Airborne SAR imaging along a circular trajectory

Abstract:
During a joint ONERA-FOI SAR acquisition campaign in Sweden, several P and L band signals have been recorded along circular trajectories. The two bands were acquired simultaneously with pulse to pulse polarisation switching yielding full polarisation imaging. One of the acquisition was repeated with two vertical offsets in order to allow for repeat pass interferometry testing in both bands. We describe here the SAR image processing issues and the first results obtained The image synthesis in such a geometry cannot use strip-map geometry, hence either flash-look geometry (constant integration interval, varying Doppler) or polar format (Radon transform based imaging) have been experimented The most significant point is the fact the focusing (and multilooking) becomes highly altitude sensitive in this geometry. First images series are promising either for the polarimetric (interferometric) studies of clutter and infrastructure targets, has well as for foliage penetration The usually high false alarm rate of this latter technique can be significantly enhanced using stereo registration or tomography.