//! Function to calculate GMST according to requested IAU conventions
double calculateGreenwichMeanSiderealTime(
const double terrestrialTime, const double universalTime1,
const double referenceJulianDay, const basic_astrodynamics::IAUConventions iauConvention )
{
// Declare GMST variable
double gmst = TUDAT_NAN;
// Check for IAU convention and retrieve requested GMST
switch( iauConvention )
{
case basic_astrodynamics::iau_2000_a:
gmst = iauGmst00( referenceJulianDay, universalTime1 / physical_constants::JULIAN_DAY,
referenceJulianDay, terrestrialTime / physical_constants::JULIAN_DAY );
break;
case basic_astrodynamics::iau_2000_b:
gmst = iauGmst00( referenceJulianDay, universalTime1 / physical_constants::JULIAN_DAY,
referenceJulianDay, terrestrialTime / physical_constants::JULIAN_DAY );
break;
case basic_astrodynamics::iau_2006:
gmst = iauGmst06( referenceJulianDay, universalTime1 / physical_constants::JULIAN_DAY,
referenceJulianDay, terrestrialTime / physical_constants::JULIAN_DAY );
break;
default:
throw std::runtime_error( "Warning, iau convention for GMST calculation not recongnized" );
}
return gmst;
}
double iauEe06a(double date1, double date2)
/*
** - - - - - - - - -
** i a u E e 0 6 a
** - - - - - - - - -
**
** Equation of the equinoxes, compatible with IAU 2000 resolutions and
** IAU 2006/2000A precession-nutation.
**
** This function is part of the International Astronomical Union's
** SOFA (Standards Of Fundamental Astronomy) software collection.
**
** Status: support function.
**
** Given:
** date1,date2 double TT as a 2-part Julian Date (Note 1)
**
** Returned (function value):
** double equation of the equinoxes (Note 2)
**
** Notes:
**
** 1) The TT date date1+date2 is a Julian Date, apportioned in any
** convenient way between the two arguments. For example,
** JD(TT)=2450123.7 could be expressed in any of these ways,
** among others:
**
** date1 date2
**
** 2450123.7 0.0 (JD method)
** 2451545.0 -1421.3 (J2000 method)
** 2400000.5 50123.2 (MJD method)
** 2450123.5 0.2 (date & time method)
**
** The JD method is the most natural and convenient to use in
** cases where the loss of several decimal digits of resolution
** is acceptable. The J2000 method is best matched to the way
** the argument is handled internally and will deliver the
** optimum resolution. The MJD method and the date & time methods
** are both good compromises between resolution and convenience.
**
** 2) The result, which is in radians, operates in the following sense:
**
** Greenwich apparent ST = GMST + equation of the equinoxes
**
** Called:
** iauAnpm normalize angle into range +/- pi
** iauGst06a Greenwich apparent sidereal time, IAU 2006/2000A
** iauGmst06 Greenwich mean sidereal time, IAU 2006
**
** Reference:
**
** McCarthy, D. D., Petit, G. (eds.), 2004, IERS Conventions (2003),
** IERS Technical Note No. 32, BKG
**
** This revision: 2008 May 18
**
** SOFA release 2016-05-03
**
** Copyright (C) 2016 IAU SOFA Board. See notes at end.
*/
{
double gst06a, gmst06, ee;
/* Apparent and mean sidereal times. */
gst06a = iauGst06a(0.0, 0.0, date1, date2);
gmst06 = iauGmst06(0.0, 0.0, date1, date2);
/* Equation of the equinoxes. */
ee = iauAnpm(gst06a - gmst06);
return ee;
