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GPS Sensitivity (Droid)


think1
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First day geocacher, first day poster.

 

I probably should just give it more time, but today was the first day I took my daughters out geocaching and we got very frustrated.

 

I used a Motorola Droid to find a geocache near a river and it would point North 6yds and I would take two steps and then it would point South 10yds and then it would point West 3yds into the river! We never did find it. Of course being the Dad I didn't want to give up, but my daughters just started complaining that it wasn't fun any more.

 

I read the logs of the people who found it and they all said, "Great coordinates, pointed right to it, found it right away!" Being a guy, I don't usually ask for directions, but I have to ask:Is my experience normal?

 

Do I need a better GPS? I checked the reviews of the Droid on this site and they were pretty high. Would it make a difference if I got a real GPS device or do they all have about the same level of sensitivity? To show my GPS ignorance further, does it matter the time of day? season? weather? Is there something I can do to help with the accuracy (aluminum foil on my head)?

 

We did find 2 geocaches today and neither were at "0". We also had 2 we couldn't find. Maybe the problem has nothing to do with the GPS and more to do with the operator?

 

I thank you and my daughters thank you.

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I haven't used a droid, but I did cache with a friend and who used an iPhone and it took a while to lock on to a location. I'd be at GZ with my Garmin GPS and he'd be wandering around 50-60 feet off coords. Droid may be better, but I'd bet that nothing beats a dedicated handheld GPS device.

 

Either way, caches are very very rarely located right where your GPS says '0' is. When I first started I thought that I'd get to the coords and the cache would be right down at my foot. It doesn't work that way. All devices have a margin of error. My Garmin usually says +-9 feet on a clear day. Get under tree cover and it can fluxuate up to +-20 feet. With the margin of error for your device and the device of the cache owner, it's typical that you'll find caches anywhere between 5-25 feet from '0' (depending on tree cover, etc).

 

The best advice is to get your unit to '0' and then put it away and start looking around for potential hiding spots. Expand a little bit. Maybe send one daughter to a check a spot 15 feet to the East, one to check 15 feet to the West, etc.

 

Also, since you're just starting out, take a look at the top of the cache pages and find regular sized caches with low difficulty levels. Searching for a microcache that is rated a 4 star difficulty may even take the most experienced cachers hours to find. I wouldn't bother with those. Go for a size of "small" or greater and a difficulty less than 2 and your chances of making the find and getting the smiley will rise.

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My husband and I were just doing some experiments on this very question yesterday, so I feel in a good place to answer.

 

I have a Garmin eTrex Venture HC, and my husband uses a Droid Eris loaded with GeoBeagle.

 

Yesterday was a perfect example of the differences, since we crossed a large, open field on a clear sunny day, into a lightly wooded area.

 

Out in the field, we were both picking up about seven satelites. The Droid was much more sensative to turns (the Garmin lags terribly if you're just turning in place). Once we started geting under some tree cover, I lost one or two of my satelites, and he went down to bouncing between three and four - and this was on a clear day.

 

After some more experiments in the car and house, we decided that the Garmin must have a much more sensative GPS reciever - it's noticibly more able to pick up the signal.

 

That doesn't mean the Droid doesn't have its benefits. For one, it allows us to do paperless caching, and on-the-fly caching (for example, yesterday after we had done the ones we had planned on, we used the Droid to find a few more to do. I couldn't have done this on my own). The Droid is also fine when you're in an area with minimal overhad interference, which is true for many urban caches.

 

But, when you're in an area with overhead interference, be aware that you're going to be picking up fewer satelites, and thus be less accurate.

 

As far as the arrow bouncing around once you get in close - that's just the nature of GPSrs. Remember, the satelites are hurtling through space at thousands of miles per hour, and you're not using a device that's optimized for detecting and processing those signals. So, if you're down to two or three satelites, your Droid is going to be getting some mixed signals, and have some lag. You may need to try to slow down, give it some time to recalibrate, and try again (Also, walking ~20 PAST where it says GZ is, then walking back can help).

 

All that being said... nothing beats what simpjkee said - your GPSr has margin of error, and the owner's GPSr had a margin of error, so there's a point where you just need to work on developing your geosense. I've only got ~25 finds, so I can't say I'm a master, but after my first DNFs, I spent some time stepping back slowly looking around (without searching - just looking and enjoying the view), and thinking about what good spots would be. Are there tree roots sticking out? Does that fence over there have a gap in the inderside? Do the caps easily come off those posts? Has someone piled some rocks up against a tree? Take stock of the size of container you're looking for (as simpjekee said, larger size ones are going to be much easier), or try doing a few Earthcaches (That's what I started with - much easier, and gets you the feel of using your GPSr, with an easy way to use your brain and eyes as a backup). Also, it's ok to read hints and other logs.

 

The biggest piece of advice I'd give though? Try again! Almost everyone had several DNFs their first few times out! It gets exponentially easier as you go.

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First day geocacher, first day poster.

 

I probably should just give it more time, but today was the first day I took my daughters out geocaching and we got very frustrated.

