[time-nuts] Satellite Glitch Rekindles GPS Concerns
xde-l2g3 at myamail.com
Thu Jun 18 09:41:06 EDT 2009
An article in NetWork World discusses performance degredation in the
new Lockheed-built GPS IIR-2 satellite. Apparently. the new L5
transmissions are interfering with other signals from the satellite.
This reduces the accuracy an order of magnitude, from 2 feet to 20
feet. It should have a corresponding effect on the accuracy of the
decoded time signals.
The Air Force said it has identified several parameters in the GPS
IIR-20 (M)'s navigation message that can be corrected and is
studying the impact these may have on military and civil GPS users.
Presumably, the problem will be corrected in the 12 Boeing GPS
satellites currently being built that also feature the L5 signal.
The article discusses issues such as delays due to techical
problems, cost overruns, and aging of the fleet. These could affect
system performance in the future.
However, Col. Dave Buckman stated
"The issue is under control. We are working hard to get out the
word. The issue is not whether GPS will stop working. There's only a
small risk we will not continue to exceed our performance standard,"
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