function jdmat=jdrps2jdmat(jd);
% JDRPS2JDMAT: Convert Signell's Julian days to Matlab's Serial day
%   Usage: jdmat=jdrps2jdmat(jd);
%
%  matlab's serial date = 1 at 0000 UTC, 1-Jan-0000
jdmat=jd-julian([0000 1 1 0 0 0])+1;