ABAQ compression method and device for spaceborne multi-channel SAR Doppler domain

Abstract

The present application provides a satellite-borne multi-channel SAR Doppler domain ABAQ compression method and device, which relates to the field of digital signal processing technology. The method includes: determining the multi-weighted contribution of the Doppler domain subband based on the Doppler domain subband division; determining the Doppler domain subband non-uniform bit allocation scheme based on the multi-weighted contribution of the Doppler domain subband; compressing the satellite-borne multi-channel synthetic aperture radar SAR data based on the Doppler domain subband non-uniform bit allocation scheme. The satellite-borne multi-channel SAR Doppler domain ABAQ compression method and device provided by the present application can achieve an improvement in SQNR under the same compression quantization bit number, thereby ensuring the reliability of the communication system and further reducing the pressure of satellite-borne SAR data storage and transmission.

Description

Technical Field

[0001] The present application relates to the field of digital signal processing technology, and in particular to a satellite-borne multi-channel SAR Doppler domain ABAQ compression method and device. Background Art

[0002] Spaceborne synthetic aperture radar (SAR) is widely used in military reconnaissance and civil remote sensing satellites because it is not affected by bad weather. As the system continues to move towards high resolution and wide mapping band, which are contradictory requirements for pulse repetition frequency (PRF), along-track multi-channel technology has emerged. At the same time, the development of multi-polarization and multi-mode methods has further increased the data volume of spaceborne SAR (≥100Mbit / s). In order to meet the requirements of transmission bandwidth and real-time transmission of raw data, a high compression ratio and low distortion SAR raw data compression method is required on the satellite. So far, a large number of SAR raw data compression algorithms have been proposed, among which Block Adaptive Quantization (BAQ) has been mainstreamed due to its simplicity of algorithm and hardware implementation and high efficiency of compression effect. However, the signal-to-quantization-noise ratio (SQNR) of the BAQ algorithm is low when compressing data at a large compression ratio, which makes it difficult to ensure the reliability of the communication system. Summary of the invention

[0003] The present application provides a satellite-borne multi-channel SAR Doppler domain ABAQ compression method and device, which are used to solve the defect of poor reliability of the communication system in the prior art.

[0004] In a first aspect, an embodiment of the present application provides a satellite-borne multi-channel SAR Doppler domain ABAQ compression method, comprising:

[0005] Based on the Doppler domain sub-band division, the multi-weighted contributions of the Doppler domain sub-bands are determined;

[0006] Determining a Doppler domain subband non-uniform bit allocation scheme based on the multi-weighted contributions of the Doppler domain subband;

[0007] Based on the Doppler domain sub-band non-uniform bit allocation scheme, satellite-borne multi-channel synthetic aperture radar SAR data is compressed.

[0008] In one embodiment, based on the Doppler domain subband division, determining the multi-weighted contributions of the Doppler domain subbands includes:

[0009] Based on the Doppler domain sub-band division, determine the antenna pattern weighted contribution and effective bandwidth proportion contribution of the Doppler domain sub-band;

[0010] Based on the weighted contribution of the antenna pattern of the Doppler domain sub-band and the effective bandwidth proportion contribution, the multi-weighted contribution of the Doppler domain sub-band is determined.

[0011] In one embodiment, based on the Doppler domain sub-band non-uniform bit allocation scheme, compressing spaceborne multi-channel synthetic aperture radar SAR data includes:

[0012] Based on the Doppler domain sub-band non-uniform bit allocation scheme, constraining the bit allocation extreme value;

[0013] The spaceborne multi-channel synthetic aperture radar (SAR) data is compressed based on the block adaptive quantization algorithm ABAQ with constrained bit allocation extreme value and adjusted adaptive bit allocation.

[0014] In one embodiment, the method further comprises:

[0015] Based on the dynamic range of spaceborne multi-channel SAR data and the variance change of Doppler domain sub-band sub-block data, the bit error control part of the ABAQ algorithm is adjusted to obtain the adjusted ABAQ algorithm.

[0016] In one embodiment, the method further comprises:

[0017] Reconstruct and filter the azimuth multi-channel data to obtain the original data matrix;

[0018] Performing azimuth multi-pulse fast Fourier transform on the raw data matrix to determine a Doppler range domain coefficient matrix;

[0019] The Doppler domain subband division is determined based on the Doppler range domain coefficient matrix.

