A High-Order Motion Parameter Estimation Method for Multistatic GEO SAR Based on Improved Fractional Fourier Transform

Compared with the traditional airborne synthetic aperture radar (SAR), multistatic Geosynchronous SAR (GEO SAR) has a larger observation range and a short revisit time. These characteristics enable better observation of the interesting region. However, due to the curved orbit and high orbit altitude of GEO SAR combined with non-cooperative target movements, the instantaneous slant range between GEO SAR and a moving target will be expressed as a high order Taylor series. In this paper, a high-order motion parameter estimation method based on improved fractional Fourier transform (FrFT) is proposed. This method is designed to estimate the motion parameters in the 4thorder range model of multistatic GEO SAR and refocus the moving target. The effectiveness of the proposed method is validated by simulation results.