NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Brad Morris
Date: 2017 Feb 27, 17:26 -0500
I have just carried out a little experiment. I placed my phone on a table outside where it had a view of the clear sky. I waited until it was it had 15 satellites in view and was using 14 or 15 of them. Sometimes it dropped to 14/13. Both US and Russian satellites were used. Claimed accuracy was 5m - I assume this is calculated from the constellation.
Google Earth gives positions to three decimal place of a minute. According to Mr Google 1 nm = 1852 m so the precision [1] of GE is approximately 2m.
My measurements were:
GPS 06.454' S
05.204' E
The app gave the numbers to four decimal places which implies more precision than is real.
Google Earth 06.457' S
05.205' E
From which:
dlat = .003' approx = 6m
dlong = .001' At lat 41° dep approx equal 1.5m
Conclusion: At my location the GE and GPS positions agree within the claimed accuracy of the GPS.
There is a clear blue sky outside with no wind. I must take my sextant and determine the CORRECT position of my garden table (-;
[1] I am sure that precision is the correct word here, not accuracy.
