Spherical Wave Decomposition Based Polar Format Algorithm for ArcSAR Imaging

Abstract

Arc synthetic aperture radar (ArcSAR) is a remote imaging technology with the ability of wide field of view in the principle of ground-based synthetic aperture radar (GB-SAR). The existing ArcSAR imaging algorithms have the problems of low computational efficiency as the scene expands and reduced imaging accuracy caused by the slant-range approximation. To avoid these problems, this article proposes a polar coordinate format algorithm based on spherical wave decomposition. First, the echo signal in the form of spherical wave is decomposed into an integral of plane waves. Second, according to the integration, an angular filter can be constructed by virtue of the convolution theorem, which is used to eliminate the high-order phase error in the scanning angle direction. Next, the interpolation from the polar to rectangular coordinates on the filtered signal is performed to achieve decoupling of the scanning angle and wavenumber. Finally, the target focusing is achieved by 2-D inverse Fourier transform. In this article, the imaging process is analyzed through simulation experiments and compared with other imaging algorithms in terms of imaging accuracy and efficiency. Moreover, the actual data are used for verification.