Re: [gpsd-dev] ✘CEP(50) 0.009 meters

[Gary E. Miller]

Yo Hal!

On Mon, 25 Jul 2016 12:30:07 -0700
Hal Murray <address@hidden> wrote:

> address@hidden said:  
> > Looks like I have a bit more work to do, but close.  Changes so
> > far are in git head.  Next I'll add WGS84 ellipsoid correction for
> > latitude.     
> 
> Why?  Is that going to be significant?  

I'm being dragged in Python, like it or not.  I've created a new
Python file (test_misc.py) to test the gps/misc.py library.  It
uses the valuse from Wikipedia:

    https://en.wikipedia.org/wiki/Decimal_degrees#Precision

0.0000001 degree at the equator is 11.132 mm.

At centimeter accuracy my latest code at the equator is off by almost
40% in some test cases...

As for the altitude correction, wikipedia claims at an altitude of
6,378 meters the error is 0.1%.  So not a big deal, yet.

So more work to do.  

RGDS
GARY
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Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
        address@hidden  Tel:+1 541 382 8588

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