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Hiding a cache with a smart phone


AW738

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I am wondering if caches that are not even relitively close to GZ may be that way because of smart phones? I have found several caches that were not even close to the location that my Garmin Oregon 550 was pointing to. Most caches are within 10 to 15 feet or less. Could the GPSR in a smart phone be less acurate than a dedicated GPSR?

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It's a matter of debate, more than anything else.

 

What is true however, is that some (not all, by any means) phone geocachers are so enamored by finding the new "sport", they rush to get a hide out there. Three pitfalls to this, 1) they may well have not read any guidelines; 2) they don't really know how to obtain "good" coordinates; 3) as a part of 1) and 2) -- they rush to git 'er done. See the problem?

 

Add to that, they stay with it for a week/month/year and then move on to other things. Their "junk" hide still exists.

 

Those who know and understand how their device works (not just "phones", either) usually make for more accurate placements.

 

BTW, a fourth problem also creeps into the equation -- "cache migration". When a finder 'hides it better than they found it"; the next finder also 'hides it better than they found it" (they haven't a clue where it originally was), and so on and so on.... I think you get the picture.

 

I am not a smart phone user (nor will I say what I think of them -- the phones, not the users), but I do not see phones as being the problem. It's the users.

Edited by Gitchee-Gummee
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I am wondering if caches that are not even relitively close to GZ may be that way because of smart phones? I have found several caches that were not even close to the location that my Garmin Oregon 550 was pointing to. Most caches are within 10 to 15 feet or less. Could the GPSR in a smart phone be less acurate than a dedicated GPSR?

Here is the deal with smartphones

1) Some have good GPSr, some have poor GPSr.

2) Most users do not know when their phone is reporting GPS coordinates vs. cell tower triangulation approximation.

 

If a smartphone user has a phone with a good GPSr, and knows how to tell if it is reporting GPS data (vs cell tower triangulation), they will likely have good coordinates.

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I have a gps but use my smart phone. I use a app called GPS Averaging and seems to work well. But after I get the coords I go home and double check them on Google Earth. Most times they are good but sometimes they are off and I can correct them on google earth. I know this is not the best way but when I am mapping it on my phone it shows where it would be on google earth and has worked out pretty well. Just my thoughts.

-WarNinjas

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I have a gps but use my smart phone. I use a app called GPS Averaging and seems to work well. But after I get the coords I go home and double check them on Google Earth. Most times they are good but sometimes they are off and I can correct them on google earth. I know this is not the best way but when I am mapping it on my phone it shows where it would be on google earth and has worked out pretty well. Just my thoughts.

-WarNinjas

NEVER* use Google Earth, Google Maps, or any other such online map to adjust your coordinates. These maps are simply not consistently accurate enough to be used. Here's an excellent example in my region of why you shouldn't do this. Notice how the roads don't line up with the imagery? They're off by over 200 feet! The Google StreetView data is skewed by the same amount. Closer to home, the Google data is off by 50 feet in one direction. About 30 minutes north it's 20 feet in a different direction.

 

If you have a GPS, then please use it. Your GPS is designed specifically for determining your location. Your phone is designed specifically for communicating with other people, and it can do some other things too.

 

*Clear enough for ya? :laughing:

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Its all depend on the day, weather, and even where the satellites are in the sky. The worse places I see are around buildings and on the north side of a mountain. (south side of a mountain is where the satellites are in the sky)

 

I see smart phone way off and some right on. Same with those fancy GPS as well.

 

The key is, take a reading for like 15 mins and it will avg out, but its still not perfect.

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Its all depend on the day, weather, and even where the satellites are in the sky. The worse places I see are around buildings and on the north side of a mountain. (south side of a mountain is where the satellites are in the sky)

 

I see smart phone way off and some right on. Same with those fancy GPS as well.

 

The key is, take a reading for like 15 mins and it will avg out, but its still not perfect.

I think you are thinking of geo-synchronous satellites. GPS are in a constellation covering the entire globe.

 

One think that I have found with smartphones GPS is that even the accurate ones tend to not be very sensitive ie. not good under tree cover etc.

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It's a matter of debate, more than anything else.

 

What is true however, is that some (not all, by any means) phone geocachers are so enamored by finding the new "sport", they rush to get a hide out there. Three pitfalls to this, 1) they may well have not read any guidelines; 2) they don't really know how to obtain "good" coordinates; 3) as a part of 1) and 2) -- they rush to git 'er done. See the problem?

 

Add to that, they stay with it for a week/month/year and then move on to other things. Their "junk" hide still exists.

 

Those who know and understand how their device works (not just "phones", either) usually make for more accurate placements.

 

BTW, a fourth problem also creeps into the equation -- "cache migration". When a finder 'hides it better than they found it"; the next finder also 'hides it better than they found it" (they haven't a clue where it originally was), and so on and so on.... I think you get the picture.

