Epe 1m

[+hedberg]

I and a fellow cacher doesn't agree about the accurancy of his GPS. He has an old Magellan and says that he always have 1m accurancy. We live in Sweden where it is not possible to receive EGNOS/WAAS signals.

 

He says that EPE 1m means that he has 1 meters accuracy. He gets this even if he lays the GPS at the base of a really big tree with a lot of leafs on.

 

I have read somewhere that EPE stands for Estimated Positioning Error and are some kind of secret mathematical formulas? Your GPS says that you have 8 meters accurancy, but the GPS calculates then where it thinks the waypoint can be within the accurancy.

 

Who are right?

 

Can he have 1meters accurancy ALWAYS, even below trees and so on? I claim that he can't and that EPE means calculated positioning?

[+New England n00b]

I'm with you hedberg... 1 meter... ALL THE TIME?!?!?

 

The BEST I have ever gotten on my Garmin eTrex Legend was 10' EPE, and that was only with WAAS enabled. Mostly I get 20-30 feet...

 

What brand/model is he using again? If he is right... I'm switching!

[+phantom4099]

I wish GPS manufactures would remove EPE from their GPSr; it just confuses people that don't know better.

 

Does he have a 315, I know mine use to read an EPE of 0 feet when I first got it in 2000 (with newer firmware it is more realistic). All manufactures have a different way of measuring EPE, and it sometimes can vary from firmware to firmware. So it not enough to saw that my GPS had "8 feet of accuracy" and some one else’s had "15 feet EPE", so mine is more accurate. Also claiming to be closer to a cache is not enough to prove accuracy (how do you know the placer was accurate).

 

The only way to "prove" "accuracy" is to go to a bench march that has been significantly located by surveyors.

 

Wyatt W.

[Kerry.]

Can he have 1meters accurancy ALWAYS, even below trees and so on? I claim that he can't and that EPE means calculated positioning?

 

1 metre always, No not even 1metre any of the time really as it might display silly figures like this some of the time but really means little and shouldn't be taken seriously at all.

 

EPE is basically implemented differently by all manufacturers and shouldn't be taken as anything absolute at all. As a relative trend say if EPE improved then one might assume the accuracy is getting better but the actual accuracy would certainly not be indicated by the EPE value.

 

Cheers, Kerry.