accuracey of tom tom one

[rich5298]

Hello
I have a tom tom one and I find it is off by about 200 yards. Is this normal or does my unit need adjusting/repair/ download something to correct it? Why is it so? (taken from "subyroo")

Thank you
Richard

 

[subyroo]

Hello
I have a tom tom one and I find it is off by about 200 yards. Is this normal or does my unit need adjusting/repair/ download something to correct it?
Thank you
Richard

Same here, mine puts me on another street to where I live and it shows I am connected to 8 satellites, however, if I hook it up to the PC it locates me perfectly.
In the words of Prof Julius Sumner-Miller......."Why is it so?"

 

[MotMot]

I thought that was just me, run into this especially in remote areas of the US.

 

[The Spook]

...I find it is off by about 200 yards.

What exactly do you mean? Can you be a bit more specific? Are you trying to navigate to a particular address?

Try this: save your current position as a favourite. Drive away, then navigate back to the favourite you created. Do you get back to exact location? If you do, there is nothing wrong with the accuracy of your TomTom.

 

[ted_salad]

Greetings! I am also new to the world of GPS driving/navigation and I am trying to figure out what is "normal" by reading the threads and getting helpful answers from various forums.

My "error problem" is when I press the "your are here" in front of my house at 2943 it show I am at 2951.

The other phenomenon is, I live on a wide street divided by a physical divider. The map distinguishes the NB side from the SB side where I am. In the "ask me everytime I plan" mode. WHen I stand in front of my house. It shows I am across the street about 150' away. When I go into the backyard. It shows I am on the correct side of the street. If I set it to "walking route" this does not happen. And I also show 8 satellites.

One thing I read in another thread is that your postion is more accurate is you are moving. Is this true?

 

[Nextourer]

- I don't know how close your houses are to one another but it's possible that for your street, the house numbers are slightly off relative to their actual position. I have my friends' houses saved in my TT. One of my friend's house location is dead on on my TT. When I'm parked in front of his house (say if I'm navigating to his house), the car arrow is directly over the destination flag. However, for another of my friend, when the car arrow is over the destination flag, it's off by 2 or 3 houses. So it really depends on the street.


As for the divider thing, maybe your street is a few feet (or more?) off to one side (I dunno the orientation your street but if it was a N-S street for example, and you're on the east side of the street, then maybe on the map, it's plotted a bit too far to the west relative to the actual location on earth).


The reason why it's more accurate (if it is at all) is that the unit knows which direction you're going and can track your previous point and update it to your current point. Hope that made sense.

 

[flyer1024]

My "error problem" is when I press the "your are here" in front of my house at 2943 it show I am at 2951.

QUOTE]

It's very common I find to have addresses etc not where the tomtom maps say they are. It's the map accuracy and not the GPS.

 

[ted_salad]

Ahhh.... I begin to see. From what I deduce what Nextourer and Flyer are saying it could be the GPS co-ords are correct but the map location corresponding to them put me across the street. So when I move towards the backyard I "realign" the map to the Lat/Long and I appear on the right side of the street.

I walked around my neighborhood and yup, standing in front of some houses get me dead-on numbers. Some are off.

Iwas reading a forum for handhelds and there was some mention of "static GPS" or something like that. The writer said something to the effect that there are two kinds of systems GPS units use to fix your location and one of them he says is no as accurate when you are not moving. Let me see if I can find that thread.

Thanks Guys! Forums are some of the best places to learn stuff!

 

[The Spook]

It's very common I find to have addresses etc not where the tomtom maps say they are. It's the map accuracy and not the GPS.

Actually, it is not. The problem is that the map data does not contain every house number, it contains number ranges. You can see this by tapping on a street, it shows the number range for the point you tap on.

Hence ted_salad's problem is because his house number is somewhere in this range. For example, the range may be 2931 - 2951. He is closer to 2951, so that is the number he gets. 'Navigate to..' house number 2943 or 2951 will take you to exactly the same place, either the start or end of that range (i.e.:2931 or 2951, whichever is reached first on your route).

 

[ted_salad]

Actually, it is not. The problem is that the map data does not contain every house number, it contains number ranges. You can see this by tapping on a street, it shows the number range for the point you tap on.

Hence ted_salad's problem is because his house number is somewhere in this range. For example, the range may be 2931 - 2951. He is closer to 2951, so that is the number he gets. 'Navigate to..' house number 2943 or 2951 will take you to exactly the same place, either the start or end of that range (i.e.:2931 or 2951, whichever is reached first on your route).

Ok if that's the case then why is is possible for me to enter manually my house number as "home" and it can find it on the map? I spent a few hours last night and this morning trying to determine what kind of behaviour it's exhibiting after getting a rather unhelpful email answer from TT support.
I don't have it all down yet, but it seem that I am show across the street when I am not seems random

Here's another odd behaviour. When I am not at home location with satellite reception, and "use prepare route" starting with "home" and navigate to any give spot. It shows me starting on the correct side of the road. But if I use "prepare itinerary" it shows me staring from across the street.

That this thing charts routes for me that I have to start from across the street is not that useful for me. I have to fix this!!