Intra-pulse Spotlight SAR Imaging Method Based on Azimuth Phase Coding

Abstract

The intra-pulse spotlight imaging mode can effectively overcome the contradiction between high resolution and wide swath in spaceborne Synthetic Aperture Radar (SAR), and considers the echo’s signal-tonoise ratio. However, signal division by spatial filtering along the range direction may be impacted by fluctuating terrain. To solve this problem, a novel intra-pulse spotlight imaging method based on Azimuth Phase Coding (APC) is proposed in this paper. Using APC, the azimuth spectrum of echo data from different sub-pulses will locate in different Pulse Repetition Frequencies (PRF). As such, the signal can be divided using an azimuth adaptive beamforming technique. The signal separation method and selection of the shift factor are discussed in detail. Finally, simulation results demonstrate the effectiveness of the proposed method.