 

I used a Motorola Droid to find a geocache near a river and it would point North 6yds and I would take two steps and then it would point South 10yds and then it would point West 3yds into the river! We never did find it. Of course being the Dad I didn't want to give up, but my daughters just started complaining that it wasn't fun any more.

 

I read the logs of the people who found it and they all said, "Great coordinates, pointed right to it, found it right away!" Being a guy, I don't usually ask for directions, but I have to ask:Is my experience normal?

 

Do I need a better GPS? I checked the reviews of the Droid on this site and they were pretty high. Would it make a difference if I got a real GPS device or do they all have about the same level of sensitivity? To show my GPS ignorance further, does it matter the time of day? season? weather? Is there something I can do to help with the accuracy (aluminum foil on my head)?

 

We did find 2 geocaches today and neither were at "0". We also had 2 we couldn't find. Maybe the problem has nothing to do with the GPS and more to do with the operator?

 

I thank you and my daughters thank you.

My iPhone did the same thing yesterday on our first hunt. It wasn't has bad on the next four that we did find for some reason. It did take some time to update after moving, so you may need to just stand still for a minute after moving. I'm going to get a true GPSr and just use my iPhone for paperless or for a quick unplanned hunt when we are out.

Edited by EddieB606
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My husband and I were just doing some experiments on this very question yesterday, so I feel in a good place to answer.

 

I have a Garmin eTrex Venture HC, and my husband uses a Droid Eris loaded with GeoBeagle.

 

Yesterday was a perfect example of the differences, since we crossed a large, open field on a clear sunny day, into a lightly wooded area.

 

Out in the field, we were both picking up about seven satelites. The Droid was much more sensative to turns (the Garmin lags terribly if you're just turning in place). Once we started geting under some tree cover, I lost one or two of my satelites, and he went down to bouncing between three and four - and this was on a clear day.

 

After some more experiments in the car and house, we decided that the Garmin must have a much more sensative GPS reciever - it's noticibly more able to pick up the signal.

 

That doesn't mean the Droid doesn't have its benefits. For one, it allows us to do paperless caching, and on-the-fly caching (for example, yesterday after we had done the ones we had planned on, we used the Droid to find a few more to do. I couldn't have done this on my own). The Droid is also fine when you're in an area with minimal overhad interference, which is true for many urban caches.

 

But, when you're in an area with overhead interference, be aware that you're going to be picking up fewer satelites, and thus be less accurate.

 

As far as the arrow bouncing around once you get in close - that's just the nature of GPSrs. Remember, the satelites are hurtling through space at thousands of miles per hour, and you're not using a device that's optimized for detecting and processing those signals. So, if you're down to two or three satelites, your Droid is going to be getting some mixed signals, and have some lag. You may need to try to slow down, give it some time to recalibrate, and try again (Also, walking ~20 PAST where it says GZ is, then walking back can help).

 

All that being said... nothing beats what simpjkee said - your GPSr has margin of error, and the owner's GPSr had a margin of error, so there's a point where you just need to work on developing your geosense. I've only got ~25 finds, so I can't say I'm a master, but after my first DNFs, I spent some time stepping back slowly looking around (without searching - just looking and enjoying the view), and thinking about what good spots would be. Are there tree roots sticking out? Does that fence over there have a gap in the inderside? Do the caps easily come off those posts? Has someone piled some rocks up against a tree? Take stock of the size of container you're looking for (as simpjekee said, larger size ones are going to be much easier), or try doing a few Earthcaches (That's what I started with - much easier, and gets you the feel of using your GPSr, with an easy way to use your brain and eyes as a backup). Also, it's ok to read hints and other logs.

 

The biggest piece of advice I'd give though? Try again! Almost everyone had several DNFs their first few times out! It gets exponentially easier as you go.

Sehmke, did you get your Garmin locally? I'm in the Lexington area and that's the model I'm looking for, but haven't found one yet, haven't tried Dick's Sporting Goods yet, they have one online, but I live in the boonies on a gravel road and UPS won't deliver to the house. LOL. May have to have it shipped to a friends house instead.

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Sehmke, did you get your Garmin locally? I'm in the Lexington area and that's the model I'm looking for, but haven't found one yet, haven't tried Dick's Sporting Goods yet, they have one online, but I live in the boonies on a gravel road and UPS won't deliver to the house. LOL. May have to have it shipped to a friends house instead.

 

EddieB606, I actually recieved mine for Christmas from my in-laws, who live in Dayton, OH. I'm 98% sure they ordered it off Amazon, sorry. I'm pretty sure they looked around and decided Amazon had the best price by a fair margin.

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I use a Droid along with my Garmin, mostly for the paperless aspect. However, I can speak to the GeoBeagle/Droid issues a bit, because I've used it that way, too.

 

First thing you want to do is to look up an app in the Market called 'GPS Status' by EclipSim. It's free, get it. It will provide you a better compass for GeoBeagle- once you're navigating to the cache, just tap the compass and it'll pop over to the GPS Status compass with the cache as the target point.

