Accuracy of Smartphone GPS

[S.Bartfast]

I have tried many phones over the years and currently have a Samsung Galaxy S7 Edge but every device I've tried has on the whole given rather unreliable GPS performance.

All the phone's I used claim to have an accuracy in the order of 10m or so, and they always show an accuracy metric which typically bounce around between say 5m and 15m, with aprox. 8m being typical.  This all seems well and good as an accuracy of 10m or so would be perfectly acceptable however typically the device will say it's 30m in that direction, then it will jump to 30m in another, bounding all over the place.  Some times it will drop way down to 1.5m then head out to 25 without my moving (all with a reported accuracy of 8m).  I understand issues regarding atmospheric interference and such but when it says I'm say 70m away I'll often look at my phone and walk 25 paces expecting the distance to reduce with every step (or if not every step every few) but more often than not I can walk the full 25 paces and my reported distance won't have budged, or will only drop by 5m or so.  Often then, when I stop and stand still, the distance will continue to drop as though I am still walking.  I get that it is probably averaging readings to smooth out jitters but the lag can be so severe as to make it almost unusable, and even then the accuracy is all shot to hell anyway.

On occasion I've been next to a building or a barrier against the ocean or something and the reading will be instructing me to head 30m out to sea!  I've now done enough caching (70-ish finds) to have an idea of what a typical hide might be like so once within the general area I can usually stumble upon the hide with no help from the GPS at all.  In fact my most effective method of finding caches these days is to type the coordinates into Google Maps and eyeball where I think the location would be based on where the marker appears on the Sat Image.  While I've been able to muddle my way through most caches it's incredibly frustrating, especially if you have friends in tow.  Is this kind of experience typical, because it's most annoying!

I have been considering buying a dedicated Garmin device (or similar) but the truth is I really like using the phone so would prefer to just have my GPS unit work better, so I'm considering getting a dedicated antenna or similar to link the phone to.  I see several such devices on eBay going for a range of prices and all claim to have good accuracy, but that's exactly what my phone claimed in the first place so can I reasonably expect these to be any better?  Can anyone suggest a way to get good and reliable performance using a phone, even if it requires buying additional hardware?  I am currently considering the "Dual XGPS150A", "Qstarz BT-Q818XT 818" or the "Garmin GLO".  Anyone have an opinion on these?

[craftydogs]

I have the same problem i now just use apps to find coords

[+thebruce0]

There are many factors to consider. I can't speak for your phone model or your locale, but in my area with my iPhones (started with a 3GS in 2009, and now use a 6S+ and 8S+). Your experience seems pretty rough and sub-par, generally speaking for recent smartphone. For me, I've always balanced between patience with the coordinates and comparing to satellite imagery. In areas where imagery is properly aligned, and you're near obvious landmarks, you can use that to help determine how good your satellite reception and accuracy and speed are for the phone.

Better, if you can find a geodetic survey marker that marks a high accuracy gps location, you could use that as well to find out your device's capability in that particular region.

[+geodarts]

I have a Garmin GLO that I use with a wifi only iPad when I want a bigger screen for routing apps.    I have tried it for caching with both an iPhone and Android.  It did not seem to make any real difference.  But both devices generally get me where I want to go - within a few feet or less of my handheld Oregon 600.  

I have a clip for the GLO. Still, it was one more thing to keep track of when hiking around.  This thread made me curious so I might do some more detailed comparisons next week.   Of course that would not tell you if it would improve your experience with your phone.

Some drift is normal with any GPSr and it might vary depending on conditions.  There was one time I was coming out of a slot canyon and my handheld GPSr was bouncing around over 70 feet.  The iPhone got me to the cache.   Under those circumstances I don't know what difference the GLO would have made

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Edited October 22, 2017 by geodarts

[+arisoft]

2 hours ago, geodarts said:

I have a Garmin GLO that I use with a wifi only iPad when I want a bigger screen for routing apps.    I have tried it for caching with both an iPhone and Android.  It did not seem to make any real difference.  But both devices generally get me where I want to go - within a few feet or less of my handheld Oregon 600.  

I have used more than six years Holux M-1000C, which is same kind of BlueTooth GPS gadget as GLO.

During these years, I have found that newer mobile phones are getting better but when I go to woods thing are still really different. In most cases the external unit works and the phone does not. The reason is easy to understand when you open the device. The aerial of the external unit is so big that it will newer fit to a standard mobile phone and the size means sensitivity.