Analysis And Algorithm Of Space-borne SAR With High-resolution And Consecutive Wide-swath

High resolution and wide swath are the most important characteristics of space-borne SAR. Unfortunately, both spotlight mode and scan mode can only improve one characteristic but reduce the other one. Theoretically, multiple elevation beam (MEB) SAR, single phase center multibeam in the azimuth direction (SPCA) SAR and displaced phase center multibeam in the azimuth direction (DPCA) SAR can improve one characteristic and not affect the other one. The common drawback of MEB SAR and SPCA SAR is that adjacent beams interference with each other. So DPCA SAR is more attractive. The other reason of selecting DPCA SAR is that it can reduce PRF, which is very important for space-borne SAR system. To avoid nadir round-trip time and pulse sending time, blind zones present. The density of blind zones relate to PRF consanguineously. Lower is PRF, lower is the density of blind zones, which is to say the infection of blind zones is lower.Blind zones also exist in DPCA SAR. In this paper, the new method PRF alterable DPCA can get not only both high resolution and wide swath, but also consecutive swaths; it is a perfect mode of spcae-borne SAR. The work we do includes as follows.We analyze the spectrum, nonuniform noise and the affection of nonuniform noise of signals in the azimuth direction of DPCA SAR when PRF deviate the ideal value; analyze the location of ghost targets; anzlyze the characteristics of spectrum of ideal signals in the azimuth direction of DPCA SAR; select the method to slove the non-uniformly sampling matter of DPCA SAR when PRF deviate the ideal value; analyze the infection of coupling of range and azimuth ofDPCA SAR when PRF deviate the ideal value; demonstrate fast algorithms for spcetrum construction which can improve the effection of imaging processing of PRF alterable DPCA SAR.