Digital beam forming method and device based on multi-delay and scale correction

Abstract

The invention provides a digital beam forming method and device based on multiple time delays and scale correction, and the method comprises the steps: determining a reference time delay group based on a plurality of reference positions divided from a corresponding breadth range in a distance direction; on the basis of the reference time delay group, performing finite impulse response (FIR) time delay filtering processing, scale transformation processing and pulse compression processing on an echo signal in sequence; and on the basis of an error compensation function, receiving scanning SCORE weighting is carried out on the signal after pulse compression, and a digital beam forming DBF composite signal is obtained. Therefore, the problems of inter-channel time delay and scale mismatch caused by view angle change in a large-breadth SAR system are effectively suppressed, the signal-to-noise ratio and the target positioning precision are improved, meanwhile, residual phase errors introduced by scale change are eliminated through an error compensation mechanism, and finally high-precision digital beam forming is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of digital signal processing, and in particular to a digital beamforming method and device based on multi-delay and scale correction. Background Art

[0002] High-resolution, wide-swath synthetic aperture radar (SAR) has become the development trend of future airborne / spaceborne SAR systems.

[0003] Digital beamforming (DBF) is considered a powerful method for improving imaging capabilities in future Earth observation missions. The key innovative feature of DBF is the use of multiple channels in range and / or azimuth, where the receiving antenna is divided into multiple sub-apertures with independent receiving channels. The Scan-On-Receive (SCan-On-REceive) method steers a real-time beam scan, tracking pulse echoes arriving from different directions as a function of time, always steering toward the center of the pulse range reflected by the ground. Due to its clarity and flexibility, the SCORE method is used to suppress spatially ambiguous signals returned from the ground, increase the gain of the receiving antenna without significantly reducing the imaging area, and suppress spatially localized interference. However, as the SAR swath width increases and the field of view widens, the receiving gain at the imaging boundaries deteriorates. In this case, the SCORE process is not accurate enough.

[0004] Related technologies also provide a method for DBF using a scaling factor to achieve higher-precision DBF. However, due to the wide range of application contexts, this method still suffers from target offset at the imaging boundary without further expansion of the Taylor formula. Summary of the Invention

[0005] The present invention provides a digital beamforming method and device based on multi-delay and scale correction, which is used to solve the defect of the digital beamforming method in the prior art that there is a target offset problem at the imaging boundary, realize the correction of digital beamforming accuracy, and improve the signal-to-noise ratio after the near-end and far-end DBF synthesis.

[0006] The present invention provides a digital beamforming method based on multiple delays and scale correction, comprising the following steps: Determine a reference delay group based on a plurality of reference positions divided into corresponding width ranges in the distance direction; Based on the reference time delay group, the echo signal is sequentially subjected to finite impulse response (FIR) time delay filtering, scaling and pulse compression processing; Based on the error compensation function, the pulse compressed signal is subjected to receive scanning SCORE weighting to obtain the digital beamforming DBF synthetic signal.

[0007] According to the present invention, a digital beamforming method based on multiple delays and scale correction is provided, which determines a reference delay group based on multiple reference positions divided into corresponding width ranges in the range direction, including: Determining, based on a plurality of reference positions divided into corresponding widths in the range direction, an elevation angle between the antenna and the plurality of reference positions; A reference time delay group is determined based on elevation angles between the antenna and the multiple reference positions and a channel spacing parameter of the antenna.

[0008] According to a digital beamforming method based on multiple delays and scale correction provided by the present invention, a method of performing scale transformation processing on a signal processed by FIR delay filtering includes: Determining a scaling transformation amount corresponding to each reference time delay in the reference time delay group, and determining a pointing angle function based on an elevation angle between the antenna and the multiple reference positions; Obtaining a quadratic phase function corresponding to each reference time delay based on a scaling transformation amount under the pointing angle function; Based on the quadratic phase function corresponding to each reference time delay, a scale transformation is performed on the echo signal corresponding to each reference time delay after the FIR delay filtering process.

[0009] According to a digital beamforming method based on multiple time delays and scale correction provided by the present invention, a quadratic phase function corresponding to each reference time delay is obtained based on the scale expansion and contraction transformation amount under the pointing angle function, including: Obtaining a scale-scaling transformation function based on the scale-scaling transformation amount under the pointing angle function; Based on the approximate representation obtained by Taylor expansion of the scale-scaling transformation function, the phase function converted by the scale-scaling transformation function is solved to obtain the quadratic phase function corresponding to each reference time delay.

[0010] According to a digital beamforming method based on multiple time delays and scale correction provided by the present invention, a method of performing pulse compression processing on a scale-transformed signal includes: Based on the multiple reference positions, merging the scaled signals corresponding to each reference delay in the reference delay group to obtain fused data; Pulse compression processing is performed on the fused data.

