Doubts About Future GPS Reliability

loped_index writes "IT Week reports that the U.S. GPS system is in a delicate state, and that full coverage could be lost if older satellites fail faster than the current rate. From the article: 'The system relies on a network of satellites, which cannot be repaired once launched and have a limited lifespan. Sixteen of the present 28 satellites were built to last seven and a half years, but are now between eight and 14 years old. Twenty-four satellites are required for full coverage.'"

Oh dear

[Britissippi]

We'll never find them when they fall then..?

Always good to know...

[Nom du Keyboard]

Always good to know I'll have something more to worry about this weekend. I was afraid I was going to run short.

Time to look backward for a backup

[geomon]

I guess we shouldn't have jettisoned WBS [nist.gov] so quickly.

Re:Time to look backward for a backup

[geomon]

Pardon. I must be more specific when dealing with ACs.

Your comment might relevent if:
A. Ground-based radio time was no longer available -- it is
B. Ground-based radio timekeeping independently useful in radionavigation -- it's not

The system I work on no longer uses WBS as a timing device.

So much for /. comraderie. More like a knife to the back.

Well...

[Sheetrock]

Given that these things are about trying to figure out where you're going, we're close to the point where we don't need satellites for them anyway.

When enough people have them, it'll be just as helpful to have the devices communicate with each other and work out amongst themselves where you're trying to go. Especially when you figure in the possibility of triangulating with cell towers.

It's how the Internet works.

Re:Well...

[merreborn]

we're close to the point where we don't need satellites

That idea falls apart when you're in, say, the alps. Or the sahara. Or most of the planet.

Re:Well...

[$RANDOMLUSER]

Wasn't it the US Navy that started this whole GPS thing?
Something about knowing where you are and where you're going...

Re:Well...

[robertjw]

Exactly, GPS was started by the military, with good reason. I can't imagine the military would let the network fail, unless of course they have an alternative in place.

Re:Well...

[scotch]

The US Air Force started GPS and runs it for the benefit of all branches of service as well as civilian use as deemed acceptible.

Re:Well...

[Detritus]

The U.S. Navy made very substantial contributions [navy.mil] to the GPS program. They were the pioneers in satellite-based navigation.

Re:Well...

[scotch]

Right you are, my friend.

Re:Well...

[Asetilean]

And, last time I checked, it was looking kinda difficult to build stationary cell towers on the ocean, nevermind a pesky lack of demand...

Plus, air traffic is now highly dependant on GPS and most cell antennas aren't aimed up at the sky.

So, for imprecise civilian needs (tell me how to go from here to there), a cell tower based nav system might be fine. But GPS is capable of providing a whole lot more than that.

Re:Well...

[WhiplashII]

The Pacific ocean is 60060700 square miles. The cost of deploying GPS is about $3B, give or take a few orders of magnitude. Assuming that you would need 1 tower per square mile, you could spend $50 per tower - which might actually be possible for something just floating around transmitting a position beacon.

Not necessarily impossible... just unlikely!

Re:Well...

[Limecron]

You might be able to BUILD them for $50 a piece. (Though even this is highly unlikely if it's a government project.) But you sure as hell couldn't distribute them across 60060700 square miles for $50 a pop. Forget about monitoring and maintaining them. Also, ground based transmission makes all sorts of other problems.

Re:Well...

[camt]

When enough people have them, it'll be just as helpful to have the devices communicate with each other and work out amongst themselves where you're trying to go. Especially when you figure in the possibility of triangulating with cell towers.

Except when there is no cell coverage (which is far from "full coverage") or where there aren't very many other people (tramping/geocaching through remote areas or national parks). Not to mention that would require all those devices to transmit as well as receive, incr

Re:Well...

[Baricom]

First of all, that article says nothing except that selective availability was disabled, meaning the accuracy improves for everybody. There's some veiled tin-foil hat comments about why the government turned it off, but nothing to substantiate the fears.

Second, the GPS constellation never misrepresented the locations of the satellites. They dithered the unscrambled signal from the satellites so receivers couldn't calculate their position as accurately. The article speculates that selective availability m

Re:Well...

[ptbarnett]

Especially when you figure in the possibility of triangulating with cell towers.

The proper functioning of adjacent CDMA cell towers (i.e. Sprint, Verizon in the 1.8 GHz bands, and by US West in the 800 MHz bands) must be synchronized within 10 microseconds to support what is called "soft handoff" [rr.com].

CDMA base stations use the GPS constellation to maintain synchronization. The satellites themselves need precise clock synchronization, and this is exported to GPS receivers.

Re:Well...

[provolt]

Yeah, the thousands of cell towers that dot the pacific ocean really are a better way to navigate than an old 70's satellite system.

Re:Wrong!

[Sheetrock]

Lao Tzu teaches us that even a journey of 1,000 miles begins with a single step. I believe his wisdom can lead to discovering that where you are is as or more important than where you want to be.

