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siloans
3rd November 2004, 10:43 PM
Hi can you tell me if some gps are more acurate than others I have a garmin etrex which I think is quite good and manages to get me too within a few meters of a cache most of the time ??????????????? :) -_-

MCL
4th November 2004, 01:22 AM
I find that make and model have relatively little effect on the accuracy of a unit on a particular day and time. What has far more to do with it is the number of satellites it can "see" and their positions relative to the unit. Apart from that, they have all pretty much cracked the maths to do with getting the best accuracy out of a given set of data.

Where model and make *do* have a bearing on accuracy is only if you consider a military model over a civillian one. Since the military models employ special decryption to access much higher precision data, then yes, you could say that the type of GPSr has an effect on accuracy, but thats being a bit too pedantic I think.

Brenin Tegeingl
4th November 2004, 09:20 AM
When you are moving, all GPSr's will have a slight error in the position that it is showing. If when you get close, you just stand still and let it settle, you'll find that the position will jump slightly. I have a Etrex yellow, and have checked the accuracy against Trig points, and as long as it has had a minute or so sat on top of the pillar, the accuracy has been sub 50cm. To try and get a accurate reading for my own caches, I always take a set of readings, over several days and at different times of the day, and then average them for the final reading. The funny thing is, if I approach the first micro on my multi, the etrex shows it to be 11m away, and that is on every visit I've tried, with the actual model used to place it. This has sand dunes surrounding it, but if go to the second micro, which is out in the open, I end up within a metre of it. Unfortunately as most caches are not out in the middle of fields, the local terrain will affect the accuracy ever so slightly. Slightly long winded answer I know :rolleyes:, but as long as my etrex puts in the general area of the cache, I'm ecstatic.

Dave

The Hokesters
4th November 2004, 09:52 AM
Someone will no doubt correct me on this but I am pretty sure some models do the averaging for you. I don't know which ones though. I have a Geko 301 so if someone can tell me if this is one that averages your position I would appreciate it.

No doubt there is some techie way of working out if it does or not but if I leave mine on a table in clear view of the sats it seems to jump around constantly.

Si

siloans
4th November 2004, 08:30 PM
So am I right in thinking that there would be no benifit in getting a garmin vista for geocaching if I already have a etrex yellow garmin ???? :unsure:

Lost in Space
4th November 2004, 09:00 PM
Remember, if you only use your GPS for geocaching, then you are relying on the accuracy of the coordinates as measured by the "placer", in which case the yellow e-Trex is more than adequate.

Lost in Space
4th November 2004, 09:07 PM
For the ultimate in accuracy try this cache (https://www.geocaching.com/seek/cache_details.aspx?guid=4572e42b-8e42-4d46-ae40-acc61141eff2)