//------------------------------------------------------------------------------
Rmatrix33 ITRFAxes::Skew(Rvector3 vec)
{
Rmatrix33 r;
r.SetElement(0,0,0.0); r.SetElement(0,1,-vec.GetElement(2)); r.SetElement(0,2,vec.GetElement(1));
r.SetElement(1,0,vec.GetElement(2)); r.SetElement(1,1,0.0); r.SetElement(1,2,-vec.GetElement(0));
r.SetElement(2,0,-vec.GetElement(1)); r.SetElement(2,1,vec.GetElement(0)); r.SetElement(2,2,0.0);
return r;
}
//------------------------------------------------------------------------------
Rmatrix33 ITRFAxes::R3(Real angle)
{
Rmatrix33 r;
Real c = cos(angle);
Real s = sin(angle);
r.SetElement(0,0,c); r.SetElement(0,1,s); r.SetElement(0,2,0.0);
r.SetElement(1,0,-s); r.SetElement(1,1,c); r.SetElement(1,2,0.0);
r.SetElement(2,0,0.0); r.SetElement(2,1,0.0); r.SetElement(2,2,1.0);
return r;
}
void CoordinateConverter::RotationMatrixFromICRFToFK5(const A1Mjd &atEpoch)
{
Real theEpoch = atEpoch.Get();
#ifdef DEBUG_ICRF_TOFK5
MessageInterface::ShowMessage(
"Enter CoordinateConverter::RotationMatrixFromICRFToFK5 at epoch %18.12lf; \n\n", theEpoch);
#endif
// Specify Euler rotation vector for theEpoch:
Real vec[3];
ICRFFile* icrfFile = ICRFFile::Instance();
icrfFile->Initialize();
icrfFile->GetICRFRotationVector(theEpoch, &vec[0], 3, 9);
// Calculate rotation matrix based on Euler rotation vector:
Real angle = GmatMathUtil::Sqrt(vec[0]*vec[0]+vec[1]*vec[1]+vec[2]*vec[2]);
Real a[3];
a[0] = vec[0]/angle; a[1] = vec[1]/angle; a[2] = vec[2]/angle;
Real c = GmatMathUtil::Cos(angle);
Real s = GmatMathUtil::Sin(angle);
// rotation matrix from FK5 to ICRF:
Rmatrix33 rotM;
rotM.SetElement(0,0, c+a[0]*a[0]*(1-c));
rotM.SetElement(0,1, a[0]*a[1]*(1-c)+a[2]*s);
rotM.SetElement(0,2, a[0]*a[2]*(1-c)-a[1]*s);
rotM.SetElement(1,0, a[0]*a[1]*(1-c)-a[2]*s);
rotM.SetElement(1,1, c+a[1]*a[1]*(1-c));
rotM.SetElement(1,2, a[1]*a[2]*(1-c)+a[0]*s);
rotM.SetElement(2,0, a[0]*a[2]*(1-c)+a[1]*s);
rotM.SetElement(2,1, a[1]*a[2]*(1-c)-a[0]*s);
rotM.SetElement(2,2, c+a[2]*a[2]*(1-c));
// rotation matrix from ICRF to FK5:
icrfToFK5 = rotM.Transpose();
// rotation dot matrix from ICRF to FK5:
icrfToFK5Dot.Set(0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0);
#ifdef DEBUG_ICRF_TOFK5
MessageInterface::ShowMessage("theEpoch = %18.12lf\n",theEpoch);
MessageInterface::ShowMessage("rotation vector = %18.12e %18.12e %18.12e\n", vec[0], vec[1], vec[2]);
MessageInterface::ShowMessage("R(0,0)=%18.12e, R(0,1)=%18.12e, R(0,2)=%18.12e\n",icrfToFK5(0,0),icrfToFK5(0,1),icrfToFK5(0,2));
MessageInterface::ShowMessage("R(1,0)=%18.12e, R(1,1)=%18.12e, R(1,2)=%18.12e\n",icrfToFK5(1,0),icrfToFK5(1,1),icrfToFK5(1,2));
MessageInterface::ShowMessage("R(2,0)=%18.12e, R(2,1)=%18.12e, R(2,2)=%18.12e\n",icrfToFK5(2,0),icrfToFK5(2,1),icrfToFK5(2,2));
MessageInterface::ShowMessage("Rdot(0,0)=%18.12e, Rdot(0,1)=%18.12e, Rdot(0,2)=%18.12e\n",icrfToFK5Dot(0,0),icrfToFK5Dot(0,1),icrfToFK5Dot(0,2));
