Help With Gps Locating Caches Accurately

[+PetsAllOver]

Hey everyone. I am new to geocaching. My hubby and I have found 3 caches so far. We have a Dell Axim with a Holux 270 GPS and we are trying Mapopolis and Vito II Navigator.

 

The problem we are having with the GPS is when we get close to the cache we have a lot of jumping around. It will say it is 50 feet then 6 then 25 feet the other direction. It is hard to pinpoint a smaller search area.

 

Here are my questions:

 

Is there a way to better pinpoint the search area? I hear people talking about averaging but I could not find anywhere it was talked about.

 

How close should you be able to get with your GPS? I mean at one place today we were all over the place...probably at least a 100 foot area.

 

Would a different GPS be better? Or is there something we need to learn to do better?

 

We have found 3 and looked for 7. Is that a good number for beginners?

 

Thanks for any help you can provide. We enjoy the hiking and the parks...but we would like to find more!

[+webscouter.]

Most dedicated GPS units will get you within about 20 feet reliably. I don't know what kind of antenna your unit has but I would guess that it is a patch antenna. These don't have the sensitivity that a quad helix antenna or even one of the newer patch antennas have.

 

Also you should be using a goto arrow that only shows direction and distance from the cache. It sounds like you are trying to use the coords. This tends to be very difficult as lots of times you can see the potential hide spots from a distance if you are looking towards were an arrow is pointing.

 

Overall it sounds like you are doing pretty good with the unit you have but you could improve your find rate significantly by getting a dedicated GPS.

 

Personally I recommend the Garman E-trex line if you want to use it only for Geocaching. Lots of Geocaches have been found by cachers using the Yellow E-trex. However you will want a cable and lots of times you can find a Legend for about the same price as a yellow with a cable and it already comes with the cable.

 

If you think you might like the GPS for other uses in addition to caching I would recommend something like the GPS60C. The color is really easy to see and the navigation features are wonderful. They also tend to retain there resale value if you decide you don't like geocaching and don't use it for other reasons. (Like that would ever happen.)

[+Kai Team]

The problem with the direction jumping around as you get close to the cache is normal. It's caused by the fact that the GPS requires movement to tell which direction you're facing (if you're standing still or moving very slowly, the GPS knows where you are, but not which way you're facing - i.e. your heading relative to the cache coordinates).

 

There are a couple of ways to address this:

 

1) carry a magnetic compass and, when the GPS is still giving you a good bearing, site with the magnetic compass and use it to guide you in close to the cache.

 

2) Purchase a GPS receiver with an electronic compass built in - such as the Garmin eTrex Vista or the Garmin 60CS. On those units, when your speed drops below a certain level, the electronic compass automatically takes over and maintains a correct bearing (since it knows which way you're facing by referencing magnetic north).

 

Distance usually jumps around less than direction unless you're getting interference with the satellite signals. Interference can be caused by conditions in the ionosphere, tree cover, cloud cover, nearby cliffs or hills (which bounce the satellite signals), or picking up satellites that are too close to the horizon.

 

Contrary to popular opinion, a quad helix antenna is not inherently more accurate than a patch antenna - each has its strengths and weaknesses, under different conditions. Accuracy is generally 30-40 feet without WAAS (an augmentation system available on some GPS receivers, including the Vista and the 60 CS) and 7-20 feet with WAAS.

Edited May 22, 2005 by Kai Team

[+ZingerHead]

The GPS behavior you describe is perfectly normal. The signals from the satellites can be reflected off nearby surfaces such as cliffs or buildings, or the arrangement of the satellites in the sky (the "constellation") might have the satellites bunched together which can reduce accuracy on the ground. You might be under heavy tree cover, which reduces signal strength.

The advice about a compass is good if the problem is poor GPS reception in the immediate area of the cache. But if the problem is that the GPS is leading you straight to the cache location, but once there it starts getting loopy, then my suggestion is to put the GPS away at that point, because it's done its job. Figure a 30 foot diameter circle around "ground zero" is normal, 50' is not that unusual, and at 100' there might be a problem with the coordinates. I will usually follow the GPS until I'm close, wait a bit for it to settle, then plant my pack at the "zero" location and start looking. Your best bet is to pay less attention to the GPS, and more attention to the little clues that might give you an idea as to where the cache is located. Start with "where is there room around here to hide a cache?". Is there anything "out of place", like an unnaturally neat stack of logs, or a hollow tree with a suspiciously fresh pile of leaves inside it?

As far as following the arrow, I've become accustomed to caching with the map display. With my location pinpointed on the screen I can orient myself to features on the map and ignore the arrow, which usually doesn't update its position as often as I'd like when I'm closing in on the hide.

I'd also be sure to hunt "easy" caches, rated 2/2 or lower, to get practice with different hiding techniques. Steer clear of micro caches for a while. Micros are more challenging simply because the number of possible hiding places for a film canister is much much greater than for an ammo box .

Finally, if there is a geocaching event coming up in your area, go! You'll meet a lot of great people and you can cache with a group and see how everyone else does it.

[+Chuy!]

I have no idea what set up you have, but see if this will work:

 

When within 50 or so feet of the cache, look at the your computer's coordinates' display and move around until it matches the cache coordinates.

 

I resorted to this once with a Garmin Streetpilot III, which is a dashboard auto-routing GPS with no arrow and the maps go down only to 120 feet. But it has batteries for backup and I took this brick size GPS to the field and it put me within five feet of the cache!

[+briansnat]

When within 50 or so feet of the cache, look at the your computer's coordinates' display and move around until it matches the cache coordinates.

