Etrex Touch 35 displaying incorrect distance on trip counter

[Milesmob]

Hi all,
My Etrex Touch 35 displays the incorrect distance travelled. It is always excessive. This was recently discovered when a few of us, all with different GPS units went and walked to the summit of Snowdon mountain. I always re-set my trip counter before starting each walk, including this walk. On reaching the end we all compared our distance travelled and mine was about 2 miles more than the average reading (most were different but only by the odd 0.1 of a mile). It was decided that I had probably not reset my trip. The next day we were out walking through the Town and re-set my GPS and put it in my pocket, my friend did the same to his and we compared them on our return. They showed different reading with mine showing +1.1 miles over a 3.5 mile walk.
I then reset my GPS trip to Zero reading and left it idle and untouched for the day. On my return it said I had travelled 0.6 Miles even though it had not been moved. The GPS is only 9 months old and I now realise that all my previous recording have most probably been inaccurate.
I'm not sure if this query has been posted previously, I did take a quick gander through the headers and could not find anything at first glance. If there is a posting of this nature please accept my apologies and if you would be so kind as to point me in the right direction.
If anybody knows how I can cure this 'Trip Distance' problem I will be most grateful. Or if my device is faulty I may still have time to replace it under warranty?
Any help will be appreciated
Milesmob

 

[Nuvi-Nebie]

This is due to 'jitter', all GPSs have inaccuracies when reporting their position, so for example if you clear your Track data and leave the GPS stationary for say an hour, you will see that the unit reports movement in the form of small ' jumps' away from your current position, if these jumps are recorded in a Track, then they will add up to distance travelled even though the GPS hadn't moved, all GPSs suffer ftom this to some degree

So why are you seeing this effect more than other users ?, there are quite a few ways of reducing this effect, the problem will be more noticeable when errors are bigger, if your unit thinks you have moved say 20 metres while stationary it will create a bigger error than if it thinks it has moved only 2 meters, so units that are less accurate add more error distance when not moving, however it doesn't necessarily mean your Touch 35 is less accurate, there are setting that can help, the Touch 35 has an Auto Pause feature that detects when you are stationary and stops recording Track data all together e.g. Setup >> Activities >> Auto Pause = On, also you can edit Track recording parameters, e.g. :- Setup >> Activities >> Record Method = Distance, Time, Auto, if this is set to say Distance >> Record Interval = 10 metres, then any error (or real movement) smaller than 10 metres won't be recorded

 

[Milesmob]

Thankyou for your quick response.
The jitter problem makes sense and its good to know this is quite normal. I will also take a look at my settings and adjust as necessary.
I will let you know the outcome once I get a chance to compare my GPS with another.
Thanks again - Its nice to know that help is available and I realise I am just touching the surface of the potential of my GPS. I am quite new to the Touch 35 as I only had it for Christmas and apart from the track distance errors I think its a great piece of kit.