 

I am not a smart phone user (nor will I say what I think of them -- the phones, not the users), but I do not see phones as being the problem. It's the users.

 

Its all depend on the day, weather, and even where the satellites are in the sky. The worse places I see are around buildings and on the north side of a mountain. (south side of a mountain is where the satellites are in the sky)

 

I see smart phone way off and some right on. Same with those fancy GPS as well.

 

The key is, take a reading for like 15 mins and it will avg out, but its still not perfect.

 

I think the two quoted posts above cover my thoughts.

Inaccurate hides doesn't mean it was a smart phone. I've had days where my Oregon 300 was dead on with my other GPS units, and other times, it was all over the place.

 

A critical item I watch for is the GPS's estimated accuracy. Of my Garmin indicates above 3-4M accuracy, it's going to take some time to place the hide. If I have a 3-4M estimate accuracy, I'll do a couple tests (approach from different directions and/or with a different unit). Some area or days, accurate cords can be tough to acquire. I've had to return a couple times to place a hide because I just couldn't nail down anything remotely accurate. For a couple of my caches, I've had to give better hints as the location just wouldn't give up a satisfactory accuracy. The two caches that come to mind where both along fault lines in a rock face and/or with heavy tree coverage.

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You can accurately place caches with a smart phone, you just need to be careful.

 

Spend a few minutes averaging the co-ordinates. Go back in an hour and repeat. Go back in 6 hours and repeat. Then the next day, maybe three days after and then a week after.

 

This is probably overkill, but your cache will be placed as accurate as it ever can be...

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Older smartphones (iPhone 1-3) have infamously poor accuracy. More recent phones like the Droid series and the iPhone 4 have actual GPS receivers, just like your fancy Garmin.

 

Bad coordinates these days are more often a combination of interference (ex: tree cover) and cachers who are simply lacking proper understanding of their GPS device and its limitations (and also being hasty rather than patient).

 

Locally, we had a cache last year who quickly became notorious for his coords being off. Turned out he was using a Garmin CSx 60, a widely popular and highly regarded GPS device. Problem was he wasn't averaging coordinates or giving the device enough time to settle down and get a good reading. He got some good advice from other cachers with the same GPS, corrected coords on existing caches, and when he hid caches later the accuracy was good.

 

Meanwhile, I've hidden several caches with my Droid. I actually had one experienced cacher say they went for one of my caches to fill a calendar date because they knew the coords would be good. I also got 2nd place with my Droid in a GPS accuracy test at an event; I missed 1st place by inches and beat out dozens of "real" GPS devices.

Edited by Joshism
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What is true however, is that some (not all, by any means) phone geocachers are so enamored by finding the new "sport", they rush to get a hide out there. Three pitfalls to this, 1) they may well have not read any guidelines; 2) they don't really know how to obtain "good" coordinates; 3) as a part of 1) and 2) -- they rush to git 'er done. See the problem?

 

Add to that, they stay with it for a week/month/year and then move on to other things. Their "junk" hide still exists.

 

Those who know and understand how their device works (not just "phones", either) usually make for more accurate placements.

This

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Older smartphones (iPhone 1-3) have infamously poor accuracy. More recent phones like the Droid series and the iPhone 4 have actual GPS receivers, just like your fancy Garmin.

 

Bad coordinates these days are more often a combination of interference (ex: tree cover) and cachers who are simply lacking proper understanding of their GPS device and its limitations (and also being hasty rather than patient).

 

Locally, we had a cache last year who quickly became notorious for his coords being off. Turned out he was using a Garmin CSx 60, a widely popular and highly regarded GPS device. Problem was he wasn't averaging coordinates or giving the device enough time to settle down and get a good reading. He got some good advice from other cachers with the same GPS, corrected coords on existing caches, and when he hid caches later the accuracy was good.

 

Meanwhile, I've hidden several caches with my Droid. I actually had one experienced cacher say they went for one of my caches to fill a calendar date because they knew the coords would be good. I also got 2nd place with my Droid in a GPS accuracy test at an event; I missed 1st place by inches and beat out dozens of "real" GPS devices.

 

I think that one of the bigger errors that one can make while getting coordinates is to stand there with the device in your hand, hovering over it and effectively blocking half of the sky with your body. I set my Garmin to average and then set it on the ground next to the cache and walk away for a few minutes. I have never had anyone have a major issue with the coordinates on any of my caches.

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I think that one of the bigger errors that one can make while getting coordinates is to stand there with the device in your hand, hovering over it and effectively blocking half of the sky with your body. I set my Garmin to average and then set it on the ground next to the cache and walk away for a few minutes. I have never had anyone have a major issue with the coordinates on any of my caches.