Which, while being an excellent foundation from which to seek enlightenment, can prove a bit of an obstacle when you're simply looking to get from point A to point B... satellites or no satellites.

Well that sucks...

[Anonymous Coward]

First the Internet, now this. :/

Yada yada

[Red Flayer]

Is it just me, or does everyone else also realize we're still capable of launching new satellites into orbit?

Is there a concern about current GPS-enabled devices reading signals from new satellites?

I'd be shocked if there is not money available in the Pentagon Budget, or elswhere, for replacement of needed satellites. Then again, cutting funding of absolutely necessary programs is a great way to dodge real budget cuts... since there will need to be a "special appropriation" to cover the shortfall.

Re:Yada yada

[Osiris Ani]

Indeed, I'm sure I remember reading something somewhere [slashdot.org] about the US government recently launching newer, more accurate GPS satellites. Of course, what we need these days is more alarmist rhetoric, so I suppose this is apropos.

Re:Yada yada

[plover]

GPS satellites transmit two different signals: Precise Positioning Service (PPS) and Standard Positioning Service (SPS). PPS is carried on the dual frequency 'P code' (Precise) and the decryption keys are only present in U.S. military receivers. SPS is carried on the single frequency 'C/A code' (Coarse / Acquisition) used by civilian receivers.

It's incorrect to say the new satellites are "more accurate" -- the satellites themselves are as accurate as they ever were, (unless you're comparing them to the

Re:Yada yada

[kriston]

Didn't the advent of WAAS, the Wide-Area Augmentation System, correct the SA error and thus made the SA feature meaningless? Local municipalities started broadcasting correction signals which were used by their WAAS-enabled GPS receivers for 1-meter accuracy even when SA "dithering" was turned on. The system was ingenius--you determine the exact location of a receiver, such as a low-cost PC, then transmit the correcting factor to a local area on a public safety band. The receivers that are WAAS-enabled r

Re:Yada yada

[plover]

You just described DGPS, or Differential GPS. DGPS is a local GPS receiver placed in a precisely surveyed location that transmits a "correction" signal on an FM band. Because each station is local, it automatically corrects for local atmospheric conditions.

WAAS is almost the same thing. The difference is that instead of transmitting local corrections on the FM band, the local receivers all uplink the correction data to an FAA satellite located in a geosynchronous orbit above the U.S. This satellite th

Re:Yada yada

[Rakishi]

Yeah, why replace them when they're still working fine. That would be a waste of money, extra sats which age and provide little benefit. I mean, unless 5 fail in the time it takes to get a new one up there is no problem. Given that only 2 fail per year I don't see that happening anytime soon.

I mean, come on look at this idiotic statement:
'Bonnor said launches of new satellites are "only just keeping up" with current losses of around two satellites per year.'

What they hell is the US supposed to do, send up more satellites than they lose and waste money keeping up sats when only 24 are needed (+ a few redundant ones)?

Re:Preventive vs Curative ?

[Rakishi]

huh? If a sat dies then there are 4 working spares already in orbit which can replace it. As I said above, you'd need to have multiple sats (5, potentially less if spares can only take over certain orbits each) die in the time it takes to get replacements up for there to be any real downtime.

Redundancy is already in place, right now its all a question of "how few sats can we launch while keeping the chance of failure very low." If we launch too early then we have an extra satellite in orbit which provides u

Re:Yada yada

[Vellmont]

The concern is that 4 or 5 satellites will all fail in the same year. The current pace of only replacing 2 a year would cause gaps in the GPS coverage. Just because you allocate the funds doesn't mean you get to launch the replacement satellites tommorow to fix the problem. Not knowing much about satellite launch preparation I'm guessing it might take a month or two to get everything ready for launch.

Re:Yada yada

[GileadGreene]

The current replacement rate is designed to slowly phase out existing satellites before they hit their (statistical) expected end-of-life. It's not intended to cope with unexpected (i.e. low probability, such as 4 or 5 satellites dying at once) failures. Nor does it have to. The GPS constellation includes a number of "on-orbit spares" (i.e. spare satellites already in the GPS orbits), which can be used to ensure continuous availability in the face of an unexpected failure. AFAIK the typical scenario is something like:

1. GPS satellite fails
2. On-orbit spare is activated
3. New satellite launched some months later becomes a spare
4. Life goes on

Re:Yada yada

[Vellmont]

Based on what you an others have said this entire article should be marked troll. The most interesting comment was that satellite failure isn't unexpected as the people who manage them get information on the health status of the satellites.

Working at the GPS hub

[iamweezman]

As an active duty Air Force tech controller I work almost daily with the satellite operators that "fly" the GPS satellites. Some of their systems are more than antiquated, but still function with adequate redundancy built in. Although the lifespan might have been eclipsed the telemetry data recieved by the operators give them the state of health of the satellites which allows them to plan for future launches.

