance data filtering and decimation are achieved using a small number of FFT operations. This approach simplifies the data processing sequence, reduces the order of the anti-aliasing low-pass filter, increases the multiplexing rate of the low-pass filter, and thus reduces the hardware resource consumption for Decirp processing engineering implementation.

[0056] In one embodiment, a radar echo signal is acquired by a radar receiver, a reference signal is generated based on the radar transmitted waveform parameters, and the radar echo signal and the reference signal are digitally mixed to obtain a difference frequency signal sequence x(n).

[0057] In one embodiment, the data decimation factor D of the difference frequency signal sequence is determined based on the maximum bandwidth of the difference frequency signal sequence. An integer multiple of the data decimation factor D is selected to determine the order K-1 of the low-pass filter. The K-1 order low-pass filter is constructed using the window function method.

[0058] It is worth noting that h(m), (mK=0,1,…,K-1) is a K-1 order low-pass filter, and a complex modulation filter bank h consisting of K low-pass filters can also be constructed. k (m):

[0059]

[0060] Where, for a given k, Let be a constant, let And by The signal sequence output by the anti-aliasing low-pass filter is as follows:

[0061]

[0062] In addition, the complex modulation filter bank h k (m) is a complex modulation filter bank constructed using a K-1 order Cascade Integrator Comb Filter (CICF) as a prototype low-pass filter. The frequency response of each low-pass filter is equivalent to the frequency response of the CICF expressed in terms of f. s / K represents the step size that slides along the frequency axis. Clearly, the filter for channel 0 has a passband frequency of f. s / (2K), a K-1 order low-pass filter with a stopband attenuation of 13.2dB. Therefore, the filtering process of the difference frequency signal sequence after mixing is to perform a sliding FFT operation on the sequence x(n) with a step length of 1 at K points, and for each FFT operation result X n (k), take X n (0), at this time This forms a new sequence, which is the result y0(n) of the low-pass filter.

[0063] In one embodiment, the number of segments is generated based on the data extraction factor and the length of the difference frequency signal sequence. The difference frequency signal sequence is then stacked into segments to obtain stacked segmented subsequences. If the length of the last stacked segmented subsequence is greater than the length of the remaining data in the difference frequency signal sequence segment, the data portion of the stacked segmented subsequence exceeding the difference frequency signal sequence is padded with zeros. The stacked segmented subsequences are then reassembled to obtain the stacked segmented signal sequence.

[0064] It is worth noting that, such as Figure 2 As shown, the data extraction factor is denoted as D. If the length of the difference frequency signal sequence is N, then D can be appropriately selected so that N / D is an integer, generating a segment number I. The difference frequency signal sequence is then stacked and segmented to obtain multiple stacked segmented subsequences with a sequence length of K. Then, the output sequence in equation (2) after being extracted by a factor of D can be expressed as:

[0065]

[0066] Let K = D, then equation (3) can be further simplified to:

[0067]

[0068] Therefore, when the order of the low-pass filter is D-1, performing a D-fold decimation on the filtered data is equivalent to dividing the sequence x(n) into I segments, performing a D-point FFT operation on the i-th subsequence, and then performing the result X. i (k) Take X i (0)(At this time) This forms a new sequence. The passband frequency of the low-pass filter at this point is f. s / (2D) just meets the bandpass sampling requirement of the signal after Decirp processing. Therefore, the low-pass filtering and decimation processing of the data after digital Decirp mixing can be achieved by performing piecewise FFT operations on the data and decimating the results. The length of the data segment, i.e., the number of points in the FFT operation, is equal to the decimation factor D. However, the sidelobes of the low-pass filter are relatively high at this time, meaning that the stopband attenuation of the filter generally cannot meet the engineering requirements. At the same time, the piecewise FFT operation on x(n) will also cause a certain degree of spectral leakage and aliasing distortion. Therefore, the order of the low-pass filter is set to K-1, so that K is an integer multiple of D, and L = K / D.

[0069] In one embodiment, the stacked segmented signal sequence is windowed and reassembled into a windowed reassembled data sequence by passing each subsequence of the stacked segmented signal sequence through an anti-aliasing low-pass filter. An equivalent filtered sequence is then obtained by performing an FFT operation on the windowed reassembled data sequence based on the data decimation factor D.

[0070] It is worth noting that, such as Figure 3 As shown, when the order of the anti-aliasing low-pass filter is K-1, substituting L=K / D into equation (4) yields the output filter sequence as follows:

[0071]

[0072] In formula (6) With K / L = D as the period, let Equation (6) can then be viewed as a sequence x′ i The result of the D-point FFT operation of (q) is denoted as X′. i (k) is the equivalent filtered sequence of the difference frequency signal sequence x(n).

