Digital beamforming method and apparatus based on multi-delay and scale correction

Abstract

This invention provides a digital beamforming method and apparatus based on multiple time delays and scale correction. The method includes: determining a reference time delay group based on multiple reference positions divided according to the swath width range corresponding to the range direction; performing finite impulse response (FIR) time delay filtering, scale transformation, and pulse compression processing on the echo signal sequentially based on the reference time delay group; and weighting the pulse-compressed signal by the received scan SCORE based on an error compensation function to obtain a digital beamforming (DBF) synthesized signal. This effectively suppresses inter-channel time delay and scale mismatch problems caused by viewing angle changes in wide-swath SAR systems, improves the signal-to-noise ratio and target positioning accuracy, and eliminates residual phase errors introduced by scale transformation through the error compensation mechanism, ultimately achieving high-precision digital beamforming.

Description

Technical Field

[0001] This invention relates to the field of digital signal processing technology, and in particular to a digital beamforming method and apparatus based on multiple time delays and scale correction. Background Technology

[0002] High-resolution, wide-scan 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. A key innovation of DBF is the use of multiple channels in the range and / or azimuth directions, where the receiving antenna is divided into multiple sub-apers with independent receiving channels. The SCan On Receive (SCORE) method guides a real-time beam scan, tracking pulse echoes arriving from different directions as a function of time, with the turning direction always pointing towards the center of the pulse range reflected from the ground. Due to its sharpness and flexibility, the SCORE method can suppress spatial ambiguity signals returning from the ground, increase the gain of the receiving antenna without significantly reducing the imaging area, and suppress local spatial interference. However, as the SAR swath width and viewing angle increase, the receiving gain at the imaging boundaries deteriorates. In this case, the SCORE process scheme is not accurate enough.

[0004] Related technologies also provide a method for DBF using a scale scaling transform factor, thereby achieving high-precision DBF. However, due to the wide swath application context, this method still suffers from target offset at the imaging boundary without further expanding the Taylor formula. Summary of the Invention

[0005] This invention provides a digital beamforming method and apparatus based on multiple time delays and scale correction, which solves the defect of existing digital beamforming methods in that there is target offset at the imaging boundary, realizes the correction of digital beamforming accuracy, and improves the signal-to-noise ratio after near-far DBF synthesis.

[0006] This invention provides a digital beamforming method based on multiple time delays and scale correction, comprising the following steps:

[0007] Based on multiple reference positions divided according to the swath width range in the distance direction, a reference delay group is determined;

[0008] Based on the reference delay group, the echo signal is sequentially subjected to finite impulse response (FIR) delay filtering, scaling transformation, and pulse compression.

[0009] Based on the error compensation function, the pulse-compressed signal is weighted by the received scan SCORE to obtain the digital beamforming (DBF) synthesized signal.

[0010] According to the present invention, a digital beamforming method based on multiple time delays and scale correction determines a reference time delay group based on multiple reference positions divided into range-corresponding swath ranges, including:

[0011] Based on multiple reference positions corresponding to the range width division, the elevation angle between the antenna and the multiple reference positions is determined;

[0012] The reference delay group is determined based on the elevation angle between the antenna and the plurality of reference positions, and the channel spacing parameter of the antenna.

[0013] According to the present invention, a digital beamforming method based on multiple time delays and scale correction performs scale transformation processing on a signal after FIR time delay filtering, comprising:

[0014] Determine the scaling transformation amount corresponding to each reference delay in the reference delay group, and determine the pointing angle function based on the elevation angle between the antenna and the plurality of reference positions;

[0015] Based on the scaling transformation amount under the pointing angle function, the quadratic phase function corresponding to each reference delay is obtained;

[0016] Based on the quadratic phase function corresponding to each reference delay, the echo signal after FIR delay filtering corresponding to each reference delay is subjected to scaling transformation.

[0017] 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 the scale scaling transform under the pointing angle function, including:

[0018] Based on the scaling transformation amount under the aforementioned pointing angle function, the scaling transformation function is obtained;

[0019] Based on the approximate representation obtained by Taylor expansion of the scale-scaling transform function, the phase function transformed by the scale-scaling transform function is solved to obtain the quadratic phase function corresponding to each reference delay.

[0020] According to the present invention, a digital beamforming method based on multiple time delays and scale correction includes pulse compression processing of a scale-transformed signal, comprising:

[0021] Based on the multiple reference positions, the scale-transformed signals corresponding to each reference delay in the reference delay group are merged to obtain fused data;

[0022] The fused data is subjected to pulse compression processing.

