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Date: Wed, 10 Aug 2005 14:58:31 +0200
To: IDS Governing board <ids.governing.board@cls.fr>
From: "H.Fagard" <herve.fagard@ign.fr>
Subject: Re: temporary DORIS stations
Cc: ids.analysis.forum@cls.fr
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Dear all,

At 14:19 -0500 9/08/05, John C. Ries wrote:
>So the question is, what should the official position be on a site like WETB?

As my contribution here is a summary of the information provided in 
DORISMails regarding stations installed following IDS proposals, and 
that are not officially part of the permanent network:

WETB
DORISMail No 243 said:
>- like other stations installed following IDS proposals, it is not 
>considered part of the "DORIS permanent orbitography network".
>- in order to avoid jamming with nearby stations in Europe, the 
>transmitted frequencies have been shifted with respect to the 
>nominal DORIS frequencies.
>- because interference on the VLBI measurements due to the DORIS 
>transmissions have been noticed (there is only 140 m between both 
>antennas), the DORIS beacon will have to be switched off at least 
>three days a week, plus one hour daily on the other days. It will 
>therefore be a "part-time" DORIS station.
>- this new station has been programmed on the receivers on board 
>Jason and Envisat, the only models able to handle shifted frequency 
>beacons.

My personnal comment: very scarce data, uncertain continuation. 
Wettzell is a major IERS co-location site and a long-term DORIS 
presence at this site would be quite interesting from IERS' point of 
view, but it is not being considered for the near future because of 
the only one or two channels on the current DORIS instruments.

GAVB
DORISMail No 266 said:
>- like other stations installed following IDS proposals, it is not - 
>for the time being - considered part of the "DORIS permanent 
>orbitography network".
>- in order to avoid jamming with the Dionysos station, DIOA has been 
>temporarily turned to standby. This allows Gavdos to transmit on the 
>nominal frequency and hence be received on all DORIS-equiped 
>satellites.

Its current status is as follows: once a new beacon has been 
installed, this station will be evaluated (in terms of maintenance 
quality) to see if it can be a good replacement for Dyonisos.
Definitely worth processing IMHO as the long time span should give 
good quality velocities.

BELB/BEMB
DORISMail No 306 said:
>In view of the significant contribution this new station should 
>bring to the network robustness in this area, where access and 
>therefore maintenance are difficult, it will be regarded as part of 
>the permanent DORIS network.

Nevertheless it is not yet considered part of the permanent network 
by CNES, mainly because of the very high sigma on the Z velocity. 
This might evolve following the upgrade of the station and the 
availability of improved coordinates and velocities (see DORISMail No 
393).

As John mentionned, a few stations installed in the frame of "pilot 
experiments" well before the IDS was created, have been providing 
data for a limited time.
They are probably of little interest as far as the DORIS contribution 
to the ITRF is concerned. Re. their interest for scientific 
applications (e.g. geophysics), I wonder if somebody actually uses or 
would be interested to use such results.

Best regards,

Hervé