%                                venuecef.m
%  Scope:   This MATLAB macro performs the transformation from ENU (East, 
%           North, Up) to ECEF coordinates for a given position vector and
%           reference latitude/longitude angles.
%  Usage:   pecef = venuecef(penu,lat,lon)
%  Description of parameters:
%           penu  -  input, ENU position vector (with components in meters)
%           lat   -  input, reference latitude in radians
%           lon   -  input, reference longitude in radians
%           pecef -  output, ECEF position vector, with components in same 
%                    units as the input ENU position vector
%  Last update:  04/04/00
%  Copyright (C) 1996-00 by LL Consulting. All Rights Reserved.

function  pecef = venuecef(penu,lat,lon)

slat = sin(lat);
clat = cos(lat);
slon = sin(lon);
clon = cos(lon);

pecef = zeros(3,1);
temp = - slat * penu(2) + clat * penu(3);
pecef(1) = - slon * penu(1) + clon * temp;
pecef(2) = clon * penu(1) + slon * temp;
pecef(3) = clat * penu(2) + slat * penu(3);