[0023] According to the present invention, a digital beamforming method based on multiple time delays and scale correction is provided. Based on an error compensation function, the received scan SCORE weighting is applied to the pulse-compressed signal to obtain a digital beamforming (DBF) synthesized signal, comprising:

[0024] Based on the quadratic phase function corresponding to each reference delay, determine the error compensation function corresponding to each reference delay;

[0025] Based on the error compensation function corresponding to each reference delay and the time-varying weighting factor of the SCORE algorithm, the correction weighting factor corresponding to each reference delay is determined;

[0026] Based on the multiple reference positions, the correction weighting factors corresponding to each reference delay are merged to obtain the fused correction weighting factor;

[0027] Based on the fused data after pulse compression processing and the fusion correction weighting factor, the DBF synthesized signal is obtained.

[0028] The present invention also provides a digital beamforming apparatus based on multiple time delays and scale correction, comprising the following modules:

[0029] The determination module is used to determine the reference delay group based on multiple reference positions divided into corresponding swath width ranges according to the distance.

[0030] The processing module is used to perform finite impulse response (FIR) time delay filtering, scale transformation, and pulse compression processing on the echo signal in sequence based on the reference time delay group.

[0031] The forming module is used to perform receive scanning SCORE weighting on the pulse-compressed signal based on the error compensation function to obtain the digital beamforming (DBF) synthesized signal.

[0032] The present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the digital beamforming method based on multiple time delays and scale correction as described above.

[0033] The present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the digital beamforming method based on multiple time delays and scale correction as described above.

[0034] The present invention also provides a computer program product, including a computer program that, when executed by a processor, implements the digital beamforming method based on multiple time delays and scale correction as described above.

[0035] The digital beamforming method and apparatus based on multi-delay and scale correction provided by this invention divides the swath range corresponding to the range direction 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 received scanning weighted synthesis of 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-swath 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 realizing high-precision digital beamforming. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0037] Figure 1 This is a flowchart illustrating the digital beamforming method based on multiple time delays and scale correction provided by the present invention.

[0038] Figure 2 This is a schematic diagram of an embodiment of the digital beamforming method provided by the present invention.

[0039] Figure 3 This is a schematic diagram of the signal model for digital beamforming provided by the present invention.

[0040] Figure 4 This is a schematic diagram of the ideal time-domain waveform of the reference channel echo provided by the present invention.

[0041] Figure 5 This is a schematic diagram of the time-domain waveform of the traditional SCORE algorithm provided by this invention.

[0042] Figure 6 This is a schematic diagram of the time-domain waveform of the method provided in this embodiment of the present invention.

[0043] Figure 7 This is a schematic diagram of the near-endpoint target and ideal position provided by the present invention.

[0044] Figure 8 This is a schematic diagram of the center point target and ideal position provided by the present invention.

[0045] Figure 9 This is a schematic diagram of the remote endpoint target and ideal position provided by the present invention.

[0046] Figure 10 This is a schematic diagram of the structure of the digital beamforming device based on multiple time delays and scale correction provided by the present invention.

[0047] Figure 11 This is a schematic diagram of the structure of the electronic device provided by the present invention. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0049] Figure 1 This is a flowchart illustrating the digital beamforming method based on multiple time delays and scale correction provided by the present invention, as shown below. Figure 1 As shown, the method includes the following steps:

[0050] Step 100: Determine the reference delay group based on multiple reference positions divided according to the corresponding swath width range of the distance.

[0051] Step 101: Based on the reference delay group, the echo signal is sequentially subjected to finite impulse response (FIR) delay filtering, scale transformation, and pulse compression.

[0052] Step 102: Based on the error compensation function, the pulse-compressed signal is subjected to receive scanning SCORE weighting to obtain the digital beamforming (DBF) synthesized signal.

[0053] Specifically, in this embodiment of the invention, the swath width range corresponding to the range direction (e.g., 750.4km to 920.4km) 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: 786.84km, 835.39km, and 883.94km) can be divided according to the swath width range corresponding to the range direction. The differences in signal propagation paths in different range directions can then be converted into time delay parameters to determine the reference time delay group.

[0054] This step reduces boundary errors compared to traditional single-delay correction by using a segmented correction strategy with multiple reference locations.

[0055] After determining the reference delay group, the echo signal can be sequentially processed by finite impulse response (FIR) delay filtering, scaling transformation, and pulse compression based on the reference delay group.

