I hadn't realized that the Eurpean global positioning system was going to be a pay service. I imagine they will have to redesign the codes. Anyone know what the plan is for the Galileo satellites? Will it be illegal to use devices that just receive the American GPS signal?

News Story

Yes - it is supposed to be a pay service, though I have never understood how they think they are going to bring that off as long as the original GPS is available. I suppose they might try to outlaw GPS-only receivers in the EU but they don't have the slightest chance of enforcing that.

tty

A lot of speculation can be eliminated by just searching the web. From the Galileo web site



So Galileo will provide a free service for basic position, navigation and timing purposes ie for the sort of things folks like us use GPS for at the moment. Higher precision and more advanced services will need to be paid for and in that it is not unlike the existing US military GPS - you can only get the codes for the higher precision signal if they release them to you. At least with Galileo it should be possible to get them.

No one's going to try and ban GPS in the EU. That's an idiotic notion. There's a lot of negativity, particularly from the US, about Galileo, trying to rubbish it and spreading miss-information about how you will have to pay for it.

Have some facts...

http://news.bbc.co.uk/1/hi/sci/tech/4555276.stm

Open Access This will be 'free to air' and for use by the mass market; Simple timing and positioning down to 1m



It will be free, like GPS is, for everyone who uses a handheld or car nav device. It will offer better accuracy, for a fee, for commercial useage such as engineering, surveying etc.

Doug

The high-precision mode of GPS is always swtiched on and is freely available for use.

In theory, Galileo's open service offers 4-meter accuracy, and GPS offers 3-meter accuracy (horizontal). The commercial Galileo service is supposed to offer better than 1-meter accuracy. I'm skeptical about any of those numbers, since there are physical effects that wipe out most of that accuracy in real-world situations, (random fluctuations in atmospheric propogation of the signals, etc).

There is also an important military issue, which is that long-range weapon systems can use global positioning signals for guidance. It is important therefore that these systems can be instantly switched off during an emergancy.

Yeah - I'd forgotton that SA had been turned off.


This is true enough and there is no doubt Galileo will include the ability to turn off or degrade its signal however the real problem for the owners of the current GPS system is that they will no longer have sole control of that off switch. I cannot see that the threat posed to society at large by weapons that could not operate without GPS is very small - anyone who can build something that is a sufficient threat can acquire or build an inertial guidance system that is accurate enough. The battlefield situation is very different and I can certainly see why any military organisation would want to be able to control such capabilities in any theatre of war but it is funny that the original SA accuracy degradation system which was there for precisely that reason was turned off by the military because commercial GPS units were better (or maybe just more available) than their own during the first Gulf war.

I wouldn't bet on that. :-)

Anybody know if ESA (or whoever) plans to implement a service similar to differential GPS (DGPS) once the Galileo constellation is complete? The US Coast Guard runs most of this in the US right now, although the FAA is also moving forward for precision landing applications; DGPS is better than P-code GPS in most cases.

Pragmatically, this would be the best of all possible outcomes. The maritime shipping industry pressured Congress to keep LORAN-C on the air in order to assure that deep-sea navigation would not have to rely on GPS as the single nav system, mostly because of SA & other national security concerns that might take it offline in dire circumstances. Furthermore, high-precision nautical nav capability in crowded ports and/or narrow passages & harbors is a critical need, and again most operators are very uncomfortable with single-system dependency for these functions. If Galileo will offer a worldwide differential service, then they should find a substantial market (presuming that they back off this ludicrious subscription concept and instead collect royalties from Galileo "DGPS" receiver manufacturers, possibly by licensing the differential standard).

Oh I know that's true. Anyway when the worst comes to the worst I can always hunker down and go back to using my sextant* - on a good day it's good for around 2 kilometer accuracy or so.

This is just inaccurate, self-congratulaory hype from Cornell. All they "cracked" were the PRN codes being used on the development satellite. The PRN codes for the operational system will be publically available. The current satellite isn't useful for navigation.

Galileo's non-free services are intended to provide better than DGPS\WAAS data plus level of service\accuracy data for critical services so that systems can know when to trust the data.

There is also a provision for "Local Elements" which are intended to improve upon the service's abilities in various ways - from what I've seen that covers both terrestrial and satellite systems that provide improved cover (e.g for urban areas) and assisted accuracy (like DGPS, WAAS,EGNOS and CWADSNS). It might plausibly also cover extended systems like cellular assisted GPS (A-GPS) which can dramatically improve fix time and indoor\poor visibility operation.