Sentinel-6 altimeter Level-2 Ground Prototype Processor

Thomas Moreau (CLS, France)


Sébastien Figerou (CLS, France); Thomas Forgue (CLS, France); Jérémie Aublanc (CLS, France); Marco Fornari (ESA, The Netherlands); Mieke Kuschnerus (ESA, The Netherlands); Robert Cullen (ESA, The Netherlands); François Boy (CNES, France); Gilles Tavernier (CNES, France); Gerard Zaouche (CNES, France)

Event: 2018 Ocean Surface Topography Science Team Meeting

Session: Others (poster only)

Presentation type: Type Poster

The Sentinel-6 mission, also called Jason-CS, is part of the Copernicus programme, which aims at continuing the Jason series of operational oceanography missions for the period 2020-2030. The main payload instrument of the mission is a dual-frequency Ku/C radar altimeter (Poseidon-4), evolving significantly from its predecessors (Poseidon-3A/3B carried on-board Jason-2 and Jason-3 satellites respectively). Among notable evolutions, Poseidon-4 will operate in an innovative interleaved mode emitting pulses in continuous and at relatively high repetition rate (9kHz). That way, conventional Low Resolution Mode (LRM) and Synthetic Aperture Radar (SAR) mode data can be generated simultaneously. In addition, as the number of independent looks increases, the measurement noise in SAR processed altimeter echoes is expected to be significantly reduced. For the sake of continuity with preceding missions, low- and high-resolution products will be generated from usual data processing, called baseline processors in LR and HR modes. Beside that, the altimeter mission will experiment new products and process developments (called experimental processors: LR-RMC and LR-OS).
In the past two years, CLS has conducted the development of the level-2 prototype processor (GPP) under ESA contract. The level-2 GPP consists of four processors (two baseline and two experimental processors), each of them enabling to generate geo-located geophysical retrievals from high- or low-resolution waveforms. Furthermore, the level-2 GPP contains an innovative retracker in LR mode, ensuring high-performances and notable benefits in comparison with conventional one. The level-2 GPP has been tested and validated using simulation data, and fully assessed with reconditioned Sentinel-3 data, thus demonstrating the high-reliability and robustness of the software, and its capability to be used as a good reference for future comparisons with operational processing.
The level-2 GPP can also be interfaced with the CLS/CNES Sentinel-6 altimeter simulator to form an end-to-end simulator of the Sentinel-6 Poseidon-4 instrument. These tools, when combined, provide an opportunity to conduct performance evaluations of the instrument system over different types of surface (open ocean, coastal zones, river and lakes and other land areas). They also permit to better understand the various specificities of the altimeter processing (Doppler ambiguities, on board Range Migration Correction, unequal range bin sampling and resolution) and design and assess any innovative processing. Besides its large list of possible activities and interests, the major asset of the Sentinel-6 simulator is its capability to significantly reduce the computation time of simulation, thanks to the use of innovative and powerful simulation processes, and to process data segment longer than 1000km in quite short run time.
This poster describes the different units of the level-2 Sentinel-6 Ground Prototype Processor and its major characteristics. Validation results demonstrating the potential of this software are also provided.

Poster show times:

Room Start Date End Date
Foyer, Salao Nobre & tent Thu, Sep 27 2018,18:00 Thu, Sep 27 2018,20:00
Thomas Moreau