In fact, a newer GPS satellite was just launched weeks ago. As stated before, the DOD has a special spot in their hearts for GPS. The GPS operators get treated extra special because of the US military's reliance on them. There are already plans in place for each satellite to be super-orbited when the time comes and for a new launch to follow.

In other words, if the military isn't worried about it, neither should we be.

Absolutely

[Sycraft-fu]

People seem to forget that GPS is a military system, developed for military purposes. They opened it up for civilian use and that's wonderful, it's been a massive boon, but it was developed for the US Military alone. It is also the prime location system for just about all military units, from individual soliders up to large ships these days. While I'm sure the military COULD function without it, it would seriously screw things up.

It's a strategic asset, and they aren't going to let it fail. If it was all private run, ok maybe then there'd be a worry that someone would decide to cut costs on it and let it slide, but it's the military's toy and there's no way in hell they are letting it fail.

All the military implications aside, US commercial intrests rely very heavily on GPS these days and letting it fail would also not be in the economic intrest of the US government.

Re:Working at the GPS hub

[Phronesis]

In other words, if the military isn't worried about it, neither should we be.

I just love it when someone says, "I'm from the government. Trust me."

Capturing Osama bin Laden and building a functioning democracy in Iraq are even greater priorities for the military than maintaining GPS operations. According to the Commander in Chief, things are going swimmingly on both of those fronts so if I follow this logic, if the military is not worried about Iraq or Osama, neither should we be.

Re:Working at the GPS hub

[plover]

Nice strawman, but your argument doesn't hold water.

First, when did you discover their priority list? And second, just because George Bush is one of the biggest liars ever to disgrace the White House, and Donald Rumsfeld is by far the biggest liar ever to hold the Secretary of Defence chair DOES NOT mean the lies extend to our military. (It's really sad, when you think of it, that we can trust our Army to tell us the truth far more than we can trust our elected officials.)

Anyway, it's very simple. It

Re:Working at the GPS hub

[Phronesis]

I was too snide in my comments, and for that I owe the poster an apology.

But my major point stands. The source is someone posting to slashdot, claiming privileged information that is not subject to independent verification, telling us to trust him because he's part of a government agency (specifically the military).

Just because someone is a government functionary does not mean that I trust him when he makes claims based on evidence that's not available for scrutiny. I'm not saying that I lose sleep wor

oops (GPS goes out)

[pmike_bauer]

Toto, I don't think we're in Kansas anymore.

Re:oops (GPS goes out)

[xenocide2]

Yessir, you are a silly european. Tonto was probably an Indian in the lone ranger, and Toto was a little dog in the Wizard of Oz.

There is only one solution...

[Anonymous Coward]

We MUST hand over ALL CONTROL of the GPS system to the UN, to save it from destroying itself...

Re:There is only one solution...

[amliebsch]

Exactly! Sure, the US invented the system, launched all the satellites, and bears the maintenance cost, but everybody else in the world depends on it, so it's obviously right that the UN control it!

Re:There is only one solution...

[Just Some Guy]

We MUST hand over ALL CONTROL of the GPS system to the UN, to save it from destroying itself...

The first thing that came to mind when I read that was Emacs' "Zippy" mode. I ran M-x yow and got:

I'm RELIGIOUS!! I love a man with a HAIRPIECE!! Equip me with MISSILES!!

Swear to God. I don't know whether to laugh, cry, or lock myself into the panic room.

They'll launch more

[Frangible]

Everything dies, why is this news? GPS is an important and critical system, it will be maintained through new satellites.

I think I'm still OK

[$RANDOMLUSER]

I use one of these [wikipedia.org] as my GPS.

Re:I think I'm still OK

[stimpleton]

We use these for our navigation system for our vehicle fleet.

Oddly, our accident rate has also gone up recently.

Re:I think I'm still OK

[Christopher_G_Lewis]

Make sure you have an acurate time source, like your GPS :-)

Backup Satellites

[g4n0n]

They fail to mention that there are a number of backup satellites sitting up there, waiting to go into the consellation if any fail.

May not be that important, really....

[ip_freely_2000]

"Twenty-four satellites are required for full coverage

As long as the satellites fail over someplace unimportant like Europe, why should we care?



Please be gentle with my karma!

Re:May not be that important, really....

[fred fleenblat]

You're joking right?

For those few that don't get it, the satellites aren't geostationary, so a failed satellite (once the minimum # is reached) will probably create a dead spot that moves around the planet, in which GPS service is degraded.

Re:May not be that important, really....

[zippthorne]

It's really really expensive to change the inclination of an orbit. Even more expensive to change its axis. I think it's far more likely that the density of the constellation is such that more satellites than necessary are visible at any time. So if one gets knocked out, you've still got enough, but if several inconveniently close ones get knocked out, some areas would not have enough at certain times of day.

