An Improved Earth-Based Radar High-Resolution Imaging Technology of the Moon Based on Polar Format Algorithm

The polar format algorithm (PFA) is a high-resolution imaging algorithm suitable for earth-based radar imaging of the moon. However, the earth-based radar imaging of moon has the problem of out-of-plane motion, which seriously deteriorates the imaging quality of the PFA. This paper first analyzes the basic principles of polar format algorithm based on the geometric model of the Earth-Moon motion. Then it quantitatively analyzes the influence of plane wavefront assumption and out-of-plane motion on imaging, and proposes an improved PFA high-resolution imaging algorithm. Based on the quantitative analysis of the spatial variance of the phase error, the proposed algorithm divides the whole imaging scene into multiple sub images. Then, the proposed algorithm compensates the phase error of the sub image successively and further obtain the well-focused imaging result of the whole scene by sub image stitching. Finally, the proposed algorithm is verified by the computer simulation.