Trajectory deviations in airborne SAR: Analysis and compensation

This paper concerns the analysis and compensation of trajectory deviations in airborne synthetic aperture radar (SAR) systems. Analysis of the receive d data spectrum is carried out with respect to the system geometry in the p resence of linear, sinusoidal, and general aircraft displacements. This sho ws that trajectory deviations generally produce spectral replicas along the azimuth frequency that strongly impair the quality of the focused image. B ased on the derived model, we explain the rationale of the motion compensat ion (MOCO) strategy that must be applied at the SAR processing stage in ord er to limit the resolution loss. To this end aberration terms are separated into range space invariant and variant components. The former can be accou nted for either in a preprocessing step or efficiently at range compression stage. The latter needs a prior accommodation of range migration effect. W e design the procedure for efficient inclusion of the MOCO within a high pr ecision Scaled PT based SAR processing algorithm. Finally, we present resul ts on simulated data aimed at validating the whole analysis and the propose d procedure.