MessageInterface::ShowMessage("Rdot(1,0)=%18.12e, Rdot(1,1)=%18.12e, Rdot(1,2)=%18.12e\n",icrfToFK5Dot(1,0),icrfToFK5Dot(1,1),icrfToFK5Dot(1,2));
MessageInterface::ShowMessage("Rdot(2,0)=%18.12e, Rdot(2,1)=%18.12e, Rdot(2,2)=%18.12e\n\n\n",icrfToFK5Dot(2,0),icrfToFK5Dot(2,1),icrfToFK5Dot(2,2));
#endif
#ifdef DEBUG_ICRF_TOFK5
MessageInterface::ShowMessage("NOW exiting CoordinateConverter::RotationMatrixFromICRFToFK5 ...\n\n");
#endif
}
//------------------------------------------------------------------------------
void ITRFAxes::CalculateRotationMatrix(const A1Mjd &atEpoch,
bool forceComputation)
{
#ifdef DEBUG_FIRST_CALL
if (!firstCallFired)
MessageInterface::ShowMessage(
"Calling ITRF::CalculateRotationMatrix at epoch %18.12lf; \n", atEpoch.Get());
#endif
Real theEpoch = atEpoch.Get();
// Perform time computations and read EOP file
Real sec2rad = GmatMathConstants::RAD_PER_DEG/3600;
Real a1MJD = theEpoch;
Real utcMJD = TimeConverterUtil::Convert(a1MJD,
TimeConverterUtil::A1MJD, TimeConverterUtil::UTCMJD,
JD_JAN_5_1941);
Real offset = JD_JAN_5_1941 - JD_NOV_17_1858;
Real xp,yp,LOD,dUT1;
dUT1 = eop->GetUt1UtcOffset(utcMJD + offset);
eop->GetPolarMotionAndLod(utcMJD + offset, xp, yp, LOD);
xp = xp*sec2rad;
yp = yp*sec2rad;
Real ut1MJD = TimeConverterUtil::Convert(a1MJD,
TimeConverterUtil::A1MJD, TimeConverterUtil::UT1,
JD_JAN_5_1941);
// Compute elapsed Julian centuries (UT1)
Real tDiff = JD_JAN_5_1941 - JD_OF_J2000;
Real jdUT1 = ut1MJD + JD_JAN_5_1941;
// convert input A1 MJD to TT MJD (for most calculations)
Real ttMJD = TimeConverterUtil::Convert(a1MJD,
TimeConverterUtil::A1MJD, TimeConverterUtil::TTMJD,
JD_JAN_5_1941);
Real jdTT = ttMJD + JD_JAN_5_1941; // right?
// Compute Julian centuries of TDB from the base epoch (J2000)
// NOTE - this is really TT, an approximation of TDB *********
Real T_TT = (ttMJD + tDiff) / DAYS_PER_JULIAN_CENTURY;
// Compute the Polar Motion Matrix, W, and Earth Rotation Angle, theta
Real sPrime = -0.000047*sec2rad*T_TT;
Rmatrix33 W = R3(-sPrime)*R2(xp)*R1(yp);
Real theta = fmod(GmatMathConstants::TWO_PI*(0.7790572732640 + 1.00273781191135448*(jdUT1 - 2451545.0)),GmatMathConstants::TWO_PI);
// Compute the precession-nutation matrix
// . interpolate the XYs data file
Real data[3];
if (iauFile == NULL)
{
throw CoordinateSystemException("Error: IAUFile object is NULL. GMAT cannot get IAU data.\n");
}
iauFile->GetIAUData(jdTT,data,3,9);
Real X = data[0]*sec2rad;
Real Y = data[1]*sec2rad;
Real s = data[2]*sec2rad;
// . construct the Precession Nutation matrix
Real b = 1/(1 + sqrt(1- X*X - Y*Y));
Rmatrix33 CT;
CT.SetElement(0,0, 1-b*X*X); CT.SetElement(0,1, -b*X*Y ); CT.SetElement(0,2,X);
CT.SetElement(1,0, -b*X*Y); CT.SetElement(1,1, 1-b*Y*Y); CT.SetElement(1,2,Y);
CT.SetElement(2,0, -X); CT.SetElement(2,1, -Y); CT.SetElement(2,2,(1 - b*(X*X + Y*Y)));
CT = CT*R3(s);
