Satellite-borne SAR rapid BP imaging distributed device based on geographic coordinate system

Abstract

The invention provides a satellite-borne SAR rapid BP imaging distributed device based on a geographic coordinate system, and relates to the technical field of radar signal processing. Comprising a plurality of clustered working slave nodes used for acquiring data corresponding to each sub-aperture from a distributed storage module, and performing parallel processing on the data corresponding to all the sub-apertures in each echo data block after pulse compression in sequence by using a rapid BP imaging algorithm to obtain a processed echo data block; the method comprises the following steps: performing pulse compression on echo data blocks to obtain a plurality of sub-aperture images corresponding to each echo data block subjected to pulse compression, fusing the plurality of sub-aperture images through an up-sampling method to obtain a plurality of sub-scene images, and sending the plurality of sub-scene images to a distributed summarizing module; and the distributed summarization module is used for carrying out coherent addition on the plurality of sub-scene images to obtain at least one full-resolution single-scene image, and determining an imaging image according to the single-scene image. In this way, the imaging processing time in high-orbit imaging is short, the imaging resolution is high, and the imaging cost is low.

Description

Technical Field

[0001] The invention relates to the technical field of radar signal processing, and in particular to a spaceborne SAR fast BP imaging distributed device based on a geographic coordinate system. Background Art

[0002] As synthetic aperture radar technology becomes increasingly mature, it has high practical value and a wide range of application scenarios in the defense and civil fields. In recent years, synthetic aperture radar (SAR) imaging is developing towards ultra-high resolution and high-orbit ultra-large imaging width. Ultra-high resolution imaging and ultra-large imaging width at high orbits mean that huge amounts of data need to be processed and a huge amount of calculations need to be done, which places high demands on both algorithms and computing hardware. The fast error back propagation (BP) algorithm based on the geographic coordinate system plays an important role in high-resolution and high-orbit applications. The algorithm has high imaging quality and does not require interpolation, making it suitable for engineering. Graphics Processing Unit (GPU) is usually paired with a central processing unit (CPU) and is a computing device that can provide powerful computing power. Initially, GPUs were mainly used for computer graphics and image processing tasks, such as games and video playback. With the development of technology, the application areas of GPUs have expanded to scientific computing, machine learning, data processing and other fields. With the maturity and improvement of GPU technology, GPUs are also used as computing processing devices in the SAR imaging field to process SAR data.

[0003] At present, the fast decomposition BP algorithm is mainly used in the algorithm to realize SAR imaging, and the CPU and GPU are used in the hardware architecture. The CPU and GPU can be used for collaborative computing. As the host, the CPU is mainly responsible for preprocessing the SAR data, such as pulse compression and grid construction. The processed SAR data is distributed to the GPU for processing according to the azimuth pulse. The GPU receives the pulse data for imaging processing and transmits the processed image back to the host. However, the fast decomposition BP algorithm requires interpolation processing, which may cause the image quality to deteriorate during the interpolation conversion, and the fast decomposition BP algorithm cannot be applied to the curved surface grid in high-orbit applications, resulting in low imaging resolution. Ultra-high-resolution imaging and ultra-large imaging in high-orbit require huge amounts of computing. For the processing of large amounts of data, the collaborative computing of CPU and GPU requires an increase in the number of processors, but the computing performance of the collaborative computing of CPU and GPU with an increased number of processors is limited by the bandwidth, and the processing speed will not continue to increase with the increase in the number of processors, making the imaging processing time longer; increasing the number of processors will make the imaging cost too high. Summary of the invention

[0004] The purpose of the embodiment of the present invention is to provide a distributed device for spaceborne SAR fast BP imaging based on a geographic coordinate system to solve the problems of low imaging resolution, long imaging processing time and high imaging cost.

[0005] To solve the above technical problems, the embodiments of the present invention provide the following technical solutions:

[0006] A first aspect of the present invention provides a distributed device for spaceborne SAR fast BP imaging based on a geographic coordinate system. The distributed device for spaceborne SAR fast BP imaging based on a geographic coordinate system comprises:

[0007] A distributed resource scheduling module is used to divide the echo data into multiple echo data blocks in the azimuth direction according to the number of points in the azimuth direction, perform pulse compression on the multiple echo data blocks in the range direction to obtain multiple echo data blocks after pulse compression, take each echo data block after pulse compression as an imaging sub-scene, divide each imaging sub-scene into multiple sub-apertures according to a preset number of columns, assign a working slave node of a cluster to each sub-aperture, and send the data corresponding to each sub-aperture to the distributed storage module;

