The Sentinel-6 (Jason-CS) Poseidon-4 Ground Prototype Processor: Processing Description and Results with ESA simulated Test Data delivered to users

Mònica Roca (isardSAT Cat, United Kingdom)

CoAuthors

Roger Escolà Jané (isardSAT, Catalunya); Albert Garcia Mondéjar (isardSAT, UK); Pablo Nilo García Arnauld (isardSAT, Catalunya); Cristina Martin-Puig (isardSAT, Catalunya); Bernat Martínez (isardSAT, Catalunya); Gorka Moyano (isardSAT, United Kingdom); Marco Fornari (ESTEC/ESA, Nederlands); Richard Francis (ESTEC/ESA, Nederlands); Robert Cullen (ESTEC/ESA, The Nederlands)

Event: 2014 Ocean Surface Topography Science Team Meeting

Session: Instrument Processing: Measurement and retracking (SAR and LRM)

Presentation type: Type Oral

Sentinel-6 (Jason-CS) is an operational oceanography programme of two satellites that will ensure continuity to the Jason series of operational missions.

The main payload of the Sentinel-6 (Jason-CS) satellite, Poseidon-4, though having heritage from previous altimeters, will be the first radar altimeter embarked on a satellite that includes improved digital and radio frequency hardware and, in particular, open burst Ku-band pulse transmission. This operation (currently termed the interleaved mode), performs a near continuous transmission of Ku-band pulses, that will allow the simultaneous processing of the measurements to obtain High Resolution along-track (HR or SAR) and Low Resolution along-track (LR or LRM) data. As previous altimeters, the Poseidon-4 transmits C-band pulses in order to retrieve a correction for ionospheric path delay.

isardSAT is responsible for the development of the Ground Prototype Processor for the Poseidon-4. This prototype processes all the chains starting from the Instrument Source Packets, and producing L1A and L1B-S (only for HR processing) and Level 1B (both calibrated LR and HR data processing). The prototype has been verified using simulated data generated by the Sentinel-6 (Jason-CS) mission performance simulator and also using in-orbit CryoSat data adapted in format to Sentinel-6, provided by ESA.

At the end of summer 2014, ESA is planning to deliver a few P4 data produced by the ESTEC Sentinel-6 simulator over ocean, and processed by the P4 GPP, in all L1 data types: L1A HR (or SAR), L1B-S HR (or SAR), L1B HR (or SAR), and L1B LR (or LRM).

This paper will present the Ground Processor Prototype developed for Sentinel-6 (Jason-CS), and the results obtained (including post-processing) of the data delivered by ESA to users. Special attention will be given to the new features of the processing chain compared to previous altimeters. Typical examples concern: the assessment of performance improvement thanks to the interleaved mode; the un-correction of the Range Migration Correction (RMC) performed on-board in order to reduce the data rate; the Doppler ambiguity effects, due to the low PRF, onto the geophysical retrievals; the weighting applied to the Doppler beams before the multi-looking to correct the different echo shapes as a function of the incidence angle; or the reconstruction of the waveform scaling factor in order to be able to compute the surface backscatter.
 

Oral presentation show times:

RoomStart DateEnd Date
Ballroom Tue, Oct 28 2014,17:39 Tue, Oct 28 2014,17:51
Mònica Roca
isardSAT Cat
United Kingdom
Monica.Roca@isardSAT.cat