[time-nuts] Satellite Glitch Rekindles GPS Concerns
brooke at pacific.net
Thu Jun 18 13:00:00 EDT 2009
Hi again Mike:
The IIR-2 satellite was launched in order to meet a deadline rather than when
it was truly fully operational. The L5 module is an add on and can not run at
full power. So this is not a representative of the future sats.
Mike Monett wrote:
> 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,"
> he said.
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