Large beamwidth spaceborne SAR processing using chirp scaling

The accurate effective platform velocity and the effective closest approach range should be used to get a high resolution image when the chirp scaling algorithm (CSA) is employed in spaceborne SAR processing, especially, in the large beamwidth and squint modes. In this paper the two effective parameters are derived as a function of the Doppler centroid and the Doppler rate. Therefore, the classical clutterlock and autofocus methods can be used in CSA to get precise estimates of the effective parameters. Simulation results show that CSA using the effective velocity and closest slant range is suitable for L-band large beamwidth spaceborne SAR processing.