IERSConventions.java
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package org.orekit.utils;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Serializable;
import java.util.List;
import org.hipparchus.analysis.differentiation.DerivativeStructure;
import org.hipparchus.analysis.interpolation.HermiteInterpolator;
import org.hipparchus.util.FastMath;
import org.hipparchus.util.MathUtils;
import org.orekit.data.BodiesElements;
import org.orekit.data.DelaunayArguments;
import org.orekit.data.FieldBodiesElements;
import org.orekit.data.FundamentalNutationArguments;
import org.orekit.data.PoissonSeries;
import org.orekit.data.PoissonSeriesParser;
import org.orekit.data.PolynomialNutation;
import org.orekit.data.PolynomialParser;
import org.orekit.data.PolynomialParser.Unit;
import org.orekit.data.SimpleTimeStampedTableParser;
import org.orekit.errors.OrekitException;
import org.orekit.errors.OrekitInternalError;
import org.orekit.errors.OrekitMessages;
import org.orekit.errors.TimeStampedCacheException;
import org.orekit.frames.EOPHistory;
import org.orekit.frames.PoleCorrection;
import org.orekit.time.AbsoluteDate;
import org.orekit.time.DateComponents;
import org.orekit.time.TimeComponents;
import org.orekit.time.TimeFunction;
import org.orekit.time.TimeScale;
import org.orekit.time.TimeScalesFactory;
import org.orekit.time.TimeStamped;
/** Supported IERS conventions.
* @since 6.0
* @author Luc Maisonobe
*/
public enum IERSConventions {
/** Constant for IERS 1996 conventions. */
IERS_1996 {
/** Nutation arguments resources. */
private static final String NUTATION_ARGUMENTS = IERS_BASE + "1996/nutation-arguments.txt";
/** X series resources. */
private static final String X_Y_SERIES = IERS_BASE + "1996/tab5.4.txt";
/** Psi series resources. */
private static final String PSI_EPSILON_SERIES = IERS_BASE + "1996/tab5.1.txt";
/** Tidal correction for xp, yp series resources. */
private static final String TIDAL_CORRECTION_XP_YP_SERIES = IERS_BASE + "1996/tab8.4.txt";
/** Tidal correction for UT1 resources. */
private static final String TIDAL_CORRECTION_UT1_SERIES = IERS_BASE + "1996/tab8.3.txt";
/** Love numbers resources. */
private static final String LOVE_NUMBERS = IERS_BASE + "1996/tab6.1.txt";
/** Frequency dependence model for k₂₀. */
private static final String K20_FREQUENCY_DEPENDENCE = IERS_BASE + "1996/tab6.2b.txt";
/** Frequency dependence model for k₂₁. */
private static final String K21_FREQUENCY_DEPENDENCE = IERS_BASE + "1996/tab6.2a.txt";
/** Frequency dependence model for k₂₂. */
private static final String K22_FREQUENCY_DEPENDENCE = IERS_BASE + "1996/tab6.2c.txt";
/** {@inheritDoc} */
@Override
public FundamentalNutationArguments getNutationArguments(final TimeScale timeScale)
throws OrekitException {
return new FundamentalNutationArguments(this, timeScale,
getStream(NUTATION_ARGUMENTS), NUTATION_ARGUMENTS);
}
/** {@inheritDoc} */
@Override
public TimeFunction<Double> getMeanObliquityFunction() throws OrekitException {
// value from chapter 5, page 22
final PolynomialNutation<DerivativeStructure> epsilonA =
new PolynomialNutation<DerivativeStructure>(84381.448 * Constants.ARC_SECONDS_TO_RADIANS,
-46.8150 * Constants.ARC_SECONDS_TO_RADIANS,
-0.00059 * Constants.ARC_SECONDS_TO_RADIANS,
0.001813 * Constants.ARC_SECONDS_TO_RADIANS);
return new TimeFunction<Double>() {
/** {@inheritDoc} */
@Override
public Double value(final AbsoluteDate date) {
return epsilonA.value(evaluateTC(date));
}
};
}
/** {@inheritDoc} */
@Override
public TimeFunction<double[]> getXYSpXY2Function()
throws OrekitException {
// set up nutation arguments
final FundamentalNutationArguments arguments = getNutationArguments(null);
// X = 2004.3109″t - 0.42665″t² - 0.198656″t³ + 0.0000140″t⁴
// + 0.00006″t² cos Ω + sin ε0 { Σ [(Ai + Ai' t) sin(ARGUMENT) + Ai'' t cos(ARGUMENT)]}
// + 0.00204″t² sin Ω + 0.00016″t² sin 2(F - D + Ω),
final PolynomialNutation<DerivativeStructure> xPolynomial =
new PolynomialNutation<DerivativeStructure>(0,
2004.3109 * Constants.ARC_SECONDS_TO_RADIANS,
-0.42665 * Constants.ARC_SECONDS_TO_RADIANS,
-0.198656 * Constants.ARC_SECONDS_TO_RADIANS,
0.0000140 * Constants.ARC_SECONDS_TO_RADIANS);
final double fXCosOm = 0.00006 * Constants.ARC_SECONDS_TO_RADIANS;
final double fXSinOm = 0.00204 * Constants.ARC_SECONDS_TO_RADIANS;
final double fXSin2FDOm = 0.00016 * Constants.ARC_SECONDS_TO_RADIANS;
final double sinEps0 = FastMath.sin(getMeanObliquityFunction().value(getNutationReferenceEpoch()));
final double deciMilliAS = Constants.ARC_SECONDS_TO_RADIANS * 1.0e-4;
final PoissonSeriesParser<DerivativeStructure> baseParser =
new PoissonSeriesParser<DerivativeStructure>(12).withFirstDelaunay(1);
final PoissonSeriesParser<DerivativeStructure> xParser =
baseParser.
withSinCos(0, 7, deciMilliAS, -1, deciMilliAS).
withSinCos(1, 8, deciMilliAS, 9, deciMilliAS);
final PoissonSeries<DerivativeStructure> xSum = xParser.parse(getStream(X_Y_SERIES), X_Y_SERIES);
// Y = -0.00013″ - 22.40992″t² + 0.001836″t³ + 0.0011130″t⁴
// + Σ [(Bi + Bi' t) cos(ARGUMENT) + Bi'' t sin(ARGUMENT)]
// - 0.00231″t² cos Ω − 0.00014″t² cos 2(F - D + Ω)
final PolynomialNutation<DerivativeStructure> yPolynomial =
new PolynomialNutation<DerivativeStructure>(-0.00013 * Constants.ARC_SECONDS_TO_RADIANS,
0.0,
-22.40992 * Constants.ARC_SECONDS_TO_RADIANS,
0.001836 * Constants.ARC_SECONDS_TO_RADIANS,
0.0011130 * Constants.ARC_SECONDS_TO_RADIANS);
final double fYCosOm = -0.00231 * Constants.ARC_SECONDS_TO_RADIANS;
final double fYCos2FDOm = -0.00014 * Constants.ARC_SECONDS_TO_RADIANS;
final PoissonSeriesParser<DerivativeStructure> yParser =
baseParser.
withSinCos(0, -1, deciMilliAS, 10, deciMilliAS).
withSinCos(1, 12, deciMilliAS, 11, deciMilliAS);
final PoissonSeries<DerivativeStructure> ySum = yParser.parse(getStream(X_Y_SERIES), X_Y_SERIES);
final PoissonSeries.CompiledSeries<DerivativeStructure> xySum =
PoissonSeries.compile(xSum, ySum);
// s = -XY/2 + 0.00385″t - 0.07259″t³ - 0.00264″ sin Ω - 0.00006″ sin 2Ω
// + 0.00074″t² sin Ω + 0.00006″t² sin 2(F - D + Ω)
final double fST = 0.00385 * Constants.ARC_SECONDS_TO_RADIANS;
final double fST3 = -0.07259 * Constants.ARC_SECONDS_TO_RADIANS;
final double fSSinOm = -0.00264 * Constants.ARC_SECONDS_TO_RADIANS;
final double fSSin2Om = -0.00006 * Constants.ARC_SECONDS_TO_RADIANS;
final double fST2SinOm = 0.00074 * Constants.ARC_SECONDS_TO_RADIANS;
final double fST2Sin2FDOm = 0.00006 * Constants.ARC_SECONDS_TO_RADIANS;
return new TimeFunction<double[]>() {
/** {@inheritDoc} */
@Override
public double[] value(final AbsoluteDate date) {
final BodiesElements elements = arguments.evaluateAll(date);
final double[] xy = xySum.value(elements);
final double omega = elements.getOmega();
final double f = elements.getF();
final double d = elements.getD();
final double t = elements.getTC();
final double cosOmega = FastMath.cos(omega);
final double sinOmega = FastMath.sin(omega);
final double sin2Omega = FastMath.sin(2 * omega);
final double cos2FDOm = FastMath.cos(2 * (f - d + omega));
final double sin2FDOm = FastMath.sin(2 * (f - d + omega));
final double x = xPolynomial.value(t) + sinEps0 * xy[0] +
t * t * (fXCosOm * cosOmega + fXSinOm * sinOmega + fXSin2FDOm * cos2FDOm);
final double y = yPolynomial.value(t) + xy[1] +
t * t * (fYCosOm * cosOmega + fYCos2FDOm * cos2FDOm);
final double sPxy2 = fSSinOm * sinOmega + fSSin2Om * sin2Omega +
t * (fST + t * (fST2SinOm * sinOmega + fST2Sin2FDOm * sin2FDOm + t * fST3));
return new double[] {
x, y, sPxy2
};
}
};
}
/** {@inheritDoc} */
@Override
public TimeFunction<double[]> getPrecessionFunction() throws OrekitException {
// set up the conventional polynomials
// the following values are from Lieske et al. paper:
// Expressions for the precession quantities based upon the IAU(1976) system of astronomical constants
// http://articles.adsabs.harvard.edu/full/1977A%26A....58....1L
// also available as equation 30 in IERS 2003 conventions
final PolynomialNutation<DerivativeStructure> psiA =
new PolynomialNutation<DerivativeStructure>( 0.0,
5038.7784 * Constants.ARC_SECONDS_TO_RADIANS,
-1.07259 * Constants.ARC_SECONDS_TO_RADIANS,
-0.001147 * Constants.ARC_SECONDS_TO_RADIANS);
final PolynomialNutation<DerivativeStructure> omegaA =
new PolynomialNutation<DerivativeStructure>(getMeanObliquityFunction().value(getNutationReferenceEpoch()),
0.0,
0.05127 * Constants.ARC_SECONDS_TO_RADIANS,
-0.007726 * Constants.ARC_SECONDS_TO_RADIANS);
final PolynomialNutation<DerivativeStructure> chiA =
new PolynomialNutation<DerivativeStructure>( 0.0,
10.5526 * Constants.ARC_SECONDS_TO_RADIANS,
-2.38064 * Constants.ARC_SECONDS_TO_RADIANS,
-0.001125 * Constants.ARC_SECONDS_TO_RADIANS);
return new TimeFunction<double[]>() {
/** {@inheritDoc} */
@Override
public double[] value(final AbsoluteDate date) {
final double tc = evaluateTC(date);
return new double[] {
psiA.value(tc), omegaA.value(tc), chiA.value(tc)
};
}
};
}
/** {@inheritDoc} */
@Override
public TimeFunction<double[]> getNutationFunction()
throws OrekitException {
// set up nutation arguments
final FundamentalNutationArguments arguments = getNutationArguments(null);
// set up Poisson series
final double deciMilliAS = Constants.ARC_SECONDS_TO_RADIANS * 1.0e-4;
final PoissonSeriesParser<DerivativeStructure> baseParser =
new PoissonSeriesParser<DerivativeStructure>(10).withFirstDelaunay(1);
final PoissonSeriesParser<DerivativeStructure> psiParser =
baseParser.
