Re: [RCSE] High Altitude Glider/off subject

[Jim Prouty]

Standard GPS error (drift) can be as high as 16 meters due to the geometry 
of the constellation and path link errors in the atmosphere.  The new WAAS 
enabled GPS receivers are supposed to be accurate within 3 meters 90% of 
the time.  They use a ground based reference signal to give a more accurate 
positioning fix.  Unlike the old DGPS, all you need is a WAAS enabled 
receiver to be able to get that accuracy.  A neat test to do is take a 
non-WAAS enabled GPS and zoom in as far as you can on your position.  You 
can actually watch the fix wander around your position as the fix drifts.

There a several inexpensive GPS receivers out there that can be put in an 
RC aircraft to measure altitude and position.  The Foretrex 201is very 
light, compact, and is WAAS enabled.  There have been several posts on the 
list about using them and software that can be used to plot your flight 
when you land.  Cool Stuff.

Happy flying,
Jim
www.jtmodels.com

What are the error/accuracy/precision rates of a GPS system and how do they
compare to the pressure sensing systems?  And of course, how does the cost
of a GPS based altimeter system compare.

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