[0056] An independent FIR delay filter can be designed for each reference position to correct the delay of the data sampled by the ADC. Then, the echo signals of different channels can be scaled to achieve target alignment between channels. Finally, multiple sets of corrected data are fused and the echo energy is concentrated by pulse compression to further improve the signal-to-noise ratio.

[0057] Finally, the pulse-compressed signal can be SCORE-weighted according to the error compensation function to obtain the DBF synthesized signal. Since the scaling process introduces an error term, this embodiment of the invention incorporates a scaling error correction function into the SCORE weighting factor to eliminate the error's influence. Ultimately, the pulse-compressed signal is multiplied by the weighting factor incorporating the error correction function and summed to generate a high-precision DBF synthesized signal. This error compensation mechanism improves target positioning accuracy and enhances signal stability.

[0058] The digital beamforming method based on multi-delay and scale correction provided by this invention divides the swath range corresponding to the range direction 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. Furthermore, it introduces an error compensation function to perform received scanning weighted synthesis of the pulse-compressed signal. This method can effectively suppress the inter-channel delay and scale mismatch problems caused by the change of viewing angle in wide-swath SAR systems, improve the signal-to-noise ratio and target positioning accuracy, and eliminate the phase error introduced by scale transformation through the error compensation mechanism, ultimately achieving high-precision digital beamforming.

[0059] According to the present invention, a digital beamforming method based on multiple time delays and scale correction determines a reference time delay group based on multiple reference positions divided into range-corresponding swath ranges, including:

[0060] Based on multiple reference positions corresponding to the range width division, the elevation angle between the antenna and the multiple reference positions is determined;

[0061] The reference delay group is determined based on the elevation angle between the antenna and multiple reference positions, as well as the channel spacing parameter of the antenna.

[0062] Specifically, in embodiments of the present invention, the elevation angle between the antenna and the reference positions can be determined by dividing the swath width range according to the range and combining the radar's geometric model.

[0063] The elevation angle between the antenna and the k-th reference position can be determined using the following formula. :

[0064]

[0065] In the formula, Indicates the antenna track height. This represents the Earth's radius, and can be taken as 6371 km. This represents the slope distance at the k-th reference position.

[0066] Subsequently, the reference delay group can be determined based on the elevation angle between the antenna and the reference position, the antenna channel spacing parameters, and the mathematical relationship between the signal propagation path difference and the time delay.

[0067] The reference delay group can be determined using the following formula:

[0068]

[0069] In the formula, This represents the reference delay generated by the nth channel relative to the kth reference position; This represents the physical location parameter of the nth channel (such as the physical distance between the nth channel and the reference channel). This represents the elevation angle between the antenna and the k-th reference position; The downward angle representing the direction of the antenna array normal; It represents the speed of light.

[0070] According to the present invention, a digital beamforming method based on multiple time delays and scale correction performs scale transformation processing on a signal after FIR time delay filtering, comprising:

[0071] Determine the scaling transformation amount corresponding to each reference delay in the reference delay group, and determine the pointing angle function based on the elevation angle between the antenna and multiple reference positions;

[0072] Based on the scaling transformation under the pointing angle function, the quadratic phase function corresponding to each reference delay is obtained;

[0073] Based on the quadratic phase function corresponding to each reference delay, the echo signal after FIR delay filtering is subjected to scaling transformation.

[0074] Specifically, in the process of scaling 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 by combining the elevation angle between the antenna and multiple reference positions.

[0075] The ideal signal reference model obtained by designing an FIR delay filter based on the reference delay group can be expressed as:

[0076]

[0077] In the formula, This represents the echo signal model of the nth receiving channel at the kth reference position; It represents the signal amplitude normalization factor, and represents the overall system gain or the intensity attenuation coefficient of the echo signal; For a rectangular window function, T represents the pulse width, which is determined by the parameters of the linear frequency modulated (Chirp) signal transmitted by the radar. This represents the inherent delay of the nth channel; This represents the reference delay generated by the nth channel relative to the kth reference position; For the phase term of the Chirp signal, This is the frequency modulation slope; The carrier frequency of the radar transmitted signal The corresponding phase correction term; Indicates the channel index. This indicates the total number of channels.

[0078] Therefore, it can be known that the actual position and time of the target at the k-th reference position for the nth receiving channel are... (That is, the time offset of the signal after time delay correction) is:

[0079]

[0080] In the formula, Indicates the echo delay of the reference channel; This represents the physical location parameter of the nth channel (such as the physical distance between the nth channel and the reference channel). This indicates the actual downward viewing angle of the target (i.e., the actual elevation angle at which the radar beam points towards the target). This represents the elevation angle between the antenna and the k-th reference position; The downward angle representing the direction of the antenna array normal; It represents the speed of light.

