| Summary: | Evaluation of ice-height change in Antartica, forecasting river discharges or estimating water surface elevation in coastal waters are some of many applications of Altimetry science. The main objective of a satellite Radar Altimeter is to measure the height of reflecting objects on earth. Those reflections are obtained from the echoes of electromagnetic waves, which are continuously sent by the altimeter instrument. The conventional satellite altimeter uses the echo delays to estimate the height. One of the main features to improve in radar altimetry systems is the along-track resolution (i.e. the capacity to distinguish between two point-targets). Along-track resolution improvements can be achieved when using processing algorithms that coherently sum groups of received electromagnetic pulses, which have been reflected by the same target. Nowadays, operational altimeters achieve along-track resolutions over 200 meters thanks to Unfocused Delay-Doppler algorithms. However, Fully-Focused (FF) algorithms can improve the along-track resolution to the order of sub-meter. Two main approaches of Fully-Focused methods have been presented: Fully-Focused in Time Domain and Fully-Focused in Frequency Domain. Although both of them achieve the same along-track resolution, FF in Frequency has demonstrated to be considerably faster than FF in Time. In this thesis, we introduce the theory of both FF methods, and present the results and applications of Fully-Focused in Time Domain algorithm.
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