The PARIS in-orbit demonstrator

Mesoscale ocean altimetry remains being a challenging area for satellite observations. Conventional nadir looking radar altimeters can make observations only along the satellite ground track and many of them are needed to sample the sea surface at the required spatial and temporal resolutions. The Passive Reflectometry and Interferometry System (PARIS) using GNSS reflected signals was proposed as a means to perform ocean altimetry along several tracks simultaneously spread over a wide swath. The present paper describes such an instrument specially conceived to fully exploit the GNSS signals for best altimetric performance, and to provide multi-frequency observations to correct for the ionospheric delay. Instrument calibration strategy is also discussed. Furthermore an in-orbit demonstration mission is proposed that would prove the expected altimetric accuracy suited for mesoscale ocean science.