//! Function to calculate CIP and CIO locator according to requested IAU conventions
std::pair< Eigen::Vector2d, double > getPositionOfCipInGcrs(
const double terrestrialTime, const double julianDaysEpochShift,
const basic_astrodynamics::IAUConventions precessionNutationTheory )
{
// Declare Sofa function return arguments (by reference)
double xAngle, yAngle;
double originLocator;
// Check for IAU convention and retrieve requested values.
switch( precessionNutationTheory )
{
case basic_astrodynamics::iau_2000_a:
iauXys00a( julianDaysEpochShift, terrestrialTime / physical_constants::JULIAN_DAY,
&xAngle, &yAngle, &originLocator );
break;
case basic_astrodynamics::iau_2000_b:
iauXys00b( julianDaysEpochShift, terrestrialTime / physical_constants::JULIAN_DAY,
&xAngle, &yAngle, &originLocator );
break;
case basic_astrodynamics::iau_2006:
iauXys06a( julianDaysEpochShift, terrestrialTime / physical_constants::JULIAN_DAY,
&xAngle, &yAngle, &originLocator );
break;
default:
throw std::runtime_error( "Warning, precession nutation theory selection not recongnized" );
}
// Set and return requested values.
Eigen::Vector2d cioPosition;
cioPosition << xAngle, yAngle;
return std::pair< Eigen::Vector2d, double >( cioPosition, originLocator );
}
void mexFunction(int nlhs, mxArray *plhs[], int nrhs, const mxArray *prhs[]) {
double TT1, TT2, dX, dY, *xVec;
size_t numRow, numVec;
mxArray *retMat;
double *retData;
double GCRS2CIRS[3][3];
if(nrhs<3||nrhs>4){
mexErrMsgTxt("Wrong number of inputs");
}
if(nlhs>2) {
mexErrMsgTxt("Wrong number of outputs.");
}
checkRealDoubleArray(prhs[0]);
numRow = mxGetM(prhs[0]);
numVec = mxGetN(prhs[0]);
if(!(numRow==3||numRow==6)) {
mexErrMsgTxt("The input vector has a bad dimensionality.");
}
xVec=(double*)mxGetData(prhs[0]);
TT1=getDoubleFromMatlab(prhs[1]);
TT2=getDoubleFromMatlab(prhs[2]);
//If some values from the function getEOP will be needed.
if(nrhs<4||mxGetM(prhs[3])==0) {
mxArray *retVals[2];
double *dXdY;
mxArray *JulUTCMATLAB[2];
double JulUTC[2];
int retVal;
//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(2,retVals,2,JulUTCMATLAB,"getEOP");
mxDestroyArray(JulUTCMATLAB[0]);
mxDestroyArray(JulUTCMATLAB[1]);
//%We do not need the polar motion coordinates.
mxDestroyArray(retVals[0]);
checkRealDoubleArray(retVals[1]);
if(mxGetM(retVals[1])!=2||mxGetN(retVals[1])!=1) {
mxDestroyArray(retVals[1]);
mexErrMsgTxt("Error using the getEOP function.");
return;
}
dXdY=(double*)mxGetData(retVals[1]);
dX=dXdY[0];
dY=dXdY[1];
//Free the returned arrays.
mxDestroyArray(retVals[1]);
} else {//Get the celestial pole offsets
size_t dim1, dim2;
checkRealDoubleArray(prhs[4]);
dim1 = mxGetM(prhs[4]);
dim2 = mxGetN(prhs[4]);
if((dim1==2&&dim2==1)||(dim1==1&&dim2==2)) {
double *dXdY=(double*)mxGetData(prhs[4]);
dX=dXdY[0];
dY=dXdY[1];
} else {
mexErrMsgTxt("The celestial pole offsets have the wrong dimensionality.");
return;
}
}
{
double x, y, s;
double omega;
//Get the X,Y coordinates of the Celestial Intermediate Pole (CIP) and
//the Celestial Intermediate Origin (CIO) locator s, using the IAU 2006
//precession and IAU 2000A nutation models.
iauXys06a(TT1, TT2, &x, &y, &s);
//Add the CIP offsets.
x += dX;
y += dY;
//Get the GCRS-to-CIRS matrix
iauC2ixys(x, y, s, GCRS2CIRS);
}
//Allocate space for the return vectors.
