Precise Simulation of Spaceborne Synthetic Aperture Radar and Its Evaluation

Simulation technique becomes increasingly important with the development of Synthetic Aperture Radar (SAR). It can be applied for many purposes such as testing different imaging algorithms and validating different SAR system design parameters[1]. For improving the precision of simulator determination of the location (mainly refers to latitude) of satellite which illuminates the fixed scene center is reconsidered in this paper. As attitude of satellite strongly affects Doppler parameters, determination of attitude is also discussed for simulated system approaching real system. Although attitude determination based on Doppler centroid was studied in many articles[2][3], this paper utilizes the information about the footprint shape of beam, and develops the equations relating yaw, pitch and especially roll to slant range and Doppler shift of echo data. We can get the attitude of satellite by solving these equations. Then for validating and evaluating the simulated system, this paper describes a novel approach which involves imaging combination of real and simulated echo data. Doppler parameters adopted in imaging algorithm before and after combining are identical. Effect of focalizing simulated echo data indicates whether the simulated system is acceptable, and relative error of geometric distortion which appears in the SAR image reflects the approaching degree of simulated system to real system. Test was conducted by generating simulated data for RADARSAT-1, the result shows the precision of location and attitude determination and validation of this evaluation approach.