[0081] The ideal position should be consistent with the target position of the reference channel, which allows us to determine the scaling transformation amount of the nth receiving channel at the kth reference position (i.e., the amount corresponding to each reference delay). :

[0082]

[0083] Then, the elevation angle between the antenna and the k-th reference position can be used as a basis. Further derivation of the pointing angle function :

[0084]

[0085] In the formula, Indicates the antenna track height. This represents the Earth's radius, and can be taken as 6371 km. Indicates the time relationship between the radar and the ground target. The changing slant range. The pointing angle function describes the dynamic change in the angle at which the radar beam points towards the ground target.

[0086] Subsequently, the quadratic phase function corresponding to each reference delay can be obtained based on the scaling transformation amount under the pointing angle function.

[0087] 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 the scale scaling transform under the pointing angle function, including:

[0088] Based on the scaling transformation amount under the pointing angle function, the scaling transformation function is obtained;

[0089] Based on the approximate representation obtained by Taylor expansion of the scale-scaling transform function, the phase function transformed by the scale-scaling transform function is solved to obtain the quadratic phase function corresponding to each reference delay.

[0090] Specifically, the scaling transformation under any pointing angle function can be expressed as:

[0091]

[0092] It is used as a scaling transformation function.

[0093] Then, the phase of the scaling transformation function can be expressed as the integral of the scaling transformation quantity, resulting in:

[0094]

[0095] right Taylor expansion yields the corresponding approximate representation:

[0096]

[0097] In the formula, , This represents the reference time point corresponding to the k-th reference delay.

[0098] Therefore, the Chirp Scaling (CS) principle can be used to integrate the scaling transformation to generate a quadratic phase function. As shown in the following formula:

[0099]

[0100] 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 caused by the change of viewing angle can be effectively compensated, and the imaging quality of the wide-swath SAR system can be significantly improved.

[0101] Finally, the echo signal after FIR delay filtering corresponding to each reference delay can be scaled using the quadratic phase function (as a scaling function) corresponding to each reference delay.

[0102] According to the present invention, a digital beamforming method based on multiple time delays and scale correction includes pulse compression processing of a scale-transformed signal, comprising:

[0103] Based on multiple reference locations, the scale-transformed signals corresponding to each reference delay in the reference delay group are merged to obtain fused data.

[0104] The fused data is subjected to pulse compression processing.

[0105] Specifically, during the pulse compression process of the scale-transformed signal, multiple reference locations can be used to merge the scale-transformed signals corresponding to each reference delay in the reference delay group to obtain fused data.

[0106] After completing the multi-delay and scale transformation processing, the signal at each reference position has been dynamically corrected for its corresponding viewpoint, eliminating the inter-channel delay and scale mismatch problems caused by viewpoint changes.

[0107] At this point, the sampling points of the corresponding intervals can be extracted from each set of correction data according to the sampling intervals divided by the reference positions (e.g., if 3 reference positions are divided, the 7000-point echo signal can be divided into 1-3500, 3501-5500, and 5501-7000 points), and then stitched together in sequence to form a complete frame of data, thus forming fused data covering the entire width range.

[0108] Based on this, pulse compression can be performed on the fused data. Pulse compression can be achieved by performing convolution operations on the fused data using a matched filter, matching the corrected echo signal with the transmitted chirp signal, and utilizing the linear frequency modulation characteristics of the chirp signal to concentrate energy at the target location. By dynamically adjusting the filter parameters, the signal energy dispersed along the time axis is compressed to the time point at the target location, thereby improving the signal-to-noise ratio and suppressing pulse extension loss (PEL effect).

[0109] According to the present invention, a digital beamforming method based on multiple time delays and scale correction is provided. Based on an error compensation function, the received scan SCORE weighting is applied to the pulse-compressed signal to obtain a digital beamforming (DBF) synthesized signal, comprising:

[0110] Based on the quadratic phase function corresponding to each reference delay, determine the error compensation function corresponding to each reference delay;

[0111] Based on the error compensation function corresponding to each reference delay and the time-varying weighting factor of the SCORE algorithm, the correction weighting factor corresponding to each reference delay is determined;

[0112] Based on multiple reference locations, the correction weighting factors corresponding to each reference delay are combined to obtain the fused correction weighting factor.

[0113] The DBF synthesized signal is obtained based on the fused data after pulse compression processing and the fusion correction weighting factor.

