FieldOrbit.java

  1. /* Copyright 2002-2024 CS GROUP
  2.  * Licensed to CS GROUP (CS) under one or more
  3.  * contributor license agreements.  See the NOTICE file distributed with
  4.  * this work for additional information regarding copyright ownership.
  5.  * CS licenses this file to You under the Apache License, Version 2.0
  6.  * (the "License"); you may not use this file except in compliance with
  7.  * the License.  You may obtain a copy of the License at
  8.  *
  9.  *   http://www.apache.org/licenses/LICENSE-2.0
  10.  *
  11.  * Unless required by applicable law or agreed to in writing, software
  12.  * distributed under the License is distributed on an "AS IS" BASIS,
  13.  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  14.  * See the License for the specific language governing permissions and
  15.  * limitations under the License.
  16.  */
  17. package org.orekit.orbits;



  21. import org.hipparchus.CalculusFieldElement;
  22. import org.hipparchus.Field;
  23. import org.hipparchus.analysis.differentiation.Derivative;
  24. import org.hipparchus.geometry.euclidean.threed.FieldVector3D;
  25. import org.hipparchus.linear.FieldDecompositionSolver;
  26. import org.hipparchus.linear.FieldLUDecomposition;
  27. import org.hipparchus.linear.FieldMatrix;
  28. import org.hipparchus.linear.MatrixUtils;
  29. import org.hipparchus.util.MathArrays;
  30. import org.orekit.errors.OrekitIllegalArgumentException;
  31. import org.orekit.errors.OrekitInternalError;
  32. import org.orekit.errors.OrekitMessages;
  33. import org.orekit.frames.FieldStaticTransform;
  34. import org.orekit.frames.FieldTransform;
  35. import org.orekit.frames.Frame;
  36. import org.orekit.time.FieldAbsoluteDate;
  37. import org.orekit.time.FieldTimeShiftable;
  38. import org.orekit.time.FieldTimeStamped;
  39. import org.orekit.utils.FieldPVCoordinates;
  40. import org.orekit.utils.FieldPVCoordinatesProvider;
  41. import org.orekit.utils.TimeStampedFieldPVCoordinates;
  42. import org.orekit.utils.TimeStampedPVCoordinates;

  44. /**
  45.  * This class handles orbital parameters.

  47.  * <p>
  48.  * For user convenience, both the Cartesian and the equinoctial elements
  49.  * are provided by this class, regardless of the canonical representation
  50.  * implemented in the derived class (which may be classical Keplerian
  51.  * elements for example).
  52.  * </p>
  53.  * <p>
  54.  * The parameters are defined in a frame specified by the user. It is important
  55.  * to make sure this frame is consistent: it probably is inertial and centered
  56.  * on the central body. This information is used for example by some
  57.  * force models.
  58.  * </p>
  59.  * <p>
  60.  * Instance of this class are guaranteed to be immutable.
  61.  * </p>
  62.  * @author Luc Maisonobe
  63.  * @author Guylaine Prat
  64.  * @author Fabien Maussion
  65.  * @author V&eacute;ronique Pommier-Maurussane
  66.  * @since 9.0
  67.  * @see Orbit
  68.  * @param <T> type of the field elements
  69.  */
  70. public abstract class FieldOrbit<T extends CalculusFieldElement<T>>
  71.     implements FieldPVCoordinatesProvider<T>, FieldTimeStamped<T>, FieldTimeShiftable<FieldOrbit<T>, T> {

  73.     /** Frame in which are defined the orbital parameters. */
  74.     private final Frame frame;

  76.     /** Date of the orbital parameters. */
  77.     private final FieldAbsoluteDate<T> date;

  79.     /** Value of mu used to compute position and velocity (m³/s²). */
  80.     private final T mu;

  82.     /** Field-valued one.
  83.      * @since 12.0
  84.      * */
  85.     private final T one;

  87.     /** Field-valued zero.
  88.      * @since 12.0
  89.      * */
  90.     private final T zero;

  92.     /** Field used by this class.
  93.      * @since 12.0
  94.      */
  95.     private final Field<T> field;

  97.     /** Computed position.
  98.      * @since 12.0
  99.      */
  100.     private transient FieldVector3D<T> position;

  102.     /** Computed PVCoordinates. */
  103.     private transient TimeStampedFieldPVCoordinates<T> pvCoordinates;

  105.     /** Jacobian of the orbital parameters with mean angle with respect to the Cartesian coordinates. */
  106.     private transient T[][] jacobianMeanWrtCartesian;

  108.     /** Jacobian of the Cartesian coordinates with respect to the orbital parameters with mean angle. */
  109.     private transient T[][] jacobianWrtParametersMean;