withSinCos(0, 7, deciMilliAS, -1, deciMilliAS).
withSinCos(1, 8, deciMilliAS, -1, deciMilliAS);
final PoissonSeries<DerivativeStructure> psiSeries = psiParser.parse(getStream(PSI_EPSILON_SERIES), PSI_EPSILON_SERIES);
final PoissonSeriesParser<DerivativeStructure> epsilonParser =
baseParser.
withSinCos(0, -1, deciMilliAS, 9, deciMilliAS).
withSinCos(1, -1, deciMilliAS, 10, deciMilliAS);
final PoissonSeries<DerivativeStructure> epsilonSeries = epsilonParser.parse(getStream(PSI_EPSILON_SERIES), PSI_EPSILON_SERIES);
final PoissonSeries.CompiledSeries<DerivativeStructure> psiEpsilonSeries =
PoissonSeries.compile(psiSeries, epsilonSeries);
return new TimeFunction<double[]>() {
/** {@inheritDoc} */
@Override
public double[] value(final AbsoluteDate date) {
final BodiesElements elements = arguments.evaluateAll(date);
final double[] psiEpsilon = psiEpsilonSeries.value(elements);
return new double[] {
psiEpsilon[0], psiEpsilon[1], IAU1994ResolutionC7.value(elements)
};
}
};
}
/** {@inheritDoc} */
@Override
public TimeFunction<DerivativeStructure> getGMSTFunction(final TimeScale ut1)
throws OrekitException {
// Radians per second of time
final double radiansPerSecond = MathUtils.TWO_PI / Constants.JULIAN_DAY;
// constants from IERS 1996 page 21
// the underlying model is IAU 1982 GMST-UT1
final AbsoluteDate gmstReference =
new AbsoluteDate(DateComponents.J2000_EPOCH, TimeComponents.H12, TimeScalesFactory.getTAI());
final double gmst0 = 24110.54841;
final double gmst1 = 8640184.812866;
final double gmst2 = 0.093104;
final double gmst3 = -6.2e-6;
return new TimeFunction<DerivativeStructure>() {
/** {@inheritDoc} */
@Override
public DerivativeStructure value(final AbsoluteDate date) {
// offset in Julian centuries from J2000 epoch (UT1 scale)
final double dtai = date.durationFrom(gmstReference);
final DerivativeStructure tut1 =
new DerivativeStructure(1, 1, dtai + ut1.offsetFromTAI(date), 1.0);
final DerivativeStructure tt = tut1.divide(Constants.JULIAN_CENTURY);
// Seconds in the day, adjusted by 12 hours because the
// UT1 is supplied as a Julian date beginning at noon.
final DerivativeStructure sd = tut1.add(Constants.JULIAN_DAY / 2).remainder(Constants.JULIAN_DAY);
// compute Greenwich mean sidereal time, in radians
return tt.multiply(gmst3).add(gmst2).multiply(tt).add(gmst1).multiply(tt).add(gmst0).add(sd).multiply(radiansPerSecond);
}
};
}
/** {@inheritDoc} */
@Override
public TimeFunction<DerivativeStructure> getGASTFunction(final TimeScale ut1,
final EOPHistory eopHistory)
throws OrekitException {
// obliquity
final TimeFunction<Double> epsilonA = getMeanObliquityFunction();
// GMST function
final TimeFunction<DerivativeStructure> gmst = getGMSTFunction(ut1);
// nutation function
final TimeFunction<double[]> nutation = getNutationFunction();
return new TimeFunction<DerivativeStructure>() {
/** {@inheritDoc} */
@Override
public DerivativeStructure value(final AbsoluteDate date) {
// compute equation of equinoxes
final double[] angles = nutation.value(date);
double deltaPsi = angles[0];
if (eopHistory != null) {
deltaPsi += eopHistory.getEquinoxNutationCorrection(date)[0];
}
final double eqe = deltaPsi * FastMath.cos(epsilonA.value(date)) + angles[2];
// add mean sidereal time and equation of equinoxes
return gmst.value(date).add(eqe);
}
};
}
/** {@inheritDoc} */
@Override
public TimeFunction<double[]> getEOPTidalCorrection()
throws OrekitException {
// set up nutation arguments
// BEWARE! Using TT as the time scale here and not UT1 is intentional!
// as this correction is used to compute UT1 itself, it is not surprising we cannot use UT1 yet,
// however, using the close UTC as would seem logical make the comparison with interp.f from IERS fail
// looking in the interp.f code, the same TT scale is used for both Delaunay and gamma argument
final FundamentalNutationArguments arguments = getNutationArguments(TimeScalesFactory.getTT());
// set up Poisson series
final double milliAS = Constants.ARC_SECONDS_TO_RADIANS * 1.0e-3;
final PoissonSeriesParser<DerivativeStructure> xyParser = new PoissonSeriesParser<DerivativeStructure>(17).
withOptionalColumn(1).
withGamma(7).
withFirstDelaunay(2);
final PoissonSeries<DerivativeStructure> xSeries =
xyParser.
withSinCos(0, 14, milliAS, 15, milliAS).
parse(getStream(TIDAL_CORRECTION_XP_YP_SERIES), TIDAL_CORRECTION_XP_YP_SERIES);
final PoissonSeries<DerivativeStructure> ySeries =
xyParser.
withSinCos(0, 16, milliAS, 17, milliAS).
parse(getStream(TIDAL_CORRECTION_XP_YP_SERIES),
TIDAL_CORRECTION_XP_YP_SERIES);
final double deciMilliS = 1.0e-4;
final PoissonSeriesParser<DerivativeStructure> ut1Parser = new PoissonSeriesParser<DerivativeStructure>(17).
withOptionalColumn(1).
withGamma(7).
withFirstDelaunay(2).
withSinCos(0, 16, deciMilliS, 17, deciMilliS);
final PoissonSeries<DerivativeStructure> ut1Series =
ut1Parser.parse(getStream(TIDAL_CORRECTION_UT1_SERIES), TIDAL_CORRECTION_UT1_SERIES);
final PoissonSeries.CompiledSeries<DerivativeStructure> correctionSeries =
PoissonSeries.compile(xSeries, ySeries, ut1Series);
return new TimeFunction<double[]>() {
/** {@inheritDoc} */
@Override
public double[] value(final AbsoluteDate date) {
final FieldBodiesElements<DerivativeStructure> elements =
arguments.evaluateDerivative(date);
final DerivativeStructure[] correction = correctionSeries.value(elements);
return new double[] {
correction[0].getValue(),
correction[1].getValue(),
correction[2].getValue(),
-correction[2].getPartialDerivative(1) * Constants.JULIAN_DAY
};
}
};
}
/** {@inheritDoc} */
public LoveNumbers getLoveNumbers() throws OrekitException {
return loadLoveNumbers(LOVE_NUMBERS);
}
/** {@inheritDoc} */
public TimeFunction<double[]> getTideFrequencyDependenceFunction(final TimeScale ut1)
throws OrekitException {
// set up nutation arguments
final FundamentalNutationArguments arguments = getNutationArguments(ut1);
// set up Poisson series
final PoissonSeriesParser<DerivativeStructure> k20Parser =
new PoissonSeriesParser<DerivativeStructure>(18).
withOptionalColumn(1).
withDoodson(4, 2).
withFirstDelaunay(10);
final PoissonSeriesParser<DerivativeStructure> k21Parser =
new PoissonSeriesParser<DerivativeStructure>(18).
withOptionalColumn(1).
withDoodson(4, 3).
withFirstDelaunay(10);
final PoissonSeriesParser<DerivativeStructure> k22Parser =
new PoissonSeriesParser<DerivativeStructure>(16).
withOptionalColumn(1).
withDoodson(4, 2).
withFirstDelaunay(10);
final double pico = 1.0e-12;
final PoissonSeries<DerivativeStructure> c20Series =
k20Parser.
withSinCos(0, 18, -pico, 16, pico).
parse(getStream(K20_FREQUENCY_DEPENDENCE), K20_FREQUENCY_DEPENDENCE);
final PoissonSeries<DerivativeStructure> c21Series =
k21Parser.
withSinCos(0, 17, pico, 18, pico).
parse(getStream(K21_FREQUENCY_DEPENDENCE), K21_FREQUENCY_DEPENDENCE);
final PoissonSeries<DerivativeStructure> s21Series =
k21Parser.
withSinCos(0, 18, -pico, 17, pico).
parse(getStream(K21_FREQUENCY_DEPENDENCE), K21_FREQUENCY_DEPENDENCE);
final PoissonSeries<DerivativeStructure> c22Series =
k22Parser.
withSinCos(0, -1, pico, 16, pico).
parse(getStream(K22_FREQUENCY_DEPENDENCE), K22_FREQUENCY_DEPENDENCE);
final PoissonSeries<DerivativeStructure> s22Series =
k22Parser.
withSinCos(0, 16, -pico, -1, pico).