[0020] In one embodiment, the method further comprises:

[0021] Perform zero-filled multi-pulse fast Fourier transform on the azimuth multi-channel data to obtain the transformation result;

[0022] Reconstructing, filtering and summing the transformation results to determine a Doppler range domain coefficient matrix;

[0023] The Doppler domain subband division is determined based on the Doppler range domain coefficient matrix.

[0024] In a second aspect, an embodiment of the present application provides a satellite-borne multi-channel SAR Doppler domain ABAQ compression device, comprising:

[0025] A first determination module is used to determine the multi-weighted contribution of the Doppler domain subband based on the Doppler domain subband division;

[0026] A second determination module is used to determine a Doppler domain subband non-uniform bit allocation scheme based on the multi-weighted contributions of the Doppler domain subband;

[0027] The compression module is used to compress the satellite-borne multi-channel synthetic aperture radar SAR data based on the Doppler domain sub-band non-uniform bit allocation scheme.

[0028] In a third aspect, the present application further provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the method described in the first aspect when executing the program.

[0029] In a fourth aspect, the present application further provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the method described in the first aspect.

[0030] In a fifth aspect, the present application further provides a computer program product, comprising a computer program, which implements the method described in the first aspect when executed by a processor.

[0031] The satellite-borne multi-channel SAR Doppler domain ABAQ compression method and device provided in the embodiment of the present application realize Doppler sub-band non-uniform bit allocation through multi-weight contribution, and then compress the satellite-borne multi-channel synthetic aperture radar SAR data. When the dynamic range of the original data is low and the variance of the block data changes little, the SQNR can be improved with the same number of compressed quantization bits, thereby ensuring the reliability of the communication system and further reducing the pressure of satellite-borne SAR data storage and transmission. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the present application or the prior art, a brief introduction will be 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 application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0033] Figure 1 It is a flow chart of the ABAQ compression method of the spaceborne multi-channel SAR Doppler domain provided by the present application;

[0034] Figure 2 It is a schematic diagram of the principle of the spaceborne multi-channel SAR Doppler domain ABAQ compression method provided by this application;

[0035] Figure 3is a schematic diagram of Doppler spectrum and bandwidth provided by this application;

[0036] Figure 4 It is a structural schematic diagram of a spaceborne multi-channel SAR Doppler domain ABAQ compression device provided by the present application;

[0037] Figure 5 It is a structural schematic diagram of the electronic device provided by this application. DETAILED DESCRIPTION

[0038] At present, many SAR raw data compression algorithms have been proposed, such as: scalar quantization algorithm and vector quantization algorithm in time domain using the statistical characteristics and internal correlation of raw data; wavelet transform compression, subband coding method, fast Fourier transform (FFT) compression in transform domain, etc. have better performance and greater complexity; there are also grid coding quantization, predictive coding, compressed sensing, and entropy restricted quantization. The BAQ algorithm is a relatively mainstream application, but the BAQ algorithm also has the disadvantage of low SQNR, which makes it difficult to ensure the reliability of the communication system.

[0039] In order to further optimize the performance of the BAQ algorithm and achieve high SQNR under the same compression ratio, many BAQ optimization methods have been proposed. For example: Adaptive bit-rate allocation Block Adaptive Quantization (ABAQ): Select a variable bit rate quantizer based on the power of the block data signal to adapt to the changes in the scattering characteristics of the ground objects, but the design defects of the bit error control algorithm and the limitations of the algorithm make it impossible to achieve performance improvement in uniform areas through this method; Multi-Channels Block Adaptive Quantization (MCBAQ): Replace the original data information processing with the frequency domain information between multi-channel data, and choose to use the rate-distortion function and multi-weight contribution to allocate channel bits, but this method does not use the Doppler domain information of the multi-directional pulse range.

[0040] Based on the above analysis, the technical status of the BAQ algorithm for spaceborne multi-channel SAR raw data compression reflects the following three shortcomings:

[0041] (1) Adaptive bit allocation BAQ lacks improvement on uniform target areas, and existing bit error control algorithms fail in uniform target areas;

[0042] (2) The two-dimensional FFT-BAQ algorithm has good compression performance but high complexity. The hardware implementation of BAQ compression in the raw data domain is simple but has low compression performance.

