Research on Fast BP Imaging Algorithm of Short-Range Missile-Borne SAR Based on Attention Mechanism

For short-range synthetic aperture radar, the wavefront is needed to be processed strictly in accordance with spherical waves. BP algorithm is a vital technique to enable a short-range imaging scenario with no approximations and assumptions in its derivation. However, BP performs pixel-by-pixel processes, yields heavy computational burden and limits its realtime processing. To address these problems, a fast BP imaging algorithm for short-range missile-borne SAR based on attention mechanism is proposed. During this imaging processing, the targets range profiles after de-chirping are obtained by utilizing the range-direction pulse compression. Then by analyzing the range direction information, the regions where the target appears are used for the short-range SAR image reconstruction. Benefiting from the reducing the imaging area, the computational efficiency of back projection algorithm is greatly improved while ensuring the high azimuth. The BP fast imaging algorithm based on local attention has a speed-up factor proportional to the azimuth resolution compared to BP algorithm. The simulation demonstrates the effectiveness and efficiency improvement of the proposed BP fast imaging algorithm based on local attention.