Prepare to loose any and all privacy in your car

[andrewlee31]

Sir Humphery Applebea is alive and well and working in downing street

[Gtdog]

Naomi
PS. People have the same concerns about GPS, it means the feds can see you! GPS is a US set of satellites they can switch it on and off and see where we all are with our GPS units whenever they like![/QUOTE]


Gps is un-tracable, the unit works by listening to a series of sattelites in a geostationary orbit. It then triangulates its position using the signals received from these.
Gps plotters etc are not equip to transmit at all, as such unles you are able to monitor global power consumption down to a battery powered unit they are un-traceable.

Now moile phones are a different matter, plod knows who you are (if on contract) where you are, how long it took to get there et all.

I recently called a 999 from the M4 and was told where I was!

[BUSHWHACKER]

I thought that GPS systems receive information, like satellite TV, and can be pinpointed in order to receive that information.
In other words, the satellites know where to send the signal, thus they know where you are?


Or have I got hold of the wrong end of the logical/technical 'stick'?

[Guest]

As with all Government IT projects - they very rarely come in on time anyway so we could still be talking about this one in 10 years time.

Still sucks though

[Chillitt]

gps is basically a set of radio clocks, all the reciever does is compare the times transmitted, and from the time difference it can work out how far away it is from the recievers. as long as the unit can 'see' 3 sattelites, it has a fix in 3 dimensions.this is then applied to a map datum stored in the unit. the americans have a 'variation' built into the system, which used to keep the accuracy within 100metres, but when they are doing something dodgy (bosnia, gulf war 1) they turned off the variation and it was so much better.. differential gps also receives a signal from a ground transmitter which allows silly ammounts of accuracy. they do not send any information.

[Gtdog]

gps is basically a set of radio clocks, all the reciever does is compare the times transmitted, and from the time difference it can work out how far away it is from the recievers. as long as the unit can 'see' 3 sattelites, it has a fix in 3 dimensions.this is then applied to a map datum stored in the unit. the americans have a 'variation' built into the system, which used to keep the accuracy within 100metres, but when they are doing something dodgy (bosnia, gulf war 1) they turned off the variation and it was so much better.. differential gps also receives a signal from a ground transmitter which allows silly ammounts of accuracy. they do not send any information.

Beware though, a few of the differential units on the south coast of England, and in the med have been turned off. One of the biggest problems I have now, is convincing them that their 4k plotter is very falable. The picture on the screen is reliant upon the cartography being accurate, the signal being un-diluted by the Yanks, and the receiver being mounted clear of the radar emmisions, and fitted roughly centraly on the vessel.

The number of GPS related collisions is sadly on the up at the moment, too many nimrods setting solid objects as waypoints, and being supprised when their waypoint sinks them on arrival!

[mamadwyvin]

Naomi
PS. People have the same concerns about GPS, it means the feds can see you! GPS is a US set of satellites they can switch it on and off and see where we all are with our GPS units whenever they like! Gps is un-tracable, the unit works by listening to a series of sattelites in a geostationary orbit. It then triangulates its position using the signals received from these.
Gps plotters etc are not equip to transmit at all, as such unles you are able to monitor global power consumption down to a battery powered unit they are un-traceable.

Now moile phones are a different matter, plod knows who you are (if on contract) where you are, how long it took to get there et all.

I recently called a 999 from the M4 and was told where I was!

[/QUOTE]

Thanks for the education chaps! I was unaware that it was one way traffic with GPS, I remember the story of the lost soldier in the Rockies about 6 years back - we all mapped the roads with excellent accuracy over that week (used to work for Navteq) and were back to the 100m and differential when they brought it back down again. I had (wrongly) assumed all this time that in order to find the soldier they had been able to pin point his location. Apparently not! Maybe he was just on a mobile contract!! :-)

Nice to see so many cartographers on line!

N