/*----------------------------------------------------------------------
**
** Copyright (C) 2016
** Standards Of Fundamental Astronomy Board
** of the International Astronomical Union.
**
** =====================
** SOFA Software License
** =====================
**
** NOTICE TO USER:
**
** BY USING THIS SOFTWARE YOU ACCEPT THE FOLLOWING SIX TERMS AND
** CONDITIONS WHICH APPLY TO ITS USE.
**
** 1. The Software is owned by the IAU SOFA Board ("SOFA").
**
** 2. Permission is granted to anyone to use the SOFA software for any
** purpose, including commercial applications, free of charge and
** without payment of royalties, subject to the conditions and
** restrictions listed below.
**
** 3. You (the user) may copy and distribute SOFA source code to others,
** and use and adapt its code and algorithms in your own software,
** on a world-wide, royalty-free basis. That portion of your
** distribution that does not consist of intact and unchanged copies
** of SOFA source code files is a "derived work" that must comply
** with the following requirements:
**
** a) Your work shall be marked or carry a statement that it
** (i) uses routines and computations derived by you from
** software provided by SOFA under license to you; and
** (ii) does not itself constitute software provided by and/or
** endorsed by SOFA.
**
** b) The source code of your derived work must contain descriptions
** of how the derived work is based upon, contains and/or differs
** from the original SOFA software.
**
** c) The names of all routines in your derived work shall not
** include the prefix "iau" or "sofa" or trivial modifications
** thereof such as changes of case.
**
** d) The origin of the SOFA components of your derived work must
** not be misrepresented; you must not claim that you wrote the
** original software, nor file a patent application for SOFA
** software or algorithms embedded in the SOFA software.
**
** e) These requirements must be reproduced intact in any source
** distribution and shall apply to anyone to whom you have
** granted a further right to modify the source code of your
** derived work.
**
** Note that, as originally distributed, the SOFA software is
** intended to be a definitive implementation of the IAU standards,
** and consequently third-party modifications are discouraged. All
** variations, no matter how minor, must be explicitly marked as
** such, as explained above.
**
** 4. You shall not cause the SOFA software to be brought into
** disrepute, either by misuse, or use for inappropriate tasks, or
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**
** 5. The SOFA software is provided "as is" and SOFA makes no warranty
** as to its use or performance. SOFA does not and cannot warrant
** the performance or results which the user may obtain by using the
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** to non-infringement of third party rights, merchantability, or
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** liable to the user for any consequential, incidental, or special
** damages, including any lost profits or lost savings, even if a
** SOFA representative has been advised of such damages, or for any
** claim by any third party.
**
** 6. The provision of any version of the SOFA software under the terms
** and conditions specified herein does not imply that future
** versions will also be made available under the same terms and
** conditions.
*
** In any published work or commercial product which uses the SOFA
** software directly, acknowledgement (see www.iausofa.org) is
** appreciated.
**
** Correspondence concerning SOFA software should be addressed as
** follows:
**
** By email: [email protected]
** By post: IAU SOFA Center
** HM Nautical Almanac Office
** UK Hydrographic Office
** Admiralty Way, Taunton
** Somerset, TA1 2DN
** United Kingdom
**
**--------------------------------------------------------------------*/
}
void mexFunction(int nlhs, mxArray *plhs[], int nrhs, const mxArray *prhs[]) {
double TT1, TT2, UT11,UT12, deltaT,GMST;
int algToUse=2006;
int retVal;
if(nrhs<2||nrhs>4){
mexErrMsgTxt("Wrong number of inputs.");
return;
}
if(nlhs>1){
mexErrMsgTxt("Wrong number of outputs.");
return;
}
TT1=getDoubleFromMatlab(prhs[0]);
TT2=getDoubleFromMatlab(prhs[1]);
if(nrhs>2) {
algToUse=getIntFromMatlab(prhs[2]);
}
if(nrhs>3) {
deltaT=getDoubleFromMatlab(prhs[3]);
} else {
mxArray *retVals[4];
mxArray *JulUTCMATLAB[2];
double JulUTC[2];
//Get the time in UTC to look up the parameters by going to TAI and
//then UTC.
retVal=iauTttai(TT1, TT2, &JulUTC[0], &JulUTC[1]);
if(retVal!=0) {
mexErrMsgTxt("An error occurred computing TAI.");
}
retVal=iauTaiutc(JulUTC[0], JulUTC[1], &JulUTC[0], &JulUTC[1]);
switch(retVal){
case 1:
mexWarnMsgTxt("Dubious Date entered.");
break;
case -1:
mexErrMsgTxt("Unacceptable date entered");
break;
default:
break;
}
JulUTCMATLAB[0]=doubleMat2Matlab(&JulUTC[0],1,1);
JulUTCMATLAB[1]=doubleMat2Matlab(&JulUTC[1],1,1);
//Get the Earth orientation parameters for the given date.
mexCallMATLAB(4,retVals,2,JulUTCMATLAB,"getEOP");
//This is TT-UT1
deltaT=getDoubleFromMatlab(retVals[3]);
//Free the returned arrays.
mxDestroyArray(retVals[0]);
mxDestroyArray(retVals[1]);
mxDestroyArray(retVals[2]);
mxDestroyArray(retVals[3]);
mxDestroyArray(JulUTCMATLAB[0]);
mxDestroyArray(JulUTCMATLAB[1]);
}
//Get UT1
retVal=iauTtut1(TT1, TT2, deltaT, &UT11, &UT12);
if(retVal!=0) {
mexErrMsgTxt("An error occurred computing UT1.");
}
//Get Greenwhich mean sidereal time in radians using the chosen
//algorithm
switch(algToUse) {
case 1982:
GMST=iauGmst82(UT11, UT12);
break;
case 2000:
GMST=iauGmst00(UT11, UT12, TT1, TT2);
break;
case 2006:
GMST=iauGmst06(UT11, UT12, TT1, TT2);
break;
default:
mexErrMsgTxt("An invalid algorithm version was given.");
}
plhs[0]=doubleMat2Matlab(&GMST,1, 1);
}