Re:May not be that important, really....

[anthony_dipierro]

Its not like it costs much more to launch 3 at once over the cost of launching the first one.

It's not? Doesn't putting 3 satellites in 3 separate orbits cost roughly 3 times as much as putting 1 satellite in 1 orbit? It's not like they can launch them all on the same rocket, because the satellites have to go into different orbits. In fact, I think you'd have to launch them at different times - just like the shuttle has to be launched at a particular time in order to meet up with the ISS.

Re:May not be that important, really....

[Geoffreyerffoeg]

Please be gentle with my karma!

My dogma ran over your karma.

Wait..uh..I think I got that backwards...but you get the point.

No news here

[adsl]

If you put up satellites at a quicker rate then you have too much redunancy in the skies and too much junk in space. It's all a balance, as it should be. Another timely "This is why Europe should run everything" spin story. Be good if Europe invented something really new and useful, for American's to play with (for free)....

Re:No news here

[Lehk228]

Be good if Europe invented something really new and useful, for American's to play with (for free)....

Re:No news here

[dhakbar]

He said new and useful, key word being NEW.

Your examples are all at least 50 years behind us. In addition, none of those inventions were world-wide systems that America made power grabs for... the current situation with the UN/EU wanting power over the internet is completely different than the American use and application of those English inventions. And, for the record, the US developed a jet engine independently and simultaneously.

Re:No news here

[IvyKing]

I mean one country (England) in Europe only invented the steam engine, locomotive,

Hmmm, lessee. Seem to recall that the first steam engine was built by a Greek named Hero, although the first useful one was built by Newcomen. The first self propelled vehicle was built by Cugnot of France, another Frenchman built the first steamboat (and that was acknowledged by Fulton). The first high pressure steam engines were built by Trevithick of England and Oliver Evans of the US. Trevithick also built the first steam locomotive. While the first locomotives in the US were imported from England, the US became a net exporter of steam locomotives by the mid-1830's. The first elecric locomotive (albeit model sized) was built by Thomas Davenport of Vermont in 1834.

the telephone

Huh? I would believe "The telegraph" (Wheatstone).

internal combustion

Funny, the names for the two most common ICE cycles are Otto and Diesel - sounds suspiciously German to me.

the jet engine

Which was devloped from turbocharger technology - ISTR was a Swiss development. The Swiss had a working gas turbine in 1940.

One thing you did leave out, the steam turbine was developed by an Englishman by the name of Parsons.

jets didn't come from turbochargers

[YesIAmAScript]

Leaving off the Swiss turbocharger thing (Americans made them practical).

Jets just flat out don't come from turbochargers.

Jets use fan blades, turbochargers do not. Turbochargers use impellers and are only compressors. Jets have different compression sections, burners (flame fronts) and actually make thrust.

It's like saying cars came from trains because both have round wheels. It just doesn't work.

I don't see how England invented TV. Nipkow (German) invented mechanical TV, and Farnsworth (American) invented electronic TV (far more important to getting us to where we are now).

The grandparent did miss that England invented RADAR. A great invention.

Note to other posters, Alexander Graham Bell was not Canadian. He resided there fora while, but never changed nationality, he was a Scot up intil he became American. He was a Scot (living in Boston?) when he invented the telephone.

Re:jets didn't come from turbochargers

[IvyKing]

Jets use fan blades, turbochargers do not. Turbochargers use impellers and are only compressors. Jets have different compression sections, burners (flame fronts) and actually make thrust.

First off, turbochargers make use of a turbine to drive the compressor.
Secondly, many of the early jets used centrifugal compressors (impeller).
Thirdly, several people have made small turbojets by grafting a combustion chamber between the compressor and turbine of an off the shelf turbocharger.

One of the reasons that G

Re:jets didn't come from turbochargers

[Lord Haha]

(Alexander Bell) was Living in Cape Breton :)

Re:jets didn't come from turbochargers

[surprise_audit]

While not actually English, a Scot named John Logie Baird [wikipedia.org] is said to be the first person to demonstrate a working television.

"Although the development of television was the result of work by many inventors (including Baird, Paul Gottlieb Nipkow and Boris Rosing; see Television: History), Baird is one of its foremost pioneers. He is generally credited with being the first person to produce a discernible image on a television screen, and would go on to produce many other advances in the field."

The BBC used

Re:No news here

[martinX]

Seems an Italian migrant living in Cuba invented the telephone. http://en.wikipedia.org/wiki/Alexander_Graham_Bell #The_telephone_and_patent_issues/ [wikipedia.org]

Why this scare tactic?

[rolfwind]

The US government/military has a humongous interest in keeping the system up - why be scared about it? It will keep plodding along.

Or am I missing something here?

Ahh, yeah....

