User-Agent: Microsoft-Entourage/10.1.4.030702.0
Date: Fri, 17 Nov 2006 17:49:31 +0000
Subject: Re: [ids.analysis.forum] Scaling of DORIS solution in ITRF 2005
From: "Frank G. Lemoine" <flemoine@puuoo.gsfc.nasa.gov>
To: <ids.analysis.forum@cls.fr>
Message-ID: <C183A6AB.7CC3%flemoine@puuoo.gsfc.nasa.gov>
In-Reply-To: <455C36AB.1040302@esgt.cnam.fr>
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Dear Colleagues-

 It is not just the new DORIS stations we must consider,
 but how we introduce DORIS stations that are not part of the ITRF2005
 solution. I think we really introduce complications if we are going to
 (eventually) compare SLR/DORIS orbits with GPS produced Jason
 orbits. If you start scaling all the techniques in your
 ITRF, what is going to happen to comparisons with
 local ties?

FrankL-

 
>At 12:24 PM +0100 11/15/06, Jean-Paul Berthias wrote:
>  
>
>>Dear colleagues,
>>
>>As you probably know from previous Emails we intend to use a scaled
>>version of the ITRF2005 SLR solution as a reference for altimetry
>>missions (Jason, Topex, Envisat). This raises a question for DORIS:
>>should we scale the ITRF2005 solution in the same way as for SLR or
>>should we use the ITRF2005 DORIS solution as is ?
>>
>>I personally do not favor a scaling of the DORIS solution for
>>operational reasons: when new beacons are installed (and this
>>happens regularly with DORIS) the only coordinates that are
>>available for a long time are derived from GPS positioning. If we
>>scale ITRF2005, we will not know what to do to these coordinates,
>>scale them or not. If we use ITRF2005 as is for DORIS, we can
>>legitimately use ITRF2005 GPS based coordinates to fill in for new
>>stations. BUt this is not a very strong argument.
>>
>>I would like to hear your comments on this issue. Please let me know
>>if you have run tests with ITRF2005, with and without scaling (the
>>scaling we intend to apply to SLR is -1 ppb) and what your results
>>are.


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