ChirpScaling算法中的相位补偿因子研究.PDF

29 1 Vol.29No.1 2007 1 Journal of Electronics Information Technology Jan. 2007 Chirp Scaling ( 410073) : SAR SAR CS(Chirp Scaling) (Ultra WidebandUWB)SAR CS SAR SAR UWB SAR CS UWB SAR UWB SAR : SAR CS UWB SAR TN957.52 A 1009-5896(2007)01-0006-06 Research on Phase Compensating Factors in Chirp Scaling Algorithm Wang Liang Wang Jian Huang Xiao-tao Zhou Zhi-min (Dept. of Electronic Technology, NUDT, Changsha 410073, China) Abstract: In this paper the two-dimensional frequency expression of SAR echoes are first analyzed. Then, the standard chirp scaling algorithm and its several modified forms used both in high frequency narrow band SAR and low frequency Ultra WideBand (UWB) SAR are compared in a united frame of two-dimensional frequency expression. The approximations made by different algorithms are evaluated in detail. So a new depiction for SAR image formation is proposed, which is a process of constructing phase compensating factors in frequency or time domain according to the characteristics of echo spectrum. Especially, the accuracy of phase compensating factors for UWB SAR echoes has a direct impact on point targets focusing. Simulation results verify that the modified non-linear chirp scaling algorithm, which can compensate the more third orders phase coupling, can arrive an ideal focusing UWB SAR image in the certain of scope. Further more, the algorithm has been used successfully in raw UWB SAR data processing. Key words: SAR imaging; 2D spectrum; CS algorithms; Phase compensating factor; UWB SAR imaging 1 SAR CS (SAR) 90 (UWB)SAR