Circumferential scanning ground-based SAR frequency domain 3D imaging algorithm

Circumferential scanning ground-based SAR (GBCSAR) is a ground-based SAR system with three-dimensional imaging capabilities. Its motion trajectory is special, which makes three-dimensional imaging difficult. The Back Projection (BP) algorithm is suitable for imaging in this system, but its computational complexity is huge and it is difficult to realize real-time imaging. The frequency domain algorithm applied to the imaging of airborne circular-track SAR systems cannot be applied to GBCSAR due to the differences in imaging models and signal models between airborne circular-track SAR and GBCSAR systems. Therefore, this paper proposes a frequency domain 3D imaging algorithm for GBCSAR. Based on the GBCSAR system model, this paper derives the analytical expression of the signal converted from the slant distance plane to the imaging plane, and performs matched filtering in the frequency domain to achieve signal focusing. The applicable conditions of this algorithm will be discussed later. Finally, through simulation experiments, the algorithm proposed in this paper is verified, and the imaging quality and imaging efficiency of the algorithm in this paper and the BP algorithm are compared, which proves that the frequency domain imaging algorithm proposed in this paper can achieve efficient imaging.