function [y, m, d, sec] = Gps_to_sec(gps_week, gps_sec)

% Function converts gps time (week, sec) into date year, month, day and sec since midnight
%  [y, m, d, sec] = Gps_to_sec(gps_week, gps_sec)
%  input: gps week, gps sec
%  output: year(4digit), month, day, sec since midnight

% David Benson
% 7/5/01

%Program modified to solve incorrect output when month > January
%Paige Sturtevant
%1/31/2002

jd = 7 * gps_week + gps_sec / 86400 + 2444245;

l = floor(jd) + 68569;
n = floor(( 4 * l ) / 146097);
l = l - floor(( 146097 * n + 3 ) / 4);
i = floor(( 4000 * ( l + 1 ) ) / 1461001);
l = l - floor(( 1461 * i ) / 4) + 31;
j = floor(( 80 * l ) / 2447);
d = l - floor(( 2447 * j ) / 80);
L = j / 11;
m = j + 2 - floor(( 12 * L ));
y = 100 * ( n - 49 ) + i + L;
y = floor(y); %added 1/31/2002


if m > 1 %changed to a 1 instead of a 2 - 1/31/2002
   m = m+1; %added 1/31/2002
   M = m; Y = y;
else
   M = m + 12; Y = y - 1;
end

JD = fix(365.25*Y) + fix(30.6001*(M+1)) + d + 1720982;

sec = round((jd - JD) * 86400);


%This section added 1/31/2001
%The month does not seem to increment correctly after January,...
%...this section solves that problem
if sec > 86400
   exdays = floor(sec/86400);
   exm = round(exdays/30);
   m = m+exm;
   sec = sec-exdays*86400;
end