[0073] In one embodiment, the equivalent filtered sequence is decimated based on the ratio of the anti-aliasing low-pass filter order K to the data decimation factor D, and the first value of each segment of the equivalent filtered sequence is selected and combined to obtain the equivalent filtered decimation sequence. The equivalent filtered decimation sequence is then processed by FFT to obtain the digital Decirp processed sequence.

[0074] It is worth noting that the output of the low-pass filter at time i should be X′. i (0), and the new sequence y″0(i), (i=0,1,…,I-1) formed by this is the result of filtering and decimation after digital Decirp mixing.

[0075] In summary, by windowing and recombining the input data sequence, the passband and stopband performance of the low-pass prototype filter is improved with only a small number of addition operations, without increasing the number of FFT operation points.

[0076] In one embodiment, the data sampling point N of the radar echo signal is an integer multiple of the data decimation factor D.

[0077] In one embodiment, the radar system uses Decirp intermediate frequency direct sampling to obtain the radar echo signal in the digital domain.

[0078] In one embodiment, such as Figure 5 As shown, a digital Decirp engineering implementation device is provided, including: a difference frequency signal generation module 502, a low-pass filter construction module 504, a stacking segmentation module 506, an equivalent filtering module 508, and a digital Decirp processing sequence generation module 510, wherein:

[0079] The difference frequency signal generation module 502 is used to digitally mix the radar echo signal with the reference signal to obtain the difference frequency signal sequence.

[0080] The low-pass filter construction module 504 is used to determine the data decimation factor of the difference frequency signal sequence based on the maximum bandwidth of the difference frequency signal sequence, and to construct an anti-aliasing low-pass filter by selecting an integer multiple of the data decimation factor.

[0081] The stacking segmentation module 506 is used to stack and segment the difference frequency signal sequence according to the number of segments generated by the data extraction multiple, so as to obtain a stacked segmented signal sequence.

[0082] The equivalent filtering module 508 is used to process the stacked segmented signal sequence by windowing reconstruction and FFT operation through an anti-aliasing low-pass filter to obtain an equivalent filtered sequence.

[0083] The digital Decirp processing sequence generation module 510 is used to extract the equivalent filter sequence according to the order of the anti-aliasing low-pass filter and the data decimation factor to obtain the equivalent filter decimation sequence, reassemble the equivalent filter decimation sequence and perform FFT operation to generate the digital Decirp processing sequence.

[0084] For specific limitations regarding a digital Decirp engineering implementation device, please refer to the limitations regarding a digital Decirp engineering implementation method described above, which will not be repeated here. Each module in the aforementioned digital Decirp engineering implementation device can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in hardware or independently of the processor in a computer device, or stored in software in the memory of a computer device, so that the processor can call and execute the operations corresponding to each module.

[0085] In one embodiment, a computer device is provided, which may be a terminal, and its internal structure diagram may be as follows: Figure 6As shown, the computer device includes a processor, memory, network interface, display screen, and input devices connected via a system bus. The processor provides computing and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The network interface is used to communicate with external terminals via a network connection. When the computer program is executed by the processor, it implements a digital Dechirp engineering implementation method. The display screen can be an LCD screen or an e-ink display screen. The input devices can be a touch layer covering the display screen, buttons, a trackball, or a touchpad mounted on the computer device casing, or an external keyboard, touchpad, or mouse.

[0086] Those skilled in the art will understand that Figure 6 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0087] In one embodiment, a computer device is provided, including a memory and a processor, the memory storing a computer program, the processor executing the computer program to perform the following steps:

[0088] The radar echo signal is acquired, and the radar echo signal is digitally mixed with the reference signal to obtain the difference frequency signal sequence.

[0089] The data decimation factor of the difference frequency signal sequence is determined based on the maximum bandwidth of the difference frequency signal sequence, and an anti-aliasing low-pass filter is constructed by selecting an integer multiple of the data decimation factor.

[0090] The difference frequency signal sequence is segmented by stacking based on the number of segments generated by the data extraction factor, resulting in a stacked segmented signal sequence.

[0091] The stacked segmented signal sequence is windowed and reassembled by an anti-aliasing low-pass filter and processed by FFT operation to obtain an equivalent filtered sequence.

[0092] The equivalent filter sequence is decimated based on the order of the anti-aliasing low-pass filter and the data decimation factor to obtain the equivalent filter decimation sequence. The equivalent filter decimation sequence is then reconstructed and subjected to FFT operation to generate the digital Decirp processing sequence.

