GPS Accuracy Could Start Dropping in 2010 (Read 993 times)

Bleh. I think TidBITS is trying to make much ado about nothing to get a story going. I'd bet part of that paper was to promote GPS III. Boeing is set (already under contract) to launch another GPS (newest block IIF) satellite this year, seven more in 2010, and four more in 2011-12. Lockheed-Martin launched their seventh (almost as new IIR-M) satellite in March. The oldest of those seven is from 2005, and one more is scheduled for deployment. So that's TWENTY modern GPS II satellites in place by 2012, with 16 in place by 2010. There are also 12 block IIR (R is for replenishment) satellites in place now, of which the oldest is from 1997 and the newest from 2004. That accounts for 32 satellites all less than 13 years old in 2010, and most of them are much newer. There are 13 older block IIA satellites that are still in service despite exceeding their life expectancy. GPS III is scheduled for 2013, with an incentive in place to start in 2011. The Euro GPS (Galileo) is set for 2013 and will also provide worldwide coverage (which I'm sure high end receivers will use in conjunction with US GPS). So unless Darth Vader and a Battlecruiser show up, we'll have plenty of satellites on through 2010 and much further. (I know you weren't being to serious in posting the story, but that TidBITS article really bothered me). I should note that the original Navstar satellites had a planned life of 7.5 years. From what I'm seeing, it looks like they were being replaced before failure at 13 years. Also, you can get a good GPS lock from fewer satellites (many receivers are limited to 12 anyways), but I'm not sure how many are visible at a time from a single location.
http://en.wikipedia.org/wiki/List_of_GPS_satellite_launches

Aircraft still have a backup (although many airports are moving to GPS-based approaches). Other applications (ships, ICBM's, surveyors, etc.) may not have that luxury. As with most other things in politics, nothing is ever as it seems. Probably just angling for more money for the project. TC

Some (sort of) interesting links on this: The GAO report: http://www.gao.gov/products/GAO-09-325 Garmin and Tom-Tom say they aren't all that concerned: http://www.pcmag.com/article2/0,2817,2347447,00.asp