Accuracy of 62s?

[+KJRCaching]

Hey, everyone. New to geocaching. Just picked up a 62s yesterday...and my family (wife and 2 young girls) scored our first 6 geocaches this weekend. What fun. My question lies within wondering how accurate I can expect my 62s to be? Just about every cache we found has been a bit odd when using the compass. I would zero in on the cache...and get to about 5ft...and couldn't get any closer not matter how much more i walked. So I would look around...and then look down at the compass and it says I am now 20+ feet away. So I walk that way...and the number doesn't really drop...and then it finally does to 5 or so ft again. Then as I get close to it...it points me back to where I just came from...and says now I'm 20 or so ft away again. My wife had better luck with her iPhone then I did my expensive 62s. Am I missing something here? User error? Preconceived notions about how close it will get me to my cache? I can live with 10 or so ft of accuracy...as long as it takes me to 1 or 2 ft on the compass so i know i can start looking......but it has me on a wild goose chase of sorts.

 

Any help would be appreciated.

 

- kjrcaching

[+Woodstramp]

"Preconceived notions about how close it will get me to my cache?"

 

Yep. The "wild goose chase", from my perspective, is part of the fun. I heard a joke one time where a golfer died. Long story short...he found his self constantly playing perfect rounds of golf. One after another, after another. After a week of perfect golf he realized he was in hell.

 

BTW, from what you describe, you're getting decent accuracy.

[+KJRCaching]

Thanks for the reply, Woodstramp. Guess I hadn't expected to see 5 ft on my GPS, not move, look around, then look down again and have it jump to 24 ft -- walk to the new location -- repeat. {shrug} If this is how a GPS rolls, guess I'll find some way to make a game of it

 

- r

 

"Preconceived notions about how close it will get me to my cache?"

 

Yep. The "wild goose chase", from my perspective, is part of the fun. I heard a joke one time where a golfer died. Long story short...he found his self constantly playing perfect rounds of golf. One after another, after another. After a week of perfect golf he realized he was in hell.

 

BTW, from what you describe, you're getting decent accuracy.

[yogazoo]

KJR,

 

In what part of the country do you reside? The reason I ask is that the SE U.S. is undergoing massive GPS blackouts and unreliability to to a DOD test of their GPS system.

 

If your not from the SE, I have been out and noticed that the 62 was more accurate after a minute or so to allow the unit to settle in on the location.

 

Cheers!

[+KJRCaching]

Hey, yogazoo.....I am in central NC -- so that would most definitely be in the SE.

[+ar_kayaker]

I'm not sure if/how this might apply, but the 62 series is supposed to have some nifty new feature that keeps it from "wandering" when it is sitting still. If you even looked at the track log on one of the older models you'll know what I'm refering to. I'm not sure yet how that might affect the unit's ability to home in on a spot, but depending on how they handled the wandering issue, I can see ways it might keep the unit from updating when you make small moves trying to get closer to ground zero.

[+KJRCaching]

Thanks for the feedback, ar. i would be very helpful if i had another 62s to compare it with. it's entirely possible this is just the way they work. i have owned 7 or 8 GPSs over the years....but they have all been street-biased....and 5ft is just as good as 25ft when you are trying to find a destination via automobile or motorcycle.

 

- r

 

I'm not sure if/how this might apply, but the 62 series is supposed to have some nifty new feature that keeps it from "wandering" when it is sitting still. If you even looked at the track log on one of the older models you'll know what I'm refering to. I'm not sure yet how that might affect the unit's ability to home in on a spot, but depending on how they handled the wandering issue, I can see ways it might keep the unit from updating when you make small moves trying to get closer to ground zero.

[+dfx]

I'm not sure if/how this might apply, but the 62 series is supposed to have some nifty new feature that keeps it from "wandering" when it is sitting still. If you even looked at the track log on one of the older models you'll know what I'm refering to. I'm not sure yet how that might affect the unit's ability to home in on a spot, but depending on how they handled the wandering issue, I can see ways it might keep the unit from updating when you make small moves trying to get closer to ground zero.

 

That sort of track smoothing is applied in a rather late stage of coordinate processing in the software. If you use the waypoint averaging feature, the smoothing is disabled for the duration of the averaging and only the raw coordinates are taken into account, so there's no need to move around.

[yogazoo]

There may be others that know better since I'm going to speculate here but aren't "tracklog" and "current position" two seperate things? The track that is smoothed will not necesarily mean your coordinates stayed in one place. When your zeroing in on a cache, the tracklog would have nothing to do with your "current" coordinates in relation to the cache. For example: if you have your tracklog set to record every 30 seconds your coordinates will continue to update every second or so and not only just every 30 seconds. So just because your tracklog is smooth or has been smoothed via algorythm it doesn't mean your reported coordinates reflect that smoothness as well.

 

If you could write down your coordinates every second and plot them over your track you would be able to see the plotted coordinates deviate from that track (to whatever degree that might be). The "smooth" tracks probably have more to do with Garmins improvements of the tracklog algorythm than it would have to do with the cartesio being a better chip (although there may be some improvement). My guess is that an accelerometer inside the newer units is used to detect the degree of actual movement and contribute to the calculation in some way.

Edited February 3, 2011 by yogazoo

[+bcblues]

In short, consumer-level GPS units are doing pretty well to get within about 12' of an actual target, even under the best conditions. For geocaching, that means the GPS (in your case the 62s) will lead you pretty consistently to within about 12-20 feet of the actual cache (assuming, of course that the cache has been placed/logged accurately by the owner). Then, ignore the GPS and go into "manual caching mode". Think like a cacher and try to figure out where the cache is based on the terrain where the GPS has lead you. You can always recheck the GPS if you are having trouble finding the cache, or if you find yourself wandering off...... IMHO, that is what makes geocaching challenging - and so much fun!