  111.     /** Jacobian of the orbital parameters with eccentric angle with respect to the Cartesian coordinates. */
  112.     private transient T[][] jacobianEccentricWrtCartesian;

  114.     /** Jacobian of the Cartesian coordinates with respect to the orbital parameters with eccentric angle. */
  115.     private transient T[][] jacobianWrtParametersEccentric;

  117.     /** Jacobian of the orbital parameters with true angle with respect to the Cartesian coordinates. */
  118.     private transient T[][] jacobianTrueWrtCartesian;

  120.     /** Jacobian of the Cartesian coordinates with respect to the orbital parameters with true angle. */
  121.     private transient T[][] jacobianWrtParametersTrue;

  123.     /** Default constructor.
  124.      * Build a new instance with arbitrary default elements.
  125.      * @param frame the frame in which the parameters are defined
  126.      * (<em>must</em> be a {@link Frame#isPseudoInertial pseudo-inertial frame})
  127.      * @param date date of the orbital parameters
  128.      * @param mu central attraction coefficient (m^3/s^2)
  129.      * @exception IllegalArgumentException if frame is not a {@link
  130.      * Frame#isPseudoInertial pseudo-inertial frame}
  131.      */
  132.     protected FieldOrbit(final Frame frame, final FieldAbsoluteDate<T> date, final T mu)
  133.         throws IllegalArgumentException {
  134.         ensurePseudoInertialFrame(frame);
  135.         this.field = mu.getField();
  136.         this.zero = this.field.getZero();
  137.         this.one = this.field.getOne();
  138.         this.date                      = date;
  139.         this.mu                        = mu;
  140.         this.pvCoordinates             = null;
  141.         this.frame                     = frame;
  142.         jacobianMeanWrtCartesian       = null;
  143.         jacobianWrtParametersMean      = null;
  144.         jacobianEccentricWrtCartesian  = null;
  145.         jacobianWrtParametersEccentric = null;
  146.         jacobianTrueWrtCartesian       = null;
  147.         jacobianWrtParametersTrue      = null;
  148.     }

  150.     /** Set the orbit from Cartesian parameters.
  151.      *
  152.      * <p> The acceleration provided in {@code FieldPVCoordinates} is accessible using
  153.      * {@link #getPVCoordinates()} and {@link #getPVCoordinates(Frame)}. All other methods
  154.      * use {@code mu} and the position to compute the acceleration, including
  155.      * {@link #shiftedBy(CalculusFieldElement)} and {@link #getPVCoordinates(FieldAbsoluteDate, Frame)}.
  156.      *
  157.      * @param fieldPVCoordinates the position and velocity in the inertial frame
  158.      * @param frame the frame in which the {@link TimeStampedPVCoordinates} are defined
  159.      * (<em>must</em> be a {@link Frame#isPseudoInertial pseudo-inertial frame})
  160.      * @param mu central attraction coefficient (m^3/s^2)
  161.      * @exception IllegalArgumentException if frame is not a {@link
  162.      * Frame#isPseudoInertial pseudo-inertial frame}
  163.      */
  164.     protected FieldOrbit(final TimeStampedFieldPVCoordinates<T> fieldPVCoordinates, final Frame frame, final T mu)
  165.         throws IllegalArgumentException {
  166.         ensurePseudoInertialFrame(frame);
  167.         this.field = mu.getField();
  168.         this.zero = this.field.getZero();
  169.         this.one = this.field.getOne();
  170.         this.date = fieldPVCoordinates.getDate();
  171.         this.mu = mu;
  172.         if (fieldPVCoordinates.getAcceleration().getNormSq().getReal() == 0.0) {
  173.             // the acceleration was not provided,
  174.             // compute it from Newtonian attraction
  175.             final T r2 = fieldPVCoordinates.getPosition().getNormSq();
  176.             final T r3 = r2.multiply(r2.sqrt());
  177.             this.pvCoordinates = new TimeStampedFieldPVCoordinates<>(fieldPVCoordinates.getDate(),
  178.                                                                      fieldPVCoordinates.getPosition(),
  179.                                                                      fieldPVCoordinates.getVelocity(),
  180.                                                                      new FieldVector3D<>(r3.reciprocal().multiply(mu.negate()), fieldPVCoordinates.getPosition()));
  181.         } else {
  182.             this.pvCoordinates = fieldPVCoordinates;
  183.         }
  184.         this.frame = frame;
  185.     }

  187.     /** Check if Cartesian coordinates include non-Keplerian acceleration.
  188.      * @param pva Cartesian coordinates
  189.      * @param mu central attraction coefficient
  190.      * @param <T> type of the field elements
  191.      * @return true if Cartesian coordinates include non-Keplerian acceleration
  192.      */
  193.     protected static <T extends CalculusFieldElement<T>> boolean hasNonKeplerianAcceleration(final FieldPVCoordinates<T> pva, final T mu) {