[0008] A distributed storage module, used to store data corresponding to each sub-aperture;

[0009] The working slave nodes of the multiple clusters are used to obtain the data corresponding to each sub-aperture from the distributed storage module, and use the fast BP imaging algorithm to sequentially process the data corresponding to all sub-apertures in each echo data block after pulse compression in parallel to obtain multiple sub-aperture images corresponding to each echo data block after pulse compression, and fuse the multiple sub-aperture images by up-sampling method to obtain multiple sub-scene images, and send the multiple sub-scene images to the distributed summary module;

[0010] The distributed summarization module is used to perform coherent addition on multiple sub-scene images to obtain at least one single-scene image with full resolution, and determine an imaging image based on the single-scene image.

[0011] A second aspect of the present invention provides a distributed method for spaceborne SAR fast BP imaging based on a geographic coordinate system. The distributed method for spaceborne SAR fast BP imaging based on a geographic coordinate system comprises:

[0012] According to the number of points in the azimuth direction, the echo data is divided into a plurality of echo data blocks in the azimuth direction;

[0013] Performing range-direction pulse compression on a plurality of echo data blocks to obtain a plurality of echo data blocks after pulse compression;

[0014] Taking each echo data block after pulse compression as an imaging sub-scene, and dividing each imaging sub-scene into a plurality of sub-apertures according to a preset number of columns;

[0015] Acquire the data corresponding to each sub-aperture, use the fast BP imaging algorithm to sequentially process the data corresponding to all sub-apertures in each echo data block after pulse compression in parallel, obtain multiple sub-aperture images corresponding to each echo data block after pulse compression, and fuse the multiple sub-aperture images through an upsampling method to obtain multiple sub-scene images;

[0016] performing coherent addition on the multiple sub-scene images to obtain at least one single-scene image with full resolution;

[0017] According to the single-view image, an imaging image is determined.

[0018] Compared with the prior art, the present invention provides a distributed device for spaceborne SAR fast BP imaging based on a geographic coordinate system, and a distributed resource scheduling module, which is used to divide the echo data into multiple echo data blocks in the azimuth direction according to the number of points in the azimuth direction, perform pulse compression in the range direction on the multiple echo data blocks, obtain multiple echo data blocks after pulse compression, use each echo data block after pulse compression as an imaging sub-scene, divide each imaging sub-scene into multiple sub-apertures according to a preset number of columns, assign a cluster of working slave nodes to each sub-aperture, and send the data corresponding to each sub-aperture to the distributed storage module; the distributed storage module is used to store each sub-aperture. aperture; multiple clusters of working slave nodes, used to obtain data corresponding to each sub-aperture from the distributed storage module, and use the fast BP imaging algorithm to parallelly process the data corresponding to all sub-apertures in each echo data block after pulse compression in turn to obtain multiple sub-aperture images corresponding to each echo data block after pulse compression, and fuse the multiple sub-aperture images through an upsampling method to obtain multiple sub-scene images, and send the multiple sub-scene images to the distributed summary module; the distributed summary module is used to coherently add the multiple sub-scene images to obtain at least one single-scene image with full resolution, and determine the imaging image based on the single-scene image. In this way, the data corresponding to all sub-apertures in each echo data block after pulse compression are deployed on a distributed device, that is, deployed on working slave nodes of multiple clusters that can be processed in parallel. The working slave nodes of multiple clusters use the fast BP imaging algorithm of the geographic coordinate system to parallelly process the data corresponding to all sub-apertures in each echo data block after pulse compression. The working slave nodes of multiple clusters can process the data corresponding to multiple sub-apertures at the same time, so that the imaging processing time in high-orbit imaging is shorter even with a huge amount of data; using the fast BP imaging algorithm of the geographic coordinate system, a single-scene image with full resolution can be obtained in the end, so that the imaging resolution is higher; the working slave nodes of multiple clusters can process the data corresponding to multiple sub-apertures at the same time without increasing the number of processors, so that the imaging cost is lower. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] By reading the detailed description below with reference to the accompanying drawings, the above and other objects, features and advantages of the exemplary embodiments of the present invention will become readily understood. In the accompanying drawings, several embodiments of the present invention are shown in an exemplary and non-limiting manner, and the same or corresponding reference numerals represent the same or corresponding parts, wherein:

[0020] Figure 1 The structure of the distributed device for spaceborne SAR fast BP imaging based on the geographic coordinate system is schematically shown;

[0021] Figure 2The flowchart of the distributed method of spaceborne SAR fast BP imaging based on geographic coordinate system is schematically shown. DETAILED DESCRIPTION

[0022] The exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0023] It should be noted that, unless otherwise specified, the technical terms or scientific terms used in the present invention should have the common meanings understood by those skilled in the art to which the present invention belongs.

