function [Jul1,Jul2]=UTC2TCG(Jul1,Jul2)
%%UTC2TCG  Convert from universal coordinated time (UTC) given as a
%          two-part pseudo-Julian date to geocentric coordinate time (TCG),
%          represented as a two-part Julian date.
%
%INPUTS: Jul1, Jul2 Two parts of a pseudo-Julian date given in UTC. The
%                   units of the date are days. The full date is the sum of
%                   both terms. The date is broken into two parts to
%                   provide more bits of precision. It does not matter how
%                   the date is split.
%
%OUTPUTS: Jul1, Jul2 The time as a Julian date in TCG.
%
%The UTC date is only pseudo-Julian, because there is not a fixed number
%of seconds in a Julian day. The convention used in the IAU standard is
%that the Julian day matches the UTC day regardless of whether the UTC day
%is 86399, 86400 or 86401 SI seconds (depending on the presence of leap
%seconds).
%
%UTC began at 1960 January 1.0 (JD 2436934.5) and this function should not
%be called with an earlier date.
%
%This just calls a number of intermediate conversion functions out of the
%International Astronomical Union's (IAU) Standard's of Fundamental
%Astronomy library.
%
%Many temporal coordinate systems standards are compared in [1].
%
%REFERENCES:
%[1] D. F. Crouse, "An Overview of Major Terrestrial, Celestial, and
%    Temporal Coordinate Systems for Target Tracking," Formal Report, Naval
%    Research Laboratory, no. NRL/FR/5344--16-10,279, 10 Aug. 2016, 173
%    pages.
%
%October 2013 David F. Crouse, Naval Research Laboratory, Washington D.C.
%(UNCLASSIFIED) DISTRIBUTION STATEMENT A. Approved for public release.

[Jul1,Jul2]=UTC2TAI(Jul1,Jul2);
[Jul1,Jul2]=TAI2TT(Jul1,Jul2);
[Jul1,Jul2]=TT2TCG(Jul1,Jul2);
end

%LICENSE:
%
%The source code is in the public domain and not licensed or under
%copyright. The information and software may be used freely by the public.
%As required by 17 U.S.C. 403, third parties producing copyrighted works
%consisting predominantly of the material produced by U.S. government
%agencies must provide notice with such work(s) identifying the U.S.
%Government material incorporated and stating that such material is not
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%
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%
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%SOFTWARE AND ANY RELATED MATERIALS, AND AGREES TO INDEMNIFY THE NAVAL
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%OF RECIPIENT IN THE USE OF THE SOFTWARE.
