Efficient Simulation of Airborne SAR Raw Data of Extended Scenes

In another paper, which is the first part of this work, a 2-D Fourier domain SAR raw signal simulator, exploiting the efficiency of FFT algorithms, has been presented: it accounts for the effects of sensor trajectory deviations and is able to generate the raw signal corresponding to extended scenes in a few seconds. However, a narrow beam - slow deviation assumption is made, so that the approach can be applied only to some SAR systems and/or trajectory deviations. In order to overcome this limitation, in this paper we show that the narrow beam - slow deviation assumption can be relaxed, at the expense of computation efficiency, if use is made of a 1-D azimuth Fourier domain processing followed by a range time domain integration. This latter approach only requires some reasonable assumptions on the sensor motion and on the SAR system features, so that it can be used for airborne SAR systems, and turns out to be still much more efficient than the time domain one, so that extended scenes can still be considered. Validity limits of the approach are also analytically evaluated, and several simulation results are finally presented in order to verify the effectiveness of the proposed simulation scheme.