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accuracy & reception of smartphone vs. GPS handheld device


moi!
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Hello everyone.

 

I'm pretty new to geocaching and plan to buy myself a GPS device. I've already read dozens of info pages both on forums and company webpages. At the moment (!) for me it breaks down to a "simple" question: smartphone or handheld GPS device. I already read threads in this forum about that but most of the times it was pro and contra about battery life, when you're all alone in the outback, paperless caching and things like these.

 

What I'm interested in is opinions (and if available experiences) on accuracy and reception of these devices.

 

Accuracy: On the one hand (good) GPS handhelds can receive WAAS and therefore increase in accuracy. On the other hand mobile phones could additionally use radio cell information (if available). Which of these are better in terms of more exact? And are there mobile phones which can receive WAAS, too?

 

GPS reception: I could think of that GPS handhelds might have better antennas for receiving satellite signals than cell phones have. But actually I have borrowed an old etrex and I really struggle with the GPS fix. Even in urban sparse little woods the GPS fix breaks down easily. Which in turn might favor the radio cell version (if there are any). Do you have experiences on that?

 

So if you could help me with these questions and tell me which are better in the field you would really help me coming to a decision.

Thanks to all in advance. :)

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if you already have a smartphone usable for geocaching, then it makes perfect to use it for that, at least for getting started. you may then soon learn about its limitations and either learn to live with them, or want to upgrade to a handheld.

 

reception and accuracy will pretty much definitely be better with a handheld. the old etrex didn't have a "high sensitivity" receiver, which is why you were seeing the problems with the GPS fix. all modern models (etrex H for example) have that though and are able to retain a good quality fix even under pretty bad conditions. of course the better smartphones also have high sensitivity GPS chips, but the integrated antennas will invariably be worse quality and are thus more likely to lose reception from the satellites.

 

smartphones don't use cell information for added location accuracy. they use either GPS or cell information. locations gathered from cell info are always much much worse quality than any GPS fix, so it makes no sense to use that information to try to improve the GPS location.

 

i don't know if current smartphones are able to receive WAAS and have that option enabled too. it would make sense if they don't receive WAAS but instead get the DGPS data off the cell data network, but i don't know if they actually do that - that's just an empty suspicion from my side. in any case, even if the smartphone receives WAAS, the smaller antenna used will make it harder to get a good WAAS lock, especially if you're further up north. on the other hand, if they do get the DGPS data from the data network, then they have an advantage there over handhelds (as long as you're within cell coverage).

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Yeah your question is too general, too vague.. Comparing "every dedicated GPSr" against "every smartphone" is pointless, as the best smartphone accuracy probably is better than the worst dedicated GPSr. But what does that mean?

 

Besides, extreme smartphone accuracy isn't really a concern for most phone manufacturers, as probably +95% of smartphone users aren't trying to find micro Geocaches under heavy tree cover, they're looking for the nearest Starbucks :laughing: and even the worst Smartphone accuracy can handle that task easy.

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Well i have an HTC HD2 and its spot on for the locations i've hidden my caches at. I haven't had an chance to put it to the test searching but i know it works fine.. I have a good friend who uses the HTC HD2 aswell.

 

Even when your signal isn't uptp scratch you could always connect the phones bluetooth to the GPS's if your GPS has a bluetooth. That way you can get the benefit of the smartphones apps and interface aswell as the GPS's accuracy outside of the urban jungles. Shove your GPS in your pocket and just piggyback of the bluetooth connection.

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also keep in mind that WAAS is meant for aviation.. and really is only useful for open land, air and marine use.. up here in the Pacific Northwest, WAAS is useless unless flying or on water and it just slows down your unit significantly when attempting to lock in

not sure where you get that from. WAAS is working perfectly fine for me, even in the woods. but you're further up north, so that makes it harder for you. doesn't mean it's bad though. it definitely doesn't slow anything down.

Edited by dfx
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I have not used a handheld much, so can't comment on that much. I have a smart phone, and use it all the time. It is very accuriate in cell phone coverage area. That is due to the A-GPS (it uses a Qualcomm GPSOne chipset). It is not super sencitive though, and has the anoying static navigatoin feature.

 

However, for seriouse geocaching (including back country caching) I use a bluetooth GPS. It is 2x as sensitive as the SiRF chipsets (-165dBm) in all the handhelds, and just as accuriate.

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thank you for your replies.

I thought of more or less up-to-date models, like HTC Desire or HD2, iPhone, Samsung Galaxy, Garmin 60/62, Dakota, Oregon, .....

 

extreme smartphone accuracy isn't really a concern for most phone manufacturers

that's exactly the reason why I ask for experience with these devices :laughing:

 

Now, can someone tell me about the comparison of A-GPS and WAAS ?

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also keep in mind that WAAS is meant for aviation.. and really is only useful for open land, air and marine use.. up here in the Pacific Northwest, WAAS is useless unless flying or on water and it just slows down your unit significantly when attempting to lock in

not sure where you get that from. WAAS is working perfectly fine for me, even in the woods. but you're further up north, so that makes it harder for you. doesn't mean it's bad though. it definitely doesn't slow anything down.

 

which part?

 

from Garmin's FAQ page on WAAS

 

"For some users in the U.S., the position of the satellites over the equator makes it difficult to receive the signals when trees or mountains obstruct the view of the horizon. WAAS signal reception is ideal for open land and marine applications."

 

If your not noticing any slowness with WAAS, your probably in some pretty flat terrain with no pathing issues or anything to block the signals. The reason WAAS is slower is because once a WAAS satellite is locked, it takes a few seconds (sometimes up to 30 seconds or longer in my experience) for the GPS receiver to download enough data to be useful. And often when the signal to the WAAS satellite degrades, the unit will switch over to a GEO-SV, while at the same time attempt to reestablish a connection with the WAAS, and when this happens over and over, it makes for some difficult caching. This process also sucks up more power as well by the way because of the constant attempts of your unit lock, and stay locked onto the WAAS satellites.

 

I'm not saying don't use WAAS, it's great when it works, but for me, because of the lag time due to the terrain where I cache, and additional power requirements I simply leave it disabled.. and still find 98% of all caches I search for..

Edited by robdogg
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thank you for your replies.

I thought of more or less up-to-date models, like HTC Desire or HD2, iPhone, Samsung Galaxy, Garmin 60/62, Dakota, Oregon, .....

 

extreme smartphone accuracy isn't really a concern for most phone manufacturers

that's exactly the reason why I ask for experience with these devices :laughing:

 

Now, can someone tell me about the comparison of A-GPS and WAAS ?

Those 2 things aren't related, aren't comparable.

 

A-GPS is a process used by many smartphones to find your "general location" quickly by triangulating on the cell towers it is currently using. This will get you to wihin a few blocks of accuracy. A-GPS is also handy if you're inside a mall or other area where satellite GPS reception doesn't work.

 

WAAS is what GPS receivers use to increase satellite GPS accuracy. It's a long winded explanation, much easier for you to google "what is WAAS" than for me to get typing cramps :(

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I'm not saying don't use WAAS, it's great when it works, but for me, because of the lag time due to the terrain where I cache, and additional power requirements I simply leave it disabled.. and still find 98% of all caches I search for..

it's already been refuted that the "additional power requirements" are any real issue. i still don't know where you get the "lag" part from. maybe your GPSr behaves like that, but i've never seen any of mine behave that way. if i have a WAAS lock then i have a WAAS lock, and if i don't then i just don't. there's no negative effects of the GPS chip trying to lock onto one of the WAAS signals.

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