[Qgis-user] wishing for accurate lattitude/longitude from a cell, phone

[Garth Fletcher]

A QGIS reader pointed me to a Sep 2019 US Forest Service report,
<https://www.fs.fed.us/database/gps/mtdcrept/accuracy/index.htm>,
which compares the accuracy of various GPS instruments.

Their Garmin eTrex 30 section stated that the eTrex's accuracy was ~ 3X
poorer when using GPS+GLONASS instead of GPS-only mode.  This seemed
rather counter-intuitive.

I checked using my eTrex 20 by taking 38 measurements distributed over
an 8 hour period at a precisely known location, half using GPS only and
half using GPS+GLONASS modes. Canopy type probably "Light-Medium".

The results indicate that GPS+GLONASS does increase the accuracy, albeit
only by a modest amount.  It  most certainly does not decrease it!

A plot of my results on a 1 meter grid, along with descriptive
statistics, can be downloaded (69 KB) from:
<http://www.Mason-NH.org/Specials/GARMIN±GLONASS_TESTS.pdf>

Cordially,
-- 
Garth Fletcher