Problems with GPS accuracy !

[loba2007]

Questions :

 

1:Could someone knows anough about GPS accuracy to tell me "How accurate is a GARMIN GPS 60 "?

Is it accurate to 2 feet or 10 feet or what ... taking into account that it contacts 4 + satellites.

 

2: How long, approximately, should we wait before each satellite update, when we move ?

 

Thanks for your expertise !

 

Loba2007

[+StarBrand]

That unit has WAAS (Wide Area Augmentation System) so if it can see a WAAS sat - the best accuracy you will typically get is 3 meters or about 9 feet.

 

My experience with 5 different Garmin units is that typical accuracy is around 20 feet or so but it varies with time of day and the view of the sky and the spread and number of satellites at any given time. (lots of variables!!)

 

More sats general equals greater accuracy. With a view of 4 - I see estimated accuracy of 50 - 60 feet or more. With 8 to 10 that drops to 15 to 25 feet. But can be highly variable.

 

Keep in mind that the reported accuracy on the unit is only an estimate. You could well be dead on but the unit will report you at +/- 10 feet. The way to read the EPE (Estimated Position Error) is to read that the position reported is roughly 80% confident that you are no more than xx feet off - at the moment.

 

The unit should update and recalculate your position several times per second. For best results - turn off the battery saver mode as that gets a new reading less often.

[+imajeep]

If you have a laptop computer and Google Earth, here's how to get a pretty good idea: Connect your GPS to your laptop and fire up real time tracking on Google Earth. I did it this morning, and Google Earth had my position to within about a meter--and I was tracking from inside my house! Garmin GPSMAP 60 Csx--gotta love it.

[wvnewbie]

how do you do real time tracking?

[+briansnat]

Your GPS 60's accuracy will range from about 6 feet under the very best conditions to 50 feet under poor, but most of the time it will be more like 15-30 feet. This is the norm for nearly any consumer grade unit, regardless of brand and price.

[+trainlove]

1. Cache coordinates are only as accurate as the cacher who planted it. If they didn't wait at the spot, waymark a dozen or so sets of coords and average them, and heavens forbid, didn't look at the EPE figure on his GPS when getting his coords then +/-10 yards is as good as you can be. And if he has a Magellan which has firmware issues then all is sunk.

 

2. If by accuracy you mean the following. You pan to an intersection on the maps on your GPS and mark the spot, you then GOTO that spot and see that you are actually 100 feet away from the center of that intersection. All I can say is that most computerized maps are just plain BAD. Garmin's are better than most.

 

Oh, do I have to say, please do not stand in the center of an intersection??????

[loba2007]

1. Cache coordinates are only as accurate as the cacher who planted it. If they didn't wait at the spot, waymark a dozen or so sets of coords and average them, and heavens forbid, didn't look at the EPE figure on his GPS when getting his coords then +/-10 yards is as good as you can be. And if he has a Magellan which has firmware issues then all is sunk.

 

2. If by accuracy you mean the following. You pan to an intersection on the maps on your GPS and mark the spot, you then GOTO that spot and see that you are actually 100 feet away from the center of that intersection. All I can say is that most computerized maps are just plain BAD. Garmin's are better than most.

 

Oh, do I have to say, please do not stand in the center of an intersection??????

*************************

 

Thanks for the info !!

And don't worry. I will make sure not to get hit by a TRAIN ......, .... LOVE !

[+GrateBear]

I use a Garmin Legend Cx and other than when I'm around tall buildings or in the woods, consistently get readings under 10'. I've even gotten to 1' to 3' and there was the cache. Now that the leaves are out, in the woods the readings are 10' to 20'. But those hides so far have been fairly obvious as to where they are.