Efficient simulation of airborne stripmap SAR raw signal of extended scenes

Abstract

Synthetic aperture radar (SAR) raw signal simulation is very useful for validating SAR system design parameters, for testing the effectiveness of different processing algorithms, and for other applications. If a nominal sensor rectilinear line of flight is assumed, frequency domain raw signal simulation can be used to generate the raw data with high efficiency compared with time domain simulation. Due to the inevitable atmosphere turbulence for airborne SAR system, SAR sensors trajectory deviations and attitude variations may simultaneously occur. Some improved Fourier domain SAR raw signal simulators with respect to trajectory deviations or attitude variations have been presented several years ago. However, the improved frequency domain raw data simulation cannot account for the effects of both sensor trajectory deviations and attitude variations for non zero squint. In this paper, an efficient SAR raw signal simulator accounting for trajectory deviations and attitude variations in the non zero squint is presented, which is much more realistic for airborne SAR system. The procedure is based on the amplitude of antenna boresight pointing error is small enough compared to the beamwidth. Then the received signal can be divided into different components. The proposed simulation approach to evaluate each component relies on using one-dimensional (1-D) azimuth Fourier domain processing followed by time-domain integration. Hence, the approach has a high efficiency than the time-domain one and allows for a subsequent extended scene consideration. Validity limits of the proposed approach are analytically evaluated, and some simulation results are also given to verify the effectiveness of the proposed simulation scheme.