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Following the Jason-1 manoeuvers of this week-end, recent data from Jason-1 were not processed in Duacs in NRT. Thanks to a combination of corrections, data showed that the degradation was minor. Thus all data flows (IGDR or OGDR) from Jason-1 since the initial fuel depletion maneuver are re-injected in Duacs (along-track SLA products, multi-satellite map).

Jason-1 is still ongoing a series of manoeuvers (see mail on Thursday 29). Consequently, recent data from Jason-1 are still not processed in Duacs in Near Real Time as a conservative measure.

Since Thursday 29, the analysis of OSDR and IGDR data showed that the degradation was minor thanks to the combination of a CTGG correction based on the recent mean sea surface (MSS_CNES_CLS10) and a precise time reference from the repetitive track (mean profile). The oscillation is also much less of a problem than the periodic pointing issue associated to the loss of star traking and pointing capability on Jason-1 (degraded coverage, no recovery action is possible). Thus all data flows from Jason-1 since Thursday are re-injected in Duacs today and in the coming days and should be available as along-track SLA products, as well as used in the multi-satellite map.

However, Jason-1's cross-track distance is not stable so the automatic processing of Jason-1 data flows will not be re-activated. The quality control analyses to be performed this week will decide if newer Jason-1 data can be released. This approach will be used until the end of the series of maneuvers (2010/08/04).

We are doing the maximum to to keep providing Jason-1 data with a near real time quality as good as possible, albeit with a timeliness limited by the extended quality control performed by Jason-1's Cal/Val team. A lot of credit goes to the satellite and ground segment and operators from the Agencies as they provide Level 2 O/IGDR quality upstream data without which nothing would be possible in Duacs & SL-TAC.

Further information:

• 2010/07/29: <link http: www.aviso.oceanobs.com en news-storage news-detail temporary reintegration of jason-1 data flows in>[Jason-1]: Temporary reintegration of Jason-1 data flows in Duacs
• 2010/07/28: <link http: www.aviso.oceanobs.com en news-storage news-detail _top external-link-new-window>[Jason-1] : Low tracking performance on the star trackers.
• 2010/07/20: <link http: www.aviso.oceanobs.com en news-storage news-detail _top external-link-new-window>[Jason-1]: End of life plan