Research on nonlinearity correction imaging algorithm of FMCW SAR

The frequency modulated continuous wave synthetic aperture radar (FMCW SAR) is a newly proposed radar imaging system, which combines FMCW technique with synthetic aperture imaging methods and has the advantages such as small cubage, light weight, cost-efficient, highresolution, etc. In practical SAR system, the frequency and time of the frequency modulated signal can´t keep linearity absolutely. The effects of nonlinear frequency modulation on range resolution and FMCW SAR imaging are analyzed. A method of polynomial fit is proposed in order to estimate the nonlinearity of the frequency modulated signal, and the nonlinearity is corrected. Nonlinear FMCW SAR imaging algorithm is researched. Then the simulation results are presented. The results show that this method is valid.