[time-nuts] Slightly OT - GPS-Based Accurate Direction Finding

Attila Kinali attila at kinali.ch
Thu Aug 26 09:00:30 UTC 2010

On Thu, 26 Aug 2010 11:04:01 +1000
David Smith <david at smithfamily.net.au> wrote:

> The system seems to work by taking the raw satellite phase information 
> from two separate GPS systems and crunching the data to come up with an 
> azimuth figure.  Has anyone heard of a (Open Source?) program that could 
> be used to do these calculations?

AFAIK there is none out there (at least i've never seen one).
But it should be not too dificult write the software yourself.
The bigger problem is to get GPS receivers that provide you
with accurate phase information. Especially with a small baseline
you either need to sync the clocks of the two receivers or have
receivers with precise TCXO and take some additional samples to
calculate the frequency difference/drift. The precision you get
will mostly depend on the baseline and the number of samples you
use. The longer you have time to measure, the smaller your error-band
will be.

As GPS modules, you could use something like the LEA4-T/LEA6-T which
provide you the phase information you need.

			Attila Kinali

If you want to walk fast, walk alone.
If you want to walk far, walk together.
		-- African proverb

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