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Do You Use "average" Location?


Daren3006
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I used to worry about that last digit of accuracy, then realized that when hiding a cache under a plie of rocks in the desert, folks usually see where it is from 50 ft away. I just set the GPS down while hiding the cache (so the GPS stabalizes), then mark the waypoint. I haven't had any complaints yet. That last digit represents about 5-6 ft. Even if it's off by .003, it's still about 15-18 ft.

Edited by Moose Mob
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I recently started averaging then walking away from the cache. I then go back to the cache using a set of the coordinates. There's times I end up taking about 10 sets of coords before having a set that consistantly match up.

I find it also "helps" (meaning, I get a wider variation - but at least I learn the range of values I might get!) to switch the GPSr off and on every few measurements. Sometimes this causes everything to jump 40 feet !

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Yes, I use averaging. Although the averaging feature on a GPS will generally improve position accuracy, it can still yield poor results when done for a short period of time when satellite geometry is not good. I prefer to take a number of positions at times when the EPE (accuracy) display is at a low number, 18 feet or less. I then average these positions on the map page by placing the final position at a central spot in the points. This works even better if you can go through the process at some intervals of more than 30 minutes, i.e., take a few points now, then take a few points an hour later. If the points are spread way out on the map page, this tells me I may need to take more points. If they make a tight group, I get more confidence in the readings. If the cache is in a bad spot for reception, like under heavy vegetation, I go to a clearer spot near the cache, do the averaging there, and then project the position to the cache. Using these methods it is often possible to get a position that is true within 10 feet or less.

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YES, i allways average! But im not sure what some of you are talking about when you say that you end up with 200 waypoints when averaging. It must be a Magellan thing i suppose. :) The coordinates change automatically while the Garmin averages but to get a good reading, i do need to let it average for a couple or three minutes.

 

On a similar note, i have found that WAAS doesnt seem to help much for getting better readings unless im in an open area. Those areas are harder to find down here so i dont even use it!

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Mudfrog Posted on Mar 31 2005, 11:19 AM

im not sure what some of you are talking about when you say that you end up with 200 waypoints when averaging.

The idea of averaging is to leave the unit stationary and collect multiple solutions and average them to obtain a better answer. QUOTED from "A GPS User Manual" by Dale DePriest

 

I own a Garmin GPS Map76S. On the Averaging Screen there is a Data Box labled MEASUREMENT COUNT. A Google search tells me this term has been a "Feature" in the Garmin line for some time.

 

During auto-averaging the MEASUREMENT COUNT reflects the number of "Solutions" collected, at the rate of 1 per second.

 

If Satellite reception is lost during the auto-averaging procedure, the COUNT is frozen. If reception is re-acquired the COUNT resumes.

 

I don't know what the max COUNT obtainable is when energized by a Power Cable, but a pair of AA Batteries die before it is reached.

 

During an experiment started with nearly new Batteries, I obtained a COUNT in excess of 30,000 and then changed the Batteries again.

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The idea of averaging is to leave the unit stationary and collect multiple solutions and average them to obtain a better answer. QUOTED from "A GPS User Manual" by Dale DePriest

 

I own a Garmin GPS Map76S. On the Averaging Screen there is a Data Box labled MEASUREMENT COUNT. A Google search tells me this term has been a "Feature" in the Garmin line for some time.

 

During auto-averaging the MEASUREMENT COUNT reflects the number of "Solutions" collected, at the rate of 1 per second.

 

If Satellite reception is lost during the auto-averaging procedure, the COUNT is frozen. If reception is re-acquired the COUNT resumes.

 

I too use a GPSMAP 76s and i know what you are talking about as far as the counter. However, i didnt realize that it was counting the number of "solutions" collected. Just figured it was a timer and i usually stop it when it gets close to 200 and the estimated accuracy has come down. I do use it in the woods alot but ive never noticed it stopping because of a loss of satelite signal though. Very interesting!

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