The large-scale airborne synthetic-aperture radar (SAR) facility, referred to as F-SAR, is based at the German Aerospace Center (DLR) Microwaves and Radar Institute in Oberpfaffenhofen. Used on board the DLR Dornier DO 228-212 research aircraft, the system is in a class of its own in terms of performance. F-SAR is the only facility of its kind in the world; it provides high-quality SAR image data in five different frequency bands (X, C, S, L and P) – up to four of these bands can be used simultaneously. At the same time, F-SAR offers fully polarimetric measurement modes in all of these bands, as well as single-pass interferometric imaging.
Precise surveying of Earth’s surface along predefined flight paths
A Global Navigation Satellite System (GNSS) supported precision positioning system integrated into F-SAR enables pilots to fly predefined flight paths with metre precision. This ensures a high level of data quality, which is especially important for multi-pass SAR interferometry. Precisely flown interferometric base lines are a prerequisite for applications such as detecting elevation and subsidence of Earth’s surface (D-InSAR) or determining the height of forests (Pol-InSAR and TomoSAR). In addition, F-SAR is notable for its highly accurate measurement capabilities; this is ensured by the precise estimation of signal transmission proper-ties in the laboratory and the operation of a permanent calibration field.
This large-scale system is used to develop innovative signal processing methods and test new measure-ment processes in the fields of the environment, transport and security. For this purpose, F-SAR con-ducts targeted scientific flight campaigns, often in conjunction with external research institutions. The data obtained forms the basis for further research and teaching in Earth observation and environmental sciences. Expertise relating to synthetic-aperture radar technology and its applications is essential for the conception and optimisation of future satellite missions (such as High Resolution Wide Swath (HRWS), Tandem-L, BIOMASS). The same applies to future airborne systems, such as those focused on the monitoring and protection of coastal waters.