A numeric range migration algorithm of space- surface bistatic SAR

Focusing on the continuous wave spaceborne-airborne bistatic synthetic aperture radar (SAR) system where satellites of global navigation satellite system (GNSS) as transmitters and the airborne radar as the receiver, we propose a fast numeric range migration algorithm (RMA). Firstly, based on the concept of instantaneous Doppler wavenumber, analytic formula of the point spread response in the spectral domain is developed for bistatic SAR(BiSAR) with unequal velocity and parallel trajectory constellation. Then, relying on a first-order Taylor expansion of the above formula with respect to the parameter called the sum of closest distances on the swath center, a bistatic RMA algorithm is proposed for BiSAR imaging. Simulation results have confirmed the effectiveness of the proposed novel approach.