how good is enhanced postion technology?

[neojohn]

hi all,

first of all, this place rocks!! tomtom owes a lot to this forum things not even in the tomtom faqs, tips not even in the manual, stuff not even known to their own technological support..... alll you need to know about tomtom... its here... If some one in tomtom is reading this.....SHAME ON YOU TO STOP SUPPORTING SDK

has any one actually put the enhanced position technology put to test here? here in chicago, we have lots of underground roadways, roads sandwiched between tall buildings etc where the satellite reception may not be that good. is the enhanced position technology in 920 good enough for keeping you on the right track when there is an exit inside a tunnel?
how long will it hold good without any satellite reception?
thank you, guys....

 

[Ducati]

No. It has only worked once correctly out of approx. ten trips so far. It's pretty annoying because I'll be stuck in the middle of a tunnel due to traffic and the 920 will show that I exited the tunnel, exited the highway, and traversed some local streets. The 920 then proceeds to give commands to get back on the highway so that I may continue to my destination. What is the point of it, really? The 920 will acquire the signal as soon as I exit the tunnel anyway? I wish I could disable it.

 

[Timon]

I think what's needed is a bluetooth dongle that could connect to the speed sensor found on new cars so the TT could get realtime speed info when there is no sat lock. This is the same sensor that the add-on Nav receivers have been using for years. That would solve the problem.

 

[neojohn]

ducati,
10% success rate? that should have been really annoying Any body any ideas how to disable the "enhanced" position "technology"
WOW... Do the Tomtom guys even put these things on a trial through the tunnels before they market it? Or are we the foolish guinea pigs that buy the so called flagship models? And then see that the so called "technology" that sets apart from its lower end models is just bogus????

 

[neojohn]

Timon,
I think the tomtom 920 already gets the speed information even inside the tunnel. The unit probably has a mini gyroscope or something similar that feeds it with the linear and angular acceleration parameters. The defect that ducati noted is probably because of the data analysis error.
In his unit, it never stopped, it just kept on going even when he had stopped in a tunnel. I guess, its either the sensor (probably a gyroscope) that is sub par, or the analysis algorithm that just froze at some point or is doing erroneous calculations.

 

[Ducati]

actually, when I stop moving, the EPT does work. The map does stop moving. But when I'm moving really slowly or changing speeds, it doesn't correctly display it.

 

[Boyd]

This reviewer claims that EPT worked well for him...

http://www.gpslodge.com/archives/015350.php

I was able to test this in Boston?s Big Dig tunnels, and am happy to say that it still gives me a reasonable estimate of where I am in the tunnel and on the map. It?s good enough to deal with the bends and the turns that I need to take when I hit ramps, etc. It instructed me to get off one exit ramp, and I intentionally missed it, and sure enough it knew that I didn?t turn and instead kept going straight. Recalculated and then got me to the next exit popping up in South Boston.

 

[runarg]

It is a fact that EPT does not work! I have been testing it in at least 100 tunnels the last months, and it has been working in one of them. In one specific tunnel where I have been driving several times, the speed decreases to 0, then TomTom turns around and drives back the same direction that I came in
The reason for this is that EPT does not work when the road goes up or down, it only work when it is completely flat. And the tunnels that we have here in Norway are not flat, they all go up and down!