Two Factors Influencing Residual Motion Estimation in Airborne SAR Images with MTPT: Two Factors Influencing Residual Motion Estimation in Airborne SAR Images with MTPT

Due to the poor accuracy of navigation systems, deviations of the order of centimeters between the real and measured trajectories, called residual motion errors, frequently occur in SAR images. For airborne SAR systems with very high resolution and airborne repeat-pass SAR interferometry, the residual motion errors must be estimated and compensated. Multi-squint Technique with Point Targets (MTPT) is able to estimate the residual motion errors for an individual SAR image, but errors in the platform velocity and the slant range will deteriorate the accuracy of the method. In this paper, we validate this by performing detailed analysis of the velocity and slant range to residual motion error estimation using both simulated and real SAR data. It is also shown that MTPT is able to estimate the errors in the velocity and slant range, and it is sensitive to the phase error. Therefore, it is advised that the errors in the velocity and slant range should be removed using other precise methods before