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"Pathfinders" Take Shape For Galileo, Europe's GPS 105
oliderid sends along a BBC report on progress toward Europe's home-grown GPS system. The Galileo concept will get an initial test via four "pathfinder" satellites that will be the first in the Galileo constellation. Galileo is intended to be complementary with the US GPS system — when all 30 Galileo birds are flying, a receiver with both GS and Galileo capability should enjoy 1-meter positional accuracy, vs. the several meters available through GPS alone, according to the article. There's a video tour of the facility where the pathfinders are being built. "After all the wrangling, the delays, and the furor over cost, Europe's version of GPS is finally starting to take shape. Due for launch in pairs in late 2010 and early 2011, the 'pathfinders' will form a mini-constellation in the sky. They will transmit the navigation signals that demonstrate the European system can become a reality."
Funding (Score:2, Interesting)
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(unless they sold some babies or something)
Don't be so narrow minded. Music industry execs have to eat something.
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Huh, whuzzat? you calling me?
Yeah sure. Lightly fried in hash oil. Can't beat them. Well, shouldn't have to ; should be tender enough already. But that last shipment of babies which you sent - good capitalist pig that you are - was decidedly below standard. Tendons all stringy, guts not properly hosed through. Really poor stuff. If you don't get y
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Re:Funding (Score:4, Informative)
> How are they getting funding? As recently as yesterday I was reading about how it was pretty much an orphaned project because no one wanted to buy what was already available for free (albeit less reliably).
I can not remember the full story, but the industry funding arguments dragged along for years, and in the end the EU took over funding of the project (it was too high profile to fail !!).
http://en.wikipedia.org/wiki/Galileo_(satellite_navigation) [wikipedia.org]
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of course Glonass only works over russia. it is a little thing but I think it is important.
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It's short a few satellites for whole world coverage right now. Now that Russia has oil dollars running in, the whole world should be back up in a year or so... they've been launching satellites quite frequently the last few years.
Here is a map of current coverage.. basically everywhere except Antarctica.
map [glonass-ianc.rsa.ru] A few pieces are missing here and there, but it's a far cry from "just russia".
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Funding ? Well, in the Netherlands our government just decided to implement variable road taxes. All cars will get a GPS box that registers where you drive, and at what time, and it will automatically send that data to the central government servers.
The amount of money involved in this taxation plan alone would make it financially feasible to put a complete GPS system up there.
Of course security related government agencies will also have full access to the database as well. Believe me, it will get funded.
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How do they tax aluminum foil over the antenna?
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The amount of money involved in this taxation plan alone would make it financially feasible to put a complete GPS system up there.
Excellent. Bring in a system to monitor every movement, and make the citizens being monitored pay for it.
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Of course security related government agencies will also have full access to the database as well. Believe me, it will get funded.
Also in germany this is on the way. About time, 1984 is overdue and we need more security from terrorists, child molesters and other scum. Also we can then more easily fine for speeding. And all this on a european scale. Brave new world!
EU Vehicle Tracking Plan (Score:4, Insightful)
They are getting funding from the government.
1) They want to track all vehicles in the EU. Galileo is designed to have much better performance in urban areas than GPS.
Proposals were on the UK Department for Transport website which detailed the desire to place a satellite positioning tracker with a cellular modem in every vehicle, by law, for the alleged purpose of "road pricing" ; charging for transit on key congested roads at certain times. Road pricing is horseshit because if having to drive on a congested road isn't sufficient deterrent to stop you doing it, then taxation isn't going to achieve it. You could also achieve the same goal much more cheaply with a mandatory active RFID numberplate and a pickup loop on these "key" roads, so Occams razor says that they want something that doesn't just track your use of certain roads.
2) Military reasons
Let's face it. Would you want your military dependant on a system that a culture of well known isolationists who live half a world away can switch off at their whim? Neither would I. Independance from US control is the second motivator.
