Clutter Suppression Techniques for River Surface Current Measurements

The paper reviews our current state for river surface current measurements using SAR techniques. New results from an airborne SAR campaign conducted in 2005 are presented. The paper discusses the problem that due to the relative radial motion between the moving water surface and the sensor, the reflected energy from the river is misplaced on the river bank in the SAR image. Here it overlays with the stationary clutter like forests or agriculture fields. If the clutter amplitude is much stronger than the amplitude from the moving river surface an ATI measurement of the surface velocity becomes impossible, because the phase is dominated by the stationary clutter. We propose to use clutter suppression techniques like the Displaced Phase Centre Antenna (DPCA) or the Space Time Adaptive Filtering (STAP) method in order to cancel out the stationary signal. First results obtained with the DPCA method are presented