[net.aviation] Wanted: great circle nav programs.

llh@midacs.UUCP (Linn Hower) (08/24/85)

I now have an oportunity to get some right seat time in a Cessna
Conquest.  I was amaised to find out how dumb the expensive RNAV
computer was that is on board. It does'nt do any great circle calculations,
just straight from waypoint to waypoint.

Does anyone have any software (for un*x or hp 11c calculator) that will
allow me to do something like the following:

	give starting lat/long
	give destination lat/long
	give number of waypoints to plot along the great circle route

	get lat/long for waypoints 1 to n

With the lat/long of the waypoints I could program the RNAV to approximate
this great circle route.

If not code, do you have any pointers to the algorithms???
-- 
Linn Hower	Phone: 208-526-9353
   ...!ucbvax!ucdavis!midacs!isew02!linn

notes@harpo.UUCP (08/26/85)

The HP-25 Applications Programs Book has what you want for
taking a great circle course and breaking it into several rhumbline
courses.

Irv McNair
ATT BEll Labs Whippany

ron@brl-tgr.ARPA (Ron Natalie <ron>) (09/03/85)

> 
> I now have an oportunity to get some right seat time in a Cessna
> Conquest.  I was amaised to find out how dumb the expensive RNAV
> computer was that is on board. It does'nt do any great circle calculations,
> just straight from waypoint to waypoint.
> 
I once wrote a program to aid a friend in the charter business that
estimates the air distance betweeen two lat/long pairs.  I don't have
the program, I loaded it into a TRASH-80 pocket computer which I don't
know where it is anymore.  If you are going to do this yourself, look
up the "Spherical Law of Cosines."  It's the heart of all these
calculations.