It is probably a fairly common GPS use issue as opposed to a Garmin issue There are many reasons for this not least of which is that all manufacturers lie about the accuracy of their units in "real - world" use (as opposed to theoretical accuracy tolerances) That is why surveyors and other professionals use specialist high accuracy equipment, tables and have specialist training & qualifications to match etc.
You can find plenty more info on this by googling, some examples: http://en.wikipedia.org/wiki/Global_Positioning_System http://www.kowoma.de/en/gps/errors.htm http://gpsinformation.net/main/altitude.htm http://www.educatedguesswork.org/2009/03/correcting_for_gps_altitude_er.html The easiest ways for the OSM mapper to minimise this effect are: 1. maximum number of satellites up 2. go on multiple days to minimise daily accuracy variations 3. clearest possible view of the sky 4. average the results 2009/11/2 Apollinaris Schoell <ascho...@gmail.com>: > Nop wrote: > > Hi! > > Shalabh schrieb: > > > Would just like to figure out if any of you have had the same issue with > this model or any other Garmin GPS. > > > I have a similar Issue with the Garmin Vista HCx. Occasionally I > observe, that the GPS position is way off the known road/path I am on. > The satellite accuracy is high +-5m. > > When I switch the device off and on again, it positions me right where I > am supposed to be. So it seems to accumulate some sort of error in its > internal calculations and needs the occational reset when it is "going > wrong with great confidence" > > > > > yes this is a Garmin special feature. I believe they do some estimates when > reception isn't good. the track is drifting away and suddenly jumps back. > switching off and on is an option too. > The Vista had a couple of bug fixes in the last firmware updates. Something > to try. If you update I recommend to use the native program and not the > webupdater if the device is out of warranty. > > bye > Nop > > _______________________________________________ > talk mailing list > talk@openstreetmap.org > http://lists.openstreetmap.org/listinfo/talk > > > _______________________________________________ > talk mailing list > talk@openstreetmap.org > http://lists.openstreetmap.org/listinfo/talk > > _______________________________________________ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
