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

[David Smith]

As a fair percentage of the discussion amongst the learned gentlemen on 
this group involves GPS-based timing systems, I'd like to ask a non-time 
related, but GPS-related question.

As part of microwave radio experimentation, often on windy hilltops, I 
have a need to find direction very accurately.  I have seen advertised 
GPS-based Azimuth Pointing Systems such as this:
http://www.ascscientific.com/APS.html
However they are a little (lot) out of my budget range.

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?

Regards,
David Smith