Fast raw signal simulation based on equivalent scatterer and subaperture processing for one-stationary bistatic SAR

A fast raw signal simulation method based on the equivalent scatterer and subaperture processing for the one-stationary bistatic synthetic aperture radar (OS-BSAR) is presented. It considers the radar's motion error to simulate the more accuracy raw signal. First, the OS-BSAR geometry is built in elliptical polar coordinate, and then the scene is divided into several equidistant elliptical rings. Based on the equivalent scatterer, the approximate SAR system transfer function is derived, thus each pulse's raw signal is calculated by the convolution of the transmitted signal and transfer function, using the fast Fourier transform (FFT). To further improve the simulation speed, the subaperture and subscene processing are used. The transfer function for the same subaperture's pulses is calculated by the weighted sum of all the subscenes' equivalent scattering coefficient in the same equidistant elliptical ring, using the nonuniform FFT (NUFFT). This method involves NUFFT, FFT and complex multiplication, which means the easier operation and higher speed. Implementation of the proposed method is discussed. Simulation is given to prove the validity of the proposed method.