Satellite Glitch Rekindles GPS Concerns

coondoggie writes "News today that the Air Force is investigating signal problems with its latest Global Positioning System satellite is likely to rekindle the flames of a congressional report last month that said the current GPS coverage may not be so ubiquitous in the future. The Air Force stated that routine early orbit checkout procedures determined that the signals from the Lockheed-built GPS IIR-2 (M), which was launched in March, were inconsistent with the performance of other GPS IIR-M satellites. The Air Force said it has identified several parameters in the GPS IIR-20 (M)'s navigation message that can be corrected to bring the satellite into compliance with current GPS Performance Standards."

Re:What's The problem?

[AlecC]

"... which was launched in March". That is not "getting on a bit" - it says that replacements are not fully-functioning copies of the originals, which is worrying.

Re:What's The problem?

[Richard_at_work]

No, they are not exact replicas of the original constellation members, but they can be placed into a compatible mode to fit into the standard GPS constellation. What is happening in this story is simply that mode being callibrated. As more and more updated satellites are placed into orbit, the GPS system can be upgraded by turning on new features.

Re:Soloution?

[bberens]

I think it's bad form to call NASA a bloated behemoth while giving the US military a pass. Most military research and development has been privatized and yet it doesn't seem to be particularly non-bloated.

Re:Followup on the story

[digitig]

Yeah, cuz it's not like Galileo was purposefully designed to be easy to jam in the event of hostilities..... oh wait [absoluteastronomy.com]......:

Any satnav system is going to be easy to jam. I used to know somebody who had a cottage industry manufacturing GPS jammers for the UK military; commercialised they would have been cheap enough to drop as chaff. The only issue with Galileo is that it and GPS can be jammed independently.

The US did not want to lose the ability to themselves use accurate [Global navigation satellite system] while denying enemies the use of accurate GNSS. Some US officials became especially concerned when Chinese interest in Galileo was reported.

This is what led to some US officials to go as far as threatening to potentially shoot down Galileo satellites in the event of a conflict.

Even before Galileo was announced -- and certainly before the Chinese became interested -- the US DoD announced that in a conflict any ground stations for such a system would be "valid military targets, even if on friendly soil". So that bit about setting up your own satnav system also needed to have the rider "and you are confident that you can take on the US military and win".