A Range Ambiguity Resolution Method for High-Resolution and Wide-Swath SAR Imaging Based on Continuous Pulse Coding

In synthetic aperture radar (SAR), high-resolution and wide-swath (HRWS) imaging is a challenging problem due to the contradiction between azimuth Doppler ambiguity and range ambiguity. In order to break the limitation of the pulse repetition frequency (PRF) on the radar imaging width, a HRWS SAR imaging method based on continuous pulse coding (CPC) to solve the range ambiguity is proposed in this paper. CPC method requires the radar to transmit multi-pulse signals with varying high PRF in the original pulse repetition period. Because of the small distance between each pulse, the echo will be aliased and blocked. In order to recover the unambiguous echo, we first use the form of CPC signal and the swath width of the radar to construct a linear equation set to mathematically model the aliased echo signal of each receiving window. Next, the established linear equations are split according to the distribution law of the receiving window, and the range ambiguity of the echo is performed by solving the split sub-linear equations. Finally, imaging processing is performed on the decoded unambiguous echo to achieve HRWS SAR imaging. The experimental results have confirmed the effectiveness of the method proposed in this paper.