Tom Tom Go placing me on another road

[hmalan]

I have previously had a PDA with TT3 for a year, and recently bought my wife a Navman ICN 510.

At the weekend I purchased a TT Go for me and used it today for the first in anger on a journey to Birmingham.

I have to say I was very impressed with the Speed Camera POI alert, much better than my TT3 or Navman, and overall was very happy with the GO.

However on both journeys (out / back) it had a little blip were whilst travelling along a motorway it suddenly changed to show me on an adjacent road.

The first time I would not have noticed if I had not been looking at the screen at that exact time but on the 2nd occassion it actually gave me a voice prompt for a roundabout, whilst I was on a straight motorway.

On both occasions it quickly reset itself.

Has anyone else with a GO experienced this, as I have not experienced it with the 2 other systems I have used.

I have just ordered an external antenna so wonder if this may help.

Regards

Alan

[SGR1913]

I had this a couple of weeks ago when driving in the Alps. I was going up a motorway in a valley and it showed me as being on a parallel road.
I assume this was due to a reflected satellite signal, as the signal strength seemed fine. It did this at the same place both going and coming back. I don't have an external antenna, but am considering ordering one..

[WATSON]

Yes, I've had this when I have been on the motorway and got a prompt for a fly-over roundabout. I guess it's because it sees the roads and being "on top" of each other as there is no altitude component?

[icsys]

This is nothing to do with reflected satellite signals or lack of altitude info.
There are occasions where the map data is not 100% accurate and there is a possibility of your position drifting either to the left or right of the actual road you are on. The software is designed to 'keep you on the road' so that you dont drift off wherever these anomalies exist.

Try using OS mapping while driving. Topo software does not have the ability to put you on the road as it is not designed for street navigation and you will invariably drift off.

If the software is putting you on a parallel road then I would suggest the fault lies with the TomTom software and its ability to keep you on the correct one and should be reported to TomTom.
_________________
Ian.
iPAQ 2210 | Navman 4100 BT Receiver
Navman iCN 635
TomTom GO
Anquet OS mapping

[SGR1913]

The speed reading was also going crazy, which is why i assumed a reflected signal as opposed to a mapping issue. I'll browse the map and see if i can remember where it happened and look to reporting it.

[stix]

GPS is only accurate to something like 10 metres, so I guess if the distance between one road and the next is less, it's possible to get confused.

Happens to me also, but I just look out the windscreen to check which road I'm on

[SGR1913]

i knew which road i was on, i just ignored it for a few minutes and it corrected itself. It was constantly telling me to turn left, then right at 70mph on a motorway.
Anyway i decided there would be no harm in getting an external aerial as i've got several upcoming trips to areas i've never been to, and from time to time i loose the signal.
I'll report back in a few weeks if the aerial makes any difference on this road.

[icsys]

It is not necessarily a mapping issue but a software issue.

GPS is accurate to >5 metres 95% or the time. Thats around 15 feet.
Most street navigation software (and TomTom should be no exception) has a 'locking' feature that locks your position onto the nearest road (typically the road you are on).
If there is an error in this feature at a particular point then you can be placed on a parallel road, the wrong side of a dual carriageway or in some cases jump onto a road that goes under or over the road you are actually on thus giving irregular routing instructions as the software tries to get you back from where it thinks you are to where you should be. This anomaly is likely to happen at the same point every time.

It certainly sounds like this is the case from the examples given here.
_________________
Ian.
iPAQ 2210 | Navman 4100 BT Receiver
Navman iCN 635
TomTom GO
Anquet OS mapping

[SGR1913]

icsys,

thanks for the explanation, it's the first time i had noticed it, and probably came to the reflected signal conclusion because i was in a valley. I'm sure as the mapping and software is upgraded stuff like this will be less frequent.

Anyway i opted for ordering an aerial, as i find i loose signals now and again, and after coming out of a tunnel it can take ages to get a signal. When i do re-drive the same route with the aerial it'll be curious to see the results.

thanks
Scott

[hmalan]

Stix,

Re you're comment about looking out of the windscreen!!

This is fine in the case of the first time it happened to me as I was on a straight piece of motorway on an early part of my journey where I still actually knew where I was.

The second time it occured on the M6 around Birmingham with roads going off in differant directions in an area that I was not familiar with and started to give me voice directions ie."in 300 yards at the roundabout", when there was no roundabout.

Having used TTN3 and an ICN 510 before, this is the first time anything like this has happened to me.

With respect to the accuracy of the GPS system on the first occasion I was in the fast lane of a three lane motorway and the road adjacent to the motorway that it put me onto is at least 10 - 15 metres beyond the hard shoulder. In addition to this the road was parallel to the one I was travelling on, and not passing over or under it

Alan

[stix]

sorry alan, i wasn't meaning to sound flippant and i appreciate it can be confusing if you start getting voice commands to make turns!

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