  195.         if (mu.getField().getZero() instanceof Derivative<?>) {
  196.             return Orbit.hasNonKeplerianAcceleration(pva.toPVCoordinates(), mu.getReal()); // for performance

  198.         } else {
  199.             final FieldVector3D<T> a = pva.getAcceleration();
  200.             if (a == null) {
  201.                 return false;
  202.             }

  204.             final FieldVector3D<T> p = pva.getPosition();
  205.             final T r2 = p.getNormSq();

  207.             // Check if acceleration is relatively close to 0 compared to the Keplerian acceleration
  208.             final double tolerance = mu.getReal() * 1e-9;
  209.             final FieldVector3D<T> aTimesR2 = a.scalarMultiply(r2);
  210.             if (aTimesR2.getNorm().getReal() < tolerance) {
  211.                 return false;
  212.             }

  214.             if ((aTimesR2.add(p.normalize().scalarMultiply(mu))).getNorm().getReal() > tolerance) {
  215.                 // we have a relevant acceleration, we can compute derivatives
  216.                 return true;
  217.             } else {
  218.                 // the provided acceleration is either too small to be reliable (probably even 0), or NaN
  219.                 return false;
  220.             }
  221.         }

  223.     }

  225.     /** Returns true if and only if the orbit is elliptical i.e. has a non-negative semi-major axis.
  226.      * @return true if getA() is strictly greater than 0
  227.      * @since 12.0
  228.      */
  229.     public boolean isElliptical() {
  230.         return getA().getReal() > 0.;
  231.     }

  233.     /** Get the orbit type.
  234.      * @return orbit type
  235.      */
  236.     public abstract OrbitType getType();

  238.     /** Ensure the defining frame is a pseudo-inertial frame.
  239.      * @param frame frame to check
  240.      * @exception IllegalArgumentException if frame is not a {@link
  241.      * Frame#isPseudoInertial pseudo-inertial frame}
  242.      */
  243.     private static void ensurePseudoInertialFrame(final Frame frame)
  244.         throws IllegalArgumentException {
  245.         if (!frame.isPseudoInertial()) {
  246.             throw new OrekitIllegalArgumentException(OrekitMessages.NON_PSEUDO_INERTIAL_FRAME,
  247.                                                      frame.getName());
  248.         }
  249.     }

  251.     /** Get the frame in which the orbital parameters are defined.
  252.      * @return frame in which the orbital parameters are defined
  253.      */
  254.     public Frame getFrame() {
  255.         return frame;
  256.     }

  258.     /**Transforms the FieldOrbit instance into an Orbit instance.
  259.      * @return Orbit instance with same properties
  260.      */
  261.     public abstract Orbit toOrbit();

  263.     /** Get the semi-major axis.
  264.      * <p>Note that the semi-major axis is considered negative for hyperbolic orbits.</p>
  265.      * @return semi-major axis (m)
  266.      */
  267.     public abstract T getA();

  269.     /** Get the semi-major axis derivative.
  270.      * <p>Note that the semi-major axis is considered negative for hyperbolic orbits.</p>
  271.      * <p>
  272.      * If the orbit was created without derivatives, the value returned is null.
  273.      * </p>
  274.      * @return semi-major axis  derivative (m/s)
  275.      */
  276.     public abstract T getADot();

  278.     /** Get the first component of the equinoctial eccentricity vector.
  279.      * @return first component of the equinoctial eccentricity vector
  280.      */
  281.     public abstract T getEquinoctialEx();

  283.     /** Get the first component of the equinoctial eccentricity vector derivative.
  284.      * <p>
  285.      * If the orbit was created without derivatives, the value returned is null.
  286.      * </p>
  287.      * @return first component of the equinoctial eccentricity vector derivative
  288.      */
  289.     public abstract T getEquinoctialExDot();

  291.     /** Get the second component of the equinoctial eccentricity vector.
  292.      * @return second component of the equinoctial eccentricity vector
  293.      */
  294.     public abstract T getEquinoctialEy();

  296.     /** Get the second component of the equinoctial eccentricity vector derivative.
  297.      * <p>
  298.      * If the orbit was created without derivatives, the value returned is null.
  299.      * </p>
  300.      * @return second component of the equinoctial eccentricity vector derivative
  301.      */
  302.     public abstract T getEquinoctialEyDot();

  304.     /** Get the first component of the inclination vector.
  305.      * @return first component of the inclination vector
  306.      */
  307.     public abstract T getHx();

