Subject: [IGSMAIL-4221]: Potential Leica CORS1000 data problems at year-end
From: Herb Dragert <[email-masked]>
To: IGS Mail Recipients <[email-masked]>
Cc: [email-masked], [email-masked]
Date: Mon, 30 Dec 2002 23:55:30 +0000

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IGS Electronic Mail      30 Dec 15:55:35 PST 2002      Message Number 4221
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Author: Herb Dragert

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                     GEOLOGICAL SURVEY OF CANADA
                   WESTERN CANADA DEFORMATION ARRAY
                         GPS TRACKER ADVISORY

ADVISORY:

This message is directed at users of Leica CORS1000 receivers operating
under Firmware Version 9.00 and using "llink" for data retrieval:

We have encountered a year-end problem with time-delineated retrieval of
data. On one of our receivers (at site HOLB), we were using "weekly" files
in the ROLL delineation, and with the initiation of a new file for GPS Week
1199 on Sunday, we were unable to retrieve data from this file which had a
nominal time-span of Dec. 29, 2002, to Jan. 04, 2003. Closing this file and
setting the ROLL period to a maximum of 1 day eliminated the problem.

I suspect that the "time-indexing" fails if the requested data reside in a
file on the receiver that spans the year-end. To avoid data retrieval
problems, file structures should be such to avoid spanning a change of year
in a single file.

This incidentally was the cause of our failure to post hourly data files
for HOLB for Day 363 and Day 364, and we regret any inconvenience caused by
these data problems.

Herb Dragert
Pacific Geoscience Centre
[email-masked]