retMat=mxCreateDoubleMatrix(numRow,numVec,mxREAL);
retData=(double*)mxGetData(retMat);
{
size_t curVec;
for(curVec=0;curVec<numVec;curVec++) {
//Multiply the position vector with the rotation matrix.
iauRxp(GCRS2CIRS, xVec+numRow*curVec, retData+numRow*curVec);
//If a velocity vector was given.
if(numRow>3) {
double *velGCRS=xVec+numRow*curVec+3;//Velocity in GCRS
double *retDataVel=retData+numRow*curVec+3;
//Convert velocity from GCRS to CIRS.
iauRxp(GCRS2CIRS, velGCRS, retDataVel);
}
}
}
plhs[0]=retMat;
//If the rotation matrix is desired on the output.
if(nlhs>1) {
double *elPtr;
size_t i,j;
plhs[1]=mxCreateDoubleMatrix(3,3,mxREAL);
elPtr=(double*)mxGetData(plhs[1]);
for (i=0;i<3;i++) {
for(j=0;j<3;j++) {
elPtr[i+3*j]=GCRS2CIRS[i][j];
}
}
}
}
void mexFunction(int nlhs, mxArray *plhs[], int nrhs, const mxArray *prhs[]) {
size_t numRow,numVec;
mxArray *retMat;
double *xVec, *retData;
double TT1, TT2, UT11, UT12;
//The if-statements below should properly initialize all of the EOP.
//The following initializations to zero are to suppress warnings when
//compiling with -Wconditional-uninitialized.
double dX=0;
double dY=0;
double deltaT=0;
double LOD=0;
double GCRS2TIRS[3][3];
//Polar motion matrix. ITRS=POM*TIRS. We will just be setting it to the
//identity matrix as polar motion is not taken into account when going
//to the TIRS.
double rident[3][3]={{1,0,0},{0,1,0},{0,0,1}};
double Omega[3];//The rotation vector in the TIRS
if(nrhs<3||nrhs>6){
mexErrMsgTxt("Wrong number of inputs");
}
if(nlhs>2) {
mexErrMsgTxt("Wrong number of outputs.");
}
checkRealDoubleArray(prhs[0]);
numRow = mxGetM(prhs[0]);
numVec = mxGetN(prhs[0]);
if(!(numRow==3||numRow==6)) {
mexErrMsgTxt("The input vector has a bad dimensionality.");
}
xVec=(double*)mxGetData(prhs[0]);
TT1=getDoubleFromMatlab(prhs[1]);
TT2=getDoubleFromMatlab(prhs[2]);
//If some values from the function getEOP will be needed
if(nrhs<=5||mxIsEmpty(prhs[3])||mxIsEmpty(prhs[4])||mxIsEmpty(prhs[5])) {
mxArray *retVals[5];
double *dXdY;
mxArray *JulUTCMATLAB[2];
double JulUTC[2];
int retVal;
//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(5,retVals,2,JulUTCMATLAB,"getEOP");
mxDestroyArray(JulUTCMATLAB[0]);
mxDestroyArray(JulUTCMATLAB[1]);
//%We do not need the polar motion coordinates.
mxDestroyArray(retVals[0]);
checkRealDoubleArray(retVals[1]);
if(mxGetM(retVals[1])!=2||mxGetN(retVals[1])!=1) {
mxDestroyArray(retVals[1]);
mxDestroyArray(retVals[2]);
mxDestroyArray(retVals[3]);
mxDestroyArray(retVals[4]);
mexErrMsgTxt("Error using the getEOP function.");
return;
}
dXdY=(double*)mxGetData(retVals[1]);
dX=dXdY[0];
dY=dXdY[1];
//This is TT-UT1
deltaT=getDoubleFromMatlab(retVals[3]);
LOD=getDoubleFromMatlab(retVals[4]);
//Free the returned arrays.
mxDestroyArray(retVals[1]);
mxDestroyArray(retVals[2]);
mxDestroyArray(retVals[3]);
mxDestroyArray(retVals[4]);
}
//If deltaT=TT-UT1 is given
if(nrhs>3&&!mxIsEmpty(prhs[3])) {
deltaT=getDoubleFromMatlab(prhs[3]);
}
//Obtain UT1 from terestrial time and deltaT.
