Go 720 plots my postion 30m west of actual

[daviesr1]

I have a go720 of 2008 vintage that's been working perfectly for years, and I keep it updated regularly with all the gps fixes etc. Two days ago I went on a journey to an unfamiliar town and it plotted the route there perfectly.

When I turned it on for the route home it kept jumping all over the place, giving me random turns, and showing me driving across fields.

It's been like this ever since, and back on home turf I was able to work out the problem, it is plotting my postion approx 30 metres west of my actual.

When driving along a road heading due west, it shows me passing junctions when I can see them further ahead down the street. When I make a left turn it then shows me travelling parallel with my actual road but again west of it across country. so it's tracking my position perfectly, just offset by a consistent distance west. This problem is permanent and consistent.

Is this a known problem, is there something I can do to fix this, or is the unit toast?.

So far I've performed a master reset, and connected to home2 and downloaded a further gps fix, all to no avail. It's picking up plenty of satellites 5 to 7 of them, and quite strongly. Any help would be appreciated.

Richard

 

[Andy_P]

This seems to be a recent problem with older models and is as yet not entirely explained, but we've been seeing more and more reports of it.

It's happened to me personally, when I updated my son's Go520 a couple of weeks ago.
It had exactly the same symptoms as you've described, but last I heard from him, it seemed to sort itself out after a few days.

In fact, some of us have seen this happen before, quite a few years ago, but the "shift" was always less than this, maybe 100yds rather than the 200-250 yds I was getting this time.

Theories so far include a corrupt GPS Quickfix file, but I tried deleting it from the machine and didn't get any improvement.

The groundswell of complaints is increasing...but no definitive response from TomTom yet. Watch this space!

Do please report it to TomTom themselves on 0845 161 0009 (Monday - Friday: 08:00 to 18:30 GMT), so that they can get a better log of how many people are being affected.

 

[dhn]

I know you replaced your gps file but try once more:
1. Use Explorer to delete anything in the ephem folder on your device
2. Go here: C:\Documents and Settings\yourname\My Documents\TomTom\HOME\Downloads\complete\ephemeris\ and remove any sub-folders there.
3. Connect to Home and install the new gps fix file offered.
4. Disconnect from Home properly using the Device Disconnect icon.

Any better?

 

[Andy_P]

Or alternatively... do all the above and DON'T download a fresh one?

Try both!

 

[daviesr1]

Thanks

Thanks for the replies so far, seems hopefull it's not toast. I'm amazed to get any on a sunday morning! I'll try the suggestions, I'd also thought of removing and completly reinstalling the o/s and maps. If anyone can give me a brief guide to how to do this. (I have update subscription, and all the downloads are on my laptop)

Richard

 

[Andy_P]

There are instructions for all the standard "fixes" upto and including replacing the O/S in the "Articles" forum section (no-one ever seems to find them there )

But I wouldn't bother to be honest... I think this is a fix that needs to come from TomTom (once we can get them to acknowledge a problem exists!).

Until then... see if your position slowly improves after a bit of time. That's what I found on my son's machine... after tearing my hair out and doing several of the above "fixes" I actually saw the car cursor sliding back across the display to the correct position (just as if I was slowly driving home from a nearby street!)

 

[dhn]

Richard, I have a 720 here and just experienced the same issue with mine. I did all the steps I told you to do ..... with no success.

BUT...................

I then did a pin reset and everything was back to normal (for now, anyway). So, try that.

 

[Andy_P]

My "pin" reset, only fixed it for a short while, and the next time my son used it it was wrong again. But that was three weeks ago now and he hasn't got back to me to say it's still bad, so maybe it eventually sorts itself out. I'll have to check with him

Meanwhile, to cross-link two similar threads running today,... see also here:

https://www.tomtomforums.com/t28202...e-now-cant-find-accurate-lock.html#post163845

 

[paulo.oliveira]

Hello all,

Today I have the same problem on my 2007 Tomtom Rider 2
The strange part is that the North-South accuracy is good but the East-West accuracy is around 200m off place... I tried to reset the device but it didn't work.

I arrived home and did a photo of the Tomtom next to my garmin 62c: http://yfrog.com/es64201121j

The Gamin is perfectly locked in the correct position, but the Tomtom is of to the East by around 200m.

I've sent an email to Tomtom support to see if they can help me with this...

 

[colin12]

gps type

the same happened to me on my 730 whitch i resently bought brand new from america.and because i use my tomtom for work i keep a older 520 as a spare so when i got home i checked that and it to was showing the same fault .these two sat navs use sirfstarlll as there gps type. my son has a tomtom xl witch uses globalocate and this one did not show any fault and so for me the fault appears to be with the sirfstarlll.ps the fault has cleared up on both unit at the same time within 24 hrs

 

[dhn]

'cleared up'....... do you mean the problem is resolved?

 

[colin12]

yes both appear to show the correct position. i have only used the 730 on a short trip both it showed me driving on the road not in a field . by the way i tried everything to fix the problem including a complete wipe and reinstall of software and map on my sd card and nothing would rectify the problem. and yet today it appears to have cleared up itself.

 

[DerryUK]

I have a Go530 with the same offset problem. Yesterday I tried a pin reset with no effect. Occasionally my 530 would position itself on the correct position on the road. It was mostly wrong though (9hr trip.)

Today I downloaded the gpsfix file again and used the clock resync option and it seems to have fixed the problem (just a short trip down the road and back though.)

 

[canderson]

Or alternatively... do all the above and DON'T download a fresh one?

Try both!

Precisely. As I recommended to the user in the parallel thread, having deleted all of the ephemeris data, try using the unit WITHOUT any of these GPSQuickFix files for a while to see how things go, and only then, try allowing HOME to supply those files again and see if there is a difference.

 

[daviesr1]

Well deleting the data made no difference, though after connecting back up to home, it only offered me map corrections not quick fixes.

The pin reset is the first thing I tried when I got home after it firstr went wrong. so no luck so far. Interesting several other cases are appearing in the last few days.

I might try the software rebuild, or leave it for a week or so to see if it self corrects.

Thanks for all the input.

 

[dhn]

Please continue discussion in similar thread here:
https://www.tomtomforums.com/t28202...tom-software-now-cant-find-accurate-lock.html

I'll close this one.