inverse.m

Geodetic tools to be used in navigation analysis

function [az,va,d]=inverse(lat1,lon1,h1,lat2,lon2,h2,a,e2)
% INVERSE  Computes inverse geodetic problem.
%   Determines azimuth, vertical angle and distance
%   between 1st and 2nd points given their ellipsoidal
%   coordinates.  If az,va are local astronomic, lat,lon
%   must be astronomic.  If az,va are local geodetic,
%   lat,lon must be geodetic.  Non-vectorized.  See also
%   DIRECT.
% Version: 10 Oct 96
% Useage:  [az,va,d]=inverse(lat1,lon1,h1,lat2,lon2,h2,a,e2)
% Input:   lat1 - ellipsoidal latitude of 1st station (rads)
%          lon1 - ellipsoidal longitude of 1st station (rads)
%          h1   - ellipsoidal ht. of 1st station (m)
%          lat2 - ellipsoidal latitude of 2nd station (rads)
%          lon2 - ellipsoidal longitude of 2nd station (rads)
%          h2   - ellipsoidal ht. of 2nd station (m)
%          a    - major semi-axis of ref. ell. (m)
%          e2   - eccentricity squared of ref. ell.
% Output:  az   - azimuth from station 1 to 2 (rads)
%          va   - vertical angle from 1 to 2 (rads)
%          d    - distance from 1 to 2 (m)
[X1,Y1,Z1]=ell2xyz(lat1,lon1,h1,a,e2);
[X2,Y2,Z2]=ell2xyz(lat2,lon2,h2,a,e2);
dX=X2-X1;
dY=Y2-Y1;
dZ=Z2-Z1;
[dx,dy,dz]=ct2lg(dX,dY,dZ,lat1,lon1);
[az,va,d]=xyz2sph(dx,dy,dz);