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The US Air Force needs to act now, report says

There is growing concern that the current global positioning system network of satellites used by the United States is aging and will begin to routinely fail starting in 2010, a Government Accountability Office (GAO) report indicates.

The U.S. Air Force now uses 30 different GPS satellites -- which launched into orbit in the early 1990s -- and has become noticeably less reliable and may be sending inaccurate navigational information to people using mobile GPS units.

In 2010 "as old satellites begin to fail, the overall GPS constellation will fall below the number of satellites required to provide the level of GPS service that the U.S. government commits to," the GAO's "Global Positioning System: Significant Challenges in Sustaining and Upgrading Widely Used Capabilities" report claims.

The US government is expected to invest almost $6 billion into new GPS satellite technology over the next four years, in an attempt to try and get back on schedule after suffering several years of "significant" technical issues.  If the Air Force is unable to get back on track, however, the GAO warns there could be wide-ranging ramifications for all GPS users.

As there is growing concern regarding GPS, Boeing recently lost a lawsuit that would have prevented the Air Force from disclosing Boeing GPS satellites cost.  Boeing believes Lockheed Martin, the company's biggest competitor, may be behind the request, which was filed several years ago under a Freedom of Information request.

A few years ago only specialized GPS units made use of GPS, but now many mobile phones and smartphones now utilize the technology for consumers to enjoy.  Furthermore, an even larger number of new cars are shipping from the factory with built-in GPS units.

However, there is a much larger concern regarding possible intercontinental flights being canceled or delayed, and the military's reduced amount of "smart bombs" for use in Afghanistan.

It should be interesting to see if the Air Force is able to straighten out budget issues and make sure there isn't a serious GPS gap in the coming years.  Military officials said its IIIA block of satellites will be launched three years earlier than planned, but the GAO report said it's "optimistic given the program's late start, past trends in space acquisitions, and challenges facing the new contractor."



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RE: Definite problem
By openair on 5/20/2009 9:58:32 AM , Rating: 3
"The U.S. Air Force now uses 30 different GPS satellites -- which launched into orbit in the early 1990s"

Read again. They have been using 30 satellites since 1990s.

Each receiver requires 3 satellites because to pin point any point in space 3 reference points are needed. Each receiver doesn't require 100% of 3 satellites, more like 1%.


RE: Definite problem
By Zoomer on 5/20/2009 10:14:14 AM , Rating: 3
They might want to consider licensing fees to offset the cost. A few cents for consumer GPS devices, and maybe tens of cents or dollars for larger commercial purposes like airplane navigation/truck tracking.

I'm sure commercial users wouldn't mind paying that to help ensure that their investment stays useful.

And yes, I'm talking about charges for any installation/sale worldwide. Why should all US taxpayers subsidize the GPS using folk? Sure the sats would have been up there for military use anyway, but that's not really relevant.


RE: Definite problem
By Shadowself on 5/20/2009 10:20:31 AM , Rating: 2
This is similar to the concept behind the EU's Gallileo constellation.


RE: Definite problem
By PrinceGaz on 5/20/2009 11:37:18 AM , Rating: 4
... and the Russian's GLONASS which is almost fully operational again, and will be in a few months (Galileo is still a few years from completion).

Then there is the Chinese COMPASS system currently in its early stages, but you can be sure once they are happy with the design, they'll be sending up rockets with the satellites on faster than any other country.

The thing is, all of these alternative/additional options will provide a free lower-accuracy service to all users worldwide in addition to the higher-accuracy one which has to be paid for, and this lower-accuracy service is good enough for all ordinary uses of these devices. The consumer GPS market is very competitive where every penny counts, so the vast majority of devices sold will use the free services rather than one which involves a license fee.

One thing for sure is that there is going to be an awful lot more navigational satelittes up there in a few years. 24+spares for GPS. 24+spares for GLONASS. 30 (inc spares) for Galileo. 30 for COMPASS (plus 5 more in geo-stationery orbit).

Even if GPS did become unreliable, there would be plenty of alternative systems for devices to use (provided they had been designed to be compatible with them).