[0011] According to a digital beamforming method based on multi-delay and scale correction provided by the present invention, based on an error compensation function, a receive scan SCORE weighting is performed on the pulse compressed signal to obtain a digital beamforming DBF synthetic signal, including: determining an error compensation function corresponding to each reference time delay based on the quadratic phase function corresponding to each reference time delay; Determining a correction weighting factor corresponding to each reference time delay based on the error compensation function corresponding to each reference time delay and a time-varying weighting factor of a SCORE algorithm; Based on the multiple reference positions, combining the correction weighting factors corresponding to each reference time delay to obtain a fused correction weighting factor; A DBF composite signal is obtained based on the fused data after the pulse compression processing and the fusion correction weighting factor.

[0012] The present invention also provides a digital beamforming device based on multi-delay and scale correction, comprising the following modules: A determination module, configured to determine a reference delay group based on a plurality of reference positions divided into corresponding width ranges according to the distance; a processing module, configured to sequentially perform finite impulse response (FIR) delay filtering, scaling, and pulse compression processing on the echo signal based on the reference delay group; The forming module is used to perform receiving scanning SCORE weighting on the pulse compressed signal based on the error compensation function to obtain a digital beamforming DBF synthetic signal.

[0013] The present invention also provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the digital beamforming method based on multi-delay and scale correction as described above is implemented.

[0014] The present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the digital beamforming method based on multiple delays and scale correction as described above is implemented.

[0015] The present invention also provides a computer program product, comprising a computer program, wherein when the computer program is executed by a processor, the computer program implements any one of the above-mentioned digital beamforming methods based on multiple delays and scale corrections.

[0016] The digital beamforming method and device based on multi-delay and scale correction provided by the present invention divide the range corresponding to the distance into multiple reference positions and determine the corresponding reference delay groups. The method and device dynamically correct the echo signal by combining finite impulse response delay filtering, scale transformation and pulse compression processing, and introduce an error compensation function to perform receive scanning weighted synthesis on the pulse compressed signal. This can effectively suppress the inter-channel delay and scale mismatch problems caused by the change of viewing angle in the wide-width SAR system, improve the signal-to-noise ratio and target positioning accuracy, and eliminate the phase error introduced by the scale transformation through the error compensation mechanism, ultimately achieving high-precision digital beamforming. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction is given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 The present invention provides a flow chart of a digital beamforming method based on multiple delays and scale correction.

[0019] Figure 2 It is a schematic diagram of an embodiment of the digital beamforming method provided by the present invention.

[0020] Figure 3 It is a schematic diagram of a signal model of digital beamforming provided by the present invention.

[0021] Figure 4 It is a schematic diagram of the ideal waveform in the time domain of the reference channel echo provided by the present invention.

[0022] Figure 5 It is a time domain waveform diagram of the traditional SCORE algorithm provided by the present invention.

[0023] Figure 6 It is a schematic diagram of the time domain waveform of the method of this embodiment provided by the present invention.

[0024] Figure 7 Schematic diagram of the proximal endpoint target and ideal position provided by the present invention.

[0025] Figure 8 Schematic diagram of the center point target and ideal position provided by the present invention.

[0026] Figure 9 It is a schematic diagram of the far end point target and the ideal position provided by the present invention.

[0027] Figure 10It is a structural diagram of a digital beamforming device based on multiple delays and scale correction provided by the present invention.

[0028] Figure 11 It is a structural schematic diagram of the electronic device provided by the present invention. DETAILED DESCRIPTION

[0029] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0030] Figure 1 Schematic diagram of the flow of the digital beamforming method based on multi-delay and scale correction provided by the present invention, such as Figure 1 As shown, the method includes the following steps: Step 100: Determine a reference time delay group based on a plurality of reference positions divided into width ranges corresponding to distances.

[0031] Step 101: Based on the reference time delay group, the echo signal is sequentially subjected to finite impulse response (FIR) time delay filtering, scaling, and pulse compression processing.

[0032] Step 102: Based on the error compensation function, perform receive scanning SCORE weighting on the pulse compressed signal to obtain a digital beamforming DBF composite signal.

[0033] Specifically, in an embodiment of the present invention, the width range corresponding to the range direction (e.g., 750.4 km to 920.4 km) can be determined based on the radar echo signal model and the geometric model of the satellite during flight. Then, multiple reference positions (e.g., 3 reference positions: 786.84 km, 835.39 km, and 883.94 km) can be divided according to the width range corresponding to the range direction. The differences in signal propagation paths in different range directions are then converted into delay parameters to determine a reference delay group.