iauTtut1(TT1, TT2, deltaT, &UT11, &UT12);
//Get celestial pole offsets, if given.
if(nrhs>4&&!mxIsEmpty(prhs[4])) {
size_t dim1, dim2;
checkRealDoubleArray(prhs[4]);
dim1 = mxGetM(prhs[4]);
dim2 = mxGetN(prhs[4]);
if((dim1==2&&dim2==1)||(dim1==1&&dim2==2)) {
double *dXdY=(double*)mxGetData(prhs[4]);
dX=dXdY[0];
dY=dXdY[1];
} else {
mexErrMsgTxt("The celestial pole offsets have the wrong dimensionality.");
return;
}
}
//If LOD is given
if(nrhs>5&&mxIsEmpty(prhs[5])) {
LOD=getDoubleFromMatlab(prhs[5]);
}
//Compute the rotation matrix for going from GCRS to ITRS as well as
//the instantaneous vector angular momentum due to the Earth's rotation
//in TIRS coordinates.
{
double x, y, s, era;
double rc2i[3][3];
double omega;
//Get the X,Y coordinates of the Celestial Intermediate Pole (CIP) and
//the Celestial Intermediate Origin (CIO) locator s, using the IAU 2006
//precession and IAU 2000A nutation models.
iauXys06a(TT1, TT2, &x, &y, &s);
//Add the CIP offsets.
x += dX;
y += dY;
//Get the GCRS-to-CIRS matrix
iauC2ixys(x, y, s, rc2i);
//Find the Earth rotation angle for the given UT1 time.
era = iauEra00(UT11, UT12);
//Set the polar motion matrix to the identity matrix so that the
//conversion stops at the TIRS instead of the ITRS.
//Combine the GCRS-to-CIRS matrix, the Earth rotation angle, and use
//the identity matrix instead of the polar motion matrix to get a
//to get the rotation matrix to go from GCRS to TIRS.
iauC2tcio(rc2i, era, rident,GCRS2TIRS);
//Next, to be able to transform the velocity, the rotation of the Earth
//has to be taken into account.
//The angular velocity vector of the Earth in the TIRS in radians.
omega=getScalarMatlabClassConst("Constants","IERSMeanEarthRotationRate");
//Adjust for LOD
omega=omega*(1-LOD/86400.0);//86400.0 is the number of seconds in a TT
//day.
Omega[0]=0;
Omega[1]=0;
Omega[2]=omega;
}
//Allocate space for the return vectors.
retMat=mxCreateDoubleMatrix(numRow,numVec,mxREAL);
retData=(double*)mxGetData(retMat);
{
size_t curVec;
for(curVec=0;curVec<numVec;curVec++) {
//Multiply the position vector with the rotation matrix.
iauRxp(GCRS2TIRS, xVec+numRow*curVec, retData+numRow*curVec);
//If a velocity vector was given.
if(numRow>3) {
double *posGCRS=xVec+numRow*curVec;
double posTIRS[3];
double *velGCRS=xVec+numRow*curVec+3;//Velocity in GCRS
double velTIRS[3];
double *retDataVel=retData+numRow*curVec+3;
double rotVel[3];
//If a velocity was provided with the position, first
//convert to TIRS coordinates, then account for the
//rotation of the Earth.
//Convert velocity from GCRS to TIRS.
iauRxp(GCRS2TIRS, velGCRS, velTIRS);
//Convert position from GCRS to TIRS
iauRxp(GCRS2TIRS, posGCRS, posTIRS);
//Evaluate the cross product for the angular velocity due
//to the Earth's rotation.
iauPxp(Omega, posTIRS, rotVel);
//Subtract out the instantaneous velocity due to rotation.
iauPmp(velTIRS, rotVel, retDataVel);
}
}
}
plhs[0]=retMat;
//If the rotation matrix is desired on the output.
if(nlhs>1) {
double *elPtr;
size_t i,j;
plhs[1]=mxCreateDoubleMatrix(3,3,mxREAL);
elPtr=(double*)mxGetData(plhs[1]);
for (i=0;i<3;i++) {
for(j=0;j<3;j++) {
elPtr[i+3*j]=GCRS2TIRS[i][j];
}
}
}
}