  309.     /** Get the first component of the inclination vector derivative.
  310.      * <p>
  311.      * If the orbit was created without derivatives, the value returned is null.
  312.      * </p>
  313.      * @return first component of the inclination vector derivative
  314.      */
  315.     public abstract T getHxDot();

  317.     /** Get the second component of the inclination vector.
  318.      * @return second component of the inclination vector
  319.      */
  320.     public abstract T getHy();

  322.     /** Get the second component of the inclination vector derivative.
  323.      * @return second component of the inclination vector derivative
  324.      */
  325.     public abstract T getHyDot();

  327.     /** Get the eccentric longitude argument.
  328.      * @return E + ω + Ω eccentric longitude argument (rad)
  329.      */
  330.     public abstract T getLE();

  332.     /** Get the eccentric longitude argument derivative.
  333.      * <p>
  334.      * If the orbit was created without derivatives, the value returned is null.
  335.      * </p>
  336.      * @return d(E + ω + Ω)/dt eccentric longitude argument derivative (rad/s)
  337.      */
  338.     public abstract T getLEDot();

  340.     /** Get the true longitude argument.
  341.      * @return v + ω + Ω true longitude argument (rad)
  342.      */
  343.     public abstract T getLv();

  345.     /** Get the true longitude argument derivative.
  346.      * <p>
  347.      * If the orbit was created without derivatives, the value returned is null.
  348.      * </p>
  349.      * @return d(v + ω + Ω)/dt true longitude argument derivative (rad/s)
  350.      */
  351.     public abstract T getLvDot();

  353.     /** Get the mean longitude argument.
  354.      * @return M + ω + Ω mean longitude argument (rad)
  355.      */
  356.     public abstract T getLM();

  358.     /** Get the mean longitude argument derivative.
  359.      * <p>
  360.      * If the orbit was created without derivatives, the value returned is null.
  361.      * </p>
  362.      * @return d(M + ω + Ω)/dt mean longitude argument derivative (rad/s)
  363.      */
  364.     public abstract T getLMDot();

  366.     // Additional orbital elements

  368.     /** Get the eccentricity.
  369.      * @return eccentricity
  370.      */
  371.     public abstract T getE();

  373.     /** Get the eccentricity derivative.
  374.      * <p>
  375.      * If the orbit was created without derivatives, the value returned is null.
  376.      * </p>
  377.      * @return eccentricity derivative
  378.      */
  379.     public abstract T getEDot();

  381.     /** Get the inclination.
  382.      * <p>
  383.      * If the orbit was created without derivatives, the value returned is null.
  384.      * </p>
  385.      * @return inclination (rad)
  386.      */
  387.     public abstract T getI();

  389.     /** Get the inclination derivative.
  390.      * @return inclination derivative (rad/s)
  391.      */
  392.     public abstract T getIDot();

  394.     /** Check if orbit includes derivatives.
  395.      * @return true if orbit includes derivatives
  396.      * @see #getADot()
  397.      * @see #getEquinoctialExDot()
  398.      * @see #getEquinoctialEyDot()
  399.      * @see #getHxDot()
  400.      * @see #getHyDot()
  401.      * @see #getLEDot()
  402.      * @see #getLvDot()
  403.      * @see #getLMDot()
  404.      * @see #getEDot()
  405.      * @see #getIDot()
  406.      * @since 9.0
  407.      */
  408.     public abstract boolean hasDerivatives();

  410.     /** Get the central attraction coefficient used for position and velocity conversions (m³/s²).
  411.      * @return central attraction coefficient used for position and velocity conversions (m³/s²)
  412.      */
  413.     public T getMu() {
  414.         return mu;
  415.     }

  417.     /** Get the Keplerian period.
  418.      * <p>The Keplerian period is computed directly from semi major axis
  419.      * and central acceleration constant.</p>
  420.      * @return Keplerian period in seconds, or positive infinity for hyperbolic orbits
  421.      */
  422.     public T getKeplerianPeriod() {
  423.         final T a = getA();
  424.         return isElliptical() ?
  425.                a.multiply(a.getPi().multiply(2.0)).multiply(a.divide(mu).sqrt()) :
  426.                zero.add(Double.POSITIVE_INFINITY);
  427.     }

  429.     /** Get the Keplerian mean motion.
  430.      * <p>The Keplerian mean motion is computed directly from semi major axis
  431.      * and central acceleration constant.</p>
  432.      * @return Keplerian mean motion in radians per second
  433.      */
  434.     public T getKeplerianMeanMotion() {
  435.         final T absA = getA().abs();
  436.         return absA.reciprocal().multiply(mu).sqrt().divide(absA);
  437.     }