 

On there, you'll see a notation to the lower left of the compass that says 'Error'. To the lower right is 'Dist'. Once your distance to the cache is at or lower than the error, just put the Droid away- you're within the error radius, and watching the compass spin just just a good way to annoy yourself. Consider 'Ground Zero' to be an area about twice the size of the error you're getting, and just look for it. Between the error you get (and there's always some), and the error the original hider had, you could be a bit of a distance off. The challenge of caching is that last few feet, where technology leaves off, and your senses kick in.

 

The Droid is a pretty good GPS, but it doesn't have the antenna that a dedicated machine has, nor the battery life. I like mine as a phone, and as the paperless caching tool, but it's not really a full-on replacement, as I see it. If I weren't out for six-eight hours at a time in the rain, it might work, though. :D

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I use a Motorola clic for my main gps. Its a little squirrelly now and then but its pretty accurate. I would suggest using the application ++deleted by mod+++. The app is free and works like a charm just don't trust the compass to take you use the map option once you get close. Happy hunting.

Edited by briansnat
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I use a Motorola clic for my main gps. Its a little squirrelly now and then but its pretty accurate. I would suggest using the application ++deleted by mod++. The app is free and works like a charm just don't trust the compass to take you use the map option once you get close. Happy hunting.

The mods hate when you mention p:trb. In another thread (All the android threads are spread about, there should be one central forum IMHO) the mod told us it's a violation, it automates the data collection process. You should edit it out before they do. I hate the censorship too but it's Groundspeak's turf.

Edited by briansnat
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As others have stated, every GPS related item has an approximate area.

 

Some are able to use WAAS correction for much more accurate locations. Most of the units that have this capability, also have the option to turn it on or off, or at least has it listed in the specs. If there is no mention of WAAS then your unit likely does not have that capability since it takes extra chips and processing. Just because it is out there does not mean your unit has that capability.

 

I have a Garmin StreetPilot c330 and a Bushnell onix200CR, both have WAAS capabilities. Some older eTrex units do not but many newer ones do have the option. That setting on most Garmin units (including nuvi automotive and handheld etrex) defaults to off, so you will need to turn it on to get better accuracy.

 

With most modern GPS setups, it falls under one of these 2 areas:

 

3-5 meters (9.8 to 16.4ft): Typical differential GPS (DGPS) position accuracy.

< 3 meters (under 9.5 ft): Typical GPS + WAAS position accuracy.

 

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So a unit without WAAS correction, and/or has poor reception in trees, it may be within a 20 foot diameter of the listed coordinates.

 

Also not all are on the ground... my first was actually about 6 1/2 feet up and I was expecting it to be on the ground. Luckily I am 6'5" so it was around eye level once I knew what to look for (when I went back after looking at clues).

Edited by screwballl
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I use my Droid as I'm just starting out and have other things to spend my money on right now. Make sure the GPS is turned on so you are not using just cell towers. I am using an app called **deleted by mod** and it asked me to install Radar and I did. On most of my finds (I'm only at 26 so far), it's lead me directly to the spot. It bounces around a little bit under heavy tree cover. So far, it's been a great app and seems to be pretty accurate.

 

The only thing I'd like to see is the ability to pick up and drop off Trackables. Does anyone know if that will be a feature of the Droid app from geocaching.com?

Edited by briansnat
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I'm still a noob cacher, but I thought I would chime in with my recent experience. I just used my Motorola Droid today in a heavily wooded area for the first time. I went caching with my son today in the Florida Caverns State Park. Yes, the GPSr on board the Motorola Droid does suffer from signal loss under heavy tree cover. One of the Android apps I use gives a full appraisal of the GPS status to include number of satellite signals, signal strength and more. The signal did drop appreciably under the trees. I also experienced the "jumping" ground zero.

 

Just to clarify, the Motorola Droid shouldn't be confused with the Droid Eris or Droid Incredible both built by HTC. I know, Verizon sure doesn't make things easy by calling all their Android phones "Droids". My point being that the different hardware is bound to give different results of performance. I think under unobstructed skies, the Motorola Droid is hard to beat in accuracy. All of my urban (and suburban) caching has been really successful with accuracies of better than 3-4 yards. I fully intend on investing in a good high-sensitivity GPSr for the wooded areas. Happy caching all! :)

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I use a Sony-Ericsson Xperia (X10) android phone and I often find the same thing however, I agree with what someone above was saying about the "error" level.

 

I mainly use two applications for paperless: one talks with the geocaching.com website to get information, hints, descriptions, post logs, etc... and the other one, like you, I use for so called "off-line" paperless geocaching.

 

With both apps (or the other ones i've installed), the error level (the plus or minus accuracy) of the GPS/GPS+Network will go up and down. I suspect this is the case with most non-dedicated gps devices or even real gps devices. (There are a lot of cache descriptions saying things like "the tall buildings can throw off your GPSr", etc..)

 

However, keeping an eye on the error/accuracy indicators really helps a lot.

If the GPSr told me exactly where to look in only a 1 meter (3ft) radius, there wouldn't much actual "searching" involved. Switching between compasses using GPS bearings and the magnetic compass bearing in my device helps a lot along with making use of the mapping features.

 

In the worst case, they get me within 15-20 meters of the cache, where the search fun can begin. :ph34r:

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