[killtherat]

Given the military's dependence on GPS, do you think they would allow one second of interuption? And they use it on almost every corner of the globe. They would notice holes in service much sooner then you ever would.
Call this article what it is, FUD to prop up EU's Galileo.

Don't worry...

[Spy der Mann]

the Chinese will be happy to replace them :)

GPS Satellite Replacement

[jwink]

It sounds like they are already in the midst of replacing it - check out SpaceFlightNow [spaceflightnow.com]. The new series is going up with the next generation in the works. Maybe it's just a matter of keeping at or above the crucial 24 limit...?

Bush Administration Announces...

[ENOENT]

new "Faith-based" navigation system...

Film at 11.

Re:Bush Administration Announces...

[rubberbando]

Yes! The north star will lead the way!

Re:Bush Administration Announces...

[ENOENT]

Can't use the north star. It's obviously a pagan artifact, with a Latin name and everything.

Re:Bush Administration Announces...

[JahToasted]

And a lot of the other stars have arabic names... hmmm no wonder Bush is putting so much into space initiatives.

blind

[-ryan]

the military lives by GPS these days, no GPS (or poor coverage) would almost halt military operations above the level of a patrol on foot with compass and map. but any infantryman will tell you, there's nothing more dangerous than a cherry ass Lt. with a map.

They're up longer BECAUSE they didn't fail

[MDMurphy]

It's not that the satellites were just left up there longer because they couldn't be replaced, it's because they've lasted longer than they were intended to. Kind of a "if it's not broke, don't fix it" philosophy.

With redundant satellites and constant monitoring from the ground, it's possible to let one go until it fails, mark it as "bad" and replace it a little later.

The article is wrong about 24 satellites being required for full coverage. A full set is 21 with 3 as spares.

The article also implies that the satellites are failing at greater than planned rate, when the opposite is true.

It's probably just a coincidence that the guy quoted in the article, Norman Bonnor, is a backer of the European counterpart to GPS: Galileo. It's not like he'd have an interest in bashing the GPS system to help further justify Galileo's funding?

Re:They're up longer BECAUSE they didn't fail

[thewiz]

It's not that the satellites were just left up there longer because they couldn't be replaced, it's because they've lasted longer than they were intended to. Kind of a "if it's not broke, don't fix it" philosophy.

Actually, the military's philosophy is to over-engineer items like satellites to make sure they last awhile. If you don't believe me, read a couple of the military specifications (MIL-SPEC) manuals. There is a joke that goes:

Q: What is an elephant?
A: A mouse built to MIL-SPEC.

GPS Constellation status, with launch dates

[Anonymous Coward]

From: ftp://tycho.usno.navy.mil/pub/gps/gpstd.txt [navy.mil]

A. BLOCK II/IIA/IIR/IIR-M INDIVIDUAL SATELLITE STATUS

SVN PRN
15 15 Launched 01 OCT 1990; usable 15 OCT 1990; operating on Cs std
24 24 Launched 04 JUL 1991; usable 30 AUG 1991; operating on Cs std
25 25 Launched 23 FEB 1992; usable 24 MAR 1992; operating on Cs std
                    Scheduled unusable 20 Oct 0130 to 1330 UT for repositioning
                      maintenance (NANU 2005131/14 OCT)
26 26 Launched 07 JUL 1992; usable 23 JUL 1992; operating on Rb std
27 27 Launched 09 SEP 1992; usable 30 SEP 1992; operating on Rb std
29 29 Launched 18 DEC 1992; usable 05 JAN 1993; operating on Rb std
30 30 Launched 12 SEP 1996; usable 01 OCT 1996; operating on Rb std
31 31 Launched 30 MAR 1993; usable 13 APR 1993; operating on Rb std
                    Unusable 14 Apr 1634 UT and will remain unusable until
                      further notice (NANU 2005055)
32 01 Launched 22 NOV 1992; usable 11 DEC 1992; operating on Cs std
33 03 Launched 28 MAR 1996; usable 09 APR 1996; operating on Cs std
34 04 Launched 26 OCT 1993; usable 22 NOV 1993; operating on Rb std
35 05 Launched 30 AUG 1993; usable 28 SEP 1993; operating on Cs std
36 06 Launched 10 MAR 1994; usable 28 MAR 1994; operating on Rb std
37 07 Launched 13 MAY 1993; usable 12 JUN 1993; operating on Rb std
38 08 Launched 06 NOV 1997; usable 18 DEC 1997; operating on Cs std
39 09 Launched 26 JUN 1993; usable 20 JUL 1993; operating on Cs std
40 10 Launched 16 JUL 1996; usable 15 AUG 1996; operating on Cs std
41 14 Launched 10 NOV 2000; usable 10 DEC 2000; operating on Rb std
43 13 Launched 23 JUL 1997; usable 31 JAN 1998; operating on Rb std
44 28 Launched 16 JUL 2000; usable 17 AUG 2000; operating on Rb std
45 21 Launched 31 MAR 2003; usable 12 APR 2003; operating on Rb std
                    Unusable 13 Oct 0217 to 0905 UT due to repositioning
                      maintenance (NANUs 2005129, 2005130/13 OCT)
46 11 Launched 07 OCT 1999; usable 03 JAN 2000; operating on Rb std
47 22 Launched 21 DEC 2003; usable 12 JAN 2004; operating on Rb std
51 20 Launched 11 MAY 2000; usable 01 JUN 2000; operating on Rb std
53 17 Launched 26 SEP 2005
                    For more information about PRN17/SVN53, see:
                      http://www.spaceflightnow.com/delta/d313a/ [spaceflightnow.com]
54 18 Launched 30 JAN 2001; usable 15 FEB 2001; operating on Rb std
56 16 Launched 29 JAN 2003; usable 18 FEB 2003; operating on Rb std
59 19 Launched 20 MAR 2004; usable 05 APR 2004; operating on Rb std
60 23 Launched 23 JUN 2004; usable 09 JUL 2004; operating on Rb std
61 02 Launched 06 NOV 2004; usable 22 NOV 2004; operating on Rb std

