Two-Dimensional Phase Error Analysis and Compensation in Bistatic PFA Imagery Under Arbitrary Trajectories

In bistatic polar format processing, the planar wavefront assumption is utilized to simplify imaging processing. However, the resulted wavefront curvature error will result in severe smearing and geometry distortion in radar imagery. In this paper, a generalized model of the two-dimensional wavefront curvature error in bisatic PFA imagery under an arbitrary flight path is deduced and analyzed. Based on the derived model, a space variant refocus processing is proposed to realize wavefront curvature correction. In this method, the reference invariant compensation, range and azimuth variant filtering operations are applied sequentially. After using the space variant compensation, the effective focused scene size is extended and the refocused quality of bistatic PFA imagery is improved significantly. Finally, numerical simulations verify the validity of our method.