[IGSSTATION-2953]: Historic clock information of PERT, NNOR, MAS1 and KOUR added

[Pedro.Alfaro at esa.int]

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IGS Station Mail          26 Mar 10:47:16 PDT 2009      Message Number 2953
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Author: Pedro Alfaro Sanz

Dear colleagues,

Some of our IGS stations have had in the past some problems with their 
external reference clock.

We have used our repro1 solutions to analyse their behaviour in the period 
2000-present, and have reflected the results in new versions of the 
station logs of PERT, NNOR, MAS1 and KOUR. These logs have just been 
submitted to IGSCB.

It seems that there are several periods of time where our receivers 
reverted to their internal clock, although the external clock was 
connected. We think this might have been triggered by some sort of 
maintenance activity at the station. We are working to catch these 
problems as they occur from now on.

Other than these problems, the logs just submitted also reflect that:

KOUR has been an H-maser since Jan 2008
PERT is no longer connected to an external clock
NNOR has been reclassified as a SLAVED CRYSTAL

We would like to thank Jim Ray for the "heads up" on this issue.

Kind regards,

           Pedro Alfaro
______________________________
Pedro Alfaro Sanz
Msc. Aerospace Engineer
GMV Aerospace and Defence  S.A.
+49 6151 90 4069
Pedro.Alfaro at esa.int
Navigation Facility, OPS-GN
European Space Operations Centre
Robert Bosch Strasse 5
64293 Darmstadt
Germany