parse(getStream(K22_FREQUENCY_DEPENDENCE), K22_FREQUENCY_DEPENDENCE);
final PoissonSeries.CompiledSeries<DerivativeStructure> kSeries =
PoissonSeries.compile(c20Series, c21Series, s21Series, c22Series, s22Series);
return new TimeFunction<double[]>() {
/** {@inheritDoc} */
@Override
public double[] value(final AbsoluteDate date) {
return kSeries.value(arguments.evaluateAll(date));
}
};
}
/** {@inheritDoc} */
@Override
public double getPermanentTide() throws OrekitException {
return 4.4228e-8 * -0.31460 * getLoveNumbers().getReal(2, 0);
}
/** {@inheritDoc} */
@Override
public TimeFunction<double[]> getSolidPoleTide(final EOPHistory eopHistory) {
// constants from IERS 1996 page 47
final double globalFactor = -1.348e-9 / Constants.ARC_SECONDS_TO_RADIANS;
final double coupling = 0.00112;
return new TimeFunction<double[]>() {
/** {@inheritDoc} */
@Override
public double[] value(final AbsoluteDate date) {
final PoleCorrection pole = eopHistory.getPoleCorrection(date);
return new double[] {
globalFactor * (pole.getXp() + coupling * pole.getYp()),
globalFactor * (coupling * pole.getXp() - pole.getYp()),
};
}
};
}
/** {@inheritDoc} */
@Override
public TimeFunction<double[]> getOceanPoleTide(final EOPHistory eopHistory)
throws OrekitException {
return new TimeFunction<double[]>() {
/** {@inheritDoc} */
@Override
public double[] value(final AbsoluteDate date) {
// there are no model for ocean pole tide prior to conventions 2010
return new double[] {
0.0, 0.0
};
}
};
}
},
/** Constant for IERS 2003 conventions. */
IERS_2003 {
/** Nutation arguments resources. */
private static final String NUTATION_ARGUMENTS = IERS_BASE + "2003/nutation-arguments.txt";
/** X series resources. */
private static final String X_SERIES = IERS_BASE + "2003/tab5.2a.txt";
/** Y series resources. */
private static final String Y_SERIES = IERS_BASE + "2003/tab5.2b.txt";
/** S series resources. */
private static final String S_SERIES = IERS_BASE + "2003/tab5.2c.txt";
/** Luni-solar series resources. */
private static final String LUNI_SOLAR_SERIES = IERS_BASE + "2003/tab5.3a-first-table.txt";
/** Planetary series resources. */
private static final String PLANETARY_SERIES = IERS_BASE + "2003/tab5.3b.txt";
/** Greenwhich sidereal time series resources. */
private static final String GST_SERIES = IERS_BASE + "2003/tab5.4.txt";
/** Tidal correction for xp, yp series resources. */
private static final String TIDAL_CORRECTION_XP_YP_SERIES = IERS_BASE + "2003/tab8.2ab.txt";
/** Tidal correction for UT1 resources. */
private static final String TIDAL_CORRECTION_UT1_SERIES = IERS_BASE + "2003/tab8.3ab.txt";
/** Love numbers resources. */
private static final String LOVE_NUMBERS = IERS_BASE + "2003/tab6.1.txt";
/** Frequency dependence model for k₂₀. */
private static final String K20_FREQUENCY_DEPENDENCE = IERS_BASE + "2003/tab6.3b.txt";
/** Frequency dependence model for k₂₁. */
private static final String K21_FREQUENCY_DEPENDENCE = IERS_BASE + "2003/tab6.3a.txt";
/** Frequency dependence model for k₂₂. */
private static final String K22_FREQUENCY_DEPENDENCE = IERS_BASE + "2003/tab6.3c.txt";
/** Annual pole table. */
private static final String ANNUAL_POLE = IERS_BASE + "2003/annual.pole";
/** {@inheritDoc} */
public FundamentalNutationArguments getNutationArguments(final TimeScale timeScale)
throws OrekitException {
return new FundamentalNutationArguments(this, timeScale,
getStream(NUTATION_ARGUMENTS), NUTATION_ARGUMENTS);
}
/** {@inheritDoc} */
@Override
public TimeFunction<Double> getMeanObliquityFunction() throws OrekitException {
// epsilon 0 value from chapter 5, page 41, other terms from equation 32 page 45
final PolynomialNutation<DerivativeStructure> epsilonA =
new PolynomialNutation<DerivativeStructure>(84381.448 * Constants.ARC_SECONDS_TO_RADIANS,
-46.84024 * Constants.ARC_SECONDS_TO_RADIANS,
-0.00059 * Constants.ARC_SECONDS_TO_RADIANS,
0.001813 * Constants.ARC_SECONDS_TO_RADIANS);
return new TimeFunction<Double>() {
/** {@inheritDoc} */
@Override
public Double value(final AbsoluteDate date) {
return epsilonA.value(evaluateTC(date));
}
};
}
/** {@inheritDoc} */
@Override
public TimeFunction<double[]> getXYSpXY2Function()
throws OrekitException {
// set up nutation arguments
final FundamentalNutationArguments arguments = getNutationArguments(null);
// set up Poisson series
final double microAS = Constants.ARC_SECONDS_TO_RADIANS * 1.0e-6;
final PoissonSeriesParser<DerivativeStructure> parser =
new PoissonSeriesParser<DerivativeStructure>(17).
withPolynomialPart('t', PolynomialParser.Unit.MICRO_ARC_SECONDS).
withFirstDelaunay(4).
withFirstPlanetary(9).
withSinCos(0, 2, microAS, 3, microAS);
final PoissonSeries<DerivativeStructure> xSeries = parser.parse(getStream(X_SERIES), X_SERIES);
final PoissonSeries<DerivativeStructure> ySeries = parser.parse(getStream(Y_SERIES), Y_SERIES);
final PoissonSeries<DerivativeStructure> sSeries = parser.parse(getStream(S_SERIES), S_SERIES);
final PoissonSeries.CompiledSeries<DerivativeStructure> xys = PoissonSeries.compile(xSeries, ySeries, sSeries);
// create a function evaluating the series
return new TimeFunction<double[]>() {
/** {@inheritDoc} */
@Override
public double[] value(final AbsoluteDate date) {
return xys.value(arguments.evaluateAll(date));
}
};
}
/** {@inheritDoc} */
@Override
public TimeFunction<double[]> getPrecessionFunction() throws OrekitException {
// set up the conventional polynomials
// the following values are from equation 32 in IERS 2003 conventions
final PolynomialNutation<DerivativeStructure> psiA =
new PolynomialNutation<DerivativeStructure>( 0.0,
5038.47875 * Constants.ARC_SECONDS_TO_RADIANS,
-1.07259 * Constants.ARC_SECONDS_TO_RADIANS,
-0.001147 * Constants.ARC_SECONDS_TO_RADIANS);
final PolynomialNutation<DerivativeStructure> omegaA =
new PolynomialNutation<DerivativeStructure>(getMeanObliquityFunction().value(getNutationReferenceEpoch()),
-0.02524 * Constants.ARC_SECONDS_TO_RADIANS,
0.05127 * Constants.ARC_SECONDS_TO_RADIANS,
-0.007726 * Constants.ARC_SECONDS_TO_RADIANS);
final PolynomialNutation<DerivativeStructure> chiA =
new PolynomialNutation<DerivativeStructure>( 0.0,
10.5526 * Constants.ARC_SECONDS_TO_RADIANS,
-2.38064 * Constants.ARC_SECONDS_TO_RADIANS,
-0.001125 * Constants.ARC_SECONDS_TO_RADIANS);
return new TimeFunction<double[]>() {
/** {@inheritDoc} */
@Override
public double[] value(final AbsoluteDate date) {
final double tc = evaluateTC(date);
return new double[] {
psiA.value(tc), omegaA.value(tc), chiA.value(tc)
};
}
};
}
/** {@inheritDoc} */
@Override
public TimeFunction<double[]> getNutationFunction()
throws OrekitException {
// set up nutation arguments
final FundamentalNutationArguments arguments = getNutationArguments(null);
// set up Poisson series
final double milliAS = Constants.ARC_SECONDS_TO_RADIANS * 1.0e-3;
final PoissonSeriesParser<DerivativeStructure> luniSolarParser =
new PoissonSeriesParser<DerivativeStructure>(14).withFirstDelaunay(1);
final PoissonSeriesParser<DerivativeStructure> luniSolarPsiParser =
luniSolarParser.
withSinCos(0, 7, milliAS, 11, milliAS).
withSinCos(1, 8, milliAS, 12, milliAS);
final PoissonSeries<DerivativeStructure> psiLuniSolarSeries =
luniSolarPsiParser.parse(getStream(LUNI_SOLAR_SERIES), LUNI_SOLAR_SERIES);
final PoissonSeriesParser<DerivativeStructure> luniSolarEpsilonParser =
luniSolarParser.
withSinCos(0, 13, milliAS, 9, milliAS).
withSinCos(1, 14, milliAS, 10, milliAS);
final PoissonSeries<DerivativeStructure> epsilonLuniSolarSeries =
luniSolarEpsilonParser.parse(getStream(LUNI_SOLAR_SERIES), LUNI_SOLAR_SERIES);
final PoissonSeriesParser<DerivativeStructure> planetaryParser =
new PoissonSeriesParser<DerivativeStructure>(21).
withFirstDelaunay(2).
withFirstPlanetary(7);
final PoissonSeriesParser<DerivativeStructure> planetaryPsiParser =
planetaryParser.withSinCos(0, 17, milliAS, 18, milliAS);
final PoissonSeries<DerivativeStructure> psiPlanetarySeries =
planetaryPsiParser.parse(getStream(PLANETARY_SERIES), PLANETARY_SERIES);
final PoissonSeriesParser<DerivativeStructure> planetaryEpsilonParser =
planetaryParser.withSinCos(0, 19, milliAS, 20, milliAS);
final PoissonSeries<DerivativeStructure> epsilonPlanetarySeries =
planetaryEpsilonParser.parse(getStream(PLANETARY_SERIES), PLANETARY_SERIES);
final PoissonSeries.CompiledSeries<DerivativeStructure> luniSolarSeries =
PoissonSeries.compile(psiLuniSolarSeries, epsilonLuniSolarSeries);
final PoissonSeries.CompiledSeries<DerivativeStructure> planetarySeries =
PoissonSeries.compile(psiPlanetarySeries, epsilonPlanetarySeries);
return new TimeFunction<double[]>() {
/** {@inheritDoc} */
@Override
public double[] value(final AbsoluteDate date) {
final BodiesElements elements = arguments.evaluateAll(date);
final double[] luniSolar = luniSolarSeries.value(elements);
final double[] planetary = planetarySeries.value(elements);
return new double[] {
luniSolar[0] + planetary[0], luniSolar[1] + planetary[1],
IAU1994ResolutionC7.value(elements)
};
}
};
}
/** {@inheritDoc} */
@Override
public TimeFunction<DerivativeStructure> getGMSTFunction(final TimeScale ut1)
throws OrekitException {
// Earth Rotation Angle
final StellarAngleCapitaine era = new StellarAngleCapitaine(ut1);
// Polynomial part of the apparent sidereal time series
// which is the opposite of Equation of Origins (EO)
final double microAS = Constants.ARC_SECONDS_TO_RADIANS * 1.0e-6;
final PoissonSeriesParser<DerivativeStructure> parser =
new PoissonSeriesParser<DerivativeStructure>(17).
withFirstDelaunay(4).
withFirstPlanetary(9).
withSinCos(0, 2, microAS, 3, microAS).
