mirror of https://github.com/gnss-sdr/gnss-sdr
61 lines
1.9 KiB
Matlab
61 lines
1.9 KiB
Matlab
function [phi, lambda, h] = cart2geo(X, Y, Z, i)
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%CART2GEO Conversion of Cartesian coordinates (X,Y,Z) to geographical
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%coordinates (phi, lambda, h) on a selected reference ellipsoid.
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%
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%[phi, lambda, h] = cart2geo(X, Y, Z, i);
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%
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% Choices i of Reference Ellipsoid for Geographical Coordinates
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% 1. International Ellipsoid 1924
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% 2. International Ellipsoid 1967
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% 3. World Geodetic System 1972
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% 4. Geodetic Reference System 1980
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% 5. World Geodetic System 1984
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%Kai Borre 10-13-98
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%Copyright (c) by Kai Borre
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%Revision: 1.0 Date: 1998/10/23
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%
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% CVS record:
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% $Id: cart2geo.m,v 1.1.2.3 2007/01/29 15:22:49 dpl Exp $
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%==========================================================================
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a = [6378388 6378160 6378135 6378137 6378137];
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f = [1/297 1/298.247 1/298.26 1/298.257222101 1/298.257223563];
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lambda = atan2(Y,X);
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ex2 = (2-f(i))*f(i)/((1-f(i))^2);
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c = a(i)*sqrt(1+ex2);
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phi = atan(Z/((sqrt(X^2+Y^2)*(1-(2-f(i)))*f(i))));
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h = 0.1; oldh = 0;
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iterations = 0;
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while abs(h-oldh) > 1.e-12
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oldh = h;
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N = c/sqrt(1+ex2*cos(phi)^2);
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phi = atan(Z/((sqrt(X^2+Y^2)*(1-(2-f(i))*f(i)*N/(N+h)))));
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h = sqrt(X^2+Y^2)/cos(phi)-N;
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iterations = iterations + 1;
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if iterations > 100
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fprintf('Failed to approximate h with desired precision. h-oldh: %e.\n', h-oldh);
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break;
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end
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end
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phi = phi*180/pi;
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% b = zeros(1,3);
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% b(1,1) = fix(phi);
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% b(2,1) = fix(rem(phi,b(1,1))*60);
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% b(3,1) = (phi-b(1,1)-b(1,2)/60)*3600;
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lambda = lambda*180/pi;
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% l = zeros(1,3);
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% l(1,1) = fix(lambda);
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% l(2,1) = fix(rem(lambda,l(1,1))*60);
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% l(3,1) = (lambda-l(1,1)-l(1,2)/60)*3600;
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%fprintf('\n phi =%3.0f %3.0f %8.5f',b(1),b(2),b(3))
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%fprintf('\n lambda =%3.0f %3.0f %8.5f',l(1),l(2),l(3))
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%fprintf('\n h =%14.3f\n',h)
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%%%%%%%%%%%%%% end cart2geo.m %%%%%%%%%%%%%%%%%%%
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