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If the US switched off GPS, then we wouldn't have GPS either. Plus, there's not a chance any first world nation would ever wage an actual war with another. The stakes are way too high.
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They will not switch off the GPS signal, they will switch it to encrypted US military device only signal.
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If the US switched off GPS, then we wouldn't have GPS either.
GPS is not "switched off". Instead, "Selective Availability" (SA) is turned back on.
SA introduces random, unpredictable errors into the unencrypted signals broadcast by the GPS satellites. As a result, the accuracy of a position decreases. When the GPS system first went online and SA was still enabled, typical position accuracy was about within 10 meters:
http://en.wikipedia.org/wiki/Global_Positioning_System#Selective_availability [wikipedia.org]
SA can still be enabled (introducing errors up to 100m), and can be
Re:EU Vehicle Tracking Plan (Score:5, Interesting)
SA was a hack on the early systems and the newest sats don't have that ability at all. The SA adjuster on older sats is a motor driven thing and it has been broken on several sats since before SA was turned off. The new sats have spot beams which can be used to turn off GPS (and may have the ability to introduce random jitter in the outbound signals) in part of the world but the USAF has local GPS jamming that works far better. The problem with turning on SA or blocking GPS in a local area is that having GPS work properly is more useful than having it broken since the US is in a better position to use the technology in a hostile location than the locals are at using it to fight back.
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SA was a hack on the early systems and the newest sats don't have that ability at all.
Yea Right. And you need a warrant to get a wire tap.
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The military reasons are not so clear, both GPS and Galileo are operated by NATO members, they even reached a compromise, that Galileo was to use a different frequency. So you can jam one without degrading your own military signal in the pretty improbable case of a war where both side don't agrees to block they civilian signal.
The first version of the project with a Galileo signal on exactly the same frequency of the GPS to prevent discriminated jamming had a real military interest ( if you jam my signal yo
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>Independance from US control is the second motivator.
Primary motivator. Galileo isn't a UK department for transport initiative, you know. In fact the UK, due to it's low funding, is a bit player. ( I'm from the UK and only got to work on Galileo because I was based in another country at the time )
Road pricing is not "horseshit" (Score:4, Interesting)
I agree that mass vehicle tracking raises very serious privacy concerns, but road pricing does reduce traffic. You might be interested in the Transport For London annual report [tfl.gov.uk], which indicates that traffic in the city is about 20% lower than it otherwise would be.
The trouble with your proposal to just track "key" roads is that it encourages traffic to do rat-runs along secondary roads. I experienced this personally when tolling was brought in on a freeway near my house; the alternative routes were suddenly jam-packed with traffic, particularly at off-peak times when they were previously quiet.
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The trouble with your proposal to just track "key" roads is that it encourages traffic to do rat-runs along secondary roads. I experienced this personally when tolling was brought in on a freeway near my house; the alternative routes were suddenly jam-packed with traffic, particularly at off-peak times when they were previously quiet.
That's why variable pricing (if implemented sensibly) is a good idea. Off peak, rates should be low or free; peak, prices should rise enough to keep the volume to the point where it's just below congested. People often don't like the idea much, but it's a rational model.
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The house I've lived in for 16-and-a-bit years is within sight of two solutions to this problem : the roads that could be linked up to make a rat run around the local congestio
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Road pricing is horseshit because if having to drive on a congested road isn't sufficient deterrent to stop you doing it, then taxation isn't going to achieve it
Except that congestion charging in London has been a resounding success. I remember well how it was to drive down Oxford Street before; you could watch your children grow up in the time it took. So that is one place it has worked.
Being able to track the movements of vehicles has many merits, which tend to be forgotten by those who hide behind the freedom- and privacy slogans. And it is not only "the government" being able to spy on your every movement, as if they would want to. Personally I would find it ve
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I don't think anyone has called America isolationist since December 7, 1941. Actually I would welcome some introspective isolationism but then America would get criticized for "turning its back on the world" or something els
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Why bother spending billions on a satellite system when they already record all journeys on traffic cameras combined with numberplate recognition?