[0043] (3) The MCBAQ method is used for multi-channel raw data compression, but does not consider the impact of the FFT noise floor on the quantized compression results when the number of channels is small.

[0044] In view of the shortcomings of the above data compression methods, this application proposes a satellite-borne multi-channel SAR Doppler domain ABAQ compression method, which can effectively improve the SQNR.

[0045] In order to make the purpose, technical solutions and advantages of this application clearer, the technical solutions in this application will be clearly and completely described below in conjunction with the drawings in this application. Obviously, the described embodiments are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0046] Figure 1 : is a flow chart of the ABAQ compression method for the spaceborne multi-channel SAR Doppler domain provided in the embodiment of the present application. Figure 1 The embodiment of the present application provides a satellite-borne multi-channel SAR Doppler domain ABAQ compression method, the execution subject of which may be an electronic device, for example, a controller, and the method may include:

[0047] Step 110: determining multi-weighted contributions of Doppler domain subbands based on Doppler domain subband division;

[0048] Step 120: Determine a Doppler domain subband non-uniform bit allocation scheme based on the multi-weighted contributions of the Doppler domain subbands;

[0049] Step 130: compressing the spaceborne multi-channel synthetic aperture radar SAR data based on the Doppler domain sub-band non-uniform bit allocation scheme.

[0050] In step 110, the controller may acquire the satellite-borne multi-channel SAR data and perform Doppler domain sub-band division on the data to obtain a Doppler domain sub-band division result. The controller may determine the multi-weighted contribution of the Doppler domain sub-band based on the Doppler domain sub-band division result.

[0051] In step 120 , the controller may determine a Doppler domain subband non-uniform bit allocation scheme by combining the rate-distortion function of the slowly varying memoryless Gaussian source and the overall bit average constraint with the multi-weighted contributions of the Doppler domain subbands obtained in step 110 .

[0052] In step 130, the controller may compress the spaceborne multi-channel synthetic aperture radar SAR data based on the Doppler domain sub-band non-uniform bit allocation scheme obtained in step 120 in combination with a bit error control algorithm.

[0053] The ABAQ compression method in Doppler domain of a spaceborne multi-channel SAR provided in the embodiment of the present application realizes non-uniform bit allocation of Doppler sub-bands through multi-weighted contributions, and further compresses the spaceborne multi-channel synthetic aperture radar SAR data. It can improve the SQNR with the same number of compressed quantization bits when the dynamic range of the original data is low and the variance of the block data is small, thereby ensuring the reliability of the communication system and further reducing the pressure of storage and transmission of spaceborne SAR data.

[0054] In one embodiment, based on the Doppler domain subband division, determining the multi-weighted contributions of the Doppler domain subbands includes:

[0055] Based on the Doppler domain sub-band division, determine the weighted contribution of the antenna pattern and the effective bandwidth proportion contribution of the Doppler domain sub-band;

[0056] Based on the weighted contribution of the antenna pattern of the Doppler domain subband and the contribution of the effective bandwidth ratio, the multi-weighted contribution of the Doppler domain subband is determined.

[0057] Based on the Doppler domain subband division results, the Doppler range domain channel subband data can be determined. The controller can calculate the subband coefficient matrix power based on the Doppler range domain channel subband data, and determine the weighted contribution of the antenna pattern of the Doppler domain subband based on the subband coefficient matrix power. The controller can also determine the integral contribution of the subband on the processing bandwidth based on the integral of the subband pattern on the broadband, that is, the effective bandwidth share contribution. The controller can determine the equivalent "standard deviation" parameter of the multi-weighted contribution of the Doppler domain subband based on the weighted contribution of the antenna pattern of the Doppler domain subband and the effective bandwidth share contribution.

[0058] The satellite-borne multi-channel SAR Doppler domain ABAQ compression method provided in the embodiment of the present application determines the multi-weighted contribution of the Doppler domain subband through the weighted contribution of the antenna pattern of the Doppler domain subband and the contribution of the effective bandwidth ratio, and performs data compression based on the multi-weighted contribution of the Doppler domain subband, which can further improve the SQNR in data compression, thereby ensuring the reliability of the communication system.