withPolynomialPart('t', Unit.ARC_SECONDS);
final PolynomialNutation<DerivativeStructure> minusEO =
parser.parse(getStream(GST_SERIES), GST_SERIES).getPolynomial();
// create a function evaluating the series
return new TimeFunction<DerivativeStructure>() {
/** {@inheritDoc} */
@Override
public DerivativeStructure value(final AbsoluteDate date) {
return era.value(date).add(minusEO.value(dsEvaluateTC(date)));
}
};
}
/** {@inheritDoc} */
@Override
public TimeFunction<DerivativeStructure> getGASTFunction(final TimeScale ut1,
final EOPHistory eopHistory)
throws OrekitException {
// set up nutation arguments
final FundamentalNutationArguments arguments = getNutationArguments(null);
// mean obliquity function
final TimeFunction<Double> epsilon = getMeanObliquityFunction();
// set up Poisson series
final double milliAS = Constants.ARC_SECONDS_TO_RADIANS * 1.0e-3;
final PoissonSeriesParser<DerivativeStructure> luniSolarPsiParser =
new PoissonSeriesParser<DerivativeStructure>(14).
withFirstDelaunay(1).
withSinCos(0, 7, milliAS, 11, milliAS).
withSinCos(1, 8, milliAS, 12, milliAS);
final PoissonSeries<DerivativeStructure> psiLuniSolarSeries =
luniSolarPsiParser.parse(getStream(LUNI_SOLAR_SERIES), LUNI_SOLAR_SERIES);
final PoissonSeriesParser<DerivativeStructure> planetaryPsiParser =
new PoissonSeriesParser<DerivativeStructure>(21).
withFirstDelaunay(2).
withFirstPlanetary(7).
withSinCos(0, 17, milliAS, 18, milliAS);
final PoissonSeries<DerivativeStructure> psiPlanetarySeries =
planetaryPsiParser.parse(getStream(PLANETARY_SERIES), PLANETARY_SERIES);
final double microAS = Constants.ARC_SECONDS_TO_RADIANS * 1.0e-6;
final PoissonSeriesParser<DerivativeStructure> gstParser =
new PoissonSeriesParser<DerivativeStructure>(17).
withFirstDelaunay(4).
withFirstPlanetary(9).
withSinCos(0, 2, microAS, 3, microAS).
withPolynomialPart('t', Unit.ARC_SECONDS);
final PoissonSeries<DerivativeStructure> gstSeries = gstParser.parse(getStream(GST_SERIES), GST_SERIES);
final PoissonSeries.CompiledSeries<DerivativeStructure> psiGstSeries =
PoissonSeries.compile(psiLuniSolarSeries, psiPlanetarySeries, gstSeries);
// ERA function
final TimeFunction<DerivativeStructure> era = getEarthOrientationAngleFunction(ut1);
return new TimeFunction<DerivativeStructure>() {
/** {@inheritDoc} */
@Override
public DerivativeStructure value(final AbsoluteDate date) {
// evaluate equation of origins
final BodiesElements elements = arguments.evaluateAll(date);
final double[] angles = psiGstSeries.value(elements);
final double ddPsi = (eopHistory == null) ? 0 : eopHistory.getEquinoxNutationCorrection(date)[0];
final double deltaPsi = angles[0] + angles[1] + ddPsi;
final double epsilonA = epsilon.value(date);
// subtract equation of origin from EA
// (hence add the series above which have the sign included)
return era.value(date).add(deltaPsi * FastMath.cos(epsilonA) + angles[2]);
}
};
}
/** {@inheritDoc} */
@Override
public TimeFunction<double[]> getEOPTidalCorrection()
throws OrekitException {
// set up nutation arguments
// BEWARE! Using TT as the time scale here and not UT1 is intentional!
// as this correction is used to compute UT1 itself, it is not surprising we cannot use UT1 yet,
// however, using the close UTC as would seem logical make the comparison with interp.f from IERS fail
// looking in the interp.f code, the same TT scale is used for both Delaunay and gamma argument
final FundamentalNutationArguments arguments = getNutationArguments(TimeScalesFactory.getTT());
// set up Poisson series
final double microAS = Constants.ARC_SECONDS_TO_RADIANS * 1.0e-6;
final PoissonSeriesParser<DerivativeStructure> xyParser = new PoissonSeriesParser<DerivativeStructure>(13).
withOptionalColumn(1).
withGamma(2).
withFirstDelaunay(3);
final PoissonSeries<DerivativeStructure> xSeries =
xyParser.
withSinCos(0, 10, microAS, 11, microAS).
parse(getStream(TIDAL_CORRECTION_XP_YP_SERIES), TIDAL_CORRECTION_XP_YP_SERIES);
final PoissonSeries<DerivativeStructure> ySeries =
xyParser.
withSinCos(0, 12, microAS, 13, microAS).
parse(getStream(TIDAL_CORRECTION_XP_YP_SERIES), TIDAL_CORRECTION_XP_YP_SERIES);
final double microS = 1.0e-6;
final PoissonSeriesParser<DerivativeStructure> ut1Parser = new PoissonSeriesParser<DerivativeStructure>(11).
withOptionalColumn(1).
withGamma(2).
withFirstDelaunay(3).
withSinCos(0, 10, microS, 11, microS);
final PoissonSeries<DerivativeStructure> ut1Series =
ut1Parser.parse(getStream(TIDAL_CORRECTION_UT1_SERIES), TIDAL_CORRECTION_UT1_SERIES);
final PoissonSeries.CompiledSeries<DerivativeStructure> correctionSeries =
PoissonSeries.compile(xSeries, ySeries, ut1Series);
return new TimeFunction<double[]>() {
/** {@inheritDoc} */
@Override
public double[] value(final AbsoluteDate date) {
final FieldBodiesElements<DerivativeStructure> elements =
arguments.evaluateDerivative(date);
final DerivativeStructure[] correction = correctionSeries.value(elements);
return new double[] {
correction[0].getValue(),
correction[1].getValue(),
correction[2].getValue(),
-correction[2].getPartialDerivative(1) * Constants.JULIAN_DAY
};
}
};
}
/** {@inheritDoc} */
public LoveNumbers getLoveNumbers() throws OrekitException {
return loadLoveNumbers(LOVE_NUMBERS);
}
/** {@inheritDoc} */
public TimeFunction<double[]> getTideFrequencyDependenceFunction(final TimeScale ut1)
throws OrekitException {
// set up nutation arguments
final FundamentalNutationArguments arguments = getNutationArguments(ut1);
// set up Poisson series
final PoissonSeriesParser<DerivativeStructure> k20Parser =
new PoissonSeriesParser<DerivativeStructure>(18).
withOptionalColumn(1).
withDoodson(4, 2).
withFirstDelaunay(10);
final PoissonSeriesParser<DerivativeStructure> k21Parser =
new PoissonSeriesParser<DerivativeStructure>(18).
withOptionalColumn(1).
withDoodson(4, 3).
withFirstDelaunay(10);
final PoissonSeriesParser<DerivativeStructure> k22Parser =
new PoissonSeriesParser<DerivativeStructure>(16).
withOptionalColumn(1).
withDoodson(4, 2).
withFirstDelaunay(10);
final double pico = 1.0e-12;
final PoissonSeries<DerivativeStructure> c20Series =
k20Parser.
withSinCos(0, 18, -pico, 16, pico).
parse(getStream(K20_FREQUENCY_DEPENDENCE), K20_FREQUENCY_DEPENDENCE);
final PoissonSeries<DerivativeStructure> c21Series =
k21Parser.
withSinCos(0, 17, pico, 18, pico).
parse(getStream(K21_FREQUENCY_DEPENDENCE), K21_FREQUENCY_DEPENDENCE);
final PoissonSeries<DerivativeStructure> s21Series =
k21Parser.
withSinCos(0, 18, -pico, 17, pico).
parse(getStream(K21_FREQUENCY_DEPENDENCE), K21_FREQUENCY_DEPENDENCE);
final PoissonSeries<DerivativeStructure> c22Series =
k22Parser.
withSinCos(0, -1, pico, 16, pico).
parse(getStream(K22_FREQUENCY_DEPENDENCE), K22_FREQUENCY_DEPENDENCE);
final PoissonSeries<DerivativeStructure> s22Series =
k22Parser.
withSinCos(0, 16, -pico, -1, pico).