Hint: it says moo (Score:1)
Why, from "unspent agricultural subsidies", of course.
http://www.spacetoday.net/Summary/3994 [spacetoday.net]
general relativity at work (Score:5, Interesting)
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What I think is really cool about GPS is that without Einstein's theory of general relativity, it wouldn't work.
Oh, it would work just fine alright, in fact it would be a heck of a lot simpler to build and maintain, and probably somewhat cheaper, too. The folks that built the satellites and the base station that sets each satellite clock would have much less headache.
See:
http://www.metaresearch.org/cosmology/gps-relativity.asp [metaresearch.org]
which claims to be a rehash of a chapter of the book "Open Questions in Relativistic Physics"
"Rather than have clocks with such large rate differences, the satellite clocks are reset in rate be
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What argument are you trying to make? Are you saying that it would have been easier to build the system without understanding why it behaved the way it did?
It would have been easier to build the satellites and ground stations, if GR/SR didn't exist, but individual receiver units don't much care one way or the other. Original post sounded to me like a positioning system can't be made unless it somehow uses GR/SR... Obvious counterexample would be the old LORAN system, which doesn't need GR/SR corrections because the transmitters are stationary instead of orbiting. GR/SR is an annoyance to work around, not an inherent part of location determination.
GPS doesn't
Re:general relativity at work (Score:5, Funny)
I'm struggling to think of a positioning system design that would require GR/SR to work rather than time of flight... I think it would have to be an active transponder system, or some kind of weird gravity wave detector? It would be interesting.
If we ever need accurate positioning around a black hole, we can at least know that slashdot will be able to tell us how!
And people call us useless! Hah!
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The cool bit is that it was known that SR/GR would be an issue before they even launched the 1st sat so there are several ways they can adjust the drift in the clocks both in space and on the ground. It is one reason why GPS is good to less than 10 meters while other space based attempts were good for about a half mile or so.
The observation of GPS clocks and some unexplained issues are why Gravity Probe B was created. Dr. Parkinson was one of the project leaders on both projects.
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I'm struggling to think of a positioning system design that would require GR/SR to work rather than time of flight... I think it would have to be an active transponder system, or some kind of weird gravity wave detector? It would be interesting.
You could use relativistic effects to calculate the motion of a receiver faster than measuring the movement between two positional fixes.
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Sure, nothing to argue with here. Similarly, Ohm's law is an annoyance to work around if you want electric light, not an inherent part of lighting your house. If you're happ
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It took a couple of readings of the post at the top of this thread to figure out what it was trying to say.
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Please explain.
What in Newtonian physics precludes knowing locations or times? Especially considering that both those things are simply definitions, in terms of a locator service.
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Omg you are so wrong, it's not even funny!
The clocks run FASTER in general, in a higher orbit. Even height variations in the orbit count.
So one *has* to calculate that effect it. No getting around it.
And what I think is usually done, is run the clocks faster by the predictable amount, and then do small corrections for the unpredictable factors.
I don't know where you got the idea that it would only be launching creating an initial offset. But you are really, *really* wrong there. Sorry.
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I like the subtle derogatory typecasting for "those people on the internet" (who disagree with widely held science). You do realise that if they provide mathematical proofs that they're providing a scientific and intellectual argument and thus should be given the same fair shake as anyone publishing from a Western University.
It is attitudes like this that drive people away from science.
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I like the subtle derogatory typecasting for "those people on the internet" (who disagree with widely held science).
The funny part is the kooks are the ones who "believe" in general relativity... The history of physics is finding new explanations for weird exceptions.
So, 99.999% of the time, especially for pretty much everything earthbound, Newtonian mechanics works great.
Unless you happen to be moving at a fraction of the speed of light, in which case special relativity works great. Well, it works great 99.999% of the time.