[0024] The method in the embodiment of the present invention is described in detail below.

[0025] Figure 1 The structure diagram of the distributed device for spaceborne SAR fast BP imaging based on the geographic coordinate system in the embodiment of the present invention is schematically shown. Figure 1 As shown, the spaceborne SAR fast BP imaging distributed device based on the geographic coordinate system may include:

[0026] The distributed resource scheduling module 101 is used to divide the echo data into multiple echo data blocks in the azimuth direction according to the number of points in the azimuth direction, perform pulse compression on the multiple echo data blocks in the range direction to obtain multiple echo data blocks after pulse compression, take each echo data block after pulse compression as an imaging sub-scene, divide each imaging sub-scene into multiple sub-apertures according to a preset number of columns, assign a working slave node of a cluster to each sub-aperture, and send the data corresponding to each sub-aperture to the distributed storage module;

[0027] A distributed storage module 102, used to store data corresponding to each sub-aperture;

[0028] The working slave nodes 103 of the multiple clusters are used to obtain the data corresponding to each sub-aperture from the distributed storage module, and use the fast BP imaging algorithm to sequentially process the data corresponding to all sub-apertures in each echo data block after pulse compression in parallel to obtain multiple sub-aperture images corresponding to each echo data block after pulse compression, fuse the multiple sub-aperture images by an upsampling method to obtain multiple sub-scene images, and send the multiple sub-scene images to the distributed summary module;

[0029] The distributed summarization module 104 is used to perform coherent addition on the multiple sub-scene images to obtain at least one single-scene image with full resolution, and determine the imaging image according to the single-scene image.

[0030] Specifically, the number of multiple echo data blocks after pulse compression is the same as the number of multiple echo data blocks, and the number of multiple echo data blocks after pulse compression is the same as the number of multiple imaging sub-scenes. If the preset echo data block size is 8192*8192, the sub-apertures are divided, each sub-aperture is a power of 2, and generally 512 columns are one sub-aperture, that is, the preset number of columns can be 512 columns. Multiple sub-aperture images corresponding to an echo data block after pulse compression are fused by an upsampling method to obtain a sub-scene image, and multiple sub-aperture images corresponding to multiple echo data blocks after pulse compression are fused respectively to obtain multiple sub-scene images. Multiple sub-scene images are images with lower resolution.

[0031] The distributed resource scheduling module, the distributed storage module, the working slave nodes of multiple clusters and the distributed aggregation module are connected in sequence. The distributed resource scheduling module is used to manage the operating status of the working slave nodes of multiple clusters and distribute tasks to the working slave nodes of each cluster, that is, distribute the data corresponding to each sub-aperture, and the data corresponding to one sub-aperture is regarded as a task.

[0032] The distributed storage module is also used to store the running status of the working slave nodes of each cluster. The working slave nodes of multiple clusters are used to process the data corresponding to each sub-aperture in parallel. The distributed summary module is also used to display multiple sub-scene images.

[0033] The distributed resource scheduling module can be one or two powerful servers.

[0034] Before the distributed resource scheduling module, distributed storage module, multiple clusters of working slave nodes and distributed summary module determine the imaging image, it is necessary to build a computing framework for distributed devices, specifically: using distributed application coordination service software (Zookeeper) as a distributed coordination service tool to build a distributed environment to store the running status, load status and task execution status of distributed nodes. Using a distributed file system (Hadoop Distributed Filesystem, HDFS) as a distributed data storage environment. Using Kafka as a message middleware in a distributed environment, responsible for communication between modules and processing the push of intermediate results. Using an application container engine (Docker) to implement containerized deployment of services and container orchestration of distributed environments.

