Motion compensation for airborne interferometric SAR

In order for airborne Interferometric SAR (InSAR) to be capable of generating useful digital elevation models (DEMs), accurate motion compensation must be performed on both simultaneously received channels. The InSAR approach to motion compensation differs from the conventional single channel case due to the fact that two antennas are involved and the differential phase between the two channels is the most important parameter in InSAR. Phase compensation of both channels to the same reference track and compensation to two separate tracks are considered. The single track approach allows track segmentation to follow aircraft drifts without causing discontinuities in the differential phase, but is sensitive to range cell migration effects. The dual track approach is not sensitive to these errors but suffers from discontinuous differential phase at segmentation boundaries, which complicates the phase unwrapping process. A new approach that combines the benefits of each is proposed. This involves using dual reference tracks with a post-compression phase adjustment to simulate a single track