SR is great unless you're in a gravity well... Then you need general relativity. Now, the kooks
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The funny part is the kooks are the ones who "believe" in general relativity... The history of physics is finding new explanations for weird exceptions.
Weird? It's fairly simple, and doesn't require "belief" at all. Mass causes space to curve, and curvature causes mass to move. The application you use to effect change is geometry, not prayer.
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Weird? It's fairly simple, and doesn't require "belief" at all. Mass causes space to curve, and curvature causes mass to move. The application you use to effect change is geometry, not prayer.
What is mass? What is space? Do you mean that curvature literally, or is it simply the localized perception of the event? Gee, I guess it's not as simple as you thought it was.
The GP is correct; we cannot know that there will not be special cases where relativity breaks down, just as newtonian physics work just fine until you deal with very small scales or very small or large energy states. To believe otherwise is fairly irrational in my opinion, and unscientific at best.
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What I think is really cool about GPS is that without Einstein's theory of general relativity, it wouldn't work
Neither would the rest of the universe. Well without the physical rules which the model of general relativity approximates. As for the model itself, the universe (including any GPS equipment) ticks along just fine without the theory. The GPS units would just always be wrong (and so not terribly useful)
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Nonsense. And gravity does not have anything to do with that.
The onboard clocks run slower (and thus need to be corrected) because, for the satellites to be in a geostationary orbit at that altitude (
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The GPS satellites orbit at about 12.5 thousand miles with an orbital period of about 12 hours. They are synchronous with the sidereal day and not geostationary.
The GPS satellite clocks lag by about 7 microseconds per day do to their velocity (special relativi
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Sorry, I was sincerely convinced that the satellites were geosynchronous.
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This is incorrect. The satellites are not geostationary. Also, the gravitational time dilation effect is stronger than the special-relativistic time dilation due to motion, so the net effect is that the clocks run faster. Here [livingreviews.org] is a discussion of the physics.
Wouldn't it make more sense... (Score:2)
Seeing as civilian technologies have been demonstrated to get around the artificial limitation in the accuracy of GPS wouldn't it make more sense for the U.S. military to just allow access to the full precision signal to civilians?
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Seeing as civilian technologies have been demonstrated to get around the artificial limitation in the accuracy of GPS wouldn't it make more sense for the U.S. military to just allow access to the full precision signal to civilians?
They do. In fact the US military is reliant on consumer grade GPS gear so it is unlikely they would ever turn selective availability back on.
The real distinction now is between meter resolution and centimeter resolution.
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"They do. In fact the US military is reliant on consumer grade GPS gear so it is unlikely they would ever turn selective availability back on.
The real distinction now is between meter resolution and centimeter resolution."
That sounds great but the summary at least says this is about launching sats to use in order to bring resolution down to 1 meter from 10 meter. I believe I had heard that full resolution GPS gave more like 6 inch resolution which is obviously much better than 1 meter.
And neither the summar
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And neither the summary nor what I had heard meshes with your claim that SA has been turned off and resolutions that are far better than what this new system is supposed to attempt to achieve.
From the wiki: [wikipedia.org]
GPS includes a (currently disabled) feature called Selective Availability (SA) that adds intentional, time varying errors of up to 100 meters (328 ft) to the publicly available navigation signals. This was intended to deny an enemy the use of civilian GPS receivers for precision weapon guidance.
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Only if you trust the US to not screw around with it for political reasons. Imagine Sarah Palin as President, who is to say she wouldn't scramble GPS for France & Germany because they refuse to support her invasion of Canada? How about if they release those algorithms and keys just to US companies thus undermining European ones (TomTom etc) and say that the keys can only be exported in completed devices.
The issue with GPS is one of trust and control, simply put the Europeans don't trust the US to play
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"Only if you trust the US to not screw around with it for political reasons."
How does a system that improves accuracy of the GPS signal help you if you don't trust the signal in the first place?