 

This is so true. If you are hovering over your GPS your body can easily block half the visible satellites. This would cause your GPS to rely on reflections of those signals being bounced off of nearby objects like trees, boulders, buildings, the ground, etc. The speed of light is about 186,282 miles per second. A delay of even 1 microsecond would make your GPS "think" that that satellite was about 1000 feet further away than it really is. The software in your GPS can handle a couple of whacked out distances in it's calculations but the more bad distances there are the lower your accuracy is going to be.

 

Another issue with phones is that their primary function is as a phone. The antenna for the phone will be put in the spot that gets the best reception. The GPS antenna will not get this spot and, because phones are so small, it will be luck if it isn't just squeezed in wherever it will fit.

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Another issue with phones is that their primary function is as a phone. The antenna for the phone will be put in the spot that gets the best reception. The GPS antenna will not get this spot and, because phones are so small, it will be luck if it isn't just squeezed in wherever it will fit.

This results in a sencitivity issue (not accuracy). Of course, once the GPS signal is attenuated enough that you approach your sencitivity limit, accuracy drops. My Samsung Galaxy SII HD LTE is very accuriate, but not very sencitive. Under tree cover, it can not get updated coordinates. For someone who doesn't pay attention to their equipment, this could result in large errors.

 

It is important to know the limitations of your hardware. No mater what GPSr you use, it will have limitations. Once you know them, you can work around them.

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Another issue with phones is that their primary function is as a phone. The antenna for the phone will be put in the spot that gets the best reception. The GPS antenna will not get this spot and, because phones are so small, it will be luck if it isn't just squeezed in wherever it will fit.

This results in a sencitivity issue (not accuracy). Of course, once the GPS signal is attenuated enough that you approach your sencitivity limit, accuracy drops. My Samsung Galaxy SII HD LTE is very accuriate, but not very sencitive. Under tree cover, it can not get updated coordinates. For someone who doesn't pay attention to their equipment, this could result in large errors.

 

It is important to know the limitations of your hardware. No mater what GPSr you use, it will have limitations. Once you know them, you can work around them.

 

I understand what you are saying but I think you have some technical terms mixed.

 

In GPSr sensitivity and accuracy are related in that a unit with high sensitivity is better at receiving more satellites therefore increasing accuracy. Which as you said isn't the issue with mobile phones that are able to receive the GPS signal.

 

The issue with antenna position is that if the antenna is a location were your hand blocks some of the signals then no amount of sensitivity is going to make a your phone "hear" the signals that aren't strong enough to get to it in the first place.

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Another issue with phones is that their primary function is as a phone. The antenna for the phone will be put in the spot that gets the best reception. The GPS antenna will not get this spot and, because phones are so small, it will be luck if it isn't just squeezed in wherever it will fit.

This results in a sencitivity issue (not accuracy). Of course, once the GPS signal is attenuated enough that you approach your sencitivity limit, accuracy drops. My Samsung Galaxy SII HD LTE is very accuriate, but not very sencitive. Under tree cover, it can not get updated coordinates. For someone who doesn't pay attention to their equipment, this could result in large errors.

 

It is important to know the limitations of your hardware. No mater what GPSr you use, it will have limitations. Once you know them, you can work around them.

 

I understand what you are saying but I think you have some technical terms mixed.

 

In GPSr sensitivity and accuracy are related in that a unit with high sensitivity is better at receiving more satellites therefore increasing accuracy. Which as you said isn't the issue with mobile phones that are able to receive the GPS signal.

 

The issue with antenna position is that if the antenna is a location were your hand blocks some of the signals then no amount of sensitivity is going to make a your phone "hear" the signals that aren't strong enough to get to it in the first place.

Look, I don't want to sound rude, but you are wrong.

 

Even a GPSr with low sensitivity can receive all of the visible satellites (or as many as it's chipset is capable of) given a clear sky and low noise environment. A GPSr with high sensitivity helps you out when there is attenuation. This could be your hand holding your smartphone (my Samsung does not have this problem), tree cover, poor antenna, etc. (apperantly clouds do not attenuate the frequencies used by GPS). What sensitivity will not help with is a high inband noise environment. That will jam your receiver no mater what. (Out of band noise can also jam your receiver if your receiver does not have good out of band filtering). I am not sure why some GPSrs are more accuriate than others. Obviously WAAS and EGNOS dramaticaly improves accuracy. I think that some chipsets are capable of more accuriate calculations than others. Not sure what other factors are involved.... Most GPSr are rated for >3m accuracy (if they have WAAS or EGNOS), but some are 5m. Once they get to 10m or more, that is likely due to no WAAS or EGNOS.

