TanDEM-X Change DEM: The Latest DEM Based on New Global Acquisitions (2017-2019)

Abstract

The production of the global TanDEM-X Digital Elevation Model (DEM) clearly showed that, at this level of accuracy, height differences are visible between interferometric SAR data acquired at different periods. As a matter of fact, height changes in glaciers, forests but also those caused by agricultural activities or infrastructure changes are well defined in the X-band DEM. Therefore, in 2017 the mission decided to acquire an additional complete coverage of the Earth's landmass. The aim is to provide an independent DEM dataset within a well-defined time span from September 2017 until the end of 2019. This additional dataset will allow monitoring topographic changes with respect to the TanDEM-X DEM on a global scale. Hence the name of the resulting product is "TanDEM-X Change DEM". It benefits from improvements in the acquisition planning process and in the data processing which enable to achieve reliable DEM data of high accuracy with fewer acquisitions. For this goal, the use of an edited TanDEM-X DEM as "starting point" for the processing is mandatory allowing us to detect some 3D elevation changes.