Can I get a job

[squoozer]

I would love to have a well paid job coming up with solutions to "difficult" problems like this. I'd give my employer the first solution for free:

Launch new satelites that are compatible with the old system!

then I would charge a fortune for all the other ideas once I had got them hooked. My god I can't believe anyone is even questioning this. It's a total no brainer. Have IQs dropped recently or is it just that all the money has been spent on other things?

ya go to space with the satellites you have

[gelfling]

not with the satellites you wish you had.

Already taken care of

[iabervon]

Since that article was written, they launched a new satellite, as the article mentions at the end. This is the first of the new series, currently in testing and scheduled to be launched as older satellites fail. When the article was written, it was a vaguely reasonable concern that they didn't yet have new satellites ready to send. Also, it's traditional to post stories on a topic in chronological order, so that they make sense.

what is failure?

[morcheeba]

I know that I'm not the oldest person here, but I've been using GPS since before all the satellites were up (~1992?).

The main problem is that you need a larger view of the sky to see the minimum number of satellites (3-4) -- indoor reception was difficult because you were limited to seeing 1/2 of the sky.

With fewer satellites, their geometry in the sky can become a problem -- if they are too close together, you'll get more measurement error (or, technically, GDOP [colorado.edu]).

Back then, if you really needed a gps fix,

Such BS

[chadseld]

There is nothing to worry about, this article is inflammatory. Do you have any idea how many weapon systems rely GPS? I work in the defense industry, GPS is everywhere. When the current satellites start falling down, we will send up more. In fact, those plans to 'weaponize' space are mostly a reaction to the realization of how important the GPS system is. It is a single point of failure and must be protected. Do you really think the armed forces are going to let the system fail due to neglect?

LORAN

[ChrisMaple]

Isn't 1/4 mile accuracy good enough for anybody?

in other news...

[Yonder Way]

...the EU demands that the US cede control of the Global Positioning System.

Move Along, Nothing to See Here

[Captain Chad]

The GPS system has built-in overkill. At any given time there are about a dozen satellites within view, and a receiver only requires four to work correctly (okay, theoretically only three if you have a clock). So even if we were to lose some of the satellites, GPS receivers would still work.

There could be some degradation—using more than four satellites will give better accuracy. And a satellite on the horizon will give a weaker signal than one straight above, thus adding noise to the process and po

It's cheaper to launch a new one

[grahamsz]

A GPS satelite is relatively inexpensive.

if we were going to send something/someone up to fix repair it, then we could just as easily (probably much more easily) send a new satelite up.

Re:It's cheaper to launch a new one

[Bent Mind]

I agree, but I wonder... Sending something up (even a new satellite) is expensive. Wouldn't it be cheaper to have some kind of in-orbit repair facility? Last I checked, it cost several million just to launch. I wonder if something could be set up that was capable of robotic repair. Maybe have it refuel at the space station as needed, or have it hover in one of the Lagrange points? Just a random thought...

Re:Something doesn't make sense here.

[$RANDOMLUSER]

Um, they're in orbit?

Re:EU's Galileo

[Anonymous Coward]

Several US firms - and the US governement are active in the development of Galileo as even the most basic search will turn up. However, the big difference comes down to the desire by several of the EU backers to piggyback their encrypted signal in the same space as the GPS encrypted signal. You can imagine anyone getting upset when a newcomer decides to ride on the same signal area (i.e. BPL and hamms).

Re:EU's Galileo

[theLOUDroom]

So maybe the US will stop its attemps to prevent the European Galileo...


Actually, it looks like this whole thing may be just misinformation to drum up support for Galileo.

The satellites are lasting LONGER than expected, and we have plenty of spares. It appears the article may also have the number of necessary satellites wrong.

