TOPEX POSEIDON MISSION - GLOBAL MEASUREMENTS OF SEA-LEVEL AT UNPRECEDENTED ACCURACY/

This paper describes the TOPEX/POSEIDON mission, a joint project betwe en the United States and France with particular emphasis on measuremen t capabilities and performance. The satellite has provided unprecedent ed measurements of global sea level since it was launched on 10 August 1992 from Kourou, French Guiana with an Arianespace 42P launch vehicl e. TOPEX/POSEIDON is comprised of two microwave radar altimeters, a mi crowave radiometer, and three precision tracking systems that combine to produce an overall global sea level measurement of less than 5 cm. The accuracy of the measurement is attributed to the design and implem entation of: the satellite and its instrument complement, the precisio n orbit-determination and tracking systems, the ground processing syst em, and the verification and calibration system. The satellite and mea surement systems will be discussed, with an emphasis on the sensors, p recision orbit-determination process, and the verification process. In addition, current results provided by TOPEX/POSEIDON science investig ators will be summarized.