[0059] In one embodiment, based on the Doppler domain sub-band non-uniform bit allocation scheme, compressing spaceborne multi-channel synthetic aperture radar SAR data includes:

[0060] Based on the Doppler domain sub-band non-uniform bit allocation scheme, the bit allocation extreme value is constrained;

[0061] The spaceborne multi-channel synthetic aperture radar (SAR) data is compressed based on the block adaptive quantization algorithm ABAQ with constrained bit allocation extreme value and adjusted adaptive bit allocation.

[0062] The controller can complete data compression by allocating different bits in the sub-bands in combination with an improved adaptive bit allocation BAQ method. Specifically, the controller can constrain the bit allocation extreme value based on the Doppler domain sub-band non-uniform bit allocation scheme, and then compress the spaceborne multi-channel synthetic aperture radar SAR data based on the constrained bit allocation extreme value and the adjusted adaptive bit allocation block adaptive quantization algorithm ABAQ.

[0063] The satellite-borne multi-channel SAR Doppler domain ABAQ compression method provided in the embodiment of the present application can further improve the SQNR in data compression by constraining the extreme value of bit allocation and combining the improved ABAQ method for data compression, thereby ensuring the reliability of the communication system.

[0064] In one embodiment, the spaceborne multi-channel SAR Doppler domain ABAQ compression method further includes:

[0065] Based on the dynamic range of spaceborne multi-channel SAR data and the variance change of Doppler domain sub-band sub-block data, the bit error control part of the ABAQ algorithm is adjusted to obtain the adjusted ABAQ algorithm.

[0066] The controller can adjust the bit error control algorithm of adaptive bit allocation BAQ based on the dynamic range of the satellite-borne multi-channel SAR data and the variance change of the Doppler domain sub-band sub-block data, so that the sub-band sub-block is integer quantized and the sub-band is a preset fractional quantized value. Then, the controller can complete the high compression ratio compression of the satellite-borne multi-channel SAR data based on the constrained bit allocation extreme value combined with the adjusted ABAQ bit error algorithm.

[0067] The satellite-borne multi-channel SAR Doppler domain ABAQ compression method provided in the embodiment of the present application adjusts the ABAQ algorithm to compress the satellite-borne multi-channel synthetic aperture radar SAR data. It can achieve SQNR improvement when the dynamic range of the original data is low and the variance of the block data is small, thereby ensuring the reliability of the communication system.

[0068] In one embodiment, the spaceborne multi-channel SAR Doppler domain ABAQ compression method further includes:

[0069] Reconstruct and filter the azimuth multi-channel data to obtain the original data matrix;

[0070] Perform azimuth multi-pulse fast Fourier transform on the original data matrix to determine the Doppler range domain coefficient matrix;

[0071] Based on the Doppler range domain coefficient matrix, the Doppler domain sub-band division is determined.

[0072] The controller can use a filter (e.g., Krieger filter) to reconstruct and filter the azimuth multi-channel data, reconstruct the original data matrix of azimuth oversampling after uniform sampling, and then perform azimuth multi-pulse fast Fourier transform on the original data matrix to obtain the Doppler range domain coefficient matrix. The Doppler range domain coefficient matrix can reflect the bandwidth ratio, so as to determine the Doppler domain (frequency domain) sub-band division.

[0073] The satellite-borne multi-channel SAR Doppler domain ABAQ compression method provided in the embodiment of the present application utilizes the equivalent large "oversampling rate" of azimuth data in the multi-channel case, realizes Doppler domain non-uniform bit allocation through multi-weight contribution, and can further improve the SQNR in data compression, thereby ensuring the reliability of the communication system.

[0074] In one embodiment, the spaceborne multi-channel SAR Doppler domain ABAQ compression method further includes:

[0075] Perform zero-filled multi-pulse fast Fourier transform on the azimuth multi-channel data to obtain the transformation result;

[0076] Reconstruct, filter and sum the transformation results to determine the Doppler range domain coefficient matrix;

[0077] The Doppler domain sub-band division is determined based on a Doppler range domain coefficient matrix.

[0078] The controller can use a filter (e.g., Krieger filter) to perform zero-filled multi-pulse fast Fourier transform on the azimuth multi-channel data to obtain a transformation result, and then perform reconstruction filtering and summation on the transformation result to determine the Doppler range domain coefficient matrix. That is, the reconstruction filtering and summation results as the spectrum of the reconstructed signal can be directly used as the result of the azimuth multi-pulse FFT, and then the controller can determine the Doppler domain (frequency domain) sub-band division based on the Doppler range domain coefficient matrix.