[0034] This step reduces the boundary error by adopting a segmented correction strategy with multiple reference positions compared to the traditional single delay correction.

[0035] After the reference delay group is determined, the echo signal can be sequentially subjected to finite impulse response (FIR) delay filtering, scaling, and pulse compression processing based on the reference delay group.

[0036] An independent FIR delay filter can be designed for each reference position to perform delay correction on the data sampled by the ADC. Then, the echo signals of different channels can be scaled to achieve alignment of the observation targets between channels. Finally, multiple sets of corrected data can be fused, and the echo energy can be concentrated through pulse compression to further improve the signal-to-noise ratio.

[0037] Finally, the pulse compressed signal is weighted using the SCORE function according to the error compensation function to produce a DBF composite signal. Because the scaling process introduces error terms, embodiments of the present invention incorporate the scaling error correction function into the SCORE weighting factors to eliminate the effects of this error. Finally, the pulse compressed signal is multiplied and summed with the weighting factors added to the error correction function to generate a high-precision DBF composite signal. This error compensation mechanism improves target positioning accuracy while enhancing signal stability.

[0038] The digital beamforming method based on multiple delays and scale correction provided by the present invention divides the range corresponding to the width into multiple reference positions and determines the corresponding reference delay groups. It combines finite impulse response delay filtering, scale transformation and pulse compression processing to dynamically correct the echo signal, and introduces an error compensation function to perform receive scanning weighted synthesis on the pulse compressed signal. This can effectively suppress the inter-channel delay and scale mismatch problems caused by the change of viewing angle in the wide-width SAR system, improve the signal-to-noise ratio and target positioning accuracy, and eliminate the phase error introduced by the scale transformation through the error compensation mechanism, ultimately achieving high-precision digital beamforming.

[0039] According to the present invention, a digital beamforming method based on multiple delays and scale correction is provided, which determines a reference delay group based on multiple reference positions divided into corresponding width ranges in the range direction, including: Determine the elevation angles between the antenna and the plurality of reference positions based on the plurality of reference positions divided into corresponding widths in the range direction; A reference delay group is determined based on elevation angles between the antenna and a plurality of reference positions and a channel spacing parameter of the antenna.

[0040] Specifically, the embodiment of the present invention can determine the elevation angle between the antenna and the reference position according to a plurality of reference positions divided into a range corresponding to the distance, in combination with a geometric model of the radar.

[0041] The elevation angle between the antenna and the kth reference position can be determined by the following formula : Where, represents the antenna track height, Represents the radius of the earth, which can be 6371km. represents the slant distance of the kth reference position.

[0042] Subsequently, a reference delay group can be determined based on the elevation angle between the antenna and the reference position, antenna channel spacing parameters, and the mathematical relationship between signal propagation path differences and delay.

[0043] The reference delay group can be determined by the following formula: Where, It represents the reference delay generated by the nth channel to the kth reference position; Indicates the physical position parameters of the nth channel (such as the physical distance between the nth channel and the reference channel); represents the elevation angle between the antenna and the kth reference position; Indicates the downward viewing angle of the normal direction of the antenna array; Represents the speed of light.

[0044] According to a digital beamforming method based on multiple delays and scale correction provided by the present invention, a method of performing scale transformation processing on a signal processed by FIR delay filtering includes: Determining a scaling transformation corresponding to each reference delay in the reference delay group, and determining a pointing angle function based on an elevation angle between the antenna and a plurality of reference positions; Based on the scaling transformation under the pointing angle function, the quadratic phase function corresponding to each reference time delay is obtained; Based on the quadratic phase function corresponding to each reference time delay, a scale transformation is performed on the echo signal after FIR delay filtering corresponding to each reference time delay.

[0045] Specifically, in the process of performing scaling processing on the signal after FIR delay filtering, the scaling transformation amount corresponding to each reference delay in the reference delay group can be determined first, and the pointing angle function can be determined in combination with the elevation angles between the antenna and multiple reference positions.

[0046] The ideal signal reference model obtained by designing the FIR delay filter based on the reference delay group can be expressed as: Where, represents the echo signal model of the nth receiving channel at the kth reference position; Indicates the signal amplitude normalization factor, which represents the overall system gain or the intensity attenuation coefficient of the echo signal; is a rectangular window function, where T represents the pulse width, which is determined by the linear frequency modulation (Chirp) signal parameters emitted by the radar. represents the intrinsic delay of the nth channel; It represents the reference delay generated by the nth channel to the kth reference position; is the phase term of the Chirp signal, is the frequency modulation slope; Indicates the carrier frequency of the radar transmission signal The corresponding phase correction term; represents the channel index, Indicates the total number of channels.