  439.     /** Get the derivative of the mean anomaly with respect to the semi major axis.
  440.      * @return derivative of the mean anomaly with respect to the semi major axis
  441.      */
  442.     public T getMeanAnomalyDotWrtA() {
  443.         return getKeplerianMeanMotion().divide(getA()).multiply(-1.5);
  444.     }

  446.     /** Get the date of orbital parameters.
  447.      * @return date of the orbital parameters
  448.      */
  449.     public FieldAbsoluteDate<T> getDate() {
  450.         return date;
  451.     }

  453.     /** Get the {@link TimeStampedPVCoordinates} in a specified frame.
  454.      * @param outputFrame frame in which the position/velocity coordinates shall be computed
  455.      * @return FieldPVCoordinates in the specified output frame
  456.           * @see #getPVCoordinates()
  457.      */
  458.     public TimeStampedFieldPVCoordinates<T> getPVCoordinates(final Frame outputFrame) {
  459.         if (pvCoordinates == null) {
  460.             pvCoordinates = initPVCoordinates();
  461.         }

  463.         // If output frame requested is the same as definition frame,
  464.         // PV coordinates are returned directly
  465.         if (outputFrame == frame) {
  466.             return pvCoordinates;
  467.         }

  469.         // Else, PV coordinates are transformed to output frame
  470.         final FieldTransform<T> t = frame.getTransformTo(outputFrame, date);
  471.         return t.transformPVCoordinates(pvCoordinates);
  472.     }

  474.     /** {@inheritDoc} */
  475.     public TimeStampedFieldPVCoordinates<T> getPVCoordinates(final FieldAbsoluteDate<T> otherDate, final Frame otherFrame) {
  476.         return shiftedBy(otherDate.durationFrom(getDate())).getPVCoordinates(otherFrame);
  477.     }

  479.     /** {@inheritDoc} */
  480.     @Override
  481.     public FieldVector3D<T> getPosition(final FieldAbsoluteDate<T> otherDate, final Frame otherFrame) {
  482.         return shiftedBy(otherDate.durationFrom(getDate())).getPosition(otherFrame);
  483.     }

  485.     /** Get the position in a specified frame.
  486.      * @param outputFrame frame in which the position coordinates shall be computed
  487.      * @return position in the specified output frame
  488.      * @see #getPosition()
  489.      * @since 12.0
  490.      */
  491.     public FieldVector3D<T> getPosition(final Frame outputFrame) {
  492.         if (position == null) {
  493.             position = initPosition();
  494.         }

  496.         // If output frame requested is the same as definition frame,
  497.         // Position vector is returned directly
  498.         if (outputFrame == frame) {
  499.             return position;
  500.         }

  502.         // Else, position vector is transformed to output frame
  503.         final FieldStaticTransform<T> t = frame.getStaticTransformTo(outputFrame, date);
  504.         return t.transformPosition(position);

  506.     }

  508.     /** Get the position in definition frame.
  509.      * @return position in the definition frame
  510.      * @see #getPVCoordinates()
  511.      * @since 12.0
  512.      */
  513.     public FieldVector3D<T> getPosition() {
  514.         if (position == null) {
  515.             position = initPosition();
  516.         }
  517.         return position;
  518.     }

  520.     /** Get the {@link TimeStampedPVCoordinates} in definition frame.
  521.      * @return FieldPVCoordinates in the definition frame
  522.      * @see #getPVCoordinates(Frame)
  523.      */
  524.     public TimeStampedFieldPVCoordinates<T> getPVCoordinates() {
  525.         if (pvCoordinates == null) {
  526.             pvCoordinates = initPVCoordinates();
  527.             position      = pvCoordinates.getPosition();
  528.         }
  529.         return pvCoordinates;
  530.     }

  532.     /** Getter for Field-valued one.
  533.      * @return one
  534.      * */
  535.     protected T getOne() {
  536.         return one;
  537.     }

  539.     /** Getter for Field-valued zero.
  540.      * @return zero
  541.      * */
  542.     protected T getZero() {
  543.         return zero;
  544.     }

  546.     /** Getter for Field.
  547.      * @return CalculusField
  548.      * */
  549.     protected Field<T> getField() {
  550.         return field;
  551.     }

  553.     /** Compute the position coordinates from the canonical parameters.
  554.      * @return computed position coordinates
  555.      * @since 12.0
  556.      */
  557.     protected abstract FieldVector3D<T> initPosition();

  559.     /** Compute the position/velocity coordinates from the canonical parameters.
  560.      * @return computed position/velocity coordinates
  561.      */
  562.     protected abstract TimeStampedFieldPVCoordinates<T> initPVCoordinates();

