"KBH" wrote in message
...
You give yourself away with a comment like that...

With a PhD in mathematics specializing in an area of geometry, I think
you
misjudge me.


The terminology "...in an area of geometry..." is another give-away.

Geometric topology with graduate coursework including differential
geometry--in that you learn the substance of approximating a curved surfaces
with euclidean pieces ("maps"). And yes, I have actually studied the
differences in distances and angles from approximating the earth's surface
as rectangular on the small scale--not in a course but by doing the
calculations.

But that's not the point.

Agree.

Projects are not defined with great-circles because the direction to a
great-circle is just a beginning direction. Navigation on the other hand
seeks the shortest route and thus correction of the course is accepted. So
projection to rectangular coordinates systems is used for projects while
geodetic systems are used for navigation.

As I understand the original problem. it was to triangulate to locate one of
the NV beacons and the software I mention contains menu selection that will
do the needed calculation.

I would argue that rectangular coodrinates are used simply because we like
to think in straight lines, they are easy to construct, and on a small
scale they approximate a geodesic (great circle) on a sphere.

I might add that I have done long range triangulation of VLF stations (the
stations were 1000's of km away). This would have been impossible using
rectangular coordinates. Additonally, originally the FCC HF DF network had
to use a special device to triangulate--it would have been much easier if
they could have just done rectangular geometry. But again, the distances of
the project proposed are much smaller and that level of accurate modeling is
certainly not needed as other errors will be more significant.

Per the original plan, I like his differencing the angles from a known
source as that is better than just trusting the null to be where he things
it is in the antenna pattern. Ideally use a radio where one can turn off
the AGC--it will make things a lot easier. Be sure to make several (lots)
indpendent measurements at each location and average them. If you take
enough (ideally at least 30), you can then construct error bound for the
bearings using simple statistics. And the thing usually forgotten, practice
the technique on known locations (beacons) first to obtain realistic
expectations..