// Form the complete rotation matrix from ITRF to GCRF
Rmatrix33 R = CT*R3(-theta)*W;
Real omegaEarth = 7.292115146706979e-5*(1 - LOD/86400);
Rvector3 vec(0.0, 0.0, omegaEarth);
Rmatrix33 Rdot = CT*R3(-theta)*Skew(vec)*W;
rotMatrix = R;
rotDotMatrix = Rdot;
#ifdef DEBUG_ITRF_ROT_MATRIX
MessageInterface::ShowMessage("a1MJD = %18.10lf\n",a1MJD);
MessageInterface::ShowMessage("utcMJD = %18.10lf\n",utcMJD);
MessageInterface::ShowMessage("dUT1=%18.10e, xp=%18.10e, yp=%18.10e, LOD=%18.10e\n",dUT1,xp,yp,LOD);
MessageInterface::ShowMessage("ut1MJD = %18.10lf\n",ut1MJD);
MessageInterface::ShowMessage("ttMJD = %18.10lf\n",ttMJD);
MessageInterface::ShowMessage("jdTT = %18.10lf\n",jdTT);
MessageInterface::ShowMessage("jdUT1 = %18.10lf\n",jdUT1);
MessageInterface::ShowMessage("T_TT = %18.10lf\n\n",T_TT);
MessageInterface::ShowMessage("sPrime = %18.10lf, theta = %18.10lf\n",sPrime, theta);
MessageInterface::ShowMessage("W(0,0)=%18.10lf, W(0,1)=%18.10lf, W(0,2)=%18.10lf\n",W.GetElement(0,0),W.GetElement(0,1),W.GetElement(0,2));
MessageInterface::ShowMessage("W(1,0)=%18.10lf, W(1,1)=%18.10lf, W(1,2)=%18.10lf\n",W.GetElement(1,0),W.GetElement(1,1),W.GetElement(1,2));
MessageInterface::ShowMessage("W(2,0)=%18.10lf, W(2,1)=%18.10lf, W(2,2)=%18.10lf\n",W.GetElement(2,0),W.GetElement(2,1),W.GetElement(2,2));
MessageInterface::ShowMessage("X = %18.10lf, Y = %18.10lf, s = %18.10lf\n", X, Y, s);
MessageInterface::ShowMessage("CT(0,0)=%18.10lf, CT(0,1)=%18.10lf, CT(0,2)=%18.10lf\n",CT.GetElement(0,0),CT.GetElement(0,1),CT.GetElement(0,2));
MessageInterface::ShowMessage("CT(1,0)=%18.10lf, CT(1,1)=%18.10lf, CT(1,2)=%18.10lf\n",CT.GetElement(1,0),CT.GetElement(1,1),CT.GetElement(1,2));
MessageInterface::ShowMessage("CT(2,0)=%18.10lf, CT(2,1)=%18.10lf, CT(2,2)=%18.10lf\n",CT.GetElement(2,0),CT.GetElement(2,1),CT.GetElement(2,2));
MessageInterface::ShowMessage("R(0,0)=%18.10lf, R(0,1)=%18.10lf, R(0,2)=%18.10lf\n",R.GetElement(0,0),R.GetElement(0,1),R.GetElement(0,2));
MessageInterface::ShowMessage("R(1,0)=%18.10lf, R(1,1)=%18.10lf, R(1,2)=%18.10lf\n",R.GetElement(1,0),R.GetElement(1,1),R.GetElement(1,2));
MessageInterface::ShowMessage("R(2,0)=%18.10lf, R(2,1)=%18.10lf, R(2,2)=%18.10lf\n",R.GetElement(2,0),R.GetElement(2,1),R.GetElement(2,2));
MessageInterface::ShowMessage("Rdot(0,0)=%18.10lf, Rdot(0,1)=%18.10lf, Rdot(0,2)=%18.10lf\n",Rdot.GetElement(0,0),Rdot.GetElement(0,1),Rdot.GetElement(0,2));
MessageInterface::ShowMessage("Rdot(1,0)=%18.10lf, Rdot(1,1)=%18.10lf, Rdot(1,2)=%18.10lf\n",Rdot.GetElement(1,0),Rdot.GetElement(1,1),Rdot.GetElement(1,2));
MessageInterface::ShowMessage("Rdot(2,0)=%18.10lf, Rdot(2,1)=%18.10lf, Rdot(2,2)=%18.10lf\n\n\n",Rdot.GetElement(2,0),Rdot.GetElement(2,1),Rdot.GetElement(2,2));
#endif
#ifdef DEBUG_FIRST_CALL
firstCallFired = true;
MessageInterface::ShowMessage("NOW exiting ITRFAxes::CalculateRotationMatrix ...\n");
#endif
}
