Frequency-Domain Imaging Algorithm for SA-BiSAR Based on Azimuth Dealiasing

Abstract

For the Doppler parameters coupling and spectral aliasing in the hybrid sliding spotlight mode of the spaceborneairborne bistatic SAR, a frequency domain imaging algorithm based on echo preprocessing is proposed in this paper. The article utilizes the idea of spectral analysis (SPECAN) technology to remove the spectrum aliasing by echo preprocessing, without subaperture partition and subaperture stitching operations, which reduces the computational burden. On this basis, the Legendre orthogonal polynomial expansion method is used to achieve a high accuracy approximation of the spaceborneairborne bistatic SAR (SA-BiSAR) slant range function. Combined with the method of series reversion (MSR), the accurate two-dimensional spectrum of the point target is derived, so that the high quality decoupling of the two-dimensional spectrum is achieved. Finally, the compensation functions are designed to complete the focusing imaging in the frequency domain. The simulation results of point targets and distributed targets show that the imaging algorithm proposed in this paper has good focusing performance and can improve the imaging quality of scene edge points.