As someone else has pointed out:
Bonnor said launches of new satellites are "only just keeping up" with current losses of around two satellites per year.

So we HAVE SPARES and we're REPLACING THE SPARES AS WE USE THEM. Sounds like it's working just dandy.

Re:EU's Galileo

[theLOUDroom]

The implication is that the failure rate is going to accelerate beyond the replacement rate real soon now.

So if that *actually* happens they'll increase the replacement rate. Are we now also worried that the US is suddenly only going to be capable of two satellite launches per year?

My point is that this is all silly sensationalism. If the failure rate doubles, no big deal, we send up a few more. The system would still have 100% uptime.

For the GPS system to actually become "unreliable", failure rates would have to increase by orders of magnitude. There is no data presented to suggest such an abrupt change might take place.

Re:EU's Galileo

[clodney]

GPS is funded by the military, so they are launched by the Air Force, not NASA. I know nothing about the budget of either, but I would be surprised if the Air Force was unable to afford 2 launches a year - or even 6 or 7 if the failure rate kicks up.

Re:EU's Galileo

[theLOUDroom]

Thus, being able to "just keep up" with the current failure rate will not be sufficient to prevent the system from collapsing.

But the implication that we're only able to just keep up is false.

We're only launching that number of satellites per year because that's how many we need to provide adequate redundancy, not because it's the best we can do. We could send up more, but it would be a waste of money.

What several posts fail to understand (e.g., grand parent or a few posts in parallel threads) is that the failure rate of a system is not constant over time

I understand this concept, but what you're failing to properly acknowedge is that:
A) The system is redundant
B) The failure rate to needs to increase by orders of magnitude in order to outpace our ability to replace satellites.
I highly doubt that the stastical data supports such claims.


Go ahead fit the standard function to the availible data form the GPS satellites the have already failed. I bet it's going to agree with the course of action the the US is taking. Why? Because they can do the same math you can. As a matter of fact, I be they have even better data they don't publish.

I am not trying to enter into the politcal side of this discussion, and I agree that the author of the article may have is own motives, but this is simply not relevant to the logic of his argumentation.

There are gaping holes in his logic. Is it more likely that he's:
A) incompetent
or
B) pushing an adgenda?

Re:EU's Galileo

[surprise_audit]

We're only launching that number of satellites per year because that's how many we need to provide adequate redundancy, not because it's the best we can do. We could send up more, but it would be a waste of money.

Just as long as we can build and launch new satellites if the rate of loss increases. How long does it take to build the satellites and launchers?? I imagine there's something like an assembly line for these things - can they turn out 16 on short notice??

Re:EU's Galileo

[theLOUDroom]

This means that the failure rate can actually increase by several orders of magnitude in a very brief period.

I'd like to see some real data supporting this offhand statement. Essentially, it's claiming to be able to predict the failure rate better than the guys who actually designed and operate these satellites and have access to more data than you.
I'm not buying it. Also, both common sense and research will point out that the GPS system was put into service over a period of time. There's a pretty l [navy.mil]

Re:EU's Galileo

[Anonymous Coward]

Let me get this straight. You nearly praise the European nations and call the US incompetent, despite the EU-related solution is over 4 years off, not to mention have questionable delivery systems themselves.

You take the word of a UK individual who, like folks anywhere in the world, gives talks to promote their opinion that are largely unsubstantiated unless they are privy to manufacturing data and known defects which allow him to, within reason, truly call into question satellite failure en masse. I doubt a UK RAF person will know the intimate details of the satellites. What we do know is their failure rate to date.

It's not like nothing is being done with this problem and the problem is not unknown or being ignored; the US has known about this for some time now. Our delivery systems have had problems and huge delays (space shuttle, rockets blowing up), yet we still have been managing to replace the birds that do croak. And are replacing them next with longer lasting birds.

You overlook the fact that many satellite systems are overbuilt and typically do last well beyond their expected lifetimes. Not all do, but a good number have (classic would be the Voyager; one still is running rather well). Until these systems start dropping rapidly faster than we can replace them, I don't see the issue. 4 of them could croak now, and you'd still get accurate info. If a 5th dies, we have one waiting to be launched already and would likely ramp up replacement schedules. If a 6th dies before all that, it depends on WHICH it dies and WHERE you are to determine if it may affect you directly.

You trust this same Old World Europe at the expense of the US, yet look at the recent examples of them deliberately trying and "warning" regarding the domain system (which is something that could have occurred at any time prior anyways).

You use this as an opportunity attack ad hominum US diplomacy, when that has little to do with satellite failure and more to do with their tactics of trying to get their own system (Galileo) up.

