The new TanDEM-X DEM 2020: generation and specifications

This paper introduces the new TanDEM-X DEM 2020. The TanDEM-X mission systematically acquired data mainly between September 2017 and mid-2020 to create another global DEM, the so-called “TanDEM-X DEM 2020”, formerly also called TanDEM-X Change DEM. The present paper describes the generation of the TanDEM-X DEM 2020 in terms of the adopted acquisition planning strategy, the new interferometric processing and DEM generation as well as the final DEM product specifications. The main differences from the existing global TanDEM-X DEM (2010-2014) are the new and independent time frame and a new interferometric processing technique with lower phase unwrapping errors, allowing for a mainly single-coverage acquisition strategy except for more difficult terrain. The fewer acquisitions slightly increase the random height errors but still very high accuracy. Examples for height changes on forests and glaciers between TanDEM-X DEM and TanDEM X DEM 2020 round off the paper with large-scale mosaics of Iceland and New Zealand.