S6 P4 GPP: The Sentinel-6 Poseidon-4 Ground Processor Prototype. New simulation results.

Eduard Makhoul (isardSAT, Spain)


Roger Escolà (isardSAT, United Kingdom); Albert Garcia (isardSAT, United Kingdom); Gorka Moyano (isardSAT, United Kingdom); Pablo Garcia (isardSAT, Spain); Mònica Roca (isardSAT, United Kingdom); Marco Fornari (RHEA/ESTEC, Netherlands); Robert Cullen (ESA/ESTEC, The Netherlands)

Event: 2017 Ocean Surface Topography Science Team Meeting

Session: Instrument Processing: Measurement and Retracking

Presentation type: Type Poster

During the last decade the radar altimetry has entered its golden age as demonstrated by the different number of missions (Jason-3, CryoSat-2, SARAL/Altika, Sentinel-3) currently operating and the forthcoming Sentinel-6. The latter is an operational oceanography programme of two satellites that will ensure continuity to the Jason series of operational missions. The mission is being developed by a multi-Agency partnership consisting of ESA, EUMETSAT, NOAA, CNES and NASA-JPL. ESA is responsible for the Sentinel-6 Space Segment development along with Astrium GmbH as a prime contractor.

The main payload of the Sentinel-6 satellite is the Poseidon-4 radar altimeter, an evolution from the altimeters on-board the Jason satellites. Poseidon-4 also inherits the Synthetic Aperture Radar (SAR) High Resolution Altimeter mode from CryoSat-2 SIRAL and Sentinel-3 SRAL, with a technological evolution characterized by:
• Improved radio frequency hardware and an on-board digital architecture (matched filter digital operation instead of analog-based de-ramping)
• Interleaved Ku-band mode operation: near continuous transmission of Ku-band pulses. It allows the simultaneous operation of the low resolution mode (LR or LRM) and high resolution (HR or SAR).
• On-board processing, range migration correction (RMC), is performed to reduce the amount of data to download.
• A calibration pulse is included in the tracking cycle to monitor instrumental variations around the orbit.

This new configuration of the Poseidon-4 instrument opens a new paradigm in the capabilities offered by the Sentinel-6 radar altimeter. In order to do so, the specificities of this new instrument have to be carefully considered in order to re-adapt the Delay-Doppler Processing algorithms. isardSAT is responsible for the development of the L1 Ground Processor Prototype (GPP) for the Poseidon-4 under ESTEC/ESA contract. This prototype processes all the chains starting from the Instrument Source Packets, and producing L1A, L1B-S (only for HR processing) and Level 1B (both calibrated LR and HR data processing). This processor includes a lot of new features thanks to the experience gained with CryoSat-2 data as well as to the many studies performed during the course of the Sentinel-6 GPP project. The development of the GPP has been carried out exploiting simulated data produced by ESTEC Sentinel-6 mission performance simulator.

This poster will provide a review of the architectural and algorithmical implementation of the GPP, stressing how this processing chain has been adapted to the new characteristics of the Poseidon-4 instrument and the related implications. The operation of the GPP will be demonstrated with new simulated data (considering different scenario conditions), up to date with the last instrumental configuration. A preliminary validation of the GPP data will be included, based on the geophysical retrievals processor implemented by isardSAT in the frame of the Sentinel-6 GPP project. This processor integrates a fully analytical HR ocean retracker based on Ray et al. 2015 model and adapted to the new Sentinel-6 Poseidon-4 characteristics.


Poster show times:

RoomStart DateEnd Date
Concerto Ballroom Thu, Oct 26 2017,14:00 Thu, Oct 26 2017,18:00
Eduard Makhoul