[0047] Therefore, it can be known that the actual position time of the point target at the kth reference position of the nth receiving channel is (i.e., the time offset of the signal after delay correction) is: Where, Indicates the echo delay of the reference channel; Indicates the physical position parameters of the nth channel (such as the physical distance between the nth channel and the reference channel); Indicates the actual downward viewing angle of the target (i.e. the actual pitch angle of the radar beam pointing to the target); represents the elevation angle between the antenna and the kth reference position; Indicates the downward viewing angle of the normal direction of the antenna array; Represents the speed of light.

[0048] The ideal position should be consistent with the target position of the reference channel, so the scale scaling transformation of the nth receiving channel at the kth reference position (i.e., corresponding to each reference delay) can be determined. : Then, the elevation angle between the antenna and the kth reference position can be Further derive the pointing angle function : Where, represents the antenna track height, Represents the radius of the earth, which can be 6371km. The time between the radar and the ground target The pointing angle function describes the dynamic angle change of the radar beam pointing to the ground target.

[0049] Subsequently, the quadratic phase function corresponding to each reference time delay can be obtained according to the scaling transformation under the pointing angle function.

[0050] According to the present invention, a digital beamforming method based on multiple time delays and scale correction is provided, which obtains a quadratic phase function corresponding to each reference time delay based on a scale expansion and contraction transformation under a pointing angle function, including: Based on the scale expansion and contraction transformation amount under the pointing angle function, a scale expansion and contraction transformation function is obtained; Based on the approximate representation obtained by Taylor expansion of the scaling transformation function, the phase function converted by the scaling transformation function is solved to obtain the quadratic phase function corresponding to each reference time delay.

[0051] Specifically, the scale transformation under any pointing angle function can be expressed as: It is used as the scaling transformation function.

[0052] Then, the phase of the scaling function can be expressed as the integral of the scaling amount, which is: right Taylor expansion obtains the corresponding approximate representation: Where, , Indicates the reference time point corresponding to the kth reference delay.

[0053] Therefore, the CS (Chirp Scaling) principle can be used to integrate the scaling transformation to generate a quadratic phase function: , as shown below: It can be used as the scale transformation function of the nth receiving channel at the kth reference position. By dynamically adjusting this function, the signal scale mismatch problem caused by the change of viewing angle can be effectively compensated, and the imaging quality of the wideband SAR system can be significantly improved.

[0054] Finally, the echo signal after the FIR delay filtering corresponding to each reference time delay may be scaled according to the quadratic phase function (serving as a scale transformation function) corresponding to each reference time delay.

[0055] According to a digital beamforming method based on multiple time delays and scale correction provided by the present invention, a method of performing pulse compression processing on a scale-transformed signal includes: Based on multiple reference positions, the scale-transformed signals corresponding to each reference delay in the reference delay group are merged to obtain fused data; Perform pulse compression processing on the fused data.

[0056] Specifically, during the pulse compression process on the scaled signal, the scaled signal corresponding to each reference time delay in the reference time delay group may be merged at multiple reference positions to obtain fused data.

[0057] After completing the multi-delay and scale transformation processing, the signal at each reference position has been dynamically corrected for its corresponding viewing angle, eliminating the inter-channel delay and scale mismatch problems caused by viewing angle changes.

[0058] At this time, the sampling intervals can be divided according to the reference positions (for example, if three reference positions are divided, the 7000-point echo signal can be divided into 1-3500, 3501-5500, and 5501-7000 points). The sampling points of the corresponding intervals can be extracted from each set of correction data, and they can be spliced ​​together in sequence to form a complete frame of data to form fused data covering the entire width range.

[0059] Based on this, pulse compression can be performed on the fused data. Pulse compression uses a matched filter to convolve the fused data, matching the corrected echo signal with the transmitted chirp signal. This method leverages the chirp signal's linear frequency modulation (LFM) characteristics to focus energy at the target location. By dynamically adjusting the filter parameters, the signal energy dispersed along the time axis is compressed to the target location, thereby improving the signal-to-noise ratio and suppressing pulse extension loss (PEL).

[0060] According to a digital beamforming method based on multi-delay and scale correction provided by the present invention, based on an error compensation function, a receive scan SCORE weighting is performed on the pulse compressed signal to obtain a digital beamforming DBF synthetic signal, including: Determining an error compensation function corresponding to each reference time delay based on a quadratic phase function corresponding to each reference time delay; Determine a correction weighting factor corresponding to each reference time delay based on the error compensation function corresponding to each reference time delay and the time-varying weighting factor of the SCORE algorithm; Based on multiple reference positions, the correction weighting factors corresponding to each reference time delay are combined to obtain a fused correction weighting factor; Based on the fused data after pulse compression processing and the fusion correction weighting factor, the DBF synthetic signal is obtained.

