A dual-threshold ATI-SAR approach for detecting slow moving targets

The high false alarm associated with conventional along-track interferometric synthetic aperture radar (ATI-SAR) is a big concern for any valuable military radar. To reduce the false alarm rate, this paper proposes a dual-threshold approach that combines the conventional interferometric phase detection with the SAR image amplitude detection. This yields two results: (1) the interferometric phase map (including target velocity information) obtained by applying the interferometric phase detection only to the pixels selected by the amplitude detection; and (2) the amplitude map (including target strength information) obtained by applying the amplitude detection only to the pixels selected by the interferometric phase detection. The concept is illustrated by the results obtained using the Jet Propulsion Laboratory´s (JPL) AirSAR ATI data, collected in the Monterey Bay area, California. The ATI-SAR processing requires also a precise calibration of the platform´s crab angle. This paper presents a simple blind-calibration method that does not require any knowledge of the background and/or the actual crab angle.