Dual Baseline and Frequency Along-Track Interferometry

The JPL AIRSAR L-band along-track interferometer has in the past been successfully used to image currents and waves on the ocean surface. This was accomplished by observing the phase changes of the complex SAR images .produced from two antennas separated along track by a fixed distance or baseline. For observing these ocean signals, the baseline must be of a scale such that the ocean “features” do not completely decorrelate. By modifying the operating procedure of this existing two antenna interferometer, a technique has been developed to enable interferometric measurements to be made simultaneously at two different baselines. The availability of such data allows one to measure the decorrelation process of the Ocean in greater detail, specifically, the coherence time of the ocean surface can be measured at high resolution over large areas. In addition to the L band interferometer, a C band along-track interferometer has been developed which allows C band dual baseline measurements to be made simultaneous with the Lband measurements. In this paper, the dual baseline technique and AIRSAR implementation will be described and some example data will be presented.