Sentinel-6 Poseidon-4 RMC mode processing and expected performance

Mieke Kuschnerus (ESA, Netherlands)

Event: 2018 Ocean Surface Topography Science Team Meeting

Session: Instrument Processing: Measurement and Retracking

Presentation type: Type Oral

Sentinel-6 Poseidon-4 RMC mode processing and expected performance

Mieke Kuschnerus, Robert Cullen, Marco Fornari, Roberta Bertoni

The Sentinel-6/Jason-CS mission is the latest successor mission of the Jason altimetry mission series and part of the ESA Copernicus Programme. Its main objective is to continue the long term climate data record of sea level measurements that started in 1992 with the Topex/Poseidon mission. Sentinel-6 will operate from 2020 onwards in the same reference orbit as the current Jason-2 mission and its altimeter Poseidon 4 will retrieve sea level, wind speed and wave height measurements in near real time. Poseidon 4 is a new generation of altimeter based on the SARL instrument of the Sentinel 3 mission, operating in both SAR and low resolution mode continuously.

To reduce downlink data rate the Poseidon 4 altimeter will generate the nominal SAR RAW data over coastal zones and selected areas, and SAR RMC data over most of the open ocean. SAR RMC data is conventional SAR data reduced in size on board the satellite by truncation after a fixed range bin. To allow for truncation without loss of relevant data, the SAR RAW data is aligned on board and corrected for range migration, then truncated and send to the ground. The on-ground processing is reversing this process and providing SAR RMC data, allowing for the usual SAR ground processing.

Relative performances between SAR raw data and those undergoing the on-board ‘Range migration compensation’ are explained for nominal ocean conditions. Additionally an analysis for inclined ocean surfaces is performed. For example over ocean trenches, the sea surface can have a slope, which affects the on-board RMC algorithm. We present an analysis based on data generated with the Sentinel-6 Mission Performance Simulator, to demonstrate that for a representative case of ocean surface slope, the RMC processing allows on-ground parameter estimation within the Senitnel-6 mission requirements.

Oral presentation show times:

Room Start Date End Date
Teatro Auditorium Thu, Sep 27 2018,14:00 Thu, Sep 27 2018,14:15
Mieke Kuschnerus