lg2dg.m

gps matlab 仿真程序（A collection of geodetic functions that solve a variety of problems in geodesy. Supp

function [dlat,dlon]=lg2dg(dx,dy,lat,h,a,e2)
% LG2DG  Converts local geodetic coordinates to 恖at,恖on,恏.
%   Local origin at lat,lon.  If astronomic lat,h input,
%   then output is in local astronomic system.  Vectorized.
%   See also DG2LG.
% Version: 18 Jan 96
% Useage:  [dlat,dlon]=lg2dg(dx,dy,lat,h,a,e2)
% Input:   dx   - vector of x (N) coordinates in local system
%          dy   - vector of y (E) coordinates in local system
%          lat  - vector of lats of local system origins (rad)
%          h    - vector of hts of local system origins
%          a    - ref. ellipsoid major semi-axis
%          e2   - ref. ellipsoid eccentricity squared
% Output:  dlat - vector of latitude differences (rad)
%          dlon - vector of longitude differences (rad)
v=a./sqrt(1-e2.*sin(lat).^2);
r=v.*(1-e2)./(1-e2.*sin(lat).^2);
dlat=dx./(r+h);
dlon=dy./cos(lat)./(v+h);