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European Space Agency Developing GPS Rival
nbrimhall writes "The International Herald Tribune has a story here about the European Space Agency's plans to create a alternative to the U.S. controlled GPS. It includes some interesting information regarding the cost and possible contributors (including Canada and Russia)."
I believe the Soviet Union once launched a system of satellites called GLONASS that worked like GPS. Are they planning to do an upgrade or repair of this system? The GPS FAQ has more information (see section 5.2).
Heck, it's understandable why they'd want to build an alternative GPS; the US Department of Defense could suddenly decide to turn selective availability back on again if they felt like it someday...
Qu'on me donne six lignes écrites de la main du plus honnête homme, j'y trouverai de quoi le faire pendre.
Galileo is attempt to get around the "what if" questions however if the US shuts down the public GPS system, its also going to take out Glonass and any other location system.
When GPS was designed, they added a fudge factor in that would only allow civil recivers to get get a short term fix of about 100m but the military recivers should have been able to get under 10m but because of R&D money on the civil side, the non-military recivers would give much better results than the over priced military ones. With good differental systems you can now get sub meter precision and the fudge factor is pointless and has been turned off. It was the fudge factor that started the Galileo project in the first place.
I don't see Galileo going anywhere. It is a user pay system so are you going to use the euro system where you get to pay $30/yr on top of the reciver or the GPS system where its free thanks to the US tax payers? There will also be the problem that GPS recivers are commodity item and Galileo recivers won't be for at least a decade. Europe would be much better off provide a WAAS compatable sat system than doing their own GPS.
The Europeans can't do anything which requires cooperation... What about ESA, the european space agency.. isn't that cooperation bettwen the European states, the European Commission.. ect
Carpe meam simiam!
This is due to ionospheric interference. When a radio signal travels through the free electrosn in the ionosphere, it experiences a certain amount of delay. Signals of different frequencies are delayed differently. So in creating the GPS system the military thought of using two signals when the satellites broadcast there info. Called L1 and L2 the military use both signals mesure the amount of delay between them and make corrections for the effect of the ionosphere. The Civilian receivers cannot correct for the ionospheric interference since it only picks up the L1 frequency.
So I guess there is a good, long explanation on
why to invest the capital. Or you could buy the
military reciver.
-Scott
It is said that a child learns wisdom from the parent,
but the truly wise parent learns joy from the child
Currently, when you use a GPS, the longer you stand still the more accurate it gets. This is because it can average out the errors that occur over time. However, once you start moving, it can't do that, because it has a hard time telling movements from measurement errors.
If on the other hand, they included an accelerometer in the GPS unit they could tell with great precision which changes were due to movements, and which were due to errors. Thus, with some algorithm changes, such a GPS unit could continue to refine its measurements to greater and greater precision as long as it was turned on, even if it was moving about.
Ideally, the accelerometer would be integrated on to the same chip as the GPS or Galeon reciever, along with the logic for coorelating the results as well. Accelerometers can be built entirely on-chip, so no extra parts would be needed. I believe modern accelerometers can achieve high accuracy over a very wide range of accelerations using just 2 square millimeters of chip area, so this shouldn't add much to the manufacturing cost.
This would also increase safety in a number of ways. If an airplane in flight lost GPS signal, perhaps due to flying into a low narrow valley, it could continue to navigate electronically for a while (albiert with less precision) using only the accelerometer. If for some reason the GPS or Galeon network became suddenly unavailable due to unforseen circumstances (US goverment getting pissed off, technical issues, bizarre weather, interference, terrorists, etc.), critical systems would have a little extra time to deal with the situation before global positioning equipment failed completely.
Does this make sense to people? Think it's a good idea / bad idea?
The military GPS system had an encoded 'noise' generator in it sposition. For civilian use, it was designed to give accuracy within 100m, 95%of the time, and 200m 99% of the time. They also reserved the right to degrade civilian accuracy further (like, within several hundred meters only 50% of the time, or worse) at any time, to keep enemies from using it to lob missiles through windows. The base standard is perfectly adequate for most high-seas navigation, but sucks in tight channels or for any precision operations, like airplane taxiing or highway navigation.
Military GPS recievers had decoders built in, and were accurate to within a couple meters. This diffrence in accuracy was called 'selective availability.' BTW, during the gulf war, the military had a shortage of GPS recievers so they turned selecive availability off and used civilian recievers. Didnt seem to affect security all that much.
To get around the problem, ths US Coast Guard deployed a system called Differential GPS, or DGPS. Basically, they created fixed-position GPS recievers, which continuously compared the position derived from civilian-degraded GPS with a known position, and then broadcast the correction in real time. DGPS recievers applied the correction to the satellite position, and restored ccuracy to about 10-20 meters. In short, one branch of the military, (the coasties) were spending tens of millions to overcome the inaccuaracy included by another branch of the military.
