Code covered by the BSD License  

Highlights from
A MATLAB Script for Time and Coordinate Calculations

A MATLAB Script for Time and Coordinate Calculations

by

David Eagle (view profile)

 

Interactive MATLAB script that can be used to perform time and coordinate calculations.

lla2eci (gast, lat, long, alt)
function reci = lla2eci (gast, lat, long, alt)

% convert geodetic altitude, latitude and longitude to eci position vector
   
% input

%  gast = apparent sidereal time (radians)
%         (0 <= gast <= 2 pi)
%  lat  = geodetic latitude (radians)
%  long = geographic longitude (radians)
%  alt  = geodetic altitude (kilometers)

% output

%  reci = eci position vector (kilometers)

% Orbital Mechanics with MATLAB

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

% compute geocentric distance and declination

[rmag, decl] = geodet4 (lat, alt);

% compute right ascension (radians)

rasc = mod(gast + long, 2.0 * pi);

% compute eci position vector (kilometers)

reci(1) = rmag * cos(decl) * cos(rasc);

reci(2) = rmag * cos(decl) * sin(rasc);

reci(3) = rmag * sin(decl);

Contact us