[0114] Specifically, in the process of obtaining the DBF synthesized signal by performing SCORE weighting on the pulse-compressed signal based on the error compensation function, the corresponding error compensation function can first be determined according to the quadratic phase function corresponding to each reference delay.

[0115] After scaling at multiple reference positions, a certain phase error remains due to the introduction of the scaling function (a quadratic phase function corresponding to each reference delay). This error needs to be eliminated through an error compensation function. This error compensation function can be constructed from the inverse term of the scaling function.

[0116] Then, the correction weighting factor corresponding to each reference delay can be determined based on the error compensation function corresponding to each reference delay and the time-varying weighting factor of the SCORE algorithm.

[0117] In the traditional SCORE method, the weighting factor is typically a time-varying phase factor used to align the signal phase between channels. This invention superimposes an error compensation function onto the time-varying weighting factor in the traditional SCORE method to obtain a corrected weighting factor, ensuring that the weighting factor simultaneously incorporates dynamic correction and error suppression functions.

[0118] The correction weighting factor of the nth receiving channel at the kth reference position. It can be expressed by the following formula:

[0119]

[0120] In the formula, This is the error correction term obtained from the error compensation function. This is the time-varying weighting factor in the SCORE algorithm.

[0121] Then, the correction weighting factors can be merged based on multiple reference positions to obtain the fused correction weighting factor.

[0122] Specifically, according to the sampling intervals divided by the reference positions in the aforementioned pulse compression process (e.g., if 3 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 full width.

[0123] This process is consistent with the data segmentation and fusion strategy in pulse compression processing, ensuring that each region uses a weighting factor that matches the correction data through segmentation and merging.

[0124] Finally, a DBF synthesized signal is generated based on the fused data after pulse compression processing and the fusion correction weighting factor. In practice, the fused echo data can be multiplied point by point with the fusion correction weighting factor and then summed to output a high-precision DBF signal.

[0125] The following examples, through specific application scenarios, further illustrate the digital beamforming method based on multi-delay and scale correction provided by the present invention.

[0126] Figure 2 This is a schematic diagram of an embodiment of the digital beamforming method provided by the present invention, as shown below. Figure 2 As shown, the implementation steps of this embodiment are as follows:

[0127] 1. Figure 3 This is a schematic diagram of the signal model for digital beamforming provided by the present invention, as shown below. Figure 3 As shown, where It is the downward viewing angle along the normal direction of the antenna array. The antenna height is given by d, the distance between the antenna receiving channels is given by d, and P1, P2, and P3 are the near-end, center, and far-end point targets within the swath width, respectively. , , These are the downward perspectives corresponding to P1, P2, and P3, respectively.

[0128] The radar echo signal model generated by an ideal chirp signal is known to be:

[0129] (1)

[0130] in, The pulse echo delay corresponding to channel n can be expressed as:

[0131] (2)

[0132] in This is the echo delay under the reference channel. This corresponds to the antenna position information of channel n. It is the downward angle corresponding to the target echo.

[0133] 2. From formulas (1) and (2), it can be seen that the echo delays between different channels are different. For example, through simple pulse compression, it can be known that the target position has undergone a relative shift, and the shift amount is... Therefore, this offset is a function of the target angle and the antenna channel position. Simply using SCORE synthesis cannot directly achieve a high-precision DBF, resulting in pulse extension loss (PEL). This is corrected by designing multi-delay and multi-scale transformation functions. Specific parameters are shown in Table 1.

[0134] Table 1 Parameter Settings

[0135]

[0136] 3. Based on this, the corresponding swath width range can be obtained from the geometric model of the satellite during flight, approximately between 750.4 km and 920.4 km. Assuming the given number of time delays is 3, and the simulation uses 7 point targets evenly distributed across the swath width, the swath width is first divided into 3 parts, and the center positions are set at the 2nd, 4th, and 6th point target positions, respectively, which are 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 obtained using the following formula.

[0137] (3)

[0138] Where H is the antenna track height, The Earth's radius is 6371 km. It is the slant distance of the k-th reference position. Thus, the pitch angles corresponding to the reference point positions are obtained as 25.6788°, 31.1819°, and 35.3913°.

[0139] 4. Convert the reference position pitch angle to the reference time delay group using the following formula. This represents the reference delay generated by the nth channel relative to the kth reference position.

