%                              vecefs85.m
%  Scope:   This MATLAB macro performs the transformation from ECEF WGS-84 to 
%           SGS-85 (Soviet Geodetic System 1985) frame coordinates for a given 
%           position vector with components expressed in meters.
%  Usage:   psgs85 = vecefs85(pecef)
%  Description of parameters:
%           pecef  -  input, ECEF (WGS-84) position vector with components in 
%                     meters
%           psgs85 -  output, SGS-85 frame position vector, with components in 
%                     meters
%  Reference:
%           [1] Misra, P. N., Abbott, R. I., SGS85 - WGS84 transformation. 
%               Manuscripta geodaetica, Vol. 19, 1994, pp. 300-308.
%  Last update:  04/04/00
%  Copyright (C) 1997-00 by LL Consulting. All Rights Reserved.

function   psgs85 = vecefs85(pecef)

rotangle = 3.0e-6;       %  rotation angle in radians
d = 4.0;                 %  translation distance in meters

psgs85 = zeros(3,1);
psgs85(1) = pecef(1) + pecef(2) * rotangle;
psgs85(2) = - pecef(1) * rotangle + pecef(2);
psgs85(3) = pecef(3) - d;