[0093] In another embodiment, the results of processing field-measured data using the matched filtering method and the method of the present invention are compared. The measured data were collected from a ground-based radar experimental platform, and the main system parameters are as follows:

[0094] Table 1 System parameters of a ground-based radar experimental platform

[0095]

[0096] The target's single intermediate frequency echo is directly sampled and then digitally quadrature demodulated to obtain two complex signals, I and Q, with a data point count of 242,400. The digital Decirp reference signal's time width is consistent with the sampling gate width, and the frequency modulation slope is consistent with the transmitted signal. Calculations show that the maximum bandwidth of the signal after Decirp processing is 10MHz, so the ideal data decimation factor is 120. Considering the feasibility of a practical low-pass filter, a decimation factor of D = 100 is chosen. In the stacked segmented FFT processing, each subsequence has a length of 2000 points, and a 1999th-order Hamming window is used to suppress out-of-band signals. The number of FFT operation points in the stacked segmented FFT processing is equal to the digital decimation factor, i.e., 100 points. Figure 4 As shown, a one-dimensional range profile of a frame of data obtained by using matched filtering and a digital Decirp processing method based on stacked piecewise FFT is presented (the horizontal axis in the figure starts at 0m from the observation window). It can be seen from the figure that the digital Decirp method based on the stacked piecewise FFT algorithm can correctly perform pulse compression on the echo signal, obtaining the same one-dimensional range profile result as matched filtering pulse compression. This demonstrates that the engineering implementation of the method of this invention is correct.

[0097] Furthermore, while maintaining the same digital Decirp processing performance, multi-stage filtering and decimation methods for digital Decirp processing typically employ a cascaded CICF, HBF, and FIR filter structure. The decimation factor is decomposed into D = 100 = 5 × 2. 2×5, the decimation factor of CICF is 5 times. A 5-stage cascaded CICF is used to improve sidelobe suppression. The decimation factor of HBF is further decomposed into two 2x decimations. The final stage uses an FIR filter to implement the 5x data decimation anti-aliasing filter, with an order of 150. The above decimation filter is implemented using a Xilinx IP core. This filter bank is used to filter and decimate the digitally mixed signal. The decimated data is then weighted with a Hamming window to suppress sidelobe movement, and an FFT operation is performed (the length of the decimated data sequence is 2424 points; a 4096-point FFT IP core should be selected from Xilinx's FFT IP cores). This completes the digital Decirp pulse compression processing, yielding a one-dimensional range image. The main hardware resource estimates required for filtering and decimating the digitally mixed signal using the above scheme are shown in Table 2.

[0098] Table 2. Estimated main hardware resource consumption for multi-stage filter cascading implementation.

[0099]

[0100] When using a stacked segmented FFT operation to filter and decimate the signal after digital mixing, while ensuring that the number of filter coefficients is an integer multiple of the decimation factor, the order of the prototype filter is chosen to be 1999, meaning the segmented data length is 2000 points. The window function coefficients are the prototype filter coefficients, also 2000. The demodulated data sequence is divided into 2424 segments, padding with zeros if the length is insufficient. After signal filtering and decimation, Hamming windows are still used for sidelobe suppression. This method requires two DFT operation units, 100-point and 2424-point, to complete digital Decirp processing. When implementing with Xilinx IP cores, 128-point and 4096-point FFT IP cores should be selected respectively. The baseband data of the target echo is based on... After recombination, the result is fed into the FFT IP core for computation. Since only the first value of the FFT result is needed each time, the IP core can be reset after outputting the first value to proceed to the next 128-point FFT operation. This improves computational efficiency and ensures that 2424 128-point FFT operations are completed within the time interval between the two wideband sampling gates of the radar. Similarly, the main hardware resources required to implement the above signal filtering and decimation algorithm are estimated as shown in Table 3.

[0101] Table 3. Estimated main hardware resource consumption for segmented overlapping FFT operations.

[0102]

[0103] Comparing the resource consumption in Tables 2 and 3, it can be seen that, under the same digital Decirp processing performance, the hardware resources consumed by the multi-stage filtering and decimation method are about twice that of the stacked segmented FFT operation method. This shows that the stacked segmented FFT operation method can effectively reduce hardware resource overhead in digital Decirp processing, further verifying the effectiveness of this method.

