mecefllw.m

GPS software toolbox for GPS receiver development

%                                mecefllw.m
%  Scope:   This MATLAB macro constructs the transformation matrix from ECEF 
%           frame to LLWA (Local Level Wander Azimuth) frame.
%  Usage:   moutput = mecefllw(lat,lon,waz)
%  Description of parameters:
%           lat      -  input, reference latitude in radians
%           lon      -  input, reference longitude in radians
%           waz      -  input, wander azimuth angle in radians
%           moutput  -  output, two-dimensional real array containing the 
%                       transformation matrix from ECEF frame to LLWA frame
%  Remark:  The coordinate axes for local level wander azimuth frame are 
%           defined as follows:
%           x - axis at wander azimuth angle counter-clockwise from East in
%               local level plane,
%           y - axis at wander azimuth angle counter-clockwise from North in
%               local level plane,
%           z - axis upward along local normal
%  Last update:  04/05/00
%  Copyright (C) 1996-00 by LL Consulting. All Rights Reserved.

function   moutput = mecefllw(lat,lon,waz)

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

moutput(1,1) = - cwaz * slon - swaz * clon * slat;
moutput(1,2) =   cwaz * clon - swaz * slon * slat;
moutput(1,3) =   swaz * clat;
moutput(2,1) =   swaz * slon - cwaz * clon * slat;
moutput(2,2) = - swaz * clon - cwaz * slon * slat;
moutput(2,3) =   cwaz * clat;
moutput(3,1) =   clon * clat;
moutput(3,2) =   slon * clat;
moutput(3,3) =   slat;