parse(getStream(K22_FREQUENCY_DEPENDENCE), K22_FREQUENCY_DEPENDENCE);
final PoissonSeries.CompiledSeries<DerivativeStructure> kSeries =
PoissonSeries.compile(c20Series, c21Series, s21Series, c22Series, s22Series);
return new TimeFunction<double[]>() {
/** {@inheritDoc} */
@Override
public double[] value(final AbsoluteDate date) {
return kSeries.value(arguments.evaluateAll(date));
}
};
}
/** {@inheritDoc} */
@Override
public double getPermanentTide() throws OrekitException {
return 4.4228e-8 * -0.31460 * getLoveNumbers().getReal(2, 0);
}
/** {@inheritDoc} */
@Override
public TimeFunction<double[]> getSolidPoleTide(final EOPHistory eopHistory)
throws OrekitException {
// annual pole from ftp://tai.bipm.org/iers/conv2003/chapter7/annual.pole
final TimeScale utc = TimeScalesFactory.getUTC();
final SimpleTimeStampedTableParser.RowConverter<MeanPole> converter =
new SimpleTimeStampedTableParser.RowConverter<MeanPole>() {
/** {@inheritDoc} */
@Override
public MeanPole convert(final double[] rawFields) throws OrekitException {
return new MeanPole(new AbsoluteDate((int) rawFields[0], 1, 1, utc),
rawFields[1] * Constants.ARC_SECONDS_TO_RADIANS,
rawFields[2] * Constants.ARC_SECONDS_TO_RADIANS);
}
};
final SimpleTimeStampedTableParser<MeanPole> parser =
new SimpleTimeStampedTableParser<MeanPole>(3, converter);
final List<MeanPole> annualPoleList = parser.parse(getStream(ANNUAL_POLE), ANNUAL_POLE);
final AbsoluteDate firstAnnualPoleDate = annualPoleList.get(0).getDate();
final AbsoluteDate lastAnnualPoleDate = annualPoleList.get(annualPoleList.size() - 1).getDate();
final ImmutableTimeStampedCache<MeanPole> annualCache =
new ImmutableTimeStampedCache<MeanPole>(2, annualPoleList);
// polynomial extension from IERS 2003, section 7.1.4, equations 23a and 23b
final double xp0 = 0.054 * Constants.ARC_SECONDS_TO_RADIANS;
final double xp0Dot = 0.00083 * Constants.ARC_SECONDS_TO_RADIANS / Constants.JULIAN_YEAR;
final double yp0 = 0.357 * Constants.ARC_SECONDS_TO_RADIANS;
final double yp0Dot = 0.00395 * Constants.ARC_SECONDS_TO_RADIANS / Constants.JULIAN_YEAR;
// constants from IERS 2003, section 6.2
final double globalFactor = -1.333e-9 / Constants.ARC_SECONDS_TO_RADIANS;
final double ratio = 0.00115;
return new TimeFunction<double[]>() {
/** {@inheritDoc} */
@Override
public double[] value(final AbsoluteDate date) {
// we can't compute anything before the range covered by the annual pole file
if (date.compareTo(firstAnnualPoleDate) <= 0) {
return new double[] {
0.0, 0.0
};
}
// evaluate mean pole
double meanPoleX = 0;
double meanPoleY = 0;
if (date.compareTo(lastAnnualPoleDate) <= 0) {
// we are within the range covered by the annual pole file,
// we interpolate within it
try {
final List<MeanPole> neighbors = annualCache.getNeighbors(date);
final HermiteInterpolator interpolator = new HermiteInterpolator();
for (final MeanPole neighbor : neighbors) {
interpolator.addSamplePoint(neighbor.getDate().durationFrom(date),
new double[] {
neighbor.getX(), neighbor.getY()
});
}
final double[] interpolated = interpolator.value(0);
meanPoleX = interpolated[0];
meanPoleY = interpolated[1];
} catch (TimeStampedCacheException tsce) {
// this should never happen
throw new OrekitInternalError(tsce);
}
} else {
// we are after the range covered by the annual pole file,
// we use the polynomial extension
final double t = date.durationFrom(AbsoluteDate.J2000_EPOCH);
meanPoleX = xp0 + t * xp0Dot;
meanPoleY = yp0 + t * yp0Dot;
}
// evaluate wobble variables
final PoleCorrection correction = eopHistory.getPoleCorrection(date);
final double m1 = correction.getXp() - meanPoleX;
final double m2 = meanPoleY - correction.getYp();
return new double[] {
// the following correspond to the equations published in IERS 2003 conventions,
// section 6.2 page 65. In the publication, the equations read:
// ∆C₂₁ = −1.333 × 10⁻⁹ (m₁ − 0.0115m₂)
// ∆S₂₁ = −1.333 × 10⁻⁹ (m₂ + 0.0115m₁)
// However, it seems there are sign errors in these equations, which have
// been fixed in IERS 2010 conventions, section 6.4 page 94. In these newer
// publication, the equations read:
// ∆C₂₁ = −1.333 × 10⁻⁹ (m₁ + 0.0115m₂)
// ∆S₂₁ = −1.333 × 10⁻⁹ (m₂ − 0.0115m₁)
// the newer equations seem more consistent with the premises as the
// deformation due to the centrifugal potential has the form:
// −Ω²r²/2 sin 2θ Re [k₂(m₁ − im₂) exp(iλ)] where k₂ is the complex
// number 0.3077 + 0.0036i, so the real part in the previous equation is:
// A[Re(k₂) m₁ + Im(k₂) m₂)] cos λ + A[Re(k₂) m₂ - Im(k₂) m₁] sin λ
// identifying this with ∆C₂₁ cos λ + ∆S₂₁ sin λ we get:
// ∆C₂₁ = A Re(k₂) [m₁ + Im(k₂)/Re(k₂) m₂)]
// ∆S₂₁ = A Re(k₂) [m₂ - Im(k₂)/Re(k₂) m₁)]
// and Im(k₂)/Re(k₂) is very close to +0.00115
// As the equation as written in the IERS 2003 conventions are used in
// legacy systems, we have reproduced this alleged error here (and fixed it in
// the IERS 2010 conventions below) for validation purposes. We don't recommend
// using the IERS 2003 conventions for solid pole tide computation other than
// for validation or reproducibility of legacy applications behavior.
// As solid pole tide is small and as the sign change is on the smallest coefficient,
// the effect is quite small. A test case on a propagated orbit showed a position change
// slightly below 0.4m after a 30 days propagation on a Low Earth Orbit
globalFactor * (m1 - ratio * m2),
globalFactor * (m2 + ratio * m1),
};
}
};
}
/** {@inheritDoc} */
@Override
public TimeFunction<double[]> getOceanPoleTide(final EOPHistory eopHistory)
throws OrekitException {
return new TimeFunction<double[]>() {
/** {@inheritDoc} */
@Override
public double[] value(final AbsoluteDate date) {
// there are no model for ocean pole tide prior to conventions 2010
return new double[] {
0.0, 0.0
};
}
};
}
},
/** Constant for IERS 2010 conventions. */
IERS_2010 {
/** Nutation arguments resources. */
private static final String NUTATION_ARGUMENTS = IERS_BASE + "2010/nutation-arguments.txt";
/** X series resources. */
private static final String X_SERIES = IERS_BASE + "2010/tab5.2a.txt";
/** Y series resources. */
private static final String Y_SERIES = IERS_BASE + "2010/tab5.2b.txt";
/** S series resources. */
private static final String S_SERIES = IERS_BASE + "2010/tab5.2d.txt";
/** Psi series resources. */
private static final String PSI_SERIES = IERS_BASE + "2010/tab5.3a.txt";
/** Epsilon series resources. */
private static final String EPSILON_SERIES = IERS_BASE + "2010/tab5.3b.txt";
/** Greenwhich sidereal time series resources. */
private static final String GST_SERIES = IERS_BASE + "2010/tab5.2e.txt";
/** Tidal correction for xp, yp series resources. */
private static final String TIDAL_CORRECTION_XP_YP_SERIES = IERS_BASE + "2010/tab8.2ab.txt";
/** Tidal correction for UT1 resources. */
private static final String TIDAL_CORRECTION_UT1_SERIES = IERS_BASE + "2010/tab8.3ab.txt";
/** Love numbers resources. */
private static final String LOVE_NUMBERS = IERS_BASE + "2010/tab6.3.txt";
/** Frequency dependence model for k₂₀. */
private static final String K20_FREQUENCY_DEPENDENCE = IERS_BASE + "2010/tab6.5b.txt";
/** Frequency dependence model for k₂₁. */
private static final String K21_FREQUENCY_DEPENDENCE = IERS_BASE + "2010/tab6.5a.txt";
/** Frequency dependence model for k₂₂. */
private static final String K22_FREQUENCY_DEPENDENCE = IERS_BASE + "2010/tab6.5c.txt";
/** {@inheritDoc} */
public FundamentalNutationArguments getNutationArguments(final TimeScale timeScale)
throws OrekitException {
return new FundamentalNutationArguments(this, timeScale,
getStream(NUTATION_ARGUMENTS), NUTATION_ARGUMENTS);
}
/** {@inheritDoc} */
@Override
public TimeFunction<Double> getMeanObliquityFunction() throws OrekitException {
// epsilon 0 value from chapter 5, page 56, other terms from equation 5.40 page 65
final PolynomialNutation<DerivativeStructure> epsilonA =
new PolynomialNutation<DerivativeStructure>(84381.406 * Constants.ARC_SECONDS_TO_RADIANS,
-46.836769 * Constants.ARC_SECONDS_TO_RADIANS,
-0.0001831 * Constants.ARC_SECONDS_TO_RADIANS,
0.00200340 * Constants.ARC_SECONDS_TO_RADIANS,
-0.000000576 * Constants.ARC_SECONDS_TO_RADIANS,
-0.0000000434 * Constants.ARC_SECONDS_TO_RADIANS);
return new TimeFunction<Double>() {
/** {@inheritDoc} */
@Override
public Double value(final AbsoluteDate date) {
return epsilonA.value(evaluateTC(date));
}
};
}
/** {@inheritDoc} */
@Override
public TimeFunction<double[]> getXYSpXY2Function() throws OrekitException {
// set up nutation arguments
final FundamentalNutationArguments arguments = getNutationArguments(null);
// set up Poisson series
final double microAS = Constants.ARC_SECONDS_TO_RADIANS * 1.0e-6;
final PoissonSeriesParser<DerivativeStructure> parser =
new PoissonSeriesParser<DerivativeStructure>(17).
withPolynomialPart('t', PolynomialParser.Unit.MICRO_ARC_SECONDS).
withFirstDelaunay(4).
withFirstPlanetary(9).
withSinCos(0, 2, microAS, 3, microAS);
final PoissonSeries<DerivativeStructure> xSeries = parser.parse(getStream(X_SERIES), X_SERIES);
final PoissonSeries<DerivativeStructure> ySeries = parser.parse(getStream(Y_SERIES), Y_SERIES);
final PoissonSeries<DerivativeStructure> sSeries = parser.parse(getStream(S_SERIES), S_SERIES);
final PoissonSeries.CompiledSeries<DerivativeStructure> xys = PoissonSeries.compile(xSeries, ySeries, sSeries);
// create a function evaluating the series
return new TimeFunction<double[]>() {
/** {@inheritDoc} */
@Override
public double[] value(final AbsoluteDate date) {
return xys.value(arguments.evaluateAll(date));
}
};
}
/** {@inheritDoc} */
public LoveNumbers getLoveNumbers() throws OrekitException {
return loadLoveNumbers(LOVE_NUMBERS);
}
/** {@inheritDoc} */
public TimeFunction<double[]> getTideFrequencyDependenceFunction(final TimeScale ut1)
throws OrekitException {
// set up nutation arguments
final FundamentalNutationArguments arguments = getNutationArguments(ut1);
// set up Poisson series
final PoissonSeriesParser<DerivativeStructure> k20Parser =
new PoissonSeriesParser<DerivativeStructure>(18).
withOptionalColumn(1).
withDoodson(4, 2).
withFirstDelaunay(10);
final PoissonSeriesParser<DerivativeStructure> k21Parser =
new PoissonSeriesParser<DerivativeStructure>(18).
withOptionalColumn(1).
withDoodson(4, 3).
withFirstDelaunay(10);
final PoissonSeriesParser<DerivativeStructure> k22Parser =
new PoissonSeriesParser<DerivativeStructure>(16).
withOptionalColumn(1).
withDoodson(4, 2).
withFirstDelaunay(10);
final double pico = 1.0e-12;
final PoissonSeries<DerivativeStructure> c20Series =
k20Parser.
withSinCos(0, 18, -pico, 16, pico).
parse(getStream(K20_FREQUENCY_DEPENDENCE), K20_FREQUENCY_DEPENDENCE);
final PoissonSeries<DerivativeStructure> c21Series =
k21Parser.
withSinCos(0, 17, pico, 18, pico).
parse(getStream(K21_FREQUENCY_DEPENDENCE), K21_FREQUENCY_DEPENDENCE);
final PoissonSeries<DerivativeStructure> s21Series =
k21Parser.
withSinCos(0, 18, -pico, 17, pico).
parse(getStream(K21_FREQUENCY_DEPENDENCE), K21_FREQUENCY_DEPENDENCE);
final PoissonSeries<DerivativeStructure> c22Series =
k22Parser.
withSinCos(0, -1, pico, 16, pico).
parse(getStream(K22_FREQUENCY_DEPENDENCE), K22_FREQUENCY_DEPENDENCE);
final PoissonSeries<DerivativeStructure> s22Series =
k22Parser.
withSinCos(0, 16, -pico, -1, pico).
parse(getStream(K22_FREQUENCY_DEPENDENCE), K22_FREQUENCY_DEPENDENCE);
final PoissonSeries.CompiledSeries<DerivativeStructure> kSeries =
PoissonSeries.compile(c20Series, c21Series, s21Series, c22Series, s22Series);
return new TimeFunction<double[]>() {
/** {@inheritDoc} */
@Override
public double[] value(final AbsoluteDate date) {
return kSeries.value(arguments.evaluateAll(date));
}
};
}
/** {@inheritDoc} */
@Override
public double getPermanentTide() throws OrekitException {
return 4.4228e-8 * -0.31460 * getLoveNumbers().getReal(2, 0);
}
/** Compute pole wobble variables m₁ and m₂.
