Research On SAR Echo Simulation And Imaging Method Based On DSP Parallel Architecture

Synthetic Aperture Radar(SAR)has the characteristics of all-time,all-weather,high-resolution,and is not affected by the environment.At present,it has been widely used in military and civil fields.As SAR echo data under various conditions need to be used in the development process of SAR system,these data can not be obtained only by aircraft or satellite,so it is an important research content to generate echo data efficiently and accurately through echo simulation technology.At the same time,it is also very important to study efficient time-domain imaging methods.Starting from SAR echo simulation and Back-Projection(BP)imaging algorithm,this thesis deeply studies the basic principle of the algorithm,and deeply studies the software optimization design of the algorithm based on TMS320C6678 hardware platform.Finally,the parallel design and implementation scheme of the algorithm is studied through DSP parallel computing platform.The main work of this thesis is as follows:1.The working mechanism and high-resolution principle of SAR are analyzed,and the mathematical model of SAR echo is deduced.The principle of time-frequency domain echo simulation algorithm and BP algorithm are studied,and the formula is deduced,which lays a foundation for the hardware implementation and parallel design of the later algorithm.2.The software optimization method of TMS320C6678 chip is deeply studied,and the optimization test is carried out for vector multiplication;The SAR echo simulation and BP imaging algorithm are analyzed,and an efficient software pipeline structure is designed;The memory allocation,FFT optimization and code optimization in the process of algorithm execution are studied in detail,and the optimal design of single accounting method is realized.The echo simulation and imaging simulation experiments are carried out with standard SAR images to verify the correctness of the algorithm optimized by DSP software;After the experimental test,it is concluded that the single core acceleration ratio of echo simulation is about 20 times that of CPU,and the BP imaging is 10 times that of CPU,which greatly improves the execution speed of the algorithm.3.The workflow and usage of the parallel computing platform based on TMS320C6678 are introduced;The data stream sending and reading methods of each link of parallel processing are optimized,and the user interface is designed.The parallel mode and data storage mode of time-frequency domain echo simulation algorithm and BP imaging algorithm are studied,and the parallel implementation scheme based on the platform is given.Finally,the parallel performance of SAR echo simulation and BP imaging is analyzed.After parallel design,it can quickly complete SAR echo simulation and BP imaging processing of large scenes.