 

This can be a difficult, time consuming and (depending on your reception) a nearly imposible task. Instead, when you're down to around 40-50 feet just put your GPS away and start looking. If you still haven't found it after about 10-15 minutes, go back to your GPS and see if anything has changed. Sometimes it may be showing an entirely different spot.

 

You can take the GPS, back off and approach the area again or make a big circle and see where the navigation needle points to most consistently. Once you think you've pinpointed the location, start searching again.

[+Team Cotati]

Hey everyone.  I am new to geocaching.  My hubby and I have found 3 caches so far.  We have a Dell Axim with a Holux 270 GPS and we are trying Mapopolis and Vito II Navigator.

 

The problem we are having with the GPS is when we get close to the cache we have a lot of jumping around.  It will say it is 50 feet then 6 then 25 feet the other direction.  It is hard to pinpoint a smaller search area.

 

Here are my questions:

 

Is there a way to better pinpoint the search area?  I hear people talking about averaging but I could not find anywhere it was talked about.

 

How close should you be able to get with your GPS?  I mean at one place today we were  all over the place...probably at least a 100 foot area.

 

Would a different GPS be better?  Or is there something we need to learn to do better?

 

We have found 3 and looked for 7.  Is that a good number for beginners? 

 

Thanks for any help you can provide.  We enjoy the hiking and the parks...but we would like to find more!   

Unless there are obvious obstructions to account for this 'jumping around' there is no technical reason for the GPSr to behave differently when near a cache location as opposed to when standing in your backyard.

 

This consistient jumping around that seems to occur only when you are near a cache location is suspicious.

 

If this behavior continues you might want to checkout your unit. One way to do this might be to locate a local caching buddy and compare the performance between their unit and yours. Otherwise barring some other obvious causes your unit would be suspect.

Edited May 23, 2005 by Team cotati697

[+DaveA]

The problem we are having with the GPS is when we get close to the cache we have a lot of jumping around. It will say it is 50 feet then 6 then 25 feet the other direction. It is hard to pinpoint a smaller search area.

 

First, find out if your unit is WAAS capable. If it isn't then you are getting about as close as you can expect to the cache before the distance to the cache is closer than the positional error of your unit which results in the jumping around.

 

If you have WAAS on then you should be able to get closer in most cases before the jumping around begins. Around 20 ft or less most of the time with 30 ft out sometimes.

 

When I want to get my search field narrowed down as much as possible I generally stop moving when I am within 100ft and let the unit average awhile. Averaging in this case just means to let the unit average out the positions it is calculating. Most units update once per second so if you sit still for one minute you will have 60 coordinates averaged out which usually results in a better coordinate. From here I look in the direction the gps indicates and guestimate where the spot is based upon the distance the gps indicates. Then I go in another 50 ft and repeat. If I am still being sent to the same general area then I consider the position to likely be very accurate. If I am being directed elsewhere I might try and approach from a different direction and focus on the area where the two paths cross.

 

When I close in to begin the actual search I usually walk slowly toward the spot until such time as the position starts jumping around. At that point I turn my unit off, turn it back on and go look for the cache while the unit just sits there averaging. If I don't find the cache in a reasonable time then I go back to the unit and see what it indicates. for the direction and distance. It is very rare I have to turn the unit off and on, but it has helped at times.

[tossedsalad]

As a relatively new geocacher myself, let me add my two cents worth. I was also puzzled by the odd inconsistency in locating coordinates by my friend's Garmin eTrex. When in the open where there were no trees or other cover the unit would often get to within 5 feet or so of the location. But when under trees the unit would update sluggishly resulting in our search overshooting the location. I have been paying attention to the satellite status screen on the unit and I think this is because of the weakened signals under the trees. We can still pick up four or more satellites, but some seem to fade in and out. I believe this results in the unit having to resync to the satellites that have faded in which results in delays in the update. Sometimes I can walk 50 feet without an update in the location. This is worse with denser cover.

 

Are your problems when you are in woods or other tree cover?

[+AtoZ]

Well there are a lot of thing to consider. But the distance to location should NOT jump around to much. Since your using a PDA?GPS I might assume your also using it for in car navigation. If this is the case then go to the set up screen that allows you to change from CAR/Motorcycle to Pedestrian. I have a Garmin cfQue and use it for incar nav but going for the cache it has to wide a circle on it to function but if you change from car to pedestrian then it works better.

cheers

[+PetsAllOver]

Wow...thanks for all the replies...let's see...Here are the answers to most of the questions you all asked.

 

One of the areas we have had the hardest time with was tree covered...so that makes sense that that would be an issue. My hubby mentioned that too.

 

We are not using it really for car navigation...we both have handhelds and the $50 Holux seemed a good way to start trying it out without spending a whole bunch up front.

 

I think the basic issue is when we slow down. While we are walking through the parks it updates pretty quickly...it is when we stop to locate the cache that we start having problems.

 

We will try y'alls suggestions the next time we go out. My hubby is also going to go to GeoWoodstock III this next weekend while I am out of town so he can also check out other people's GPS' and see how different ours is.

 

I understand the concept of getting in the general direction and then looking. I guess our "Force" just isn't sharp enough yet. Although the 3 that we have found were a 1.5, a 2 difficulty and a micro. The ones in the woods are killing us though!

 

But it is so fun..I dreamt about it last night...I am hooked. I appreciate all your ideas and suggestions and I will try them out. Thanks.

[+Miragee]

. . . But it is so fun..I dreamt about it last night...I am hooked.  I appreciate all your ideas and suggestions and I will try them out.  Thanks.

Oh, I'm so glad to know I'm not alone. I've had some sort of Geocaching dream every night for the past four months, ever since I found my first cache January 17th . . .