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

Thomas A. Frank ka2cdk at cox.net
Fri Aug 27 05:10:24 UTC 2010

I would suggest you buy an old surveying transit.

This is what largely they were intended for.

With the industry going electronic, really nice ones can be found  
fairly inexpensively (considering the quality of the optics on the  
good ones).

I picked up a nice K+E with the tripod for $300.

Tom Frank

On Aug 26, 2010, at 10:09 AM, David Smith wrote:

> Thanks for all the interesting responses.
> Some background - I'm needing an accuracy of 1 degree or better.   
> The experiments are using digital communication modes and sometimes  
> aircraft scatter so signals are regularly inaudible and often non- 
> existent, so peaking "by ear" is not usually an option.
> I've paced out direction using a handheld GPS (GPSMap 60CSX) and  
> this gives reasonable results if there's a reasonable baseline.   
> It's a bit impractical when operating from a firetower though!
> Using Sun/Moon/Stars is difficult when there's cloud. We've tried  
> using Sun RF Noise, but accuracy declines significantly when the  
> sun is high in the sky.
> VOR is an interesting suggestion, but a very sharp (and large)  
> antenna would be needed and multi-pathing may cause problems.
> So, my interest turns back to a GPS-based solution and the military  
> units suggested by Brooke look perfect ... except that they are  
> most likely a restricted export and unavailable to us Down Under.
> Other links on Brooke's site have lead me to many papers  
> researching GPS-based attitude systems.  I note that the Uni of  
> Calgary have developed a package called HEADRT+ that can take raw  
> measurements from several GPS mounted on a small baseline and  
> produce attitude information.  This is the sort of thing I'm after,  
> but I get the impression that licensing costs are high.
> As Atilla says, the software is probably not that fundamentally  
> complicated.  However, the devil is possibly in the detail of  
> aligning sample timing, positioning ...
> Any other suggestions?
> Regards,
> Dave

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