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GPS vs. Galileo; Where Are They Headed?
ben_ writes "This keynote speech from the recent European Navigation Conference talks about the history between the US military's GPS and the proposed EU Galileo system, as well as where they're both going. Interested in how you know where you are and what's going to happen to those satellites?"
The correct links for the US-administered GPS satellite constellation, known as NAVSTAR:
NAVSTAR GPS Joint Program Office - responsible for operational maintenance of NAVSTAR GPS equipment, services, and infrastructure
Interagency GPS Executive Board - executive management of NAVSTAR GPS
GPS fact sheet - US Air Force facts about NAVSTAR GPS
US Naval Observatory NAVSTAR GPS home page
Further information:
FAS GPS background info
Global Security GPS background info
For more information look at the Article featured on Slashdot about 6 months ago.
:)
Galileo System To Include Jamming Capability
+++ MELON MELON MELON +++ Out of Cheese Error +++ redo from start +++
The paper says that by necessity, the two systems need be compatible on several fronts. OK, that is good, saves everyone money, too, by not obsoleting all your GPS hardware when the EU system goes live.
The EU system will also provide "additional commercial services, on a user-pays basis." That could be good too, but the basic "where am I now" function of GPS works fine for me. I'm leery of a govt body stacking commercial features on to a pretty well proven system.
"Galileo thus requires US cooperation for its commercial success, while at the same time apparently threatening US national security and industrial advantage!" To which I say Bah! Unless the US has really been dragging its heels in cooperating, I say, build your nav sat system and go for it! Our (the US) present obsession with security is mostly the work of a paranoid few. Let the US take care of itself and power to the EU for whatever they can do.
Sure, there may be a few Pentagon types who might drag their feet, but the timing and communications methods aren't rocket science... and even the rocket science part can be easily handled.
They're in on Galileo: see here
Here is a technical comparison. They seem more alike than different to me.
I know of a few very high-powered geologists who cross-check GPS with GLONASS. Having a third system would seem to only help.
You're mostly correct. Selective Availibility can be done region by region (I don't know the resolution of this), and the signal can be degraded with rather fine-grained control (the whole world was degraded to 200meter-ish accuracy until the late 90s). SA does not effect military recievers; when supplied with the days proper P(Y) code, they are as accurate as the GPS spec allows (~1 meter resolution, best case).
So the US can degrade the signal in a fine grained way, without affecting military / government systems.
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Phil
It can be turned off selectively. Furthermore, as I understand it, "turned off" only means that the unencrypted data stream is gone. The military has the keys to the encrypted stream, so their GPS units still work.
I have also heard of GPS jammers, but anyone could use those, so that would effectively negate the US's GPS advantage.
GPS jammers are nearly useless. They are only powerful enough to cover a small area, so their only use is to protect a stationary target from attack by GPS guided bombs. Unfortunately, as demonstrated in the Iraq war last year, they don't even do that effectively. All six of the Russian-made GPS jammers fielded by Iraq were destroyed in short order, some of them by GPS guided missiles!
If a job's not worth doing, it's not worth doing right.
HUH? are you nuts?
the GPS system CAN be turned off or rendered pretty much useless for anyone except the US troops. the DOP can be adjusted from zero to insanely high for non-military units. (DOP is dilution of Precision) I work with a guy that just came back from NORAD and his main job was dealing with the GPS systems. (Luetenant who is back only to gather his things and return back to full active duty due to an offer from the military he could not refuse)
the non-classified things he was able to tell me is that the DOP can be adjusted a very wide range to the point that even DGPS can be rendered pretty useless unless both recievers were in very close proximity.
if anyone ever thought that a military system would not have the ability to be disabled for all but military use they are horribly mistaken. the lives of the service men on the ground and the sucess of a mission is much more important than some businesses using it for navigation.
SA can be turned back on at any time if it is needed.
Do not look at laser with remaining good eye.