[0035] Build a distributed resource scheduling module to become the master node (Manager node). The function of the Manager node is to be responsible for task scheduling and load balancing of distributed devices, manage the operating status of multiple clusters of working slave nodes, the distribution of data corresponding to each sub-aperture, that is, tasks, task load status and task progress management, etc. It is also necessary to build multiple clusters of working slave nodes (Worker nodes). There are P working slave nodes in multiple clusters, P ≥ 2. The specific number of working slave nodes in multiple clusters can be configured according to actual task requirements. The function of the working slave nodes of multiple clusters is to be responsible for executing the tasks distributed by the master node, that is, the data corresponding to each sub-aperture. After building multiple clusters of working slave nodes, build a distributed file system, and divide the distributed file system into a storage source node (Storage Source) and a storage destination node (StorageDestination). There is one storage source node and multiple storage destination nodes.

[0036] Since the number of echo data blocks after pulse compression is large enough, the number of imaging sub-scenes is large enough, and the calculation time for the data corresponding to each sub-aperture is much longer than the time for pre-fetching echo data blocks, the transmission and calculation time can be better hidden.

[0037] The master node and slave node provided in the embodiment of the present invention, in conjunction with the distributed computing framework of the corresponding low-coupling algorithm, can be applicable to echo data processing in various situations. The modules are fully decoupled, and can achieve dynamic reduction and expansion of capacity, rapid data processing, rapid display of results, dynamic task scheduling and other functions.

[0038] In this embodiment, the working slave nodes 103 of the multiple clusters are specifically used to obtain the data corresponding to all sub-apertures in the first echo data block after pulse compression from the distributed storage module, and use the fast BP imaging algorithm to parallelly process the data corresponding to all sub-apertures in the first echo data block after pulse compression to obtain multiple first sub-aperture images corresponding to the first echo data block after pulse compression, and fuse the multiple first sub-aperture images through an upsampling method to obtain a first sub-scene image; the mth processing: obtaining the data corresponding to all sub-apertures in the mth echo data block after pulse compression from the distributed storage module, and using the fast BP imaging algorithm to parallelly process the data corresponding to all sub-apertures in the mth echo data block after pulse compression Perform parallel processing to obtain multiple m-th sub-aperture images corresponding to the m-th echo data block after pulse compression, fuse the multiple m-th sub-aperture images through an upsampling method to obtain the m-th sub-scene image; determine whether the m-th echo data block after pulse compression is the last echo data block after pulse compression, if so, take the first sub-scene image and the m-th sub-scene image as multiple sub-scene images, and send the multiple sub-scene images to the distributed summary module; if not, return to the m-th processing until the m-th echo data block after pulse compression is the last echo data block after pulse compression, stop processing, take the first sub-scene image and the m-th sub-scene image as multiple sub-scene images, and send the multiple sub-scene images to the distributed summary module.

[0039] In this embodiment, the distributed aggregation module 104 determines the imaging image based on the single-scene image, including: judging whether the single-scene image is of a preset size, if so, using the single-scene image as the imaging image; if not, splicing the single-scene images, outputting the full-scene image, and using the full-scene image as the imaging image.

[0040] Specifically, the preset size may be 8192*8192 or 4096*4096. The preset size is not specifically limited here, and is determined according to actual echo data.

[0041] In this embodiment, the distributed device for spaceborne SAR fast BP imaging based on the geographic coordinate system further includes a distributed file system, and the distributed file system includes a storage source node and a plurality of storage destination nodes.

[0042] In this embodiment, a storage source node is allocated in the distributed resource scheduling module, and multiple storage destination nodes are allocated in the working slave nodes of multiple clusters. The storage source node is used to store echo data in a distance-continuous manner, and the multiple storage destination nodes are used to store data corresponding to each sub-aperture.

[0043] In this embodiment, the number of the plurality of storage destination nodes is the same as the number of the plurality of working slave nodes of the cluster, and the plurality of storage destination nodes and the plurality of working slave nodes of the cluster are allocated in a one-to-one correspondence.

[0044] Specifically, when there are P working slave nodes in the multiple clusters and P≥2, there are also P corresponding multiple storage destination nodes and P≥2.

[0045] In this embodiment, the working slave nodes 103 of the multiple clusters are also used to send multiple sub-scene images to multiple storage destination nodes, and when there is an image query demand, read the corresponding sub-scene images and send the read sub-scene images to the distributed summary module.

[0046] In this embodiment, the distributed summarizing module 104 is used to obtain the read sub-scene image and display the read sub-scene image.