[0104] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), Rambus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0105] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0106] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A digital Decirp engineering implementation method, characterized in that, The method includes: The radar echo signal is acquired, and the radar echo signal is digitally mixed with a reference signal to obtain a difference frequency signal sequence. The data decimation factor of the difference frequency signal sequence is determined based on the maximum bandwidth of the difference frequency signal sequence. An anti-aliasing low-pass filter is constructed by selecting an integer multiple of the data decimation factor. The specific steps are as follows: Determine the data decimation factor of the difference frequency signal sequence based on the maximum bandwidth of the difference frequency signal sequence. In addition to the passband and stopband characteristics requirements of the anti-aliasing low-pass filter, the data decimation factor is selected. The order of the anti-aliasing low-pass filter is determined by an integer multiple thereof. Construct using the window function method The anti-aliasing low-pass filter described above; The difference frequency signal sequence is segmented by stacking according to the number of segments generated by the data extraction multiple to obtain a stacked segmented signal sequence. The stacked segmented signal sequence is processed by the anti-aliasing low-pass filter through windowing reconstruction and FFT operation to obtain an equivalent filtered sequence. Specifically, the stacked segmented signal sequence is processed by the anti-aliasing low-pass filter, where each sub-sequence of the stacked segmented signal sequence is windowed and reconstructed to obtain a windowed reconstructed data sequence. The windowed reconstructed data sequence is then processed according to the data extraction factor. Perform FFT operation to obtain the equivalent filtered sequence; The equivalent filter sequence is decimated according to the order of the anti-aliasing low-pass filter and the data decimation factor to obtain an equivalent filter decimation sequence. The equivalent filter decimation sequence is then recombined and an FFT operation is performed to generate a digital Decirp processing sequence.

2. The method according to claim 1, characterized in that, Acquire radar echo signals, and digitally mix the radar echo signals with a reference signal to obtain a difference frequency signal sequence, including: The radar echo signal is acquired by a radar receiver, a reference signal is generated based on the radar transmitted waveform parameters, and the radar echo signal and the reference signal are digitally mixed to obtain a difference frequency signal sequence.

3. The method according to claim 2, characterized in that, The difference frequency signal sequence is segmented by stacking according to the number of segments generated by the data extraction factor to obtain a stacked segmented signal sequence, including: Extract multiples based on the data. The number of segments is generated based on the length of the difference frequency signal sequence, and the difference frequency signal sequence is stacked and segmented to obtain stacked segmented subsequences; If the length of the last segment of the stacked subsequence is greater than the length of the remaining data in the difference frequency signal sequence segment, then the data portion of the stacked subsequence that exceeds the difference frequency signal sequence is padded with zeros. The stacked segmented subsequences are recombined to obtain the stacked segmented signal sequence.

4. The method according to claim 3, characterized in that, The equivalent filter sequence is decimated based on the anti-aliasing low-pass filter order and the data decimation factor to obtain an equivalent filter decimation sequence. The equivalent filter decimation sequence is then reconstructed and subjected to an FFT operation to generate a digital Dechirp processing sequence, including: According to the order of the anti-aliasing low-pass filter With the data extraction multiple The ratio is used to extract the equivalent filter sequence, and the first value of each segment of the equivalent filter sequence is selected and combined to obtain the equivalent filter extraction sequence. The equivalent filtered decimation sequence is processed by FFT to obtain the digital Decirp processed sequence.

5. The method according to claim 4, characterized in that, The data sampling points of the radar echo signal Extract multiple of the data Integer multiples of.

6. The method according to claim 5, characterized in that, Before the step of acquiring the radar echo signal and mixing the radar echo signal with a reference signal to obtain a difference frequency signal sequence, the method further includes: The radar system uses Decirp intermediate frequency direct sampling to obtain the radar echo signal in the digital domain.

7. A digital Decirp engineering implementation device, characterized in that, The device includes: The difference frequency signal generation module is used to digitally mix the radar echo signal with the reference signal to obtain the difference frequency signal sequence. The low-pass filter construction module is used to determine the data decimation factor of the difference frequency signal sequence based on the maximum bandwidth of the difference frequency signal sequence, and to construct an anti-aliasing low-pass filter by selecting an integer multiple of the data decimation factor. Specifically, the steps are: determining the data decimation factor of the difference frequency signal sequence based on the maximum bandwidth of the difference frequency signal sequence. In addition to the passband and stopband characteristics requirements of the anti-aliasing low-pass filter, the data decimation factor is selected. The order of the anti-aliasing low-pass filter is determined by an integer multiple thereof. Construct using the window function method The anti-aliasing low-pass filter described above; The stacked segmentation module is used to stack and segment the difference frequency signal sequence according to the number of segments generated by the data extraction multiple, so as to obtain a stacked segmented signal sequence. The equivalent filtering module is used to process the stacked segmented signal sequence through windowing reconstruction and FFT operation of the anti-aliasing low-pass filter to obtain an equivalent filtered sequence. Specifically, the stacked segmented signal sequence is processed by the anti-aliasing low-pass filter, and each sub-sequence of the stacked segmented signal sequence is windowed and reconstructed to obtain a windowed reconstructed data sequence. The windowed reconstructed data sequence is then processed according to the data extraction factor. Perform FFT operation to obtain the equivalent filtered sequence; The digital Decirp processing sequence generation module is used to extract the equivalent filter sequence according to the order of the anti-aliasing low-pass filter and the data extraction factor to obtain an equivalent filter extraction sequence, reassemble the equivalent filter extraction sequence and perform FFT operation to generate a digital Decirp processing sequence.

8. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 6.

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