[0140] (4)

[0141] This time delay parameter is designed as an FIR time delay filter. Time delay filtering is applied to the data sampled by the ADC and after down-conversion in the actual system to obtain the ideal signal reference model as follows:

[0142] (5)

[0143] 5. From formula (5), we can know that the target point is located at this time:

[0144] (6)

[0145] The ideal position should be consistent with the target position of the reference channel, which is the scaling transformation amount at this time:

[0146] (7)

[0147] 6. The pointing angle function at any given time can also be obtained through formula (3):

[0148] (8)

[0149] Furthermore, the scaling transformation under any pointing angle function can be expressed as:

[0150] (9)

[0151] Since the phase of the scaling transformation function is represented as the integral of the corresponding offset frequency, we have:

[0152] (10)

[0153] right Taylor expansion yields the corresponding approximate representation:

[0154] (11)

[0155] in, Then, the quadratic phase function is obtained by solving formula (10):

[0156] (12)

[0157] in, It is the scaling transformation function corresponding to the k-th delay parameter of the n-th channel.

[0158] 7. Multiply the formula (12) as a multiplication factor with the FIR-filtered echo signal to obtain the echo signal that corrects the target offset problem under different channel perspectives.

[0159] Based on the existing reference time delay positions, echo signals under different time delays are filtered. Assuming each frame of echo signal has 7000 samples, the echo time delay group set according to the current reference position contains 3 reference times, meaning the reference positions are the 2nd, 4th, and 6th points among the 7 target points evenly distributed within the swath width. Therefore, the echo selection under the first set of reference time delays is 1-3500, the second set is 3501-5500, and the third set is 5501-7000. This ensures that each echo sample point has the best time delay + scale transformation correction.

[0160] 8. Merge multiple sets of point target echoes under time delay according to the location allocation strategy, and further concentrate the echo energy by using range-direction echo data pulse compression on the fused data.

[0161] 9. The introduction of the scaling transformation function introduces an error term, which needs to be removed when performing time-varying weighted DBF. The weighting factor introduced is:

[0162] (13)

[0163] In this equation, the first exponential term on the right-hand side 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 exactly inversely related.

[0164] 10. Based on the location allocation strategy provided in step 7, process the time-varying weighted factor with error correction term generated in step 9 in the same way.

[0165] 11. By multiplying the fused echo data with the weighting factor that has also been fused and summing them, a high-resolution 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.

[0166] Figure 4 This is a schematic diagram of the ideal time-domain waveform of the reference channel echo provided by the present invention; Figure 5 This is a schematic diagram of the time-domain waveform of the traditional SCORE algorithm provided by this invention; Figure 6 This is a schematic diagram of the time-domain waveform of the method provided in this embodiment of the present invention. For example... Figures 4-6 The figures show the ideal echo modulation, the echo modulation under the traditional SCORE method, and the modulation under the method of this embodiment, respectively. It can be seen that the echo modulation and PEL effect suppression under the method of this embodiment are significantly improved.

[0167] Figure 7 This is a schematic diagram of the near-endpoint target and ideal position provided by the present invention. Figure 7As can be seen, this method utilizes the time 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 scaling function but does not perform multi-time delay processing, it has a significant improvement, including 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. Figure 8 As can be seen, the performance of the method in this embodiment is the same as that of the existing methods, both of which utilize the time delay parameter of the center point Rcenter; Figure 9 This is a schematic diagram of the remote target and ideal position provided by the present invention. Figure 9 As seen in the study, this method utilizes the time delay parameter of the far endpoint Rfar, resulting in a very small deviation from the ideal position. Compared with the existing DBF method that introduces a scaling function but does not perform multi-time delay processing, it has a significant improvement, including signal-to-noise ratio and target position accuracy.

[0168] The digital beamforming apparatus based on multiple time delays and scale correction provided by the present invention is described below. The digital beamforming apparatus based on multiple time delays and scale correction described below can be referred to in correspondence with the digital beamforming method based on multiple time delays and scale correction described above.

[0169] Figure 10 This is a schematic diagram of the structure of the digital beamforming device based on multiple time delays and scale correction provided by the present invention, which includes the following modules:

[0170] The module 1000 is used to determine a reference delay group based on multiple reference positions divided according to the corresponding swath width range in the distance direction;

[0171] Processing module 1010 is used to sequentially perform finite impulse response (FIR) time delay filtering, scale transformation, and pulse compression processing on the echo signal based on a reference time delay group.

[0172] The forming module 1020 is used to perform receive scanning SCORE weighting on the pulse compressed signal based on the error compensation function to obtain the digital beamforming (DBF) synthesized signal.

