Frequency ADapter for Interferometric applications (FADI) technique for SAR burst mode

Abstract

Interferometric products carry important information that enables some of the most important applications of Earth Observation with SAR sensors (e.g. generation of digital elevation models, deformation/subsidence monitoring, change detection, etc). In some cases interferometric applications may be limited by specific satellite pointing performance. It will be presented in this paper how the “Frequency Adapter for Interferometric Applications ” (FADI) innovative processing can improve the performance of the final products, with particular emphasis on burst-modes SAR acquisitions. One of the main hypothesis of current processing algorithms is the use of a single processing Doppler centroid, both for focusing and for radiometry equalization i.e. the whitening filter), while FADI technique uses indeed two: two distinct values of Doppler centroid, estimated in each original image, are used for the equalization of the radiometric pattern; on the other hand the same value of Doppler centroid is used for focusing in order to cancel out the term causing decorrelation. Last section of the paper will show how this technique can be applied in particular to burst modes (e.g., Ping-Pong and ScanSAR), offering the possibility to obtain images with correct radiometry and maximum spectral overlap (and thus with maximum coherence).