Space-time adaptive processing for synthetic aperture radar

Synthetic aperture radar (SAR) provides high-resolution images of the non-moving ground scene, but fails for the indication and positioning of moving objects. Like in airborne MTI systems the solution to this problem is to use an array of antennas or subapertures and several receiving channels (`MSAR´=multi-channel SAR), and to apply multi-channel clutter suppression. One of the most efficient methods is adaptive space-time processing (STAP), which can be simplified to frequency-dependent spatial processing in the Doppler domain. Some of these techniques applied to SAR are reviewed and illustrated with data gathered by the German experimental multi-channel SAR system `AER-II´