Russian GLONASS Down For 12 Hours

http://tech-beta.slashdot.org/story/14/04/03/1240258/russian-glonass-down-for-12-hours

http://gpsworld.com/glonass-gone-then-back/

That is really interesting, particularly one of the comments speculating that this might have been a test by the Russians of an "encrypted mode" for the system.

Altus Positioning Systems Pinpoints Cause for GLONASS Default
April 4, 2014

Regarding the April 1–2 11-hour downtime for the full GLONASS constellation, president and CEO Neil Vancans of Altus Positioning Systems provides this additional information:

“From the reports on GLONASS problems, we have an explanation that may be used in our technical support replies:

“Our analysis reveals the GLONASS integration algorithms skipped an interval of around 1.5 minutes at the control centre software.

“At 21:00 UTC April 1, all GLONASS satellites received an orbit state (ephemeris) which was clearly several minutes ahead of the current orbit shape without actually changing the applicable reference time stamp. In other words, future orbit-position, velocity and accelerations were assigned to a current reference timestamp.

“This led to incorrect orbit positions for all GLONASS satellites and subsequent problems with receiver using GLONASS measurements.

“In our receivers, RAIM rejected the solutions because of the large GLONASS errors, and could only work with GPS only and the recently revised RAIM settings for a Base (SRL,ON,-6,-4,-4).

“The issue is now rectified, and the GLONASS constellation is back to normal.”

http://gpsworld.com/altus-positioning-systems-pinpoints-cause-for-glonass-default/

kriseric said:

That is really interesting, particularly one of the comments speculating that this might have been a test by the Russians of an "encrypted mode" for the system.

Click to expand...

Those comments are made by people who don't understand how GLONASS (or GPS) works. Both systems already broadcast separate military-grade navigation signals (GLONASS refers to this as L1SF/L2SF, the GPS equivalent is the P(Y) code). These are already encrypted or obfuscated. These are distinct from the civilian unencrypted L1OF/L2OF or GPS C/A codes.


If the Russians wanted to deny non-military use of GLONASS, they'd just turn off the civilian L1OF/L2OF signals entirely. But of course no one sensible outside of Russia relies exclusively on GLONASS (and probably the Russians don't either). Certainly no Western military assets depend on GLONASS, so what good would it do for the Russians to shut it off?

GLONASS Loses Control Again

http://gpsworld.com/glonass-loses-control-again/