RE: Definite problem
By Shadowself on 5/20/2009 10:19:09 AM , Rating: 4
They've launched GPS satellites since 2000. Anyone can look that up and verify that. The satellites currently up there have most definitely *not* been up there since the early 90s!

You need four satellites to get a proper fix. Three for the physical calculation and one more for time relevance (all the calculations are based upon time). In theory, if your receive from more satellites than four you can get a slightly better fix.

You need to be able to "see" a minimum of four satellites to get a fix. Even if there are only four satellites and not 24 IF all four are over you at one time you can get a fix. In fact, the "Initial Operational Capability" of the GPS system was declared before they had 24 fully operational satellites in orbit.

Additionally, as I've said, they don't "use" 30 satellites at a time. The operational constellation has 24 satellites with six on orbit spares.


RE: Definite problem
By BadCat351w on 5/20/2009 2:01:53 PM , Rating: 3
Thanks for the info, but maybe you should take your own advice and look up the info,
http://en.wikipedia.org/wiki/Global_Positioning_Sy...
quote:
Since it became fully operational on April 27, 1995


RE: Definite problem
By openair on 5/20/2009 2:19:46 PM , Rating: 2
READ... From your own link.

"By December 1993 the GPS achieved initial operational capability.[11]
By January 17, 1994 a complete constellation of 24 satellites was in orbit."


RE: Definite problem
By BadCat351w on 5/20/2009 2:27:10 PM , Rating: 2
What I posted was one factual line stating when it was fully operational, thus pointing out that it has been fully operational long before 2000, there are many dates in the article with different outcomes going back to 1960, it was a reference, you want me to list all dates? No, you can do that,


RE: Definite problem
By openair on 5/20/2009 2:53:04 PM , Rating: 2
Ahh, I see. But of course it has. The op doesn't say otherwise. He mearly said that they have already replaced many satellites over the past 20 years.


RE: Definite problem
By jhb116 on 5/20/2009 5:10:54 PM , Rating: 2
You also inaccurately quote 24 versus 30. 24 is the minimum number required (evenly spread over a number of orbital planes) to provide 24/7 global coverage. The system is actually able to use up to 30 satellites for active use by consumers. If the wiki link is accurate - there is one stand-by spare (31 satellites).

The GAO report is probably alluding to the fact that probably more than half the constellation is past the design life and/or a large number of satellites might be what is referred to as a single point of failure away from becoming inoperable.


RE: Definite problem
By Lifted on 5/20/2009 10:43:52 AM , Rating: 2
quote:
Each receiver doesn't require 100% of 3 satellites, more like 1%.


wha?


RE: Definite problem
By PrinceGaz on 5/20/2009 11:01:25 AM , Rating: 4
quote:
Each receiver requires 3 satellites because to pin point any point in space 3 reference points are needed. Each receiver doesn't require 100% of 3 satellites, more like 1%.


Each receiver doesn't require any percentage of the satellites resources. The clue is in the name: they are *receivers*. They don't transmit anything to the satelitte in order to function, so it makes no difference whether one or one million receivers are getting a signal from it.


RE: Definite problem
By openair on 5/20/2009 11:21:46 AM , Rating: 1
READ... I was simply replying to the first post in terms he could understand.

"But from my basic understanding of GPS, each civilian receiver requires a minimum of three satellites to lock onto to get coordinates. With a constellation of 30 units, the service would quickly fail."


RE: Definite problem
By Samus on 5/21/2009 5:24:58 PM , Rating: 2
we're not talking about two-way communication here. gps receivers are dummy devices that just look for the wavelength of pre-programmed satellites. it them times the pulse of the signal to determine distance. pulses generated by three satellites can be timed to triangulate your position. it's amazingly accurate because the pulses are timed in nanoseconds. the more satellites it locks on to, the more accurate it becomes as there is even more timing detail to coordinate.

at no point is data sent back into space, as it is completely unneccessary. therefor, no "wear-and-tear" is caused by an unlimited number of people using the technology.

according to you, its like saying you 'use' bandwidth when you watch television over the air. you dont use anything, all you do is decode the signal thats already in the air.


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