[0061] Specifically, in the process of performing SCORE weighting on the pulse compressed signal based on the error compensation function to obtain the DBF synthetic signal, the corresponding error compensation function can first be determined according to the quadratic phase function corresponding to each reference time delay.

[0062] After completing the scaling process for multiple reference positions, the scaling function (the quadratic phase function corresponding to each reference delay) introduces a residual phase error, which needs to be eliminated using an error compensation function. This error compensation function can be composed of the inverse of the scaling function.

[0063] Then, the correction weighting factor corresponding to each reference time delay may be determined according to the error compensation function corresponding to each reference time delay and the time-varying weighting factor of the SCORE algorithm.

[0064] The weighting factor in the traditional SCORE method is typically a time-varying phase factor used to align the signal phases between channels. This embodiment of the present invention superimposes an error compensation function on the time-varying weighting factor in the traditional SCORE method to obtain a corrected weighting factor, ensuring that the weighting factor incorporates both dynamic correction and error suppression functions.

[0065] Correction weighting factor of the nth receiving channel at the kth reference position It can be expressed by the following formula: Where, is the error correction term obtained by the error compensation function, is the time-varying weighting factor in the SCORE algorithm.

[0066] Then, the correction weighting factors may be combined according to multiple reference positions to obtain a fused correction weighting factor.

[0067] Specifically, according to the sampling intervals divided by the reference positions in the aforementioned pulse compression processing process (for example, if three reference positions are divided, the 7000-point echo signal can be divided into 1-3500, 3501-5500, and 5501-7000 points), the correction weighting factors corresponding to each reference position are merged according to the same interval to form a fused correction weighting factor covering the entire width.

[0068] This process is consistent with the data segmentation fusion strategy in the pulse compression processing process, and segmentation merging ensures that each region uses a weighting factor that matches the correction data.

[0069] Finally, a DBF composite signal is generated based on the pulse compression-processed fused data and the fusion correction weighting factor. In specific implementation, the fused echo data and the fusion correction weighting factor can be multiplied point by point and then summed to output a high-precision DBF signal.

[0070] The digital beamforming method based on multiple delays and scale correction provided by the present invention is further described below through embodiments in specific application scenarios.

[0071] Figure 2Schematic diagram of an embodiment of the digital beamforming method provided by the present invention, such as Figure 2 As shown, the implementation steps of this embodiment are as follows: 1. Figure 3 Schematic diagram of the signal model of the digital beamforming provided by the present invention, such as Figure 3 As shown, is the downward viewing angle in the normal direction of the antenna array, is the antenna height, the distance between antenna receiving channels is d, P1, P2, and P3 are point targets at the near end, center, and far end of the bandwidth, respectively. 、 、 They correspond to the lower viewing angles of P1, P2, and P3 respectively.

[0072] It is known that the radar echo signal model generated by the ideal chirp signal is: (1) in, The pulse echo delay corresponding to the n-channel can be expressed as: (2) in is the echo delay in the reference channel, is the antenna position information corresponding to channel n, is the lower viewing angle corresponding to the target echo.

[0073] 2. Formulas (1) and (2) show that the echo delays between different channels are different. For example, simple pulse pressure can be used to know that the point target position has a relative offset. The offset is , so the offset is a function of the target angle and antenna channel position. Simply using SCORE synthesis cannot directly achieve high-precision DBF, resulting in pulse extension loss (PEL). Correction is achieved by designing multi-delay and multi-scale transformation functions. Specific parameters are shown in Table 1.

[0074] Table 1 Parameter settings

[0075] 3. Based on this, the corresponding swath width can be calculated from the geometric model of the satellite during flight, which is approximately 750.4 km to 920.4 km. Assuming the number of multi-delays is 3, and the number of point targets in the simulation is set to 7, evenly distributed across the swath width, the swath width is first divided into three parts and the center positions are set at the second, fourth, and sixth point targets, respectively, at 786.84 km, 835.39 km, and 883.94 km. Based on this position information, the elevation angle between the antenna and the reference swath width is calculated using the following formula.

[0076] (3) Where H is the antenna orbit height, The radius of the Earth is 6371 km. is the slant distance of the kth reference position. The pitch angles corresponding to the reference point positions are 25.6788°, 31.1819°, and 35.3913° respectively.

[0077] 4. Convert the reference position pitch angle to the reference delay group using the following formula: is the reference delay generated by the nth channel for the kth reference position.

