On 30/04/2014 17:37, Douglas Bateman wrote:
This is a new club consisting, so far, of two members: Frank King and myself.
After the successful British Sundial Society conference, the Sunday morning was
allocated to tours of the Greenwich Observatory. Quite independently, Frank and
I had the intention of location the WGS84 meridian, some 90m east of the
Greenwich brass strip. Frank had an eTrex tracker and an app on his mobile
phone, and I had an Axxera GPS tracker linked to my iPad.
The images, if the system will let them through, show 0º 0' 0". Anyone else
willing to join this new exclusive club? Plenty of places to straddle the line
between the north pole and the south pole.
Doug (and Frank)
I have been looking up the reviews on Android GPS apps (though many of
the comments are generally applicable) and it seems that (unless you use
surveying equipment, or you are in the armed forces) up to ten metres
accuracy is about the best that you can expect.
GPS Test for Android or GPS Status for Apple (more limited - apparently
Apple releases fewer secrets to developers) seem to be recommended to
see how accurate you are. I guess, when you use those, the more dots
you get near the centre of the circle, the better ?
Apparently you should spin the device on three axes (preferably more
than once each) to get a better fix (you need to get at least 4
satellites, preferably 6-9). This seems to work for most people, much
better than waving in a figure of eight motion.
If you travel, wait until you're outside (away from buildings, vehicles
and trees) before you try to get a fix, so that it can learn the new
location more quickly.
Any other hints and tips ?
Here are my results (indoors, and without spinning) from a few free
Android apps :-
Mobiwia GPS Status & Toolbox Lat. 51°52.68' N 0°35.71' W (third decimal
place changing)
GPS Status Test & Fix Lat. 51.878° N 0.595° W (fourth decimal place
changing)
GPS Averaging Lat. 51°52.68' N 0°35.71' W (third decimal place changing)
Sciencewithandroid Precision GPS 51°52'41'' N 0°35'43'' W (first decimal
place changing)
So it seems that you can probably get precision of 0.001° or 0.01' or 1"
which seems pretty good to me for free apps.
--
--
Richard Mallett
Eaton Bray, Dunstable
South Beds. UK
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