A Fourth-Order Imaging Algorithm for Spaceborne Bistatic SAR

Eldhuset´s research, the fourth-order Extended Exact Transfer Function (EETF4), indicates that the range history of a high spatial resolution spaceborne SAR can be modeled by a fourth-order Taylor expansion in azimuth time. In this paper, this point of view is introduced in bistatic SAR, and the transfer functions in the 2-D frequency and the range-Doppler domains are derived. Using this method, an efficient bistatic focusing solution based on squinted mode chirp scaling (CS) algorithm which accommodates both tandem and TI case is developed. Quantitative analysis and simulations are also provided.