[IGSMAIL-5507]: GLONASS tracking anomaly wrt R03, R04

[Stefan Schaer]

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IGS Electronic Mail      20 Dec 06:21:51 PST 2006      Message Number 5507
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Author: Stefan Schaer, Michael Meindl


Dear IGS/IGLOS colleagues,

We're confronted with serious GLONASS tracking data problems
with respect to
- R03 since 26 Nov 2006 (day 330),
- R04 since 17 Dec 2006 (day 351).

Note: The two satellites are active, but marked unusable. R03, R04
broadcast messages are no longer available.

A dedicated analysis revealed that there is a significant number of AIV
tracking receivers that seem to observe/record R03 and R04 on frequency
channel 0 (instead of 12 and 6, respectively). We could verify this
misbehavior with respect to
- R03 on day 336 for the TPS E_GGD receivers at OHI3, SOFI, WTZR,
- R04 on day 352 for the TPS E_GGD receivers at OHI3, WTZR.

The described data problems make POD difficult or even impossible (as in
extreme cases POD for R03, R04 is based just on one single baseline).

Best regards,

The CODE AC Team