TanDEM-X acquisition status and calibration of the interferometric system

TanDEM-X is a spaceborne SAR mission with the goal to derive a global Digital Elevation Model (DEM) with unprecedented accuracy. This paper describes the way how the global DEM is acquired, explains the changes that have been applied during the first almost 1.5 years in orbit and shows the actual status of the global acquisitions. In the second part, the calibration of the bi-static interferometer is explained. The implications to correct the different effects coming from the baseline, the internal delays in the instrument and the phase measurements themselves enabling the derivation of the height are described and the actual results are presented.