RAPID was a joint project of the Deutschen Fernerkundungsdatenzentrum (DFD) and Institut fuer Hochfrequenztechnik from the German Aerospace Center (DLR) and Institut fuer Nachrichtenverarbeitung from the University GH-Siegen as partner. The goal was to develop and approve theories, algorithm and processingssystems to use the interferometric data from ERS. In a preoperational processing chain it is possible to generate coherence - and phase products and as final results digital elevation models (DEM). These products can be used by other projects, therefore other geoscientist must not developed these basics products for there applications. Specially DEMs are very necessary and useful. In various test regions the accuracies were investigated. ...