  564.     /** Get a time-shifted orbit.
  565.      * <p>
  566.      * The orbit can be slightly shifted to close dates. This shift is based on
  567.      * a simple Keplerian model. It is <em>not</em> intended as a replacement
  568.      * for proper orbit and attitude propagation but should be sufficient for
  569.      * small time shifts or coarse accuracy.
  570.      * </p>
  571.      * @param dt time shift in seconds
  572.      * @return a new orbit, shifted with respect to the instance (which is immutable)
  573.      */
  574.     public abstract FieldOrbit<T> shiftedBy(T dt);

  576.     /** Compute the Jacobian of the orbital parameters with respect to the Cartesian parameters.
  577.      * <p>
  578.      * Element {@code jacobian[i][j]} is the derivative of parameter i of the orbit with
  579.      * respect to Cartesian coordinate j. This means each row corresponds to one orbital parameter
  580.      * whereas columns 0 to 5 correspond to the Cartesian coordinates x, y, z, xDot, yDot and zDot.
  581.      * </p>
  582.      * @param type type of the position angle to use
  583.      * @param jacobian placeholder 6x6 (or larger) matrix to be filled with the Jacobian, if matrix
  584.      * is larger than 6x6, only the 6x6 upper left corner will be modified
  585.      */
  586.     public void getJacobianWrtCartesian(final PositionAngleType type, final T[][] jacobian) {

  588.         final T[][] cachedJacobian;
  589.         synchronized (this) {
  590.             switch (type) {
  591.                 case MEAN :
  592.                     if (jacobianMeanWrtCartesian == null) {
  593.                         // first call, we need to compute the Jacobian and cache it
  594.                         jacobianMeanWrtCartesian = computeJacobianMeanWrtCartesian();
  595.                     }
  596.                     cachedJacobian = jacobianMeanWrtCartesian;
  597.                     break;
  598.                 case ECCENTRIC :
  599.                     if (jacobianEccentricWrtCartesian == null) {
  600.                         // first call, we need to compute the Jacobian and cache it
  601.                         jacobianEccentricWrtCartesian = computeJacobianEccentricWrtCartesian();
  602.                     }
  603.                     cachedJacobian = jacobianEccentricWrtCartesian;
  604.                     break;
  605.                 case TRUE :
  606.                     if (jacobianTrueWrtCartesian == null) {
  607.                         // first call, we need to compute the Jacobian and cache it
  608.                         jacobianTrueWrtCartesian = computeJacobianTrueWrtCartesian();
  609.                     }
  610.                     cachedJacobian = jacobianTrueWrtCartesian;
  611.                     break;
  612.                 default :
  613.                     throw new OrekitInternalError(null);
  614.             }
  615.         }

  617.         // fill the user provided array
  618.         for (int i = 0; i < cachedJacobian.length; ++i) {
  619.             System.arraycopy(cachedJacobian[i], 0, jacobian[i], 0, cachedJacobian[i].length);
  620.         }

  622.     }

  624.     /** Compute the Jacobian of the Cartesian parameters with respect to the orbital parameters.
  625.      * <p>
  626.      * Element {@code jacobian[i][j]} is the derivative of Cartesian coordinate i of the orbit with
  627.      * respect to orbital parameter j. This means each row corresponds to one Cartesian coordinate
  628.      * x, y, z, xdot, ydot, zdot whereas columns 0 to 5 correspond to the orbital parameters.
  629.      * </p>
  630.      * @param type type of the position angle to use
  631.      * @param jacobian placeholder 6x6 (or larger) matrix to be filled with the Jacobian, if matrix
  632.      * is larger than 6x6, only the 6x6 upper left corner will be modified
  633.      */
  634.     public void getJacobianWrtParameters(final PositionAngleType type, final T[][] jacobian) {

  636.         final T[][] cachedJacobian;
  637.         synchronized (this) {
  638.             switch (type) {
  639.                 case MEAN :
  640.                     if (jacobianWrtParametersMean == null) {
  641.                         // first call, we need to compute the Jacobian and cache it
  642.                         jacobianWrtParametersMean = createInverseJacobian(type);
  643.                     }
  644.                     cachedJacobian = jacobianWrtParametersMean;
  645.                     break;
  646.                 case ECCENTRIC :
  647.                     if (jacobianWrtParametersEccentric == null) {
  648.                         // first call, we need to compute the Jacobian and cache it
  649.                         jacobianWrtParametersEccentric = createInverseJacobian(type);
  650.                     }
  651.                     cachedJacobian = jacobianWrtParametersEccentric;
  652.                     break;
  653.                 case TRUE :
  654.                     if (jacobianWrtParametersTrue == null) {
  655.                         // first call, we need to compute the Jacobian and cache it
  656.                         jacobianWrtParametersTrue = createInverseJacobian(type);
  657.                     }
  658.                     cachedJacobian = jacobianWrtParametersTrue;
  659.                     break;
  660.                 default :
  661.                     throw new OrekitInternalError(null);
  662.             }
  663.         }

