A new dual baseline phase unwrapping algorithm for the TanDEM-X Mission

The TanDEM-X Mission goal is to generate a high resolution global Digital Elevation Model of the whole landmass over an acquisition time of three years. The biggest part of the landmass will be covered twice with the same geometry (incidence and look angles) but two different baselines. This paper presents a new phase unwrapping algorithm which uses the two interferograms and combines global and local phase unwrapping. Both interferograms are first unwrapped independently with the Minimum Cost Flow algorithm, then unwrapping errors are found comparing the two phases and finally a region growing phase unwrapping algorithm is applied on all the wrong areas which exhibit significant discrepancies.