function epoch=stdepoch(N,type)
%STDEPOCH  Sets standard epoch in YMDhms format.
%   EPOCH = STDEPOCH([N[,TYPE]]) is the standard epoch
%   of either type AD, J2000 or B1950. If omitted then
%   DATE defaults to current date. N is the number of
%   satellites (defaults to N=1).
%
%   See also CLOCK.

% Copyright (c) 2003-06-09, B. Rasmus Anthin.

if ~nargin, N=1;end
if nargin<2, type='';end
switch(upper(type))
case 'AD'
   date=zeros(1,6);
case 'J2000'
   date=[2000 1 1, 12 0 0];
case 'B1950'
   date=[1949 12 31, 22 9 7.2];
otherwise
   date=clock;
end
epoch=repmat(date,N,1);