Focusing Multistatic GEO SAR With Two Stationary Receivers Using Spectrum Alignment and Extrapolation

Multistatic geosynchronous synthetic aperture radar (GEO SAR) system, with a geosynchronous illuminator and two stationary receivers, can provide high-resolution images for certain area. The spatially variant gaps in the azimuth spectrum, however, may introduce artifacts into images, which degrade the image quality. To fill the spectrum gaps, a new imaging method using spectrum alignment and extrapolation is proposed in this letter. The spectrum of the scene is aligned based on spectrum shifting and range Doppler projection, and a complete azimuth spectrum is obtained by spectrum extrapolation and coherent summation. Simulation results of point targets and extended targets verify the efficacy of the proposed method.