Obviously the idea is to improve the accuracy of consumer devices. Who cares about France and Germany? I think the EU is building their own system, let them use that.
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J
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"kill switches" in military equipment are SOP and hit the news here recently. on the other hand, trying to paint "the europeans" as one group is as ridiculous as the idea that the EU can accurately represent all its members. You talk about the US government banning export of crypto? Until recently, it was illegal to use almost any cryptography at all in France.
That's not really how SA works (Score:2)
That's really not how selective availability works. You can't just enable SA for certain people - it's either on (in which case nobody but those with the encryption keys gets it, which would black out high precision GPS for all commercial receivers, world wide), or it's off (in which case everyone gets the unencrypted signal). You can't just punish individu
Europe's GPS? (Score:2)
Wow, thanks! And I thought it would be pretty funny, to see a couple of satellites in 17th century clothes, float trough space... )
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Oh, I meant a couple of *bearded* satellites. ^^
Hmm... after looking at the Wikipedia disambiguation page, it could be bearded cars, battleships, aircrafts, or military units too. :)
The more, the better. (Score:2)
This is good. High-precision GPS, which requires seeing 5 or more satellites, is intermittent in urban canyon situations. With the ability to use GPS, GLONASS, and Galileo signals, the odds of having five sats high in your local sky improve substantially. The high-precision (15cm) receivers will be less flakey.
ACES to follow Gravity Probe B (Score:2)
Re:The EU system won't get used (Score:5, Funny)
GPS is so standard now, and it is bugfree. It's hard to imagine anyone switching.
Yeah, "complementary" is a long word, isn't it? I wonder what it means.
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It seems you can use it as a quality-enhancing addition to GPS instead of a replacement - that might help.
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Assuming the US stick to their promise to keep SA turned off...
The whole point of the EU system during normal use is not to REPLACE GPS but act as a ADDITIONAL aid which should improve accuracy.
Of course only America matters and the rest of the world doesn't...
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[quote]Assuming the US stick to their promise to keep SA turned off...[/quote]
Well, turning on SA would screw airplanes everywhere, and new GPS III satellites aren't going to have SA (this was announced in 2007 so it may have already started), so it is pretty hard to not keep their promise.
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Well, turning on SA would screw airplanes everywhere...
No it wouldn't. How the hell do to you think they flew planes around in the 80's. Do you really think the only navigation device on a plane is GPS? Furthermore they usually have (commercial airliners at least) military grade GPS and SA won't disrupt them. Finally what the hell are pilots for?
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Doubt civi airliners use the L2 gps as the US are very sensitive about who gets to use SAAS modules let alone who gets hold of the keys...
(SAAS = Selective availability / Anti-Spoofing, the bit for the L2 PY code signal)
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The whole point of the EU system during normal use is not to REPLACE GPS but act as a ADDITIONAL aid which should improve accuracy.
Of course only America matters and the rest of the world doesn't...
I always thought the point of Galileo was to have a positioning service that is not controlled by the military. NAVSTAR-GPS is american military, GLONASS russian military.
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Think I must have hit the wrong key as I did put a line about it not being subject to SA... Ok, SA is currently at 0 but the capability to degrade the L1 / CA position is still there...
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There was a point in time where the Russians didn't have the money to maintain the system, however that has changed, and I believe they have been adding satt
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A gps time source is only off by a handful of ns. You then want to send that time over NTP and add milliseconds of year?
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A gps time source is only off by a handful of ns. You then want to send that time over NTP and add milliseconds of year?
How else would you distribute your time reference?
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If you need precision you could use IEEE 1588v2 with or without synchronous Ethernet.
IEEE 1588v2 Precision Time Protocol [wikipedia.org]
Synchronous Ethernet [wikipedia.org]
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Thanks. That looks interesting. It is the type of thing we should probably be using in my day job.
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the precision of any of these systems is much higher then NTP; there's no point.