[0173] According to the present invention, a digital beamforming apparatus based on multiple time delays and scale correction determines a reference time delay group based on multiple reference positions divided into range-corresponding swath ranges, including:

[0174] Based on multiple reference positions corresponding to the range width division, the elevation angle between the antenna and the multiple reference positions is determined;

[0175] The reference delay group is determined based on the elevation angle between the antenna and multiple reference positions, as well as the channel spacing parameter of the antenna.

[0176] According to the present invention, a digital beamforming apparatus based on multiple time delays and scale correction performs scale transformation processing on a signal after FIR time delay filtering, comprising:

[0177] Determine the scaling transformation amount corresponding to each reference delay in the reference delay group, and determine the pointing angle function based on the elevation angle between the antenna and multiple reference positions;

[0178] Based on the scaling transformation under the pointing angle function, the quadratic phase function corresponding to each reference delay is obtained;

[0179] Based on the quadratic phase function corresponding to each reference delay, the echo signal after FIR delay filtering is subjected to scaling transformation.

[0180] According to the present invention, a digital beamforming apparatus based on multiple time delays and scale correction obtains a quadratic phase function corresponding to each reference time delay based on the scale scaling transform under the pointing angle function, including:

[0181] Based on the scaling transformation amount under the pointing angle function, the scaling transformation function is obtained;

[0182] Based on the approximate representation obtained by Taylor expansion of the scale-scaling transform function, the phase function transformed by the scale-scaling transform function is solved to obtain the quadratic phase function corresponding to each reference delay.

[0183] According to the present invention, a digital beamforming apparatus based on multiple time delays and scale correction performs pulse compression processing on a scale-transformed signal, comprising:

[0184] Based on multiple reference locations, the scale-transformed signals corresponding to each reference delay in the reference delay group are merged to obtain fused data.

[0185] The fused data is subjected to pulse compression processing.

[0186] According to the present invention, a digital beamforming apparatus based on multiple time delays and scale correction is provided. Based on an error compensation function, the pulse-compressed signal is weighted by the received scan SCORE to obtain a digital beamforming (DBF) synthesized signal, comprising:

[0187] Based on the quadratic phase function corresponding to each reference delay, determine the error compensation function corresponding to each reference delay;

[0188] Based on the error compensation function corresponding to each reference delay and the time-varying weighting factor of the SCORE algorithm, the correction weighting factor corresponding to each reference delay is determined;

[0189] Based on multiple reference locations, the correction weighting factors corresponding to each reference delay are combined to obtain the fused correction weighting factor.

[0190] The DBF synthesized signal is obtained based on the fused data after pulse compression processing and the fusion correction weighting factor.

[0191] Figure 11 This is a 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 communications interface 1120, a memory 1130, and a communication bus 1140, wherein the processor 1110, the communications interface 1120, and the memory 1130 communicate with each other via the communication bus 1140. The processor 1110 can call logic instructions in the memory 1130 to execute a digital beamforming method based on multiple time delays and scale correction, the method including:

[0192] Based on multiple reference positions divided according to the swath width range in the distance direction, a reference delay group is determined;

[0193] Based on the reference delay group, the echo signal is sequentially processed by finite impulse response (FIR) delay filtering, scaling transformation, and pulse compression.

[0194] Based on the error compensation function, the pulse-compressed signal is weighted by the received scan SCORE to obtain the digital beamforming (DBF) synthesized signal.

[0195] Furthermore, the logical 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, essentially, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0196] On the other hand, the present invention also provides a computer program product, the computer program product comprising a computer program that can be stored on a non-transitory computer-readable storage medium, wherein when the computer program is executed by a processor, the computer is able to execute the digital beamforming method based on multiple time delays and scale correction provided by the above methods, the method comprising:

[0197] Based on multiple reference positions divided according to the swath width range in the distance direction, a reference delay group is determined;

[0198] Based on the reference delay group, the echo signal is sequentially processed by finite impulse response (FIR) delay filtering, scaling transformation, and pulse compression.

[0199] Based on the error compensation function, the pulse-compressed signal is weighted by the received scan SCORE to obtain the digital beamforming (DBF) synthesized signal.

[0200] In another aspect, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the digital beamforming method based on multiple time delays and scale correction provided by the methods described above, the method comprising:

[0201] Based on multiple reference positions divided according to the swath width range in the distance direction, a reference delay group is determined;

[0202] Based on the reference delay group, the echo signal is sequentially processed by finite impulse response (FIR) delay filtering, scaling transformation, and pulse compression.

