Modified Polar Format Algorithm for Spotlight SAR with High Squint and Dive Angle

Polar format algorithm (PFA) is a popular imaging algorithm for squint mode SAR due to its high computational efficiency and high focus accuracy. However, when the radar platform has a high dive angle, the conventional PFA will suffer from poor computational efficiency due to the distorted 2-D spectrum support in high dive mode. In this paper, a modified PFA is proposed. The new algorithm chooses the slant plane, instead of the ground plane in the conventional PFA, as the image formation plane. Because the 2-D spectrum support in the slant plane will have much less distortion than the ground plane, the polar reformatting process in the PFA will have much higher computational efficiency. Finally, a modified geometric distortion correction from the slant plane to the ground plane is proposed to compensate for the wavefront curvature effect in the PFA.