60CSx, waypoint averaging

[+Ultimate 5]

The manual says very little. I want to make sure any Cache's I hide have really good coordinates. What is the best way to get most accurate coord's?

 

Should I click on ave. wp then stand there, if so, how long do I let it count to?

 

OR

 

Should I walk in a radius around the cache.... 10 or 20' out? Seems I should just stand in one spot.

 

thanks, I am learing slowly!

[+PFF]

Good point about the lack of direction in the manual regarding averaging.

 

Stand in one point. Hold the unit as steady as possible.

 

In testing with points of known accuracy (USGS benchmarks with "adjusted" coordinates), a measurement for two minutes has produced really good results. Four minutes is even better. Beyond that, it won't improve much because of the built-in limitations of a consumer-grade GPS receiver.

 

When I want really precise coordinates, I support the antenna on a 7-foot tripod made from a shop-style utility light. (I don't have the patience to hold the unit up in the air for four minutes--grin.)

 

One tip I heard several months ago is take a reading, and then walk away 15 to 20 feet and come at the cache from a different direction. Take another reading and compare. One person said he does this several times when setting a new cache. I've not tried it, but it seems logical. I think this is called "reproducibility of results" in scientific circles.

 

And a Gold Star to you for caring about getting the coordinates as close as possible! Keep up the good work!

 

-Paul-

 

[Aushiker]

G'day

 

Since getting my 60CSx I have used the averaging feature. I tend to rest it on a rock or the ground as close to the cache as possible and let it run for a count of about 200. I have found the coordinates tend not to change after about 200 cycles so I haven't seen any point of continuing the averaging beyond that amount. So far it seems to have provided reasonably accurate coordinates based on others feedback.

 

Before that with my old Geko 301 I took three independent readings by walking away and then coming back. I averaged the three readings.

 

Have fun with the 60CSx

 

Regards

Andrew

[+Ultimate 5]

cool, anybody else have other ideas?

[+hogrod]

cool, anybody else have other ideas?

 

One thing to look at is when your using the average waypoint feature it's only averaging for that given day and time. when you average with the 60csx it takes about 60 readings a minute. so even if you average to 450readings it's still only an average of about 5 minutes of data.

your best bet is to take a couple averages over a few days/weeks and average those numbers together.

[Aushiker]

your best bet is to take a couple averages over a few days/weeks and average those numbers together.

 

G'day

 

I wonder if that is really necessary for cache hiding? Most people seem to be able to find caches pretty well even when they are placed by cachers using less sophisticated GPSr units.

 

I am curious as to how much of an accuracy improvement is likely over say three days of readings? Do you believe that such an increase in accuracy would really improve the ablity of the cachers following to find the cache given the variety of GPSr used, caching on different days etc?

 

Regards

Andrew

Edited December 15, 2006 by Aushiker

[+hogrod]

your best bet is to take a couple averages over a few days/weeks and average those numbers together.

 

G'day

 

I wonder if that is really necessary for cache hiding? Most people seem to be able to find caches pretty well even when they are placed by cachers using less sophisticated GPSr units.

 

I am curious as to how much of an accuracy improvement is likely over say three days of readings? Do you believe that such an increase in accuracy would really improve the ablity of the cachers following to find the cache given the variety of GPSr used, caching on different days etc?

 

Regards

Andrew

 

in a poor signal enviroment, you bet! even the 60csx/60cx get different readings over time. check out some of your known averaged waypoints after a few months, if there in the open they may be great still, but in a deep tree covered gorge they maybe off a bit. so the best way to get super accurate coords is to take a few averages over a couple days.

[+briansnat]

I wonder if that is really necessary for cache hiding? Most people seem to be able to find caches pretty well even when they are placed by cachers using less sophisticated GPSr units.

 

No, its not really necessary. If your unit doesn't average I wouldn't even bother with manual averaging. If your unit does average it can't hurt letting it sit there for 5 minutes and average, but coming back over a period of days is simply a waste of time. Its a lot of work to get perhaps 5-10 feet of additional accuracy.

 

If you get complaints about the coordinates, then you should head back for another reading, but I'm willing to bet that 95 percent of the time your coordinates will be just fine.

[Aushiker]

in a poor signal enviroment, you bet! even the 60csx/60cx get different readings over time. check out some of your known averaged waypoints after a few months, if there in the open they may be great still, but in a deep tree covered gorge they maybe off a bit. so the best way to get super accurate coords is to take a few averages over a couple days.

 

Right. If you have done this for a cache then that is pretty impressive or you have very easily accessible gorges. Gorges around here take a lot of efffort to get to once let alone repeat visits over weeks or months! Guess any caches I place in these conditions will just have to have poor coordinates.

 

I think we need to be realistic for caching as briansnat has indicated.

 

Regards

Andrew

[+budd-rdc]

cool, anybody else have other ideas?

PFF pretty much covered it.

 

Some people go by the number of samples (100+ points averaged) instead of minutes, but that's essentially the same thing, increasing your data sample. He said the keyword, which is reproducibility.

 

There are times when the location doesn't receive signals well, or suffer from multipathing (signals bouncing off objects before reaching your GPSr) - standing next to walls, large trees, and cyclone fences, for example. In that case, you can stand away from the obstruction, take your reading, then project, triangulate, use maps, or find other creative ways to guess the coordinates to the best of your ability. If you are still not confident, you can always write explicit hints.

[+Red90]

On these new units, an "estimated accuracy" is provided on the averaging page which changes with the averaging. I always try and get tha below 3 meters. Note that it will INCREASE if the reception quality degrades during the averaging, so keep an eye on that. IME, the nunber provided is a very good indication of the overall accuracy of the averaged coordinates.

[Aushiker]

If you are still not confident, you can always write explicit hints.

 

and/or add a photo or three .

 

Andrew

[Aushiker]

On these new units, an "estimated accuracy" is provided on the averaging page which changes with the averaging. I always try and get tha below 3 meters. Note that it will INCREASE if the reception quality degrades during the averaging, so keep an eye on that. IME, the nunber provided is a very good indication of the overall accuracy of the averaged coordinates.

 

I initially did that, that is kept watching the degree of accuracy but then noticed often that the actual coordinates stopped changing after awhile even though the accuracy would continue to be fine tuned. As we quote the coordinates I wonder if there is any point watching the accuracy for any period of time?

 

My approach is now to watch the coordinates and when they apppear to have settled down, that is not changed for 50+ cycles take them as the reading.

 

Andrew