A Global Assessment of the Ra-2 Performance over All Surfaces

The EnviSat RA-2 has collected a huge volume of echoes from the earth's surface. Its unique modeswitching capability has enabled it to remain in lock even over mountainous terrain, and has resulted in the most complete sampling of the earth's surface by a satellite radar altimeter. This paper presents results from the global analysis of the RA-2 echoes over all surfaces, including a comparison of the RA-2 performance with that of TOPEX, Jason-1 and ERS-1/2. The results show superb echo capture even over extreme terrain, a very good outcome over most land surfaces but a sub-optimal performance over inland water. The interplay between surface targets, tracker response and autonomous mode switching is illustrated to explain the RA-2 behaviour. The results have implications for future instrument design and demonstrate very clearly the overall excellent performance of the RA-2.