 

Here is an example of a sensitivity calculation. I will compare 2 different GPSrs

Qstarz BT-Q818X: -165 dBm receiver sensitivity (typical for high sensitivity GPSr)

USGlobalSat BT-821: -158 dBm receiver sensitivity (typical for average GPSr)

 

I have read that about -136 dBm of power gets to your antenna given ideal conditions. So as you can see, both GPSrs will work great under normal conditions, having more than 22-29 dB of tolerance. However, the Qstarz GPSr has about 8dB (i.e. 5 times) as much tolerance to unexpected attenuation. This could be your hand holding your smartphone, tree cover, poor antenna, your body, the roof of your car, etc.

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I know someone who was using their smartphone and I asked him where his cache was because I looked all over the anchor.

What anchor he said.

I said the one at your coords.

He said it's not at the anchor it's at the steps.

I said the steps are 60ft away.

He said the FTF had no problem.

I said what were you using?

He said an iphone

I asked what was the FTFer using?

He said an iphone.

DUH!!!!!!! I said

To A Team

I told him to look at GC maps and Google maps. The coords he had were at the anchor my garmin took me to.

The end of the story, he went and bought an Etrex. Most of his coords are better now.

P.S. That FTFer is now having trouble finding his caches because he is using a GPS and not the iphone

I suggested maybe he can put both GPS and iphone coords on.

Moral of the story. Double check your coords. Yes even I have messed up.

Edited by jellis
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Look, I don't want to sound rude, but you are wrong.

 

Even a GPSr with low sensitivity can receive all of the visible satellites (or as many as it's chipset is capable of) given a clear sky and low noise environment. A GPSr with high sensitivity helps you out when there is attenuation. This could be your hand holding your smartphone (my Samsung does not have this problem), tree cover, poor antenna, etc. (apperantly clouds do not attenuate the frequencies used by GPS). What sensitivity will not help with is a high inband noise environment. That will jam your receiver no mater what. (Out of band noise can also jam your receiver if your receiver does not have good out of band filtering). I am not sure why some GPSrs are more accuriate than others. Obviously WAAS and EGNOS dramaticaly improves accuracy. I think that some chipsets are capable of more accuriate calculations than others. Not sure what other factors are involved.... Most GPSr are rated for >3m accuracy (if they have WAAS or EGNOS), but some are 5m. Once they get to 10m or more, that is likely due to no WAAS or EGNOS.

 

Here is an example of a sensitivity calculation. I will compare 2 different GPSrs

Qstarz BT-Q818X: -165 dBm receiver sensitivity (typical for high sensitivity GPSr)

USGlobalSat BT-821: -158 dBm receiver sensitivity (typical for average GPSr)

 

I have read that about -136 dBm of power gets to your antenna given ideal conditions. So as you can see, both GPSrs will work great under normal conditions, having more than 22-29 dB of tolerance. However, the Qstarz GPSr has about 8dB (i.e. 5 times) as much tolerance to unexpected attenuation. This could be your hand holding your smartphone, tree cover, poor antenna, your body, the roof of your car, etc.

 

Sensitivity isn't a measurement of received signal strength. It is a measurement of signal to noise. The noise isn't environmental noise. It is noise that is generated by the amplifier in the receiver itself.

 

A quieter (aka more sensitive) receiver will help with the reception of weak signals, most notably from satellites that are located near the horizon. It does not do a good job correcting for poor antenna placement or environmental noise.

 

All things being equal, except antenna placement, the GPS/phone/device with the better antenna placement will be more accurate. This is because the other devices will not receive as many satellites and be subject to poor constellation geometry and may also be subject to more multipath signals.

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I've been using my iphone to find geocaches since I first started hunting. Most of the time my phone takes me to the right spot. Occasionally I'm looking in the wrong area, but I accept that could be due to a number of things. Most of my finds though are in mainly clear areas, I haven't gone searching for caches in thick woods, that certainly would make a big difference!!!

 

You have to know your device, it's limitations, and what you can do to improve and work with it. I certainly wouldn't use my iphone to hide a cache in the woods for example, but I have used it accurately to hide caches in more open areas.

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I had a friend who was caching with her I-phone.

She started placing caches with her phone. When a lot of people complained she asked that I go out with her and check them. One was over 100 feet off.

She went out and got a GPS after that.

 

There is another story about someone who was trying to place a cache.

They changed the coords about 20 times before the reviewer told them to get a GPS or find someone with a GPS to help with the coords. They were using Google Earth. The cache finally was archived. No one was ever able to find it.

 

Now, all that being said, the first is an old story, so perhaps phones are more accurate now.

And you've got to use a device correctly AND it turns out, have fresh batteries.

 

I moved a cache to a better location and took new coords. The batteries were about to go out in my good GPS. I waypoint averaged, and the coords turned out to be 100 feet off!!!!! Yowsa. This thing is normally really good!!! I went back with fresh batteries and got the EXACT same coords as someone else (who I had given directions to the cache to see if the problem was me or him).

 

There's nothing better to hide a cache than a GPS, and you've got to use it correctly and have good batteries in it that are not near the end of their life.

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