[0203] Based on the error compensation function, the pulse-compressed signal is weighted by the received scan SCORE to obtain the digital beamforming (DBF) synthesized signal.

[0204] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0205] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part 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, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0206] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A digital beamforming method based on multiple time delays and scale correction, characterized in that, include: Based on multiple reference positions divided according to the swath width range in the distance direction, a reference delay group is determined; Based on the reference delay group, the echo signal is sequentially subjected to finite impulse response (FIR) delay filtering, scaling transformation, and pulse compression. Based on the error compensation function, the pulse-compressed signal is weighted by the received scan SCORE to obtain the digital beamforming (DBF) synthesized signal. Based on multiple reference locations divided according to the swath width range along the distance, a reference delay group is determined, including: Based on multiple reference positions corresponding to the range width division, the elevation angle between the antenna and the multiple reference positions is determined; Based on the elevation angle between the antenna and the plurality of reference positions, and the channel spacing parameter of the antenna, a reference delay group is determined; Methods for scaling the signal after FIR time delay filtering include: Determine the scaling transformation amount corresponding to each reference delay in the reference delay group, and determine the pointing angle function based on the elevation angle between the antenna and the plurality of reference positions; Based on the scaling transformation amount under the pointing angle function, the quadratic phase function corresponding to each reference delay is obtained; Based on the quadratic phase function corresponding to each reference delay, the echo signal after FIR delay filtering corresponding to each reference delay is subjected to scaling transformation.

2. The digital beamforming method based on multiple time delays and scale correction according to claim 1, characterized in that, Based on the scaling transformation amount under the aforementioned pointing angle function, the quadratic phase function corresponding to each reference delay is obtained, including: Based on the scaling transformation amount under the aforementioned pointing angle function, the scaling transformation function is obtained; Based on the approximate representation obtained by Taylor expansion of the scale-scaling transform function, the phase function transformed by the scale-scaling transform function is solved to obtain the quadratic phase function corresponding to each reference delay.

3. The digital beamforming method based on multiple time delays and scale correction according to any one of claims 1 or 2, characterized in that, Methods for pulse compression processing of signals after scaling transformation include: Based on the multiple reference positions, the scale-transformed signals corresponding to each reference delay in the reference delay group are merged to obtain fused data; The fused data is subjected to pulse compression processing.

4. The digital beamforming method based on multiple time delays and scale correction according to claim 3, characterized in that, Based on the error compensation function, the pulse-compressed signal is weighted by the received scan SCORE to obtain the digital beamforming (DBF) synthesized signal, including: Based on the quadratic phase function corresponding to each reference delay, determine the error compensation function corresponding to each reference delay; Based on the error compensation function corresponding to each reference delay and the time-varying weighting factor of the SCORE algorithm, the correction weighting factor corresponding to each reference delay is determined; Based on the multiple reference positions, the correction weighting factors corresponding to each reference delay are merged to obtain the fused correction weighting factor; Based on the fused data after pulse compression processing and the fusion correction weighting factor, the DBF synthesized signal is obtained.

5. A digital beamforming apparatus based on multiple time delays and scale correction, characterized in that, include: The determination module is used to determine the reference delay group based on multiple reference positions divided into corresponding swath width ranges according to the distance. The processing module is used to perform finite impulse response (FIR) time delay filtering, scale transformation, and pulse compression processing on the echo signal in sequence based on the reference time delay group. The forming module is used to perform receive scanning SCORE weighting on the pulse compressed signal based on the error compensation function to obtain the digital beamforming (DBF) synthesized signal; The determining module is specifically used for: Based on multiple reference positions corresponding to the range width division, the elevation angle between the antenna and the multiple reference positions is determined; Based on the elevation angle between the antenna and the plurality of reference positions, and the channel spacing parameter of the antenna, a reference delay group is determined; The processing module is specifically used for: Determine the scaling transformation amount corresponding to each reference delay in the reference delay group, and determine the pointing angle function based on the elevation angle between the antenna and the plurality of reference positions; Based on the scaling transformation amount under the pointing angle function, the quadratic phase function corresponding to each reference delay is obtained; Based on the quadratic phase function corresponding to each reference delay, the echo signal after FIR delay filtering corresponding to each reference delay is subjected to scaling transformation.

6. 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, it implements the digital beamforming method based on multiple time delays and scale correction as described in any one of claims 1 to 4.

7. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the digital beamforming method based on multiple time delays and scale correction as described in any one of claims 1 to 4.

8. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by the processor, it implements the digital beamforming method based on multiple time delays and scale correction as described in any one of claims 1 to 4.

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