[0078] (4) The delay parameter is designed as an FIR delay filter, and the data after ADC sampling and down-conversion in the actual system is subjected to delay filtering to obtain the ideal signal reference model as follows: (5) 5. According to formula (5), the point target position at this time is: (6) The ideal position should be consistent with the target position of the reference channel, that is, the scale transformation amount at this time: (7) 6. The pointing angle function at any time can also be obtained through formula (3): (8) And the scale transformation under any pointing angle function can be expressed as: (9) The phase of the scale-scaling function is expressed as the integral of the corresponding offset frequency, so: (10) right Taylor expansion obtains the corresponding approximate representation: (11) in, Then, the quadratic phase function is obtained by solving formula (10): (12) in, is the scaling function of the kth delay parameter corresponding to the nth channel.

[0079] 7. Multiply the FIR-filtered echo signal with formula (12) as a multiplication factor to obtain the echo signal that corrects the target offset problem under different channel viewing angles.

[0080] Based on the existing reference delay positions, echo signals at different delays are screened. Assuming each frame of the echo signal has 7000 sampling points, the echo delay group set according to the current reference position contains three reference times. That is, the reference positions are the 2nd, 4th, and 6th points of the 7 point targets evenly distributed within the width. Therefore, the echoes under the first group of reference delays are selected from sampling points 1-3500, the second group from 3501-5500, and the third group from 5501-7000. This ensures that each echo sampling point has the optimal delay + scale transformation correction.

[0081] 8. Merge multiple groups of point target echoes under time delay according to the position allocation strategy, and further use range-directed echo data pulse compression to concentrate the echo energy on the fused data.

[0082] 9. The introduction of the scale transformation function will bring about an error term. This error needs to be removed when performing time-varying weighted DBF. The weighting factor introduced is: (13) The first exponential term on the right side of the equation is the error correction term introduced by the scaling function, and the second exponential term is the time-varying weighting factor in the SCORE algorithm. It should be noted that the ideal signal representation of the error correction term and the introduced scaling function are inversely proportional.

[0083] 10. Based on the location allocation strategy provided in step 7, the time-varying weighting factor with error correction term generated in step 9 is processed in the same way.

[0084] 11. By multiplying and summing the fused echo data with the weighted factors of the same fusion process, a high-progress DBF synthesized echo signal is obtained, which effectively improves the signal-to-noise ratio on both sides of the echo width and reduces the PEL effect.

[0085] Figure 4 Schematic diagram of the ideal waveform of the reference channel echo time domain provided by the present invention; Figure 5 Schematic diagram of the time domain waveform of the traditional SCORE algorithm provided by the present invention; Figure 6 : is a schematic diagram of the time domain waveform of the method of this embodiment provided by the present invention. Figure 4-Figure 6 As shown in FIG. 1 , the ideal echo modulation situation, the echo modulation under the traditional SCORE method, and the modulation under the method of this embodiment are respectively shown. It can be seen that the echo modulation and PEL effect suppression under the method of this embodiment are significantly improved.

[0086] Figure 7This is a schematic diagram of the near-end point target and the ideal position provided by the present invention. Figure 7 As can be seen in the figure, this method uses the delay parameter of the near endpoint Rnear, which has a very small deviation from the ideal position. Compared with the existing DBF method that introduces a scale scaling function but does not perform multi-delay processing, it has a significant improvement in signal-to-noise ratio and target position accuracy. Figure 8 This is a schematic diagram of the center point target and ideal position provided by the present invention, from Figure 8 As can be seen from the figure, the performance of the method in this embodiment is the same as that of the existing method, both of which use the delay parameter of the center point Rcenter; Figure 9 This is a schematic diagram of the far end point target and the ideal position provided by the present invention, Figure 9 As can be seen from the figure, this method uses the time delay parameter of the far end point Rfar, which has a very small deviation compared to the ideal position. Compared with the existing DBF method that introduces a scale scaling function but does not perform multi-delay processing, it has a significant improvement in signal-to-noise ratio and target position accuracy.

[0087] The following describes a digital beamforming device based on multiple delays and scale corrections provided by the present invention. The digital beamforming device based on multiple delays and scale corrections described below and the digital beamforming method based on multiple delays and scale corrections described above can refer to each other.

[0088] Figure 10 This is a schematic diagram of the structure of a digital beamforming device based on multi-delay and scale correction provided by the present invention, which includes the following modules: A determination module 1000 is configured to determine a reference delay group based on a plurality of reference positions divided into corresponding width ranges according to distance; The processing module 1010 is used to sequentially perform finite impulse response (FIR) delay filtering, scaling, and pulse compression processing on the echo signal based on the reference delay group. The forming module 1020 is configured to perform a receive scan SCORE weighting on the pulse compressed signal based on an error compensation function to obtain a digital beamforming DBF synthesized signal.

