SAR Signal Processing Departement

Synthetic Aperture Radar (SAR)

A SAR instrument scans the earth’s surface from aircraft or satellites with the help of microwave pulses. High resolution images and data products are generated from the reflected echoes. SAR methodology has two important advantages: it functions also at night and despite cloud cover, and it can be used to obtain reliable geophysical measurements such as backscatter constants or distances. This cannot be achieved with other imaging approaches and so SAR is preferentially employed during disaster situations, and also for continuous monitoring of polar areas, earthquake risk zones and volcanoes.

From raw data to geoscientific information

The raw data supplied by the radar must be processed with high precision for the user, i.e. focused in the direction of flight and distance, radiometrically calibrated and rectified from the sensor geometry into a map projection.

Processors for space missions

The SAR processors developed by the department are used in all civilian German SAR missions and in some cases for Copernicus missions. At present these are the TerraSAR-X, the TanDEM-X and the Sentinel-1 missions. An important milestone was also the Shuttle Radar Topography Mission (SRTM).

The most important products resulting from these missions are calibrated SAR images, digital terrain models, and ground movement maps for science and commercial users.

Research topics

The department’s research specializes on measuring small movements of the earth surface with the help of SAR interferometry. The focus of interest is metropolitan areas, volcanoes, earthquake regions and glaciers.

In addition to relative interferometric measurements, we have developed a new method for absolute geodetic measurements with SAR: Imaging Geodesy provides absolute coordinates of ground points from space, comparable to GNSS.