Engineering Optimization And Verification For Spaceborne Multi-mode SAR Imaging Algorithm

Synthetic aperture radar-SAR is a kind of all-day,all-weather;two-dimensional imaging radar and it has been extensively applied in military and civilian aspects.Spaceborne SAR imaging processing technology is an important means of remote sensing and earth observation.Spaceborne SAR has many imaging modes and processing algorithms.The development of Spaceborne SAR with high resolution produce instant access to tremendous up-to-date SAR data,which requiring Spaceborne SAR processors with high computing power and large storage capacity.But,because of space environment,Spaceborne SAR imaging system had some restrictions on physical size,weight,and power consumptions,it blocked to achieving real-time processing for the space-borne SAR imaging system.So how to solving the contradiction between high resolution and large hardware utilization become one of most urgent topic.In this paper,we utilize fixed-point algorithms and engineering optimization of complex operation to get a trade-off between precision and memory occupation.All of main works are as follows:1.Study of fixed-point algorithm for multi-mode spaceborne SAR imaging algorithm.By analyzing amount of computations in the Multi-mode spaceborne SAR imaging algorithm,FFT is chosen as a key operation to realize fixed-point algorithm.By analyzing the error propagation of fixed-point FFT algorithm,a analytical relationship between word configuration and fixed-point FFT output signal to noise ratio is obtained and verified.The analytical relationship is help to determine the optimal word-length configuration for fixed-point FFT algorithm.2.Study of engineering optimization for complex operations in multi-mode spaceborne SAR imaging algorithm.Linearing the process of prescribing and fitting operation,it will reduce the implementation complexity.By analyzing the influence of phase compensation factor on the multi-mode spaceborne SAR imaging algorithm,adopting area invariant compensation factor.This method as the premise of ensuring imaging quality,and it can decrease the computation complex of compensation factor and improve SAR imaging processing algorithm efficiency.By analyzing the number of multiplier in FFT algorithm,high-radix FFT algorithm is ultilized to reduce the number of multiplications.High-radix FFT algorithm will improve the real-time processing capabilities of FFT.Realizing big points FFT module based on small points FFT module,it will reduce hardware consumption.3.Build system-level verification environment for multi-mode spaceborne SAR imaging algorithm to verify the superiority of proposed optimal solution.The SystemC-based verification platform is established to assess the effect of optimization method.By combining theoretical analysis and simulation methods,the optimal operation optimization scheme and the optimal word-length configuration for fied-point FFT are determined.The results of simulation indicate that the scheme of engineering optimization can meet the imaging precision,it can reduc resources occupation and meet the requirement of real-time processing.