[0089] According to the present invention, a digital beamforming device based on multiple delays and scale correction is provided, which determines a reference delay group based on multiple reference positions divided into corresponding width ranges in the range direction, including: Determine the elevation angles between the antenna and the plurality of reference positions based on the plurality of reference positions divided into corresponding widths in the range direction; A reference delay group is determined based on elevation angles between the antenna and a plurality of reference positions and a channel spacing parameter of the antenna.

[0090] According to a digital beamforming device based on multiple delays and scale correction provided by the present invention, a method for performing scale transformation processing on a signal processed by FIR delay filtering includes: Determining a scaling transformation corresponding to each reference delay in the reference delay group, and determining a pointing angle function based on an elevation angle between the antenna and a plurality of reference positions; Based on the scaling transformation under the pointing angle function, the quadratic phase function corresponding to each reference time delay is obtained; Based on the quadratic phase function corresponding to each reference time delay, a scale transformation is performed on the echo signal after FIR delay filtering corresponding to each reference time delay.

[0091] According to the present invention, a digital beamforming device based on multiple time delays and scale correction is provided, which obtains a quadratic phase function corresponding to each reference time delay based on a scale expansion and contraction transformation under a pointing angle function, including: Based on the scale expansion and contraction transformation amount under the pointing angle function, a scale expansion and contraction transformation function is obtained; Based on the approximate representation obtained by Taylor expansion of the scaling transformation function, the phase function converted by the scaling transformation function is solved to obtain the quadratic phase function corresponding to each reference time delay.

[0092] According to the present invention, a digital beamforming device based on multiple time delays and scale correction is provided, which performs pulse compression processing on a scale-transformed signal, including: Based on multiple reference positions, the scale-transformed signals corresponding to each reference delay in the reference delay group are merged to obtain fused data; Perform pulse compression processing on the fused data.

[0093] According to the present invention, a digital beamforming device based on multi-delay and scale correction is provided. Based on an error compensation function, a receive scan SCORE weighting is performed on a pulse compressed signal to obtain a digital beamforming DBF synthetic signal, including: Determining an error compensation function corresponding to each reference time delay based on a quadratic phase function corresponding to each reference time delay; Determine a correction weighting factor corresponding to each reference time delay based on the error compensation function corresponding to each reference time delay and the time-varying weighting factor of the SCORE algorithm; Based on multiple reference positions, the correction weighting factors corresponding to each reference time delay are combined to obtain a fused correction weighting factor; Based on the fused data after pulse compression processing and the fusion correction weighting factor, the DBF synthetic signal is obtained.

[0094] Figure 11 Schematic diagram of the structure of the electronic device provided by the present invention, such as Figure 11 As shown, the electronic device may include: a processor 1110, a communication interface 1120, a memory 1130, and a communication bus 1140, wherein the processor 1110, the communication interface 1120, and the memory 1130 communicate with each other via the communication bus 1140. The processor 1110 may call logic instructions in the memory 1130 to execute a digital beamforming method based on multiple delays and scale corrections, the method including: Determine a reference delay group based on a plurality of reference positions divided into corresponding width ranges in the distance direction; Based on the reference delay group, the echo signal is sequentially processed with finite impulse response (FIR) delay filtering, scaling and pulse compression. Based on the error compensation function, the pulse compressed signal is subjected to receive scanning SCORE weighting to obtain the digital beamforming DBF synthetic signal.

[0095] Furthermore, the logic instructions in the aforementioned memory 1130 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the portion that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product, stored in a storage medium, includes instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the methods described in various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as a USB flash drive, a mobile hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0096] In another aspect, the present invention further provides a computer program product, comprising a computer program. The computer program may be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer is capable of performing the digital beamforming method based on multiple delays and scale corrections provided by the above methods. The method comprises: Determine a reference delay group based on a plurality of reference positions divided into corresponding width ranges in the distance direction; Based on the reference delay group, the echo signal is sequentially processed with finite impulse response (FIR) delay filtering, scaling and pulse compression. Based on the error compensation function, the pulse compressed signal is subjected to receive scanning SCORE weighting to obtain the digital beamforming DBF synthetic signal.

[0097] In yet another aspect, the present invention further provides a non-transitory computer-readable storage medium having a computer program stored thereon. When executed by a processor, the computer program is implemented to perform the digital beamforming method based on multiple delays and scale corrections provided by the above methods, the method comprising: Determine a reference delay group based on a plurality of reference positions divided into corresponding width ranges in the distance direction; Based on the reference delay group, the echo signal is sequentially processed with finite impulse response (FIR) delay filtering, scaling and pulse compression. Based on the error compensation function, the pulse compressed signal is subjected to receive scanning SCORE weighting to obtain the digital beamforming DBF synthetic signal.

