Question About Accuracy

[k5hokie]

I bought my first GPS unit today, a Garmin etrex Legend. I have no prior experience with using GPS. The accuracy remained at least 30 ft. and often was above 75 ft. I do understand that this is due to the number of satellites picked up , and it was least accurate when few sats registered, and when these few were in a straight line.

My question, was this due to tree cover, it was not a thick forest, actually a suburban park? Could it be because I used weak batteries?

[+Renegade Knight]

Tree cover does bad things for your reception. Much more so than batteries ever will. I've heard tell of batteries having an impact but practically speaking I've never seen it in using my GPS. Trees though. Gack.

[+JamesJM]

True many things can cause interference.

 

If it's any consolation, and hopefully this isn't just MY experience, I have rarely been further than 15' from a cache even when my GPS, a Vista, is reporting 60' accuracy. Often I'm dead on the cache when the accuracy reads no better than 35' or so. - JamesJM

[+EraSeek]

Sats in a straight line? Loosy geometry! Tough to triangulate a position like that. It happens sometimes. Tree cover always makes things tougher. Low batteries can have some effect. Accuracy reading is only an estimate. Don't put too much into that. It just gives you an idea about how well your signal is doing.

[+Stem]

Another thing to check - is your gps in "battery save" mode. If it is and you switch it to normal, that can increase youer accuracy

[Hopsahi Harry]

An E-Trex Legend! Cool! I have one, too and it is a fun toy...tool, I mean. Eraseek has a pretty good answer. I find that when the satellites that are on line are scattered all over the place, I get good accuracy. However, when they are all bunched up, it doesn't seem to matter how many are on line, accuracy suffers. That's even true with the WAAS satellite (#35) correcting some of the other satellites (they have the "D" on the bars).

 

And as the others have pointed out, I've stumbled all over the woods and found nothing, even with good accuracy, and vice versa. Either way I enjoy the hunt.

[+Brenin Tegeingl]

The terrain of your current position will affect accuracy, even if it's a dip in the ground. As a example of accuracy, I have a multi located in sand dunes. My etrex constantly shows me to be 7m away for the first part (that's with a error of 5m showing) which is in the middle of several dunes. The second part is out in a open area, the etrex will put me virtually on top off it every time. I've checked the accuracy of the etrex at trig points (benchmarks) and had a accuracy of less than .5 of a metre, and that's been with a error of 7m. This is just normal for all GPSr's.

Dave

[+horsegeeks]

I looked in the manual and couldn't figure out how to disable the power saving mode. Any help would be appreciated.

[+briansnat]

Since its new, it may not have found all the sattelittes yet. Take it to an open field, turn it on and let sit for about 5-10 mins.

 

Also, turn it on while driving to the trail head and well before entering the woods. If it knows where the sats are, it will find them again quickly if it does lose them under tree cover. If you wait until you get into the woods to turn it on it won't work as well sometimes.

[+harleycache]

I looked in the manual and couldn't figure out how to disable the power saving mode.  Any help would be appreciated.

Go to setup options, then system page. Highlight GPS, change to normal if you are in battery saver. Page 47 in the manual.

 

 

edited to add page #

Edited March 26, 2004 by harleycache