Development of an Optimal and Automated Radar Altimeter Waveform Processor

The primary objective of the proposed investigation is to develop an optimal radar altimeter waveform processor for (1) enhancing the accuracy of the altimetric oceanographic height measurements, especially near the coastal regions and ice-sheet boundaries, and for (2) autonomous and efficient processing of respective altimeter waveforms over deep ocean, shallow water, near ice-boundaries, ice sheets/terrains, and over continents. The significance of the autonomous processor is to allow near real-time extraction of accurate coastal sea surface height information and is applicable to Navy operations such as coastal navigation and coastal military maneuvers. The proposed approach is to improve the currently available state-of-the-art algorithms which employ maximum likelihood estimators, by (1) introducing adaptive algorithm to modify the estimator accordingly for processing of waveforms over different surfaces and terrains, and (2) improving the computational speed of the processor, for consideration of autonomous operation onboard of the satellite. The proposed six-month Phase I effort includes (1) a complete evaluation of existing waveform tracking algorithms, e.g., Brenner et al., [1993], Srokosz and Challenor, [1988], Rodriguez [1988], and Rapley et al., [1983], (2) the conceptual design of the adaptive, maximum likelihood estimator for altimeter waveform processing, and (3) a proof-of-concept initial development of the proposed waveform processor. The proposed three-month Phase I Option effort will follow with a preliminary testing of the processor using waveform data from TOPEX/Poseidon, ERS-1 and Geosat Exact Repeat Mission (ERM).