* @param date current date
* @param eopHistory EOP history
* @return array containing m₁ and m₂
*/
private double[] computePoleWobble(final AbsoluteDate date, final EOPHistory eopHistory) {
// polynomial model from IERS 2010, table 7.7
final double f0 = Constants.ARC_SECONDS_TO_RADIANS / 1000.0;
final double f1 = f0 / Constants.JULIAN_YEAR;
final double f2 = f1 / Constants.JULIAN_YEAR;
final double f3 = f2 / Constants.JULIAN_YEAR;
final AbsoluteDate changeDate = new AbsoluteDate(2010, 1, 1, TimeScalesFactory.getTT());
// evaluate mean pole
final double[] xPolynomial;
final double[] yPolynomial;
if (date.compareTo(changeDate) <= 0) {
xPolynomial = new double[] {
55.974 * f0, 1.8243 * f1, 0.18413 * f2, 0.007024 * f3
};
yPolynomial = new double[] {
346.346 * f0, 1.7896 * f1, -0.10729 * f2, -0.000908 * f3
};
} else {
xPolynomial = new double[] {
23.513 * f0, 7.6141 * f1
};
yPolynomial = new double[] {
358.891 * f0, -0.6287 * f1
};
}
double meanPoleX = 0;
double meanPoleY = 0;
final double t = date.durationFrom(AbsoluteDate.J2000_EPOCH);
for (int i = xPolynomial.length - 1; i >= 0; --i) {
meanPoleX = meanPoleX * t + xPolynomial[i];
}
for (int i = yPolynomial.length - 1; i >= 0; --i) {
meanPoleY = meanPoleY * t + yPolynomial[i];
}
// evaluate wobble variables
final PoleCorrection correction = eopHistory.getPoleCorrection(date);
final double m1 = correction.getXp() - meanPoleX;
final double m2 = meanPoleY - correction.getYp();
return new double[] {
m1, m2
};
}
/** {@inheritDoc} */
@Override
public TimeFunction<double[]> getSolidPoleTide(final EOPHistory eopHistory)
throws OrekitException {
// constants from IERS 2010, section 6.4
final double globalFactor = -1.333e-9 / Constants.ARC_SECONDS_TO_RADIANS;
final double ratio = 0.00115;
return new TimeFunction<double[]>() {
/** {@inheritDoc} */
@Override
public double[] value(final AbsoluteDate date) {
// evaluate wobble variables
final double[] wobbleM = computePoleWobble(date, eopHistory);
return new double[] {
// the following correspond to the equations published in IERS 2010 conventions,
// section 6.4 page 94. The equations read:
// ∆C₂₁ = −1.333 × 10⁻⁹ (m₁ + 0.0115m₂)
// ∆S₂₁ = −1.333 × 10⁻⁹ (m₂ − 0.0115m₁)
// These equations seem to fix what was probably a sign error in IERS 2003
// conventions section 6.2 page 65. In this older publication, the equations read:
// ∆C₂₁ = −1.333 × 10⁻⁹ (m₁ − 0.0115m₂)
// ∆S₂₁ = −1.333 × 10⁻⁹ (m₂ + 0.0115m₁)
globalFactor * (wobbleM[0] + ratio * wobbleM[1]),
globalFactor * (wobbleM[1] - ratio * wobbleM[0])
};
}
};
}
/** {@inheritDoc} */
@Override
public TimeFunction<double[]> getOceanPoleTide(final EOPHistory eopHistory)
throws OrekitException {
return new TimeFunction<double[]>() {
/** {@inheritDoc} */
@Override
public double[] value(final AbsoluteDate date) {
// evaluate wobble variables
final double[] wobbleM = computePoleWobble(date, eopHistory);
return new double[] {
// the following correspond to the equations published in IERS 2010 conventions,
// section 6.4 page 94 equation 6.24:
// ∆C₂₁ = −2.1778 × 10⁻¹⁰ (m₁ − 0.01724m₂)
// ∆S₂₁ = −1.7232 × 10⁻¹⁰ (m₂ − 0.03365m₁)
-2.1778e-10 * (wobbleM[0] - 0.01724 * wobbleM[1]) / Constants.ARC_SECONDS_TO_RADIANS,
-1.7232e-10 * (wobbleM[1] - 0.03365 * wobbleM[0]) / Constants.ARC_SECONDS_TO_RADIANS
};
}
};
}
/** {@inheritDoc} */
@Override
public TimeFunction<double[]> getPrecessionFunction() throws OrekitException {
// set up the conventional polynomials
// the following values are from equation 5.40 in IERS 2010 conventions
final PolynomialNutation<DerivativeStructure> psiA =
new PolynomialNutation<DerivativeStructure>( 0.0,
5038.481507 * Constants.ARC_SECONDS_TO_RADIANS,
-1.0790069 * Constants.ARC_SECONDS_TO_RADIANS,
-0.00114045 * Constants.ARC_SECONDS_TO_RADIANS,
0.000132851 * Constants.ARC_SECONDS_TO_RADIANS,
-0.0000000951 * Constants.ARC_SECONDS_TO_RADIANS);
final PolynomialNutation<DerivativeStructure> omegaA =
new PolynomialNutation<DerivativeStructure>(getMeanObliquityFunction().value(getNutationReferenceEpoch()),
-0.025754 * Constants.ARC_SECONDS_TO_RADIANS,
0.0512623 * Constants.ARC_SECONDS_TO_RADIANS,
-0.00772503 * Constants.ARC_SECONDS_TO_RADIANS,
-0.000000467 * Constants.ARC_SECONDS_TO_RADIANS,
0.0000003337 * Constants.ARC_SECONDS_TO_RADIANS);
final PolynomialNutation<DerivativeStructure> chiA =
new PolynomialNutation<DerivativeStructure>( 0.0,
10.556403 * Constants.ARC_SECONDS_TO_RADIANS,
-2.3814292 * Constants.ARC_SECONDS_TO_RADIANS,
-0.00121197 * Constants.ARC_SECONDS_TO_RADIANS,
0.000170663 * Constants.ARC_SECONDS_TO_RADIANS,
-0.0000000560 * Constants.ARC_SECONDS_TO_RADIANS);
return new TimeFunction<double[]>() {
/** {@inheritDoc} */
@Override
public double[] value(final AbsoluteDate date) {
final double tc = evaluateTC(date);
return new double[] {
psiA.value(tc), omegaA.value(tc), chiA.value(tc)
};
}
};
}
/** {@inheritDoc} */
@Override
public TimeFunction<double[]> getNutationFunction()
throws OrekitException {
// set up nutation arguments
final FundamentalNutationArguments arguments = getNutationArguments(null);
// set up Poisson series
final double microAS = Constants.ARC_SECONDS_TO_RADIANS * 1.0e-6;
final PoissonSeriesParser<DerivativeStructure> parser =
new PoissonSeriesParser<DerivativeStructure>(17).
withFirstDelaunay(4).
withFirstPlanetary(9).
withSinCos(0, 2, microAS, 3, microAS);
final PoissonSeries<DerivativeStructure> psiSeries = parser.parse(getStream(PSI_SERIES), PSI_SERIES);
final PoissonSeries<DerivativeStructure> epsilonSeries = parser.parse(getStream(EPSILON_SERIES), EPSILON_SERIES);
final PoissonSeries.CompiledSeries<DerivativeStructure> psiEpsilonSeries =
PoissonSeries.compile(psiSeries, epsilonSeries);
return new TimeFunction<double[]>() {
/** {@inheritDoc} */
@Override
public double[] value(final AbsoluteDate date) {
final BodiesElements elements = arguments.evaluateAll(date);
final double[] psiEpsilon = psiEpsilonSeries.value(elements);
return new double[] {
psiEpsilon[0], psiEpsilon[1], IAU1994ResolutionC7.value(elements)
};
}
};
}
/** {@inheritDoc} */
@Override
public TimeFunction<DerivativeStructure> getGMSTFunction(final TimeScale ut1) throws OrekitException {
// Earth Rotation Angle
final StellarAngleCapitaine era = new StellarAngleCapitaine(ut1);
// Polynomial part of the apparent sidereal time series
// which is the opposite of Equation of Origins (EO)
final double microAS = Constants.ARC_SECONDS_TO_RADIANS * 1.0e-6;
final PoissonSeriesParser<DerivativeStructure> parser =
new PoissonSeriesParser<DerivativeStructure>(17).
withFirstDelaunay(4).
withFirstPlanetary(9).
withSinCos(0, 2, microAS, 3, microAS).
withPolynomialPart('t', Unit.ARC_SECONDS);
final PolynomialNutation<DerivativeStructure> minusEO =
parser.parse(getStream(GST_SERIES), GST_SERIES).getPolynomial();
// create a function evaluating the series
return new TimeFunction<DerivativeStructure>() {
/** {@inheritDoc} */
@Override
public DerivativeStructure value(final AbsoluteDate date) {
return era.value(date).add(minusEO.value(dsEvaluateTC(date)));
}
};
}
/** {@inheritDoc} */
@Override
public TimeFunction<DerivativeStructure> getGASTFunction(final TimeScale ut1,
final EOPHistory eopHistory)
throws OrekitException {
// set up nutation arguments
final FundamentalNutationArguments arguments = getNutationArguments(null);
// mean obliquity function
final TimeFunction<Double> epsilon = getMeanObliquityFunction();
// set up Poisson series
final double microAS = Constants.ARC_SECONDS_TO_RADIANS * 1.0e-6;
final PoissonSeriesParser<DerivativeStructure> baseParser =
new PoissonSeriesParser<DerivativeStructure>(17).
withFirstDelaunay(4).
withFirstPlanetary(9).
withSinCos(0, 2, microAS, 3, microAS);
final PoissonSeriesParser<DerivativeStructure> gstParser = baseParser.withPolynomialPart('t', Unit.ARC_SECONDS);
final PoissonSeries<DerivativeStructure> psiSeries = baseParser.parse(getStream(PSI_SERIES), PSI_SERIES);
final PoissonSeries<DerivativeStructure> gstSeries = gstParser.parse(getStream(GST_SERIES), GST_SERIES);
final PoissonSeries.CompiledSeries<DerivativeStructure> psiGstSeries =
PoissonSeries.compile(psiSeries, gstSeries);
// ERA function
final TimeFunction<DerivativeStructure> era = getEarthOrientationAngleFunction(ut1);
return new TimeFunction<DerivativeStructure>() {
/** {@inheritDoc} */
@Override
public DerivativeStructure value(final AbsoluteDate date) {
// evaluate equation of origins
final BodiesElements elements = arguments.evaluateAll(date);
final double[] angles = psiGstSeries.value(elements);
final double ddPsi = (eopHistory == null) ? 0 : eopHistory.getEquinoxNutationCorrection(date)[0];
final double deltaPsi = angles[0] + ddPsi;
final double epsilonA = epsilon.value(date);
// subtract equation of origin from EA
// (hence add the series above which have the sign included)
return era.value(date).add(deltaPsi * FastMath.cos(epsilonA) + angles[1]);
}
};
}
/** {@inheritDoc} */
@Override
public TimeFunction<double[]> getEOPTidalCorrection()
throws OrekitException {
// set up nutation arguments
// BEWARE! Using TT as the time scale here and not UT1 is intentional!
