A High Accurate Approach for InSAR Flat Earth Effect Removal

Synthetic aperture radar interferometry (InSAR) technique is an effective measurement for generating large scale and accurate digital elevation modeling (DEM). The removal of the flat earth effect is a necessary step in the InSAR processing. It makes the phase of interferogram exhibit the contour line of terrain and makes the unwrapping processing easily. In this paper, the reasons to form the horizontal round effect of interference pattern in InSAR imaging technology were discussed, and the common methods of eliminating the horizontal ground effect were explained suitable. Especially, the frequency shift method was introduced because it is easy to implement. A high accurate algorithm to obtain a precision result based on frequency shift and linear interpolation technology was proposed. The interferogram after earth flat removal can show the geometry directly and greatly reduce the number of the phase residual. The actual data shows the feasibility and validity of the algorithm in the processing.