Theoretical Analysis on the Mismatch Influence of Displaced Phase Center Multiple-beam SAR Systems

By using multiple-receive apertures in azimuth, Synthetic Aperture Radar (SAR) systems are enabled with high-resolution and wide-swath imaging ability. In this paper, influence of channel imbalances on SAR systems with multiple-receive apertures in azimuth is derived theoretically. Azimuth multi-channel sequence is related with the single-channel sequence by use of zero padding. The result of the compression on mismatched multi-channel sequence shows that several ghosting peaks are presented around the main peak. Analytical formulas to calculate the Peek-to-Ghost-Ratio (PGR) and ghost locations are given, which show that the PGR is determined by the magnitude of channel mismatch, the number of the channels, the Doppler bandwidth and the azimuth oversampling ratio. The correctness of these formulas is validated further by simulation experiments.