  665.         // fill the user-provided array
  666.         for (int i = 0; i < cachedJacobian.length; ++i) {
  667.             System.arraycopy(cachedJacobian[i], 0, jacobian[i], 0, cachedJacobian[i].length);
  668.         }

  670.     }

  672.     /** Create an inverse Jacobian.
  673.      * @param type type of the position angle to use
  674.      * @return inverse Jacobian
  675.      */
  676.     private T[][] createInverseJacobian(final PositionAngleType type) {

  678.         // get the direct Jacobian
  679.         final T[][] directJacobian = MathArrays.buildArray(getA().getField(), 6, 6);
  680.         getJacobianWrtCartesian(type, directJacobian);

  682.         // invert the direct Jacobian
  683.         final FieldMatrix<T> matrix = MatrixUtils.createFieldMatrix(directJacobian);
  684.         final FieldDecompositionSolver<T> solver = new FieldLUDecomposition<>(matrix).getSolver();
  685.         return solver.getInverse().getData();

  687.     }

  689.     /** Compute the Jacobian of the orbital parameters with mean angle with respect to the Cartesian parameters.
  690.      * <p>
  691.      * Element {@code jacobian[i][j]} is the derivative of parameter i of the orbit with
  692.      * respect to Cartesian coordinate j. This means each row correspond to one orbital parameter
  693.      * whereas columns 0 to 5 correspond to the Cartesian coordinates x, y, z, xDot, yDot and zDot.
  694.      * </p>
  695.      * @return 6x6 Jacobian matrix
  696.      * @see #computeJacobianEccentricWrtCartesian()
  697.      * @see #computeJacobianTrueWrtCartesian()
  698.      */
  699.     protected abstract T[][] computeJacobianMeanWrtCartesian();

  701.     /** Compute the Jacobian of the orbital parameters with eccentric angle with respect to the Cartesian parameters.
  702.      * <p>
  703.      * Element {@code jacobian[i][j]} is the derivative of parameter i of the orbit with
  704.      * respect to Cartesian coordinate j. This means each row correspond to one orbital parameter
  705.      * whereas columns 0 to 5 correspond to the Cartesian coordinates x, y, z, xDot, yDot and zDot.
  706.      * </p>
  707.      * @return 6x6 Jacobian matrix
  708.      * @see #computeJacobianMeanWrtCartesian()
  709.      * @see #computeJacobianTrueWrtCartesian()
  710.      */
  711.     protected abstract T[][] computeJacobianEccentricWrtCartesian();

  713.     /** Compute the Jacobian of the orbital parameters with true angle with respect to the Cartesian parameters.
  714.      * <p>
  715.      * Element {@code jacobian[i][j]} is the derivative of parameter i of the orbit with
  716.      * respect to Cartesian coordinate j. This means each row correspond to one orbital parameter
  717.      * whereas columns 0 to 5 correspond to the Cartesian coordinates x, y, z, xDot, yDot and zDot.
  718.      * </p>
  719.      * @return 6x6 Jacobian matrix
  720.      * @see #computeJacobianMeanWrtCartesian()
  721.      * @see #computeJacobianEccentricWrtCartesian()
  722.      */
  723.     protected abstract T[][] computeJacobianTrueWrtCartesian();

  725.     /** Add the contribution of the Keplerian motion to parameters derivatives
  726.      * <p>
  727.      * This method is used by integration-based propagators to evaluate the part of Keplerian
  728.      * motion to evolution of the orbital state.
  729.      * </p>
  730.      * @param type type of the position angle in the state
  731.      * @param gm attraction coefficient to use
  732.      * @param pDot array containing orbital state derivatives to update (the Keplerian
  733.      * part must be <em>added</em> to the array components, as the array may already
  734.      * contain some non-zero elements corresponding to non-Keplerian parts)
  735.      */
  736.     public abstract void addKeplerContribution(PositionAngleType type, T gm, T[] pDot);

  738.         /** Fill a Jacobian half row with a single vector.
  739.      * @param a coefficient of the vector
  740.      * @param v vector
  741.      * @param row Jacobian matrix row
  742.      * @param j index of the first element to set (row[j], row[j+1] and row[j+2] will all be set)
  743.      */

  745.     protected void fillHalfRow(final T a, final FieldVector3D<T> v, final T[] row, final int j) {
  746.         row[j]     = a.multiply(v.getX());
  747.         row[j + 1] = a.multiply(v.getY());
  748.         row[j + 2] = a.multiply(v.getZ());
  749.     }