[0079] The satellite-borne multi-channel SAR Doppler domain ABAQ compression method provided in the embodiment of the present application reconstructs the azimuth multi-channel signal and shares the spectrum results of the azimuth multi-pulse FFT. This method has a small increase in one-dimensional FFT complexity, is simple to implement in algorithm engineering applications, can further reduce the amount of calculation, and has the characteristics of both computational simplicity and optimized performance.

[0080] The technical solutions of the above embodiments are further described below with reference to specific examples.

[0081] Figure 2 This is a schematic diagram of the principle of this application, refer to Figure 2 , this application may include the following steps:

[0082] (1) According to the radar parameters, the number of along-track antenna channels K, the pulse repetition frequency PRF, and the Doppler bandwidth PBW are determined. According to the processing range, the number of single-channel sampling points Na1 in azimuth, the Doppler domain subband division N, and the total number of FFT pulses Na are determined. According to the target requirements, the number of quantization bits B is determined. The specific parameter settings are shown in the following table:

[0083]

[0084]

[0085] (2) When the PRF sampling of a single channel is lower than the PBW, the dual-channel merging causes uneven sampling and generates false targets. The Krieger filter can be used to reconstruct and merge the data of the two azimuth channels, making the azimuth data signal equivalent to a uniform sampling rate of N*PRF. In this process, the azimuth aliasing caused by too low PRF and the false targets caused by uneven sampling are avoided.

[0086] (3) The 2-channel merged data obtained at this time can be regarded as the single-channel data of the azimuth pulse 3000, and the sampling rate is PRF eff =N*PRF=4358, and do FFT with Na=3000 in azimuth. Compared with the inter-channel FFT of MCBAQ, the FFT noise floor effect during ADC sampling is reduced, and the Doppler spectrum is obtained as follows Figure 3 As shown, according to PBW / PRF eff The ratio determines the sub-band division into 6;

[0087] (4) Calculate the weighted contribution of each sub-band spectrum coefficient to the antenna pattern using the power (energy) of the spectrum coefficient of each sub-band:

[0088]

[0089] Among them, P k represents the weighted contribution of the subband antenna pattern, L represents the number of subband coefficients, and y k Represents the coefficients of the Doppler range domain subband.

[0090] The weighted contributions of the antenna patterns of the six sub-bands can be obtained by calculation, as shown in the following table:

[0091] Sub-band Subband 1 Subband 2 Subband 3 Subband 4 Subband 5 Subband 6 <![CDATA[P k ]]> 36618.566 98511.561 304079.900 454177.608 316437.520 94296.215

[0092] (5) The number of subband divisions determines the position of each subband. The integral of the Dirichlet kernel of the Discrete Fourier Transform (DFT) on the PBW is used to represent the subband frequency band to bandwidth ratio. The calculation formula is as follows:

[0093]

[0094] Among them, A k It represents the ratio of sub-band frequency band k to bandwidth, PBW represents Doppler bandwidth, PRF represents pulse repetition frequency, N represents Doppler domain sub-band division, and k represents the kth frequency band.

[0095] The calculation results are as follows:

[0096] <![CDATA[A1]]> <![CDATA[A2]]> <![CDATA[A3]]> <![CDATA[A4]]> <![CDATA[A5]]> <![CDATA[A6]]> 1983.6 6214.1 24588 25189 24588 6214.1

[0097] (6) Using the multi-weight contribution method, calculate the equivalent “standard deviation” parameter σ:

[0098]

[0099] Among them, σ k represents the standard deviation parameter of the multi-weighted contribution of the kth frequency band, P k represents the weighted contribution of the antenna pattern of the k-th frequency band subband, A k represents the ratio of sub-band frequency k to bandwidth, and N represents the Doppler domain sub-band division.

[0100] The Doppler domain non-uniform bit allocation under the optimal solution is obtained by using the rate-distortion function and the Lagrangian algorithm:

[0101]

[0102] Among them, R k Indicates the number of bits obtained by the kth subband, represents the preset number of compressed quantization bits, K represents the total number of frequency bands, σ k represents the standard deviation parameter of the multi-weighted contribution of the kth subband, ΔR k Indicates the number of bits that need to be adjusted for the kth subband.