[0098] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, i.e., they may be located in one location or distributed across multiple network units. Some or all of the modules may be selected based on actual needs to achieve the objectives of the present embodiment. Persons of ordinary skill in the art will be able to understand and implement the present invention without inventive effort.

[0099] Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented using software plus a necessary general-purpose hardware platform, or of course, hardware. Based on this understanding, the essence of the above technical solution, or the portion that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a magnetic disk, or an optical disk, and includes a number of instructions for causing a computer device (such as a personal computer, server, or network device) to execute the methods described in each embodiment or certain portions of the embodiments.

[0100] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A digital beamforming method based on multi-delay and scale correction, characterized in that: include: Determine a reference delay group based on a plurality of reference positions divided into corresponding width ranges in the distance direction; Based on the reference time delay group, the echo signal is sequentially subjected to finite impulse response (FIR) time delay filtering, scaling and pulse compression processing; Based on the error compensation function, the pulse compressed signal is subjected to receive scanning SCORE weighting to obtain the digital beamforming DBF synthetic signal.

2. The digital beamforming method based on multiple delay and scale correction according to claim 1, characterized in that: Determine the reference delay group based on multiple reference positions divided into corresponding width ranges along the distance direction, including: Determining, based on a plurality of reference positions divided into corresponding widths in the range direction, an elevation angle between the antenna and the plurality of reference positions; A reference time delay group is determined based on elevation angles between the antenna and the multiple reference positions and a channel spacing parameter of the antenna.

3. The digital beamforming method based on multiple delay and scale correction according to claim 2, characterized in that: Methods for performing scale transformation on the signal after FIR delay filtering include: Determining a scaling transformation amount corresponding to each reference time delay in the reference time delay group, and determining a pointing angle function based on an elevation angle between the antenna and the multiple reference positions; Obtaining a quadratic phase function corresponding to each reference time delay based on a scaling transformation amount under the pointing angle function; Based on the quadratic phase function corresponding to each reference time delay, a scale transformation is performed on the echo signal corresponding to each reference time delay after the FIR delay filtering process.

4. The digital beamforming method based on multiple delay and scale correction according to claim 3, characterized in that: Obtaining a quadratic phase function corresponding to each reference time delay based on the scaling transformation under the pointing angle function includes: Obtaining a scale-scaling transformation function based on the scale-scaling transformation amount under the pointing angle function; Based on the approximate representation obtained by Taylor expansion of the scale-scaling transformation function, the phase function converted by the scale-scaling transformation function is solved to obtain the quadratic phase function corresponding to each reference time delay.

5. The digital beamforming method based on multiple delay and scale correction according to claim 1, 3 or 4, characterized in that: Methods for performing pulse compression processing on the scale-transformed signal include: Based on the multiple reference positions, merging the scaled signals corresponding to each reference delay in the reference delay group to obtain fused data; Pulse compression processing is performed on the fused data.

6. The digital beamforming method based on multiple delay and scale correction according to claim 5, characterized in that: Based on the error compensation function, the pulse compressed signal is subjected to receive scan SCORE weighting to obtain a digital beamforming DBF synthetic signal, including: determining an error compensation function corresponding to each reference time delay based on the quadratic phase function corresponding to each reference time delay; Determining a correction weighting factor corresponding to each reference time delay based on the error compensation function corresponding to each reference time delay and a time-varying weighting factor of a SCORE algorithm; Based on the multiple reference positions, combining the correction weighting factors corresponding to each reference time delay to obtain a fused correction weighting factor; A DBF composite signal is obtained based on the fused data after the pulse compression processing and the fusion correction weighting factor.

7. A digital beamforming device based on multi-delay and scale correction, characterized in that: include: A determination module, configured to determine a reference delay group based on a plurality of reference positions divided into corresponding width ranges according to the distance; a processing module, configured to sequentially perform finite impulse response (FIR) time delay filtering, scaling, and pulse compression processing on the echo signal based on the reference time delay group; The forming module is used to perform receiving scanning SCORE weighting on the pulse compressed signal based on the error compensation function to obtain a digital beamforming DBF synthetic signal.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that: When the processor executes the computer program, the digital beamforming method based on multi-delay and scale correction according to any one of claims 1 to 6 is implemented.

9. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the digital beamforming method based on multiple delays and scale correction according to any one of claims 1 to 6 is implemented.

10. A computer program product comprising a computer program, characterized in that When the computer program is executed by a processor, the digital beamforming method based on multiple delays and scale correction according to any one of claims 1 to 6 is implemented.

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