I found an interesting article I’d like to share. Credit goes to “The Straight Dope”
Is it true our GPS satellites are deteriorating and there’s no good fix?
— Imtazman1963
Cecil replies:
Pretty much. Frightening, isn’t it? We’ll have to go back to using maps.
One doesn’t wish to make light of the situation. For most of us, failure of the Global Positioning System merely increases the likelihood we’ll get lost in Pennsylvania. For the military and some emergency services, matters are more urgent. The satellites have limited life, typically seven to ten years. There’s no practical way to fix them once they break. Of the 59 GPS satellites launched to date, 31 are still operating. Of those 31, 17 are past their life expectancy — the oldest was launched in 1990. So if I were planning a military incursion into yet another trackless third-world region, I’d have reason to think better of it.
Worries about the GPS arose in May 2009 when the U.S. Government Accountability Office (GAO) released a report saying, “It is uncertain whether the Air Force will be able to acquire new satellites in time to maintain current GPS service without interruption. If not, some military operations and some civilian users could be adversely affected.”
The problem is that 24 functional GPS satellites are required for complete global coverage. With 31 still beeping we’ve got plenty of spares for the moment. However, due to a combination of schedule slips, construction problems, and cost overruns, we haven’t been launching new satellites fast enough to replace those likely to fail soon. The GAO estimated that over the next four years or so the probability that at least 24 satellites will remain operational will be less than 95 percent, at times dipping as low as 80 percent.
Having something fewer than 24 working satellites wouldn’t mean total system failure. The GAO says possible adverse effects are “hard to precisely define,” but reception could suffer in dense urban zones and mountainous regions. One urban GPS-dependent technology is the “bus tracker” feature used by some transit systems — including Chicago’s. So if too many GPS satellites go dark, not only will some Straight Dope readers be freezing on a corner waiting for the bus, they won’t even have the comfort of knowing the next one is running 19 minutes late.
Don’t be alarmed, though — the air force is on the case. Two days after the GAO report was released, they responded with a Twitter news conference, confidently tweeting that “going below 24 won’t happen.” This was followed up with a plan to move spare satellites closer to those expected to fail, improving current coverage, minimizing outages, and buying time to get new satellites aloft.
The fact that GPS technology has become ubiquitous is the best guarantee that the system won’t be out of action for long, if at all. Ten years ago civilian GPS use was confined to a gaggle of geeks. Today if the system goes down, just imagine the screaming: fix this sucker now.
With GPS units costing less than $100 dollars these days, they are quite ubiquitous, and I can’t imagine the GPS system going kaput. There are too many players and people relying on GPS for it to completely fail. Please don’t let it fail!