Adaptive frequency domain imaging algorithm in geosynchronous SAR

The biggest challenge for GEO SAR imaging is to compensate the Doppler parameter space-variance properly. The problem of velocity space-variance becomes severe in GEO SAR due to the effect of earth rotation and large imaging area. In addition, the direction of velocity space-variance is very difficult to determine in Equator due to the very complex geometry relationship among satellite motion, earth rotation and imaging scene, thus making it difficult to be compensated. These problems can´t be solved with present GEO SAR imaging algorithm. This literature proposes an improved secondary range compression (SRC) algorithm. The GEO SAR signal model is obtained firstly. The effects of velocity space-variance on each term of GEO SAR signal two-dimension spectrum are analyzed. Then, the velocity space-variance is described based on a velocity model, the effect of velocity space-variance is compensated by means of adaptive phase compensation processing. Finally, the correctness of this method is proved through target points simulation.