Motion errors in airborne SAR interferometry

The focus of this paper is on estimating the errors introduced by roll acceleration in interferometric elevation models. It is shown how the reference elevation offset introduced by offline motion compensation contributes to an elevation error in the resulting interferometric terrain model when sizable roll accelerations occur. From the derived error estimation one finds that the elevation errors increase in a quadratic manner with azimuth resolution. The elevation error increases in a nearly linear manner with roll acceleration and reference elevation offset. In order to onset these elevation errors the authors propose two different approaches. The first method uses nonoverlapping subaperture interferograms to produce differential interferograms which are then used along with the attitude data to obtain the reference elevation offsets. The second method utilizes a third antenna located at the baseline center to obtain the residual roll angle of the inteferometric baseline