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Accurate GPS / Grid Ref App for mobile phones

PostPosted: Tue Jun 05, 2018 8:33 am
by FrankR
HI all,
Was just wondering if anyone could recommend a good app for a smartphone that gives an accurate 10 figure grid reference. The one I currently use is good but can be a bit glitchy, and I spent a good hour and a half digging around for a block yesterday that I couldn't find in the end.
I'm presuming most people just use a proper GPS thing (Garmin or whatever) but I don't really want the outlay and another gadget added to my collection.
Thanks
Frank

Re: Accurate GPS / Grid Ref App for mobile phones

PostPosted: Tue Jun 05, 2018 5:44 pm
by agentmancuso
Even with a decent Garmin, you're looking at a 3m radius on a good day. I doubt if any mobile phone app gets anywhere near that.

Re: Accurate GPS / Grid Ref App for mobile phones

PostPosted: Thu Jun 07, 2018 8:40 am
by FrankR
Thanks for that, I always kinda figured that actual GPS units would be more accurate than a phone app. So far my general philosophy has been to get to where I think the location is based on the phone app, and then if there is a higher point in the very immediate vicinity, I start there.

Re: Accurate GPS / Grid Ref App for mobile phones

PostPosted: Thu Jun 07, 2018 4:01 pm
by stripybadger
One other thing to consider is Galileo, as this is supposed to offer higher accuracy (1 metre compared with GPS's 5 metres or so). Some recent phones (e.g. Galaxy S8) have a Galileo reciever built in, so if you have one of those then the accuracy might drop to an acceptable level and render a standalone reciever unecessary.

Supposedly Galileo is capable of centimetre accuracy, but it seems that won't be available to general public (and possibly not at all in the UK depending how the whole brexit thing goes!)

Re: Accurate GPS / Grid Ref App for mobile phones

PostPosted: Fri Jun 08, 2018 2:59 pm
by FrankR
Thanks for the info StripyBadger.
I will have a look at that, but I expect that even if it does become widely available, I'm probably never likely to have a smartphone fancy enough to have that facility.
Ultimately I was just seeing what was about, as I just thought that Garmins etc would be more accurate than free apps on phones, as thats what they're specifically designed for. Also that there may have been an app better than the one I'm using.
In this presumption then, I gather that when people re-discover long lost trig points, it could involve considerable effort and much digging about.

Re: Accurate GPS / Grid Ref App for mobile phones

PostPosted: Fri Jun 08, 2018 5:28 pm
by ted
I gather that when people re-discover long lost trig points, it could involve considerable effort and much digging about.


Thats part of the fun of this absurd game :)

Is there any likelihood of functional Galileo receivers, at a sane price,
in the not too distant future? Any improvement in accuracy would make
prospecting for blocks much easier, not to mention reduced wear and tear
on the knees.


Regards
Ted

Re: Accurate GPS / Grid Ref App for mobile phones

PostPosted: Wed Jun 27, 2018 9:11 pm
by Cootking
The Galileo accuracy might go to cm but, do we have the locations of blocks etc to this degree of accuracy? Most of the sketches I've seen are fairly crude. When I retire It'll be the scythe, big screwdriver and spade I suspect.

Re: Accurate GPS / Grid Ref App for mobile phones

PostPosted: Thu Jun 28, 2018 9:18 pm
by MAC.HAWK

Re: Accurate GPS / Grid Ref App for mobile phones

PostPosted: Wed Aug 01, 2018 10:27 pm
by TrigJS
The more GNSS constellations you can use concurrently the better but the benefit might be more related to being able to get a reliable position in areas where sky visibility is limited (eg forests and urban canyons) rather than significant improvements in accuracy and precision.

What maybe more significant when searching for trig points is ensuring the datum transformation from the GNSS datum (eg WGS84) to OSGB36 is suitable (errors could be in the 10s metres or greater if incorrect). Due to various errors in OSGB36 a single 3 or 7 parameter transformation for the whole UK will result in inconsistent errors and OSTN15 is the OS recommended transformation. I’ve been using an iOS app called GPS OS, which though basic, uses OSTN15 and I’ve been getting a good correlation (usually less than a couple of meters) between the historic OS locations and the output from GPS OS.