Now you can't speed.....

[g_attrill]

bluepolarbear said:

g_attrill said: Relax, this kind of thing will not be technically feasible until the EU Gallileo project is launched, and they haven't started building the satellites yet. There are two existing "GPS" systems - we have no need to spend billions of tax payers money on a third. The system is technically feasible now

It's feasible in carefully controlled circumstances, but not for general roll-out even to new cars. The hardware would need to be solid-state so that there are no parts to wear out, it would have to be extremely rugged and resiliant.

The trial systems almost certainly use a CD-ROM drive with the speed limit data. Then you need to figure out a way of downloading updates - how often will this happen, MOT time, new flash card in the post?

Then, as mentioned, the GPS signals are relatively weak and take a while to lock-on, especially if it hasn't had a lock for a while. Even with a good external antenna all you need is some leaves or a building and you lose the lock.

Finally the GPS system (there is only one GPS system) is owned and operated by the US government. It would be EXTREMELY unwise to spend billions on hardware that relies on the goodwill of another country. Yes, Gallileo won't be "ours" but it will be joinly owned by many countries and a better bet.

Gareth

[V8 Archie]

Hey guys! I can see a benefit.

I never drive the Chim in London, but I'd like the cheaper insurance. As long as I could turn the thing off outside of London, I'd be sorted .

[swilly]

All this talk og high-technology makes me laugh.

By this time this scheme gets through the various comitees and the spending reviews, all that will be left will be 20 million cars with big numbers painted on their roofs.


"Number 2,065,434, come in your time is up" to the driver over his handheld mobile phone, causing him to lose concentration and crash illustrating the point of mobile phone use when driving on the other thread.

[DennisTheMenace]

GPS works really well in London ....... Not !

And if anybody comes near me with a limiter i will fit it to them where the sun dont shine , also being an engineer means that should any get fitted to the car it WILL be disabled

[Pigeon]

g_attrill said:

bluepolarbear said: There are two existing "GPS" systems - we have no need to spend billions of tax payers money on a third. Finally the GPS system (there is only one GPS system) is owned and operated by the US government.

There's only one system called GPS, but there are two systems that provide that functionality. The other one is the Russian GLONASS.

Cooperman said:

Then again, how long would it be before someone worked out how to generate a spoof GPS signal to confuse the limiter unit into thinking the vehicle was not on a public road and, therefore, no limit applied.

No need for such complexity. The GPS signal is at such a low level that it needs a pretty sensitive receiver. Anything local transmitting on the same frequency will have little difficulty in totally overloading the front end. All you need is a Gunn diode and a little metal box.

[bluepolarbear]

pmanson said:

Could some explain what happens when the GPS signal gets weak or is lost by the car. I have Sat Nav in my car via my iPAQ. It can take over 30secs to get a lock and it may drop the signal during the journey. Will the car stop when this happens etc.

I would expect it would take info from a secondary feed from the car. This would allow the device to dead reckoning when there is no GPS coverage. Similar systems are in use in high end car sat nav systems which allow them to plot position through say a tunnel