An efficient Non-Linear Chirp Scaling method of focusing bistatic SAR images

Bistatic SAR data processing parameters, unlike monostatic SAR data, are generally azimuth-variant. The Non-Linear Chirp Scaling (NLCS) algorithm introduced in this paper is able to handle the azimuth variance. It focuses a bistatic image by first introducing a bulk linear range cell migration correction followed by a chirp scaling process to equalize the azimuth chirp rates for all targets in the same range gate. Efficiency is achieved by applying matched filtering in the azimuth frequency domain. A technique to perform image registration from the focused image to the ground plane is also discussed. This algorithm is verified with a simulation experiment.