Dual-Baseline Phase Unwrapping Challenges in the TanDEM-X Mission

Abstract

A correct phase unwrapping is a critical step to obtain a high resolution and high accuracy (global) DEM. Thus, for the TanDEM-X mission, dual-baseline phase unwrapping approach is necessary to correct possible unwrapping errors. However, incoming interferometric data have highly different quality due to the different acquisition parameters (heights of ambiguity, coherence,...) fixed and/or forced by the satellites flying formation. Moreover, the latter has been adapted to several terrain types after various observations done in the early mission phase. For example, dense forested areas are acquired with a higher height of ambiguity to reduce volume decorrelation. This paper presents the challenges caused by these data of different quality.