NavList:

Geoffrey, you wrote:
"Firstly, you may be correct that GPS has never been turned off globally. But I would suggest that a localised or regionalised shut down of GPS may well be possible."

How? Certainly local jamming is possible. Would the US military jam its own system? Well maybe. If they had some sort of filter to remove the jamming signal. That's not really the same thing as shutting down GPS.

You added:
"There were some fellas at the conference who seem to have ' been there' in sensitive areas at sensitive times who are pretty sure that is what took place."

I would not be surprised if they saw some targeted jamming, like above. It's also possible that they saw something coincidental. For example, in the relatively early days of GPS, if two satellites had suffered temporary outages simultaneously by coincidence, many people would assume it was intentional. And there's no way to prove them wrong until records are de-classified.

And you wrote:
"Of course, why should we believe them? But then, why should we believe you?"

First, I know you were being rhetorical here, but for the record, I trust Richard Langley's comments on this topic, because he's a world-renowned expert on GPS, and, since he's Canadian, not bound by any narrow patriotism (except to hockey and maple leafs and whatever else they have up there... ;) ). That out of the way, I don't trust anyone without evidence. Where is the evidence that the Pentagon shut off GPS? An anecdote is worth looking into, but it's not evidence.

On the general topic, clearly the GPS system was bought and paid for as a weapons-targeting system. It was also separately sold for its tremendous spin-off in civilian systems, and this was clear right from the beginning. Civilian spin-off, however, does not invalidate the thesis that this was "all about the Cold War". I recall somewhere a story (can anyone remind me?) about GPS being demo-ed somewhere in Europe as an example of the transformative technological advantages of the West. In other words, "look at our cool stuff! don't you want to be on this side of the Cold War?" The actual civilian payoff from GPS, continuing long after the end of the Cold War, has probably paid for the system twice over, but it's highly unlikely that it ever would have been funded at such an early date without the requirements of weapons targeting. The Cold War made it happen.

-FER
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