[0103] According to the weighted sub-band Doppler power spectrum of the antenna pattern, it can be concluded that the closer the part is to the sampling frequency, the more it belongs to the clutter band in the spectrum, and the smaller the gain in the antenna pattern, which is consistent with experience. The standard deviation parameters are shown in the following table:

[0104]

[0105] (7) When the number of sub-band divisions is 6, some sub-bands fall completely in the clutter band. The formula calculation will result in excessive bit allocation due to discarding the frequency band. Under the condition of large compression ratio and small quantization bit number, the extreme value of bit allocation is constrained, and the non-uniform bit allocation in the Doppler domain is obtained as shown in the following table:

[0106] <![CDATA[ΔR1]]> <![CDATA[ΔR2]]> <![CDATA[ΔR3]]> <![CDATA[ΔR4]]> <![CDATA[ΔR5]]> <![CDATA[ΔR6]]> -2.000 -0.623 0.991 1.266 1.017 -0.652

[0107] (8) In the uniform scenario, the adaptive bit allocation BAQ method is used to compress the coefficient matrices of different subbands with non-uniform bits. In order to overcome the bit allocation defects of sub-block data under low dynamic range and small data standard deviation changes, the bit error control algorithm is adjusted to meet the sub-block integer quantization bit number and the sub-band preset fractional quantization bit number. In order to ensure the communication transmission data bandwidth requirements, the difference threshold between the actual and preset quantization bit number of the last sub-band is set to 0.005bit, and the relative quantization bit error is 0.25%. It can be considered that the preset compression target has been achieved.

[0108] By comparing the data compression performance of classic BAQ, adaptive bit allocation BAQ (A-BAQ), multi-channel BAQ (MC-BAQ) and this method, the results shown in the following table are obtained:

[0109] Data compression method BAQ A-BAQ MCBAQ 3MBAQ SQNR / dB 9.4566 9.4566 9.6462 10.7385

[0110] Note: 3MBAQ is the abbreviation of this method, and its full name is Multi-channel / Multi-pulse / multi-weightBlock Adaptive Quantization.

[0111] For uniform scene targets, the performance of A-BAQ has not changed compared to BAQ. The essence is that the bit allocation scheme of ABAQ fails when the sub-block has a low dynamic range and a small standard deviation change, and due to the defects of the original bit error control algorithm, performance will also degrade under such circumstances. For MCBAQ, when the number of channels is 2, the frequency domain obtained by performing only 2-point FFT is not completely accurate. The difference between the FFT noise floor and the SQNR of the ADC is 10log(M / 2)=10log(2 / 2)=0dB, which is of the same order of magnitude as the SQNR.

[0112] Under the same flight target and flight parameters, the Doppler frequency domain subband division is obtained by azimuth multi-pulse FFT, and the non-uniform bit allocation is obtained by using multi-weight contribution and rate-distortion function. The subsequent A-BAQ can significantly improve the SQNR performance. At the same time, the increased computational complexity is not high and is within an acceptable range.

[0113] The above actual data experiments show that compared with the existing BAQ data compression method, the method described in this application can significantly improve the SQNR of data compression for uniform scene targets by utilizing Doppler sub-band division under multi-pulse FFT and non-uniform bit allocation under multi-weight contribution.

[0114] The following is a description of the satellite-borne multi-channel SAR Doppler domain ABAQ compression device provided by the present application. The satellite-borne multi-channel SAR Doppler domain ABAQ compression device described below and the satellite-borne multi-channel SAR Doppler domain ABAQ compression method described above can refer to each other.

[0115] Figure 4 Schematic diagram of the structure of the satellite-borne multi-channel SAR Doppler domain ABAQ compression device provided in the embodiment of the present application. Figure 4 The satellite-borne multi-channel SAR Doppler domain ABAQ compression device provided in the embodiment of the present application may include:

[0116] A first determination module 410 is used to determine the multi-weighted contributions of the Doppler domain subbands based on the Doppler domain subband division;

[0117] A second determination module 420 is used to determine a Doppler domain subband non-uniform bit allocation scheme based on the multi-weighted contributions of the Doppler domain subband;

[0118] The compression module 430 is used to compress the spaceborne multi-channel synthetic aperture radar SAR data based on the Doppler domain sub-band non-uniform bit allocation scheme.

