GPS Selective Availability (SA) Now Off !
0800 Tuesday 2nd May 2000 UK Time
Many Thanks to all those who sent me this great news this morning, 2nd May. I understand that yesterday, President Clinton ordered that SA be switched off, for good, starting at 2000 Eastern Standard Time 1st May 2000. The practical effect of this, of course, is that all GPS receivers will now work to nearer 5m accuracy, rather than 50m. (50m R.M.S was the typical "deliberate error" fed in for S.A., with it occasionally creeping out to 100m)
I've been waiting for this news for what must be over 6 years - ever since the Schlesinger GPS Report was published (in 1995?) and strongly reccomended that S.A. be switched off "immediately" - in politics, even "immediate" can take a little longer :-) It was, of course, a political decision - since, within the GPS-related industry, there will be "winners" and "losers". The "losers" are in the minority - perhaps those offering DGPS (Differential GPS) services - who will now have to concentrate on much more specialised markets. Other "losers" might be those that have spent years developing sophisticated (and expensive) in-car navigation systems, which use both GPS and wheel sensors to improve accuracy. (although these will still perform better in some citiies, where GPS signals are masked by tall buildings).
The main people to benifit will be the millions of "GPS enthusiasts" around the World, using low cost GPS receivers (some as little as 80USD) plugged into their Laptop PC's. Many of these use GPSS off this web site - being used in 131 countries when S.A. was switched off.
Now those wishing to offer the consumer high quality but low cost in-car solutions need look no further than this web site, to see how it can be achieved.
Here is a link to a Reuters News Article on