Research On Real-time Imaging Technology Of Spaceborne SAR

The spaceborne synthetic aperture radar has a high orbit and wide geographic coverage,and has broad application prospects.Traditional remote sensing satellites need to go through spaceborne storage,satellite-to-ground data transmission,and ground reception to process multiple link links.The time delay is long and the response speed is slow.In order to improve the timeliness of the application of spaceborne SAR,this paper studies the real-time imaging technology of spaceborne SAR,and the main work completed is as follows:1.Based on the basic working principle of real-time imaging of spaceborne SAR,the indicators of real-time imaging scheme of spaceborne SAR are demonstrated based on the inherent relationship between parameters.Subsequently,the real-time imaging algorithm of spaceborne SAR is described,and the imaging effects of distance Doppler algorithm and linear frequency modulation algorithm under spaceborne conditions are compared through point target simulation,and profile diagrams evaluate algorithm performance.2.According to the real-time and large calculation requirements,a real-time imaging processing board for spaceborne SAR is designed.Through the design of common pulse pressure modules,the three software development methods,traditional register transfer level development,system generator development and high-level synthesis development,are compared.Aiming at the problem of long development cycle of spaceborne SAR real-time imaging software,the development and design method combining SYSGEN development and traditional RTL development is studied to accelerate the design and development of spaceborne SAR real-time imaging software.3.Optimized the calculation process of the CS imaging algorithm,and completed the task segmentation and hardware mapping for the spaceborne SAR algorithm process.Aiming at the problem of large data transposition delay,the switching process of the working state of DDR3 SDRAM in pipeline mode is designed.Accelerate the development of real-time imaging function modules for spaceborne SAR with the help of SYSGEN development methods,including spectrum centralization coefficient calculation module and CS phase factor calculation module.Simulate and verify the functionality of the module in Vivado software and analyze its errors.After the function module is encapsulated with IP,the control module is designed through the traditional RTL development method to complete the development of real-time imaging software for spaceborne SAR.4.Analyzed the resource consumption and real-time performance of the spaceborne SAR real-time imaging software,and used the spaceborne measured data as the data source to simulate the radar echo scene,and tested the function of the spaceborne SAR real-time imaging software.The isolated target points extracted from the imaging results are analyzed to evaluate the performance of real-time imaging software for spaceborne SAR.This paper first introduces the basic principles and algorithms of real-time imaging technology of spaceborne SAR,and compares the performance of RD algorithm and CS algorithm.According to real-time requirements,a real-time imaging processing board for spaceborne SAR was designed.Then,through the development and design method combining SYSGEN development method and traditional RTL development method,the real-time imaging software design of spaceborne SAR is completed.Finally,the actual performance of spaceborne SAR imaging software is evaluated using the measured data from spaceborne data as the data source.The spaceborne SAR real-time imaging processing software designed in this paper can effectively improve the efficiency of spaceborne SAR applications and reduce the pressure of satellite-to-ground digital transmission.