During the Clinton administratioin, it bacame apparent that civilian uses of GPS were becoming signivicant to the economy, so Clinton ordered selective availability turned off (or turned down) to increase civilian accuracy. However, the military still reserves the right to degrade the civilian signal at any time without warning, if they percieve a national security risk.
So, the interest in a European GPS network is at least in part to remove the control from the US military, and remove the hreat of having the system degraded when they may want to use it.
China is also attempting to launch their own GPS network, and infact, they are actually farther along then the EU, having launched their first sat.
e s/ flash2000-082.shtml
http://www.spaceandtech.com/digest/flash-articl
There has also been talk of China financing the the Glonass system (Russia's GPS) for their own use.
http://www.spacedaily.com/news/gps-00h.html
yes, the US military can selectively jam GPS signals, or control the precision of the signals in certain geographic locations.. I actually worked on a project with the NAWC about 6 years ago to do this.. The jammers were small enough that they could fit in something about the size of a suitcase, and be dropped from a plane into enemy territory..
4 7_ STO65096,00.html
In fact, this article suggests that they're doing it now in Afghanistan:
http://www.computerworld.com/storyba/0,4125,NAV
If more satellites for a GPS-like system, wouldn't it be possible to get a more accurate fix on your location? According to this page, three satellites are required to get a fix on your location (four to perform time correction). However, a number of problems exist: (taken from above site)
1. The receiver clock is not exactly synchronized with the satellite clock so the time of flight will be imprecise.
2.The satellite and receiver are in different velocity reference frames and gravitational regimes so there are relativistic differences (both special and general)
3. The speed of light is 300,000 km/s in a vaccum. However, while travelling through the Earth Ionosphere and Troposphere, the radio waves travel at slightly slower speeds
4. Radio signals traveling through the atmosphere travel differents paths depending on the location of the receiver.
Although the first problem is correctable using a fourth satellite, the remaining three problems persist. However, if you receive signals from several satellites (not just your minimum 4), if you average your reported locations, you should be able to get a more accurate fix on your location.
I am an Engineering student at the University of Calgary, in Canada. As a writer for the student newspaper, I had the chance to write a story about a project called the AUTO21 project.
This is a multi-million dollar venture by the Canadian government that involves researchers in all fields, including sciences and humanities. Essentially what they are trying to achieve is a car that drives itself.
I interviewed the head of the U of C's Geomatics department, Dr. Gerard Lachapelle. He mentioned the European "rival" to GPS (he called it "Galileo"), but he did not seem to think of it as a rivalry at all. Quite on the contrary, he and his department plan on using both technologies extensively in their coming work on the project.
All the same, he seemed extremely excited about the prospect of a second system.
~windside
...Whether my Maker is prepared for the great ordeal of meeting me is another matter.
Churchill
The problem wasn't that the votes were not counted. The problem was that they were counted over, and over, and over again. Even if the supreme court had allowed a several county recount bush still would have won. If the democrats had asked for an entire state recount and got it (which seemed like a bad idea at the time) Gore would have won. However, when it's so close, it's more important that somebody win sooner rather the right person 6 months after the election.
is planing to do away with trials, replacing them by tribunals.
Heh, but not for U.S. citizens. Only for alleged terrorists in a certain situation. Since 90% of americans probably think shooting them on sight is our the idea, a trial at all is pretty good.
Meanwhile the Bush admin. has declared that it will unilaterally withdraw from any agreements it finds to be inconvenient
First of all, the bush administration seems less likely to do this now that international support is more necessary for the war in afghanistan. Secondly, no countries ever follow treaties if it doesn't suit them. If any other country had the money lying around to develop an ABM system you bet your asteroids they would (except maybe switzerland).
I actually think that another system is a good idea, because american GPS systems are such a great military target, and redundancy is good. I just dislike half-informed country bashing.
Jack Valenti and the MPAA are to technology as the Boston strangler is to the woman home alone
The GPS was effectively 'turned off' during the Gulf war, when satellites were diverted to increase coverage (and resolution) over the battle site. This lead to a lack of coverage over the west coast, disturbing a boatload of fishers.
HI. DGPS does not by itself give centimeter accuracy. It requires postprocessing of the pseudo-range data etc., either with a very gulky GPS receiver or over a cellphone link to stations that have very accurate atmospheric delay and orbit jitter data.
Also, this is not the first time this story has been on Slashdot. However, I follow alt.geo.satellite-nav, and the general opinion there is that the EU is not actually going through with this system.