I'm not a bible thumper. And yet even I know the problems with the proverb you quote and at the very least, it points to lack of real world experience on your part. Anytime I've spoken softly, the other person being receptive listened, but they weren't, I've watched people get pushed around and one person punched. Anytime I've yelled at someone, they overwhelmingly back down or at the very least snap from the focus, if temporarily, from the object of their violence. I just choose to yell when the situation merits it and that's not often, only when I've or another has been physically threatened and do so then to try to avoid or head off fights.

You attack the right, making no distinction between it and the religious right, just to be critical of the US, meanwhile the EU (multiple nations too) kisses the ass of some of the most suppressive fascist and religious states in the world. Freakin hypocrite. Anytime the Old World gets involved in diplomacy, nothing of substance positive comes about to improve the world order. It's not like the EU is doing this out of the goodness of their hearts either; they want the markets, a price cut, the membership, the money just as well if not more so than the US counterparts.

There will always be those who read a story about "US companies do [questionable or suspected evil activity]" and say, damn, it's all the US's fault, never asking or researching the EU or any other nation's track record on that same matter. But if the EU ballerinas in and bends over before doing a twirl and says "all will be okay, we're here", you're more inclined to take their word for it.

You want to doubt and disagree with the US government? Good. I'm with you. But don't think that because you do and can that the US government is worse than some other half-baked government out there; that's a totally different set of standards and questions which you certainly have not addressed yourself.

Re:EU's Galileo

[quax]

But don't think that because you do and can that the US government is worse than some other half-baked government out there.

Sorry, but I think this speaks of lack of real world experience in international settings on your part. The US winner take all election system can produce some really nasty outliers when it comes to the quality of your government. BTW I mean the whole selection process - just imagine McCaine winning the 2000 primaries.

In the EU all member nations need to compromise to get anything done. This process certainly squashes all brilliance but it also quite reliably squashes complete and utter idiocy. And guess what, because the EU only moves by compromise the government that yells the loudest hardly ever wins. It is the ones that can moderate compromises the best that end up with the most influence.

Re:EU's Galileo

[quax]

Do you mean kind of what your government tried recently in order to influence EU media [fpp.co.uk]?

Lucky you, that we do not take this very serious. No, in my view that was really stupid on part of the Bush administration, but it certainly was not an act of war.

But then again in your world view I probably may as well be one of those foreign agents trying to influence the /. crowd, so why would you believe anything I write anyway.

Please wrap your head a bit tighter with your tin foil, after all the EU Galileo satellite

Re:EU's Galileo

[mosb1000]

Apparently you can't tell the difference between some half-baked defense department plan and official government policy. The defense department comes up with a lot of bone-headed ideas, that's why we don't let them make all the decisions.

Military people just don't think right sometimes, I'd doubt the military commanders of rest of the worlds armies make better judgment calls on this sort of matter. What else would you expect from someone whose job is to resolve problems by force? It's just par for the co

Re:EU's Galileo

[Fred_A]

It's as a great american once said "war is to important to be left to the generals."

Yes. Right. Except that the quote you're looking for is "La guerre est une affaire trop sérieuse pour être confiée à des militaires" (War is too serious a matter to be left to the military) and that the author is Georges Clemenceau [wikipedia.org] (1841-1929). Damn, and he was a leftist too (that would be a commie to you). I wasn't aware he was a great american though... He probably wasn't aware of it either.

Re:EU's Galileo

[quax]

Look, my link was in response to an AC claiming that the EU was officially doing something that your government on the other hand has actually been looking into to do to us (I am a EU citizen).

Now, if you can provide me with any evidence that the EU ever wasted any of my taxpayer's money on trying to sway public opinion in the US I'd be inclined to listen.

What this AC was spouting was borderline hysterical drivel. That you have nothing better to do than to attack my response to him reinforces my impression

Re:EU's Galileo

[hey!]

Let me get this straight. You nearly praise the European nations and call the US incompetent, despite the EU-related solution is over 4 years off, not to mention have questionable delivery systems themselves.

Nope. You don't get this straight. I didn't praise the EU, but I wouldn't be ashamed of it if I did.

I didn't call the US incompetent. I called the Administration conduct of US diplomacy incomptent.

You take the word of a UK individual who, like folks anywhere in the world, gives talks to promote their o

Re:hmmm...

[LnxAddct]

The article is pretty much an advertisement for the European Galileo system.
Regards,
Steve

Re:I don't care who does what with who

[Poltras]

"Only wimps use tape backup: real men just upload their important stuff on ftp, and let the rest of the world mirror it." [Linus B. Torvalds]

Re:Am I reading this right?

[afidel]

It's called reading comprehension.... They were built to last 7.5 years, they have been in service between 8 and 14 years, .5 to 6.5 years longer then their origional design life. Like everything else in space they were overengineered and have surpassed their design life (the minimum time that they should last given expected MTBF of components). This isn't the first time this has happened, and as long as NASA and their contractors (and military contractors) keep up the good engineering principal of overdesi

Re:who pays for this...

[scotch]

Get a room, you two.