  751.     /** Fill a Jacobian half row with a linear combination of vectors.
  752.      * @param a1 coefficient of the first vector
  753.      * @param v1 first vector
  754.      * @param a2 coefficient of the second vector
  755.      * @param v2 second vector
  756.      * @param row Jacobian matrix row
  757.      * @param j index of the first element to set (row[j], row[j+1] and row[j+2] will all be set)
  758.      */
  759.     protected void fillHalfRow(final T a1, final FieldVector3D<T> v1, final T a2, final FieldVector3D<T> v2,
  760.                                       final T[] row, final int j) {
  761.         row[j]     = a1.linearCombination(a1, v1.getX(), a2, v2.getX());
  762.         row[j + 1] = a1.linearCombination(a1, v1.getY(), a2, v2.getY());
  763.         row[j + 2] = a1.linearCombination(a1, v1.getZ(), a2, v2.getZ());

  765.     }

  767.     /** Fill a Jacobian half row with a linear combination of vectors.
  768.      * @param a1 coefficient of the first vector
  769.      * @param v1 first vector
  770.      * @param a2 coefficient of the second vector
  771.      * @param v2 second vector
  772.      * @param a3 coefficient of the third vector
  773.      * @param v3 third vector
  774.      * @param row Jacobian matrix row
  775.      * @param j index of the first element to set (row[j], row[j+1] and row[j+2] will all be set)
  776.      */
  777.     protected void fillHalfRow(final T a1, final FieldVector3D<T> v1,
  778.                                final T a2, final FieldVector3D<T> v2,
  779.                                final T a3, final FieldVector3D<T> v3,
  780.                                       final T[] row, final int j) {
  781.         row[j]     = a1.linearCombination(a1, v1.getX(), a2, v2.getX(), a3, v3.getX());
  782.         row[j + 1] = a1.linearCombination(a1, v1.getY(), a2, v2.getY(), a3, v3.getY());
  783.         row[j + 2] = a1.linearCombination(a1, v1.getZ(), a2, v2.getZ(), a3, v3.getZ());

  785.     }

  787.     /** Fill a Jacobian half row with a linear combination of vectors.
  788.      * @param a1 coefficient of the first vector
  789.      * @param v1 first vector
  790.      * @param a2 coefficient of the second vector
  791.      * @param v2 second vector
  792.      * @param a3 coefficient of the third vector
  793.      * @param v3 third vector
  794.      * @param a4 coefficient of the fourth vector
  795.      * @param v4 fourth vector
  796.      * @param row Jacobian matrix row
  797.      * @param j index of the first element to set (row[j], row[j+1] and row[j+2] will all be set)
  798.      */
  799.     protected void fillHalfRow(final T a1, final FieldVector3D<T> v1, final T a2, final FieldVector3D<T> v2,
  800.                                       final T a3, final FieldVector3D<T> v3, final T a4, final FieldVector3D<T> v4,
  801.                                       final T[] row, final int j) {
  802.         row[j]     = a1.linearCombination(a1, v1.getX(), a2, v2.getX(), a3, v3.getX(), a4, v4.getX());
  803.         row[j + 1] = a1.linearCombination(a1, v1.getY(), a2, v2.getY(), a3, v3.getY(), a4, v4.getY());
  804.         row[j + 2] = a1.linearCombination(a1, v1.getZ(), a2, v2.getZ(), a3, v3.getZ(), a4, v4.getZ());

  806.     }

  808.     /** Fill a Jacobian half row with a linear combination of vectors.
  809.      * @param a1 coefficient of the first vector
  810.      * @param v1 first vector
  811.      * @param a2 coefficient of the second vector
  812.      * @param v2 second vector
  813.      * @param a3 coefficient of the third vector
  814.      * @param v3 third vector
  815.      * @param a4 coefficient of the fourth vector
  816.      * @param v4 fourth vector
  817.      * @param a5 coefficient of the fifth vector
  818.      * @param v5 fifth vector
  819.      * @param row Jacobian matrix row
  820.      * @param j index of the first element to set (row[j], row[j+1] and row[j+2] will all be set)
  821.      */
  822.     protected void fillHalfRow(final T a1, final FieldVector3D<T> v1, final T a2, final FieldVector3D<T> v2,
  823.                                       final T a3, final FieldVector3D<T> v3, final T a4, final FieldVector3D<T> v4,
  824.                                       final T a5, final FieldVector3D<T> v5,
  825.                                       final T[] row, final int j) {
  826.         row[j]     = a1.linearCombination(a1, v1.getX(), a2, v2.getX(), a3, v3.getX(), a4, v4.getX()).add