Comment Re:suspend GPS? (Score 1) 522
There are enough errors in the parent that I think a few corrections are necessary.
(1) The USA GPS system was designed from Reagan's 1983 directive onwards to be used by both civilians and the military, and to provide better accuracy to the military. The first GPS satellites were launched in 1989. So it's not really accurate to say "when the system was opened up to civilian use in the late 90's."
(2) The "discrepancy" in civilian signals was known as "Selective Availability" (SA) by "dithering" the clock, and it was designed in from the start so that if an enemy tried to use civilian GPS, civilian GPS could be degraded worldwide without disturbing military GPS. That doesn't mean SA was always enabled. In fact, during the Gulf War, there was a shortage of military GPS units, so the military handed out civilian GPSs and turned off SA.
(3) The " idea of checking GPS against a known good reading" has three forms: differential GPS; only useful locally for work like surveying; WAAS, designed and implemented by the Federal Aviation Administration; and NDGPS, which is still being implemented on US land by Dept of Transportation (it's fully for US waterways thanks to the Coast Guard). WAAS is what you're using now unless you're a ship captain. The point is that except for local surveying equipment, the "someone" who made GPS better is your federal government. This is not a case of clever entrepreneurs outsmarting the government, this is another case of the government providing a new infrastructure that enabled new industries and widespread benefits.
(4) The reason President Clinton turned of the global selective availability dithering is because by then the GPS constellation had a new ability to deny civilian GPS regionally. So it's not accurate to say, as you did, " that the military eventually discarded the idea of putting in an intentional margin of error for civilian signals." In fact, the military has a better method than ever for putting error into some regional civilian signals. http://archive.wired.com/polit...