OVERVIEW OF ALTIMETER DATA-PROCESSING AT THE UK EARTH OBSERVATION DATA CENTER

ERS-1 carries the fifth radar altimeter to be launched into Earth orbi t. Although similar in concept and design to earlier altimeters, it is the first to include operation over non-ocean surfaces as one of its design requirements. The increased capabilities of the instrument allo w for the generation of a variety of data products. The generation of these products calls for an extensive suite of software covering the p rocessing of the raw data into basic 'waveform products', and the subs equent generation of higher level, geophysical products covering ocean , sea-ice, land-ice, land and lakes. This paper gives an overview of t he ERS-1 altimeter data processing carried out at the U.K. Earth Obser vation Data Centre (EODC) at Farnborough. Besides processing the data from the satellite, a significant quantity of support data also have t o be acquired and processed (e.g., improved orbit ephemerides, meteoro logical data, ionospheric data, etc.). The initial low-level processin g of the raw data into the Waveform Foundation Product is common to al l altimeter data products and is described in detail.