PFA Algorithm for Processing of Squint Spotlight Mode SAR Data

摘要

We developed a nonuniform-interpolation polar format algorithm for processing squint spotlight SAR data. Instead of two uniform interpolations for conventional polar format algorithm (PFA), this algorithm employs a one-dimensional uniform interpolation in range direction, a one-dimensional nonuniform interpolation in azimuth direction to remove squint and other along-track motion effects. The computational load of azimuth-nonuniform interpolation is almost the same as azimuth-uniform interpolation. For azimuth-nonuniform interpolation, the output sample spacing change as a function of the pulse number, squint angle and range, and can be easily computed. Theoretically, this algorithm can produce image with the same quality for squint image geometry as for broadside. Like conventional PFA, it can implement real-time compensation for cross-track motions and correct the effects of the out-of-plane. It is also compatible with autofocus. The computer-simulation results validate our algorithm and show good agreement with the analysis on the conventional PFA.