[0119] The satellite-borne multi-channel SAR Doppler domain ABAQ compression device provided in the embodiment of the present application realizes Doppler sub-band non-uniform bit allocation through multi-weight contribution, and then compresses the satellite-borne multi-channel synthetic aperture radar SAR data. When the dynamic range of the original data is low and the variance of the block data changes little, the SQNR can be improved under the same compression quantization bit number, thereby ensuring the reliability of the communication system and further reducing the pressure of satellite-borne SAR data storage and transmission.

[0120] Specifically, the above-mentioned satellite-borne multi-channel SAR Doppler domain ABAQ compression device provided in the embodiment of the present application can implement all the method steps implemented by the method embodiment in which the execution subject is the controller, and can achieve the same technical effect. The parts and beneficial effects of this embodiment that are the same as those of the method embodiment will not be described in detail here.

[0121] Figure 5 An example of a physical structure diagram of an electronic device is shown in FIG. Figure 5As shown, the electronic device may include: a processor 510, a communication interface 520, a memory 530 and a communication bus 540, wherein the processor 510, the communication interface 520 and the memory 530 communicate with each other through the communication bus 540. The processor 510 may call the logic instructions in the memory 530 to execute the spaceborne multi-channel SAR Doppler domain ABAQ compression method, for example, including:

[0122] Based on the Doppler domain sub-band division, the multi-weighted contributions of the Doppler domain sub-bands are determined;

[0123] Determining a Doppler domain subband non-uniform bit allocation scheme based on the multi-weighted contributions of the Doppler domain subband;

[0124] Based on the Doppler domain sub-band non-uniform bit allocation scheme, satellite-borne multi-channel synthetic aperture radar SAR data is compressed.

[0125] In addition, the logic instructions in the above-mentioned memory 530 can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when it is sold or used as an independent product. Based on this understanding, the technical solution of the present application can be essentially or partly embodied in the form of a software product that contributes to the prior art, and the computer software product is stored in a storage medium, including several instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (Read-Only Memory, ROM), random access memory (Random Access Memory, RAM), disk or optical disk and other media that can store program codes.

[0126] On the other hand, the present application also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the spaceborne multi-channel SAR Doppler domain ABAQ compression method provided by the above methods, for example, including:

[0127] Based on the Doppler domain sub-band division, the multi-weighted contributions of the Doppler domain sub-bands are determined;

[0128] Determining a Doppler domain subband non-uniform bit allocation scheme based on the multi-weighted contributions of the Doppler domain subband;

[0129] Based on the Doppler domain sub-band non-uniform bit allocation scheme, satellite-borne multi-channel synthetic aperture radar SAR data is compressed.

[0130] In another aspect, the present application further provides a computer program product, the computer program product comprising a computer program, the computer program may be stored on a non-transitory computer-readable storage medium, and when the computer program is executed by a processor, the computer can execute the steps of the spaceborne multi-channel SAR Doppler domain ABAQ compression method provided by the above methods, for example, including:

[0131] Based on the Doppler domain sub-band division, the multi-weighted contributions of the Doppler domain sub-bands are determined;

[0132] Determining a Doppler domain subband non-uniform bit allocation scheme based on the multi-weighted contributions of the Doppler domain subband;

[0133] Based on the Doppler domain sub-band non-uniform bit allocation scheme, satellite-borne multi-channel synthetic aperture radar SAR data is compressed.

[0134] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0135] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0136] It should also be noted that the terms "first", "second", etc. in the embodiments of the present application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchangeable under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first" and "second" are generally of the same type, and the number of objects is not limited. For example, the first object can be one or more.

[0137] In the embodiments of the present application, the term "and / or" describes the association relationship of the associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the associated objects before and after are in an "or" relationship.

[0138] "Determine B based on A" in the embodiments of the present application means that the factor A should be considered when determining B. It is not limited to "B can be determined based on A alone", but should also include: "Determine B based on A and C", "Determine B based on A, C and E", "Determine C based on A, and further determine B based on C", etc. In addition, it can also include taking A as a condition for determining B, for example, "When A meets the first condition, use the first method to determine B"; for another example, "When A meets the second condition, determine B", etc.; for another example, "When A meets the third condition, determine B based on the first parameter", etc. Of course, it can also be a condition that takes A as a factor for determining B, for example, "When A meets the first condition, use the first method to determine C, and further determine B based on C", etc.

