GPS FORUM

> When first used my Garmin Etrex was about 1/2 kilometre out.
> This was caused by wrong settings, I changed to GBNG and everything was
> fine. Look in the set up menu.

> ISTR a thread recently where someone had a TomTom unit where the
> position shown by the GPS was 100 yards away from the true position as
> though the entire map system was shifted, but i`ve drawn a blank on
> google...
>
> Can anyone remember any further details ? (a thread on Expansys suggests
> changing the datum (?) format to long/lat as a fix for a garmin unit)
>
> Thanks in advance of any assistance / clues :-)
>
> (this is for a unit in work I have no direct access to)

> I use Tom Tom Navigator 5, I dont recall there being a preference or
> setting for changing datums on it. I dont think it would be needed
> since they provide their own mapping and either use the same datum for
> all of it or control the datum changes in software when maps using
> different datums are used. As far as I know there are no third party
> maps available Tom Tom units.

>> I use Tom Tom Navigator 5, I dont recall there being a preference or
>> setting for changing datums on it. I dont think it would be needed
>> since they provide their own mapping and either use the same datum
>> for all of it or control the datum changes in software when maps
>> using different datums are used. As far as I know there are no
>> third party maps available Tom Tom units.
>
> I think the devices in question also use TTN5, but they`re used in
> conjunction with a vehicle tracking system which I believe feeds TTN5
> with the GPS signal.
>
> Not all units show the offset, which would seem to rule out a
> generalised receiver issue, but I suppose depending on what it goes
> through first, any delay passing that signal on might lead to a
> variable discrepancy.
>
> Unfortunately I have zero information to work from at present - our
> local admin contact is on holiday, another (to whom i`ve never
> spoken) is 200 miles away, and the third party tracking system is
> based in another country :-}
>
> My query here originated from a single line in an email, and I
> remembered reading about someone else having a similar problem :-}

>I think the devices in question also use TTN5, but they`re used in
>conjunction with a vehicle tracking system which I believe feeds TTN5
>with the GPS signal.