[0047] Based on the above Figure 1It can be seen from the implementation method that the distributed resource scheduling module of the embodiment of the present invention is used to divide the echo data into multiple echo data blocks in the azimuth direction according to the number of points in the azimuth direction, perform pulse compression in the range direction on the multiple echo data blocks to obtain multiple echo data blocks after pulse compression, use each echo data block after pulse compression as an imaging sub-scene, divide each imaging sub-scene into multiple sub-apertures according to a preset number of columns, assign a cluster of working slave nodes to each sub-aperture, and send the data corresponding to each sub-aperture to the distributed storage module; the distributed storage module is used to store the data corresponding to each sub-aperture; multiple clusters The working slave node of the group is used to obtain the data corresponding to each sub-aperture from the distributed storage module, and use the fast BP imaging algorithm to parallelly process the data corresponding to all sub-apertures in each echo data block after pulse compression in turn to obtain multiple sub-aperture images corresponding to each echo data block after pulse compression, and fuse the multiple sub-aperture images through an upsampling method to obtain multiple sub-scene images, and send the multiple sub-scene images to the distributed summary module; the distributed summary module is used to coherently add the multiple sub-scene images to obtain at least one full-resolution single-scene image, and determine the imaging image based on the single-scene image. In this way, the data corresponding to all sub-apertures in each echo data block after pulse compression are deployed on a distributed device, that is, deployed on working slave nodes of multiple clusters that can be processed in parallel. The working slave nodes of multiple clusters use the fast BP imaging algorithm of the geographic coordinate system to parallelly process the data corresponding to all sub-apertures in each echo data block after pulse compression. The working slave nodes of multiple clusters can process the data corresponding to multiple sub-apertures at the same time, so that the imaging processing time in high-orbit imaging is shorter even with a huge amount of data; using the fast BP imaging algorithm of the geographic coordinate system, a single-scene image with full resolution can be obtained in the end, so that the imaging resolution is higher; the working slave nodes of multiple clusters can process the data corresponding to multiple sub-apertures at the same time without increasing the number of processors, so that the imaging cost is lower.

[0048] Based on the same inventive concept, as an implementation of the above-mentioned distributed device for spaceborne SAR fast BP imaging based on a geographic coordinate system, an embodiment of the present invention further provides a distributed method for spaceborne SAR fast BP imaging based on a geographic coordinate system. Figure 2 FIG. 1 is a flow chart of a distributed method for spaceborne SAR fast BP imaging based on a geographic coordinate system in an embodiment of the present invention, see Figure 2 As shown, the distributed method for spaceborne SAR fast BP imaging based on the geographic coordinate system may include:

[0049] S201. Divide the echo data into a plurality of echo data blocks in the azimuth direction according to the number of points in the azimuth direction.

[0050] S202: Perform range-direction pulse compression on a plurality of echo data blocks to obtain a plurality of pulse-compressed echo data blocks.

[0051] S203: taking each echo data block after pulse compression as an imaging sub-scene, and dividing each imaging sub-scene into a plurality of sub-apertures according to a preset number of columns.

[0052] S204, obtaining data corresponding to each sub-aperture, and using a fast BP imaging algorithm to perform parallel processing on the data corresponding to all sub-apertures in each echo data block after pulse compression in turn, to obtain multiple sub-aperture images corresponding to each echo data block after pulse compression, and to fuse the multiple sub-aperture images through an upsampling method to obtain multiple sub-scene images.

[0053] Specifically, the data corresponding to each sub-aperture is obtained, and the fast BP imaging algorithm is used to sequentially process the data corresponding to all sub-apertures in each echo data block after pulse compression in parallel to obtain multiple sub-aperture images corresponding to each echo data block after pulse compression, and the multiple sub-aperture images are fused by an upsampling method to obtain multiple sub-scene images, including:

[0054] Step A1: Acquire the data corresponding to all sub-apertures in the first echo data block after pulse compression, use the fast BP imaging algorithm to parallel process the data corresponding to all sub-apertures in the first echo data block after pulse compression, obtain multiple first sub-aperture images corresponding to the first echo data block after pulse compression, and fuse the multiple first sub-aperture images through an upsampling method to obtain a first sub-scene image.

[0055] Step A2: mth processing: obtain the data corresponding to all sub-apertures in the mth echo data block after pulse compression, use the fast BP imaging algorithm to parallel process the data corresponding to all sub-apertures in the mth echo data block after pulse compression, obtain multiple mth sub-aperture images corresponding to the mth echo data block after pulse compression, and fuse the multiple mth sub-aperture images through the upsampling method to obtain the mth sub-scene image.