// as this correction is used to compute UT1 itself, it is not surprising we cannot use UT1 yet,
// however, using the close UTC as would seem logical make the comparison with interp.f from IERS fail
// looking in the interp.f code, the same TT scale is used for both Delaunay and gamma argument
final FundamentalNutationArguments arguments = getNutationArguments(TimeScalesFactory.getTT());
// set up Poisson series
final double microAS = Constants.ARC_SECONDS_TO_RADIANS * 1.0e-6;
final PoissonSeriesParser<DerivativeStructure> xyParser = new PoissonSeriesParser<DerivativeStructure>(13).
withOptionalColumn(1).
withGamma(2).
withFirstDelaunay(3);
final PoissonSeries<DerivativeStructure> xSeries =
xyParser.
withSinCos(0, 10, microAS, 11, microAS).
parse(getStream(TIDAL_CORRECTION_XP_YP_SERIES), TIDAL_CORRECTION_XP_YP_SERIES);
final PoissonSeries<DerivativeStructure> ySeries =
xyParser.
withSinCos(0, 12, microAS, 13, microAS).
parse(getStream(TIDAL_CORRECTION_XP_YP_SERIES), TIDAL_CORRECTION_XP_YP_SERIES);
final double microS = 1.0e-6;
final PoissonSeriesParser<DerivativeStructure> ut1Parser = new PoissonSeriesParser<DerivativeStructure>(11).
withOptionalColumn(1).
withGamma(2).
withFirstDelaunay(3).
withSinCos(0, 10, microS, 11, microS);
final PoissonSeries<DerivativeStructure> ut1Series =
ut1Parser.parse(getStream(TIDAL_CORRECTION_UT1_SERIES), TIDAL_CORRECTION_UT1_SERIES);
final PoissonSeries.CompiledSeries<DerivativeStructure> correctionSeries =
PoissonSeries.compile(xSeries, ySeries, ut1Series);
return new TimeFunction<double[]>() {
/** {@inheritDoc} */
@Override
public double[] value(final AbsoluteDate date) {
final FieldBodiesElements<DerivativeStructure> elements =
arguments.evaluateDerivative(date);
final DerivativeStructure[] correction = correctionSeries.value(elements);
return new double[] {
correction[0].getValue(),
correction[1].getValue(),
correction[2].getValue(),
-correction[2].getPartialDerivative(1) * Constants.JULIAN_DAY
};
}
};
}
};
/** IERS conventions resources base directory. */
private static final String IERS_BASE = "/assets/org/orekit/IERS-conventions/";
/** Get the reference epoch for fundamental nutation arguments.
* @return reference epoch for fundamental nutation arguments
* @since 6.1
*/
public AbsoluteDate getNutationReferenceEpoch() {
// IERS 1996, IERS 2003 and IERS 2010 use the same J2000.0 reference date
return AbsoluteDate.J2000_EPOCH;
}
/** Evaluate the date offset between the current date and the {@link #getNutationReferenceEpoch() reference date}.
* @param date current date
* @return date offset in Julian centuries
* @since 6.1
*/
public double evaluateTC(final AbsoluteDate date) {
return date.durationFrom(getNutationReferenceEpoch()) / Constants.JULIAN_CENTURY;
}
/** Evaluate the date offset between the current date and the {@link #getNutationReferenceEpoch() reference date}.
* @param date current date
* @return date offset in Julian centuries
* @since 6.1
*/
public DerivativeStructure dsEvaluateTC(final AbsoluteDate date) {
return new DerivativeStructure(1, 1, evaluateTC(date), 1.0 / Constants.JULIAN_CENTURY);
}
/** Get the fundamental nutation arguments.
* @param timeScale time scale for computing Greenwich Mean Sidereal Time
* (typically {@link TimeScalesFactory#getUT1(IERSConventions, boolean) UT1})
* @return fundamental nutation arguments
* @exception OrekitException if fundamental nutation arguments cannot be loaded
* @since 6.1
*/
public abstract FundamentalNutationArguments getNutationArguments(final TimeScale timeScale)
throws OrekitException;
/** Get the function computing mean obliquity of the ecliptic.
* @return function computing mean obliquity of the ecliptic
* @exception OrekitException if table cannot be loaded
* @since 6.1
*/
public abstract TimeFunction<Double> getMeanObliquityFunction() throws OrekitException;
/** Get the function computing the Celestial Intermediate Pole and Celestial Intermediate Origin components.
* <p>
* The returned function computes the two X, Y components of CIP and the S+XY/2 component of the non-rotating CIO.
* </p>
* @return function computing the Celestial Intermediate Pole and Celestial Intermediate Origin components
* @exception OrekitException if table cannot be loaded
* @since 6.1
*/
public abstract TimeFunction<double[]> getXYSpXY2Function()
throws OrekitException;
/** Get the function computing the raw Earth Orientation Angle.
* <p>
* The raw angle does not contain any correction. If for example dTU1 correction
* due to tidal effect is desired, it must be added afterward by the caller.
* The returned value contain the angle as the value and the angular rate as
* the first derivative.
* </p>
* @param ut1 UT1 time scale
* @return function computing the rawEarth Orientation Angle, in the non-rotating origin paradigm,
* the return value containing both the angle and its first time derivative
* @since 6.1
*/
public TimeFunction<DerivativeStructure> getEarthOrientationAngleFunction(final TimeScale ut1) {
return new StellarAngleCapitaine(ut1);
}
/** Get the function computing the precession angles.
* <p>
* The function returned computes the three precession angles
* ψ<sub>A</sub> (around Z axis), ω<sub>A</sub> (around X axis)
* and χ<sub>A</sub> (around Z axis). The constant angle ε₀
* for the fourth rotation (around X axis) can be retrieved by evaluating the
* function returned by {@link #getMeanObliquityFunction()} at {@link
* #getNutationReferenceEpoch() nutation reference epoch}.
* </p>
* @return function computing the precession angle
* @exception OrekitException if table cannot be loaded
* @since 6.1
*/
public abstract TimeFunction<double[]> getPrecessionFunction() throws OrekitException;
/** Get the function computing the nutation angles.
* <p>
* The function returned computes the two classical angles ΔΨ and Δε,
* and the correction to the equation of equinoxes introduced since 1997-02-27 by IAU 1994
* resolution C7 (the correction is forced to 0 before this date)
* </p>
* @return function computing the nutation in longitude ΔΨ and Δε
* and the correction of equation of equinoxes
* @exception OrekitException if table cannot be loaded
* @since 6.1
*/
public abstract TimeFunction<double[]> getNutationFunction()
throws OrekitException;
/** Get the function computing Greenwich mean sidereal time, in radians.
* @param ut1 UT1 time scale
* @return function computing Greenwich mean sidereal time,
* the return value containing both the angle and its first time derivative
* @exception OrekitException if table cannot be loaded
* @since 6.1
*/
public abstract TimeFunction<DerivativeStructure> getGMSTFunction(TimeScale ut1)
throws OrekitException;
/** Get the function computing Greenwich apparent sidereal time, in radians.
* @param ut1 UT1 time scale
* @param eopHistory EOP history
* @return function computing Greenwich apparent sidereal time,
* the return value containing both the angle and its first time derivative
* @exception OrekitException if table cannot be loaded
* @since 6.1
*/
public abstract TimeFunction<DerivativeStructure> getGASTFunction(TimeScale ut1,
EOPHistory eopHistory)
throws OrekitException;
/** Get the function computing tidal corrections for Earth Orientation Parameters.
* @return function computing tidal corrections for Earth Orientation Parameters,
* for xp, yp, ut1 and lod respectively
* @exception OrekitException if table cannot be loaded
* @since 6.1
*/
public abstract TimeFunction<double[]> getEOPTidalCorrection()
throws OrekitException;
/** Get the Love numbers.
* @return Love numbers
* @exception OrekitException if table cannot be loaded
* @since 6.1
*/
public abstract LoveNumbers getLoveNumbers()
throws OrekitException;
/** Get the function computing frequency dependent terms (ΔC₂₀, ΔC₂₁, ΔS₂₁, ΔC₂₂, ΔS₂₂).
* @param ut1 UT1 time scale
* @return frequency dependence model for tides computation (ΔC₂₀, ΔC₂₁, ΔS₂₁, ΔC₂₂, ΔS₂₂).
* @exception OrekitException if table cannot be loaded
* @since 6.1
*/
public abstract TimeFunction<double[]> getTideFrequencyDependenceFunction(TimeScale ut1)
throws OrekitException;
/** Get the permanent tide to be <em>removed</em> from ΔC₂₀ when zero-tide potentials are used.
* @return permanent tide to remove
* @exception OrekitException if table cannot be loaded
*/
public abstract double getPermanentTide() throws OrekitException;
/** Get the function computing solid pole tide (ΔC₂₁, ΔS₂₁).
* @param eopHistory EOP history
* @return model for solid pole tide (ΔC₂₀, ΔC₂₁, ΔS₂₁, ΔC₂₂, ΔS₂₂).
* @exception OrekitException if table cannot be loaded
* @since 6.1
*/
public abstract TimeFunction<double[]> getSolidPoleTide(EOPHistory eopHistory)
throws OrekitException;
/** Get the function computing ocean pole tide (ΔC₂₁, ΔS₂₁).
* @param eopHistory EOP history
* @return model for ocean pole tide (ΔC₂₀, ΔC₂₁, ΔS₂₁, ΔC₂₂, ΔS₂₂).