[0139] In the embodiments of the present application, the term "plurality" refers to two or more than two, and other quantifiers are similar.

[0140] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application 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 embodiments of the present application.

Claims

1. A spaceborne multi-channel SAR Doppler domain ABAQ compression method, characterized in that: include: Based on the Doppler domain sub-band division, the multi-weighted contributions of the Doppler domain sub-bands are determined; Determine a Doppler domain subband non-uniform bit allocation scheme by combining the multi-weighted contribution of the Doppler domain subband with the rate-distortion function of the slowly varying memoryless Gaussian source and the overall bit average constraint; Based on the Doppler domain sub-band non-uniform bit allocation scheme and in combination with a bit error control algorithm, satellite-borne multi-channel synthetic aperture radar SAR data is compressed.

2. The spaceborne multi-channel SAR Doppler domain ABAQ compression method according to claim 1, characterized in that: Based on the Doppler domain sub-band division, the multi-weighted contributions of the Doppler domain sub-bands are determined, including: Based on the Doppler domain sub-band division, determine the antenna pattern weighted contribution and effective bandwidth proportion contribution of the Doppler domain sub-band; Based on the weighted contribution of the antenna pattern of the Doppler domain sub-band and the effective bandwidth proportion contribution, the multi-weighted contribution of the Doppler domain sub-band is determined.

3. The spaceborne multi-channel SAR Doppler domain ABAQ compression method according to claim 1, characterized in that: Based on the Doppler domain sub-band non-uniform bit allocation scheme and in combination with a bit error control algorithm, the satellite-borne multi-channel synthetic aperture radar SAR data is compressed, including: Based on the Doppler domain sub-band non-uniform bit allocation scheme, constraining the bit allocation extreme value; The spaceborne multi-channel synthetic aperture radar (SAR) data is compressed based on the block adaptive quantization algorithm ABAQ with constrained bit allocation extreme value and adjusted adaptive bit allocation.

4. The spaceborne multi-channel SAR Doppler domain ABAQ compression method according to claim 3, characterized in that: The method further comprises: Based on the dynamic range of spaceborne multi-channel SAR data and the variance change of Doppler domain sub-band sub-block data, the bit error control part of the ABAQ algorithm is adjusted to obtain the adjusted ABAQ algorithm.

5. The spaceborne multi-channel SAR Doppler domain ABAQ compression method according to claim 1, characterized in that: The method further comprises: Reconstruct and filter the azimuth multi-channel data to obtain the original data matrix; Performing azimuth multi-pulse fast Fourier transform on the raw data matrix to determine a Doppler range domain coefficient matrix; The Doppler domain subband division is determined based on the Doppler range domain coefficient matrix.

6. The spaceborne multi-channel SAR Doppler domain ABAQ compression method according to claim 1, characterized in that: The method further comprises: Perform zero-filled multi-pulse fast Fourier transform on the azimuth multi-channel data to obtain the transformation result; Reconstructing, filtering and summing the transformation results to determine a Doppler range domain coefficient matrix; The Doppler domain subband division is determined based on the Doppler range domain coefficient matrix.

7. A satellite-borne multi-channel SAR Doppler domain ABAQ compression device, characterized in that: include: A first determination module is used to determine the multi-weighted contribution of the Doppler domain subband based on the Doppler domain subband division; A second determination module is used to determine a Doppler domain sub-band non-uniform bit allocation scheme by combining a rate-distortion function of a slowly varying memoryless Gaussian source and an overall bit average constraint with multi-weighted contributions of the Doppler domain sub-band; The compression module is used to compress the satellite-borne multi-channel synthetic aperture radar SAR data based on the Doppler domain sub-band non-uniform bit allocation scheme combined with a bit error control algorithm.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the program, the spaceborne multi-channel SAR Doppler domain ABAQ compression method 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 Doppler domain ABAQ compression method of the spaceborne multi-channel SAR 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 Doppler domain ABAQ compression method of the spaceborne multi-channel SAR according to any one of claims 1 to 6 is implemented.

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