Efficient Rotating Synthetic Aperture Radar Imaging via Robust Sparse Array Synthesis

TL;DR

This paper introduces a robust sparse array synthesis method for rotating SAR imaging that significantly reduces computational complexity while maintaining high image quality, enabling real-time applications.

Contribution

It proposes a novel robust sparse array synthesis approach with an efficient optimization algorithm, improving SAR imaging speed without sacrificing accuracy.

Findings

Achieves up to 90% reduction in computational time.

Maintains image quality comparable to traditional BPA.

Validated through extensive simulations and real-world experiments.

Abstract

Rotating Synthetic Aperture Radar (ROSAR) can generate a 360$^\circ$ image of its surrounding environment using the collected data from a single moving track. Due to its non-linear track, the Back-Projection Algorithm (BPA) is commonly used to generate SAR images in ROSAR. Despite its superior imaging performance, BPA suffers from high computation complexity, restricting its application in real-time systems. In this paper, we propose an efficient imaging method based on robust sparse array synthesis. It first conducts range-dimension matched filtering, followed by azimuth-dimension matched filtering using a selected sparse aperture and filtering weights. The aperture and weights are computed offline in advance to ensure robustness to array manifold errors induced by the imperfect radar rotation. We introduce robust constraints on the main-lobe and sidelobe levels of filter design. The resultant robust sparse array synthesis problem is a non-convex optimization problem with quadratic constraints. An algorithm based on feasible point pursuit and successive convex approximation is devised to solve the optimization problem. Extensive simulation study and experimental evaluations using a real-world hardware platform demonstrate that the proposed algorithm can achieve image quality comparable to that of BPA, but with a substantial reduction in computational time up to 90%.