I think you'll find it's nearer to 5m for civilian's also. How comes it knows when I'm at the end of a road and then tells me to left when I'm 20m away, what you say indicates it would need to say it atleast 75m away to make sure it tells me in time.
Jon.
In a word NO.
As stated already ALL GPS satellites are owned and run by US Military, they can and do move the satellites to areas they want to look at more closely when they want ie the are in conflict with someone like Iraq, they can also switch them off to civilians when they want, they did on 9/11 as possibility of remote detonation devices was suspected, think laptop, mobile phone, and GPS device linked together do you want them to be really accurate
There is a Russian system called Glonas which uses less satellites than US system but in many ways in more accurate as satellites have fixed paths.
Because of the reliance on US Military hardware Europe has considered setting up its own system now for a while, if it happens is anyones guess.
As yet GPS approaches (aircraft landing) have been trailed in UK but are known as NON PRECISION APPROACHES, unlike ILS (Instrument landing systems) or MLS (microwave landing systems) which are PRECISION APPROACHES, this is due to GPS not being accurate enough.
So if they were accurate to within 5m aviation would have made more use of this because aviation uses things way before the man in the street ever will.
They do use lots of trick software to try and overcome the deficiencies and these do work well to a certain extent, but this can sometime slow down the rate of information, I know if you accelerate fast or brake hard the GPS lags behind by someway, or if you approach say a slip road roundabout off a motorway you can get round the bend before its knows where you are.