* @exception OrekitException if table cannot be loaded
* @since 6.1
*/
public abstract TimeFunction<double[]> getOceanPoleTide(EOPHistory eopHistory)
throws OrekitException;
/** Interface for functions converting nutation corrections between
* δΔψ/δΔε to δX/δY.
* <ul>
* <li>δΔψ/δΔε nutation corrections are used with the equinox-based paradigm.</li>
* <li>δX/δY nutation corrections are used with the Non-Rotating Origin paradigm.</li>
* </ul>
* @since 6.1
*/
public interface NutationCorrectionConverter {
/** Convert nutation corrections.
* @param date current date
* @param ddPsi δΔψ part of the nutation correction
* @param ddEpsilon δΔε part of the nutation correction
* @return array containing δX and δY
* @exception OrekitException if correction cannot be converted
*/
double[] toNonRotating(AbsoluteDate date, double ddPsi, double ddEpsilon)
throws OrekitException;
/** Convert nutation corrections.
* @param date current date
* @param dX δX part of the nutation correction
* @param dY δY part of the nutation correction
* @return array containing δΔψ and δΔε
* @exception OrekitException if correction cannot be converted
*/
double[] toEquinox(AbsoluteDate date, double dX, double dY)
throws OrekitException;
}
/** Create a function converting nutation corrections between
* δX/δY and δΔψ/δΔε.
* <ul>
* <li>δX/δY nutation corrections are used with the Non-Rotating Origin paradigm.</li>
* <li>δΔψ/δΔε nutation corrections are used with the equinox-based paradigm.</li>
* </ul>
* @return a new converter
* @exception OrekitException if some convention table cannot be loaded
* @since 6.1
*/
public NutationCorrectionConverter getNutationCorrectionConverter()
throws OrekitException {
// get models parameters
final TimeFunction<double[]> precessionFunction = getPrecessionFunction();
final TimeFunction<Double> epsilonAFunction = getMeanObliquityFunction();
final AbsoluteDate date0 = getNutationReferenceEpoch();
final double cosE0 = FastMath.cos(epsilonAFunction.value(date0));
return new NutationCorrectionConverter() {
/** {@inheritDoc} */
@Override
public double[] toNonRotating(final AbsoluteDate date,
final double ddPsi, final double ddEpsilon)
throws OrekitException {
// compute precession angles psiA, omegaA and chiA
final double[] angles = precessionFunction.value(date);
// conversion coefficients
final double sinEA = FastMath.sin(epsilonAFunction.value(date));
final double c = angles[0] * cosE0 - angles[2];
// convert nutation corrections (equation 23/IERS-2003 or 5.25/IERS-2010)
return new double[] {
sinEA * ddPsi + c * ddEpsilon,
ddEpsilon - c * sinEA * ddPsi
};
}
/** {@inheritDoc} */
@Override
public double[] toEquinox(final AbsoluteDate date,
final double dX, final double dY)
throws OrekitException {
// compute precession angles psiA, omegaA and chiA
final double[] angles = precessionFunction.value(date);
// conversion coefficients
final double sinEA = FastMath.sin(epsilonAFunction.value(date));
final double c = angles[0] * cosE0 - angles[2];
final double opC2 = 1 + c * c;
// convert nutation corrections (inverse of equation 23/IERS-2003 or 5.25/IERS-2010)
return new double[] {
(dX - c * dY) / (sinEA * opC2),
(dY + c * dX) / opC2
};
}
};
}
/** Load the Love numbers.
* @param nameLove name of the Love number resource
* @return Love numbers
* @exception OrekitException if the Love numbers embedded in the
* library cannot be read
*/
protected LoveNumbers loadLoveNumbers(final String nameLove) throws OrekitException {
try {
// allocate the three triangular arrays for real, imaginary and time-dependent numbers
final double[][] real = new double[4][];
final double[][] imaginary = new double[4][];
final double[][] plus = new double[4][];
for (int i = 0; i < real.length; ++i) {
real[i] = new double[i + 1];
imaginary[i] = new double[i + 1];
plus[i] = new double[i + 1];
}
try (final InputStream stream = IERSConventions.class.getResourceAsStream(nameLove)) {
if (stream == null) {
// this should never happen with files embedded within Orekit
throw new OrekitException(OrekitMessages.UNABLE_TO_FIND_FILE, nameLove);
}
// setup the reader
try (final BufferedReader reader = new BufferedReader(new InputStreamReader(stream, "UTF-8"))) {
String line = reader.readLine();
int lineNumber = 1;
// look for the Love numbers
while (line != null) {
line = line.trim();
if (!(line.isEmpty() || line.startsWith("#"))) {
final String[] fields = line.split("\\p{Space}+");
if (fields.length != 5) {
// this should never happen with files embedded within Orekit
throw new OrekitException(OrekitMessages.UNABLE_TO_PARSE_LINE_IN_FILE,
lineNumber, nameLove, line);
}
final int n = Integer.parseInt(fields[0]);
final int m = Integer.parseInt(fields[1]);
if ((n < 2) || (n > 3) || (m < 0) || (m > n)) {
// this should never happen with files embedded within Orekit
throw new OrekitException(OrekitMessages.UNABLE_TO_PARSE_LINE_IN_FILE,
lineNumber, nameLove, line);
}
real[n][m] = Double.parseDouble(fields[2]);
imaginary[n][m] = Double.parseDouble(fields[3]);
plus[n][m] = Double.parseDouble(fields[4]);
}
// next line
lineNumber++;
line = reader.readLine();
}
}
}
return new LoveNumbers(real, imaginary, plus);
} catch (IOException ioe) {
// this should never happen with files embedded within Orekit
throw new OrekitException(OrekitMessages.NOT_A_SUPPORTED_IERS_DATA_FILE, nameLove);
}
}
/** Get a data stream.
* @param name file name of the resource stream
* @return stream
*/
private static InputStream getStream(final String name) {
return IERSConventions.class.getResourceAsStream(name);
}
/** Correction to equation of equinoxes.
* <p>IAU 1994 resolution C7 added two terms to the equation of equinoxes
* taking effect since 1997-02-27 for continuity
* </p>
*/
private static class IAU1994ResolutionC7 {
/** First Moon correction term for the Equation of the Equinoxes. */
private static final double EQE1 = 0.00264 * Constants.ARC_SECONDS_TO_RADIANS;
/** Second Moon correction term for the Equation of the Equinoxes. */
private static final double EQE2 = 0.000063 * Constants.ARC_SECONDS_TO_RADIANS;
/** Start date for applying Moon corrections to the equation of the equinoxes.
* This date corresponds to 1997-02-27T00:00:00 UTC, hence the 30s offset from TAI.
*/
private static final AbsoluteDate MODEL_START =
new AbsoluteDate(1997, 2, 27, 0, 0, 30, TimeScalesFactory.getTAI());
/** Evaluate the correction.
* @param arguments Delaunay for nutation
* @return correction value (0 before 1997-02-27)
*/
public static double value(final DelaunayArguments arguments) {
if (arguments.getDate().compareTo(MODEL_START) >= 0) {
// IAU 1994 resolution C7 added two terms to the equation of equinoxes
// taking effect since 1997-02-27 for continuity
// Mean longitude of the ascending node of the Moon
final double om = arguments.getOmega();
// add the two correction terms
return EQE1 * FastMath.sin(om) + EQE2 * FastMath.sin(om + om);
} else {
return 0.0;
}
}
};
/** Stellar angle model.
* <p>
* The stellar angle computed here has been defined in the paper "A non-rotating origin on the
* instantaneous equator: Definition, properties and use", N. Capitaine, Guinot B., and Souchay J.,
* Celestial Mechanics, Volume 39, Issue 3, pp 283-307. It has been proposed as a conventional
* conventional relationship between UT1 and Earth rotation in the paper "Definition of the Celestial
* Ephemeris origin and of UT1 in the International Celestial Reference Frame", Capitaine, N.,
* Guinot, B., and McCarthy, D. D., 2000, “,” Astronomy and Astrophysics, 355(1), pp. 398–405.
* </p>
* <p>
* It is presented simply as stellar angle in IERS conventions 1996 but as since been adopted as
* the conventional relationship defining UT1 from ICRF and is called Earth Rotation Angle in
* IERS conventions 2003 and 2010.
* </p>
*/
private static class StellarAngleCapitaine implements TimeFunction<DerivativeStructure> {
/** Reference date of Capitaine's Earth Rotation Angle model. */
private static final AbsoluteDate REFERENCE_DATE = new AbsoluteDate(DateComponents.J2000_EPOCH,
TimeComponents.H12,
TimeScalesFactory.getTAI());
/** Constant term of Capitaine's Earth Rotation Angle model. */
private static final double ERA_0 = MathUtils.TWO_PI * 0.7790572732640;
/** Rate term of Capitaine's Earth Rotation Angle model.
* (radians per day, main part) */
private static final double ERA_1A = MathUtils.TWO_PI / Constants.JULIAN_DAY;
/** Rate term of Capitaine's Earth Rotation Angle model.
* (radians per day, fractional part) */
private static final double ERA_1B = ERA_1A * 0.00273781191135448;
/** Total rate term of Capitaine's Earth Rotation Angle model. */
private static final double ERA_1AB = ERA_1A + ERA_1B;
/** UT1 time scale. */
private final TimeScale ut1;
/** Simple constructor.
* @param ut1 UT1 time scale
*/
StellarAngleCapitaine(final TimeScale ut1) {
this.ut1 = ut1;
}
/** {@inheritDoc} */
@Override
public DerivativeStructure value(final AbsoluteDate date) {
// split the date offset as a full number of days plus a smaller part
final int secondsInDay = 86400;
final double dt = date.durationFrom(REFERENCE_DATE);
final long days = ((long) dt) / secondsInDay;
final double dtA = secondsInDay * days;
final double dtB = (dt - dtA) + ut1.offsetFromTAI(date);
return new DerivativeStructure(1, 1,
ERA_0 + ERA_1A * dtB + ERA_1B * (dtA + dtB),
ERA_1AB);
}
}
/** Mean pole. */
private static class MeanPole implements TimeStamped, Serializable {
/** Serializable UID. */
private static final long serialVersionUID = 20131028l;
/** Date. */
private final AbsoluteDate date;
/** X coordinate. */
private double x;
/** Y coordinate. */
private double y;
/** Simple constructor.
* @param date date
* @param x x coordinate
* @param y y coordinate
*/
MeanPole(final AbsoluteDate date, final double x, final double y) {
this.date = date;
this.x = x;
this.y = y;
}
/** {@inheritDoc} */
@Override
public AbsoluteDate getDate() {
return date;
}
/** Get x coordinate.
* @return x coordinate
*/
public double getX() {
return x;
}
/** Get y coordinate.
* @return y coordinate
*/
public double getY() {
return y;
}
}
}