Which is more accurate?

[semtex]

ok, an odd question guys but here you go...

I was out in the car yesterday for a 'spirited' drive shall we say, and i had my sattelite navigation running at the time (on my pda with a gps aerial and tomtom navigator) i noticed though that when my car speedo said i was doing 70mph, tomtom said i was only doing 62 as i was cruising along. The difference in reading just got larger as i drove faster, by the time i hit 130 (according to the car), tomtom said i was only doing 118. So one of these has to be wrong - the car or sattelite navigation?

 

[XPUser1]

The one in the car is likely to be more accurate - it works the same way the new black box does - it record everything in addition to the speed. The satellite is "very" approximate IMHO.

 

[jac006]

Well, considering the car's meter is on your car... I say the car. GPS isn't always that reliable. But just in case, go to the dealer and have them check the speedometer. Where were you going 130? The autoban? Lmao...

 

[XPUser1]

Well, considering the car's meter is on your car... I say the car. GPS isn't always that reliable. But just in case, go to the dealer and have them check the speedometer. Where were you going 130? The autoban? Lmao...

I think he meant Indy 500 racetrack - you can go as fast as you like

 

[Kage]

Hehe, yeah I'd guess everyone is right in saying the cars will be more accurate.

Though the satlight navigation systems are usually rather accurate, though I guess it being 15mph out isn't too bad as long as it still gives you accurate times.

I've heard that satilight system is actually quite good too, though the PDA couldn't beat a version made for the car which would plug up straight to it.

 

[XPUser1]

Speaking of the GPS satellite, I hope there never will be a day when every one of us have to be implanted with the GPS chip so that no one will be lost (in the U.S. we call it Alert Amber). At the same time did you know that Volva is the first one to standardize builtin black box? This tells me that in the coming years all autos will also have it.

 

[Kage]

Yea probs.

In a way though, wouldn't it be good if we could all be tracked? Maybe not in all circumstances, though it seems a good idea in some, like if you got lost, or kidnapped. Though the people taking you would probably have ways of finding out if you have one...

 

[XPUser1]

In other words this GPS chip (if implanted) can very well be the "Mark of the beast" prominently quoted in the Book of Revelations.

 

[Starr]

Well, I good way to find out is go driving really fast and get pulled over by the cops and ask them how fast you were going. Will only cost you a couple 100 in fines.

 

[lurkswithin]

actually they both could be right!
You have to remeber that the GPS only does point to point and does not take in the consideration of altitude (although it may record it), nor does it reflect the distances of curved or inclined surfaces. So the gps would read a ten mile trip over a curved or inclined surface as that of being only8 miles and would relate it as such...while the car actually had to travel faster to make the whole 10 miles in the same time frame.