Deramp based frequency scaling algorithm suitable for tandem bistatic SAR in the spotlight mode

Using an analytical bistatic spectrum and the spectrum analysis (SPECAN) method, an algorithm that is suitable for constant-offset spotlight bistatic SAR is presented. Firstly, the deramp function for bistatic SAR is deduced by analog of the monostatic case, which accomplishes the coarse focusing in the azimuth direction and solves the azimuth spectral folding problem effectively. Then an analytical bistatic spectrum based frequency scaling algorithm is applied to achieve the range cell migration correction, which is implemented through phase multiplication instead of interpolation. Data obtained with the large baseline can be processed accurately. The effectiveness of the proposed algorithm is verified with simulation experiments.