[0056] Step A3: Determine whether the mth echo data block after pulse compression is the last echo data block after pulse compression.

[0057] Specifically, it is determined whether the mth echo data block after pulse compression is the last echo data block after pulse compression. If so, step A4 is executed; if not, step A5 is executed.

[0058] Step A4: taking the first sub-scene image and the m-th sub-scene image as a plurality of sub-scene images.

[0059] Specifically, when the m-th echo data block after pulse compression is the last echo data block after pulse compression, the first sub-scene image and the m-th sub-scene image are taken as the multiple sub-scene images.

[0060] Step A5: Return to the mth processing until the mth echo data block after pulse compression is the last echo data block after pulse compression, then stop processing and treat the first sub-scene image and the mth sub-scene image as multiple sub-scene images.

[0061] Specifically, when the mth echo data block after pulse compression is not the last echo data block after pulse compression, return to the mth processing, that is, return to step A2, until the mth echo data block after pulse compression is the last echo data block after pulse compression, then stop processing and take the first sub-scene image and the mth sub-scene image as multiple sub-scene images.

[0062] S205 . Perform coherent addition on the multiple sub-scene images to obtain at least one single-scene image with full resolution.

[0063] S206: Determine an imaged image according to the single-view image.

[0064] Specifically, determining the imaging image according to the single-view image includes:

[0065] Step B1: Determine whether the single-view image is of a preset size.

[0066] Specifically, it is determined whether the single-view image is of a preset size, if so, executing step B2, if not, executing step B3.

[0067] Step B2: Use the single-view image as the imaging image.

[0068] Specifically, when the single-view image is of a preset size, the single-view image is used as the imaging image.

[0069] Step B3: stitching the single scene images, outputting the full scene image, and using the full scene image as the imaging image.

[0070] Specifically, when the single-scene images are not of the preset size, the single-scene images are spliced ​​to output a full-scene image, which is used as the imaging image.

[0071] It should be pointed out here that: the above description of the embodiment of the distributed method of spaceborne SAR fast BP imaging based on the geographic coordinate system is similar to the description of the embodiment of the distributed device of spaceborne SAR fast BP imaging based on the geographic coordinate system, and has similar beneficial effects as the embodiment of the distributed device of spaceborne SAR fast BP imaging based on the geographic coordinate system. For technical details not disclosed in the embodiment of the distributed method of spaceborne SAR fast BP imaging based on the geographic coordinate system of the embodiment of the present invention, please refer to the description of the embodiment of the distributed device of spaceborne SAR fast BP imaging based on the geographic coordinate system of the present invention for understanding.

[0072] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art who is familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A distributed device for spaceborne SAR fast BP imaging based on a geographic coordinate system, characterized in that: The spaceborne SAR fast BP imaging distributed device based on the geographic coordinate system includes: A distributed resource scheduling module is used to divide the echo data into multiple echo data blocks in the azimuth direction according to the number of points in the azimuth direction, perform pulse compression in the range direction on the multiple echo data blocks to obtain multiple echo data blocks after pulse compression, take each echo data block after pulse compression as an imaging sub-scene, divide each imaging sub-scene into multiple sub-apertures according to a preset number of columns, assign a working slave node of a cluster to each sub-aperture, and send the data corresponding to each sub-aperture to the distributed storage module; The distributed storage module is used to store the data corresponding to each sub-aperture; The working slave nodes of the multiple clusters are used to obtain the data corresponding to each sub-aperture from the distributed storage module, and use the fast BP imaging algorithm to sequentially process the data corresponding to all sub-apertures in each echo data block after pulse compression in parallel to obtain multiple sub-aperture images corresponding to each echo data block after pulse compression, fuse the multiple sub-aperture images by an upsampling method to obtain multiple sub-scene images, and send the multiple sub-scene images to the distributed summary module; The distributed aggregation module is used to perform coherent addition on the multiple sub-scene images to obtain at least one single-scene image with full resolution, and determine an imaging image based on the single-scene image.

2. The distributed device for spaceborne SAR fast BP imaging based on geographic coordinate system according to claim 1, characterized in that: The working slave nodes of the multiple clusters are specifically used to obtain data corresponding to all sub-apertures in the first echo data block after pulse compression from the distributed storage module, use the fast BP imaging algorithm to parallelly process the data corresponding to all sub-apertures in the first echo data block after pulse compression, obtain multiple first sub-aperture images corresponding to the first echo data block after pulse compression, and fuse the multiple first sub-aperture images through an upsampling method to obtain a first sub-scene image; the mth processing: obtaining data corresponding to all sub-apertures in the mth echo data block after pulse compression from the distributed storage module, use the fast BP imaging algorithm to parallelly process the data corresponding to all sub-apertures in the mth echo data block after pulse compression, and obtain the mth sub-scene image. a plurality of m-th sub-aperture images corresponding to the echo data block after pulse compression, and fusing the plurality of m-th sub-aperture images by an upsampling method to obtain an m-th subscene image; judging whether the m-th echo data block after pulse compression is the last echo data block after pulse compression, if so, taking the first subscene image and the m-th subscene image as the plurality of subscene images, and sending the plurality of subscene images to the distributed summary module; if not, returning to the m-th processing until the m-th echo data block after pulse compression is the last echo data block after pulse compression, then stopping the processing, taking the first subscene image and the m-th subscene image as the plurality of subscene images, and sending the plurality of subscene images to the distributed summary module.

3. The distributed device for spaceborne SAR fast BP imaging based on geographic coordinate system according to claim 1, characterized in that: The distributed aggregation module determines the imaging image based on the single-scene image, including: judging whether the single-scene image is of a preset size, if so, using the single-scene image as the imaging image; if not, splicing the single-scene images to output a full-scene image, and using the full-scene image as the imaging image.

4. The distributed device for spaceborne SAR fast BP imaging based on geographic coordinate system according to claim 1, characterized in that: The distributed device for spaceborne SAR fast BP imaging based on geographic coordinate system also includes a distributed file system, and the distributed file system includes a storage source node and a plurality of storage destination nodes.

5. The distributed device for spaceborne SAR fast BP imaging based on geographic coordinate system according to claim 4, characterized in that: The storage source node is allocated in the distributed resource scheduling module, and the multiple storage destination nodes are allocated in the working slave nodes of the multiple clusters. The storage source node is used to store the echo data in a distance-continuous manner, and the multiple storage destination nodes are used to store the data corresponding to each sub-aperture.

6. The distributed device for spaceborne SAR fast BP imaging based on geographic coordinate system according to claim 5, characterized in that: The number of the multiple storage destination nodes is the same as the number of the multiple working slave nodes of the cluster, and the multiple storage destination nodes and the multiple working slave nodes of the cluster are allocated in a one-to-one correspondence.

7. The distributed device for spaceborne SAR fast BP imaging based on geographic coordinate system according to claim 6, characterized in that: The working slave nodes of the multiple clusters are also used to send the multiple sub-scene images to the multiple storage destination nodes, and when there is an image query demand, read the corresponding sub-scene images and send the read sub-scene images to the distributed summary module.

8. The distributed device for spaceborne SAR fast BP imaging based on geographic coordinate system according to claim 7, characterized in that: The distributed summary module is used to obtain the read sub-scene image and display the read sub-scene image.

9. A distributed method for spaceborne SAR fast BP imaging based on geographic coordinate system, characterized in that: The distributed method for spaceborne SAR fast BP imaging based on geographic coordinate system includes: According to the number of points in the azimuth direction, the echo data is divided into a plurality of echo data blocks in the azimuth direction; Performing range-direction pulse compression on the plurality of echo data blocks to obtain a plurality of pulse-compressed echo data blocks; Taking each echo data block after pulse compression as an imaging sub-scene, and dividing each imaging sub-scene into a plurality of sub-apertures according to a preset number of columns; Acquire data corresponding to each sub-aperture, use a fast BP imaging algorithm to sequentially and in parallel process data corresponding to all sub-apertures in each echo data block after pulse compression, obtain multiple sub-aperture images corresponding to each echo data block after pulse compression, and fuse the multiple sub-aperture images by an upsampling method to obtain multiple sub-scene images; performing coherent addition on the multiple sub-scene images to obtain at least one single-scene image with full resolution; An imaging image is determined according to the single-view image.

10. The distributed method for spaceborne SAR fast BP imaging based on geographic coordinate system according to claim 9, characterized in that: The step of determining an imaging image according to the single-view image comprises: Determining whether the single-view image is of a preset size; If yes, the single scene image is used as the imaging image; If not, the single scene images are spliced ​​to output a full scene image, and the full scene image is used as the imaging image.

Images