Overview of the performances and tracking design of the SIRAL altimeter for the CryoSat mission

This paper presents the principle of the measurements, the main system features and the basic ground processing of SIRAL. Simulations of the main performances in the different modes are also discussed including the bidimensional impulse response (range and azimuth). A major scientific requirement is to ensure the continuity of the measurements. This is particularly challenging for the on-board tracker over the steepest parts of the Antarctica. As a consequence a new tracking algorithm has been designed for SIRAL with the expertise of CNES. The algorithm has been derived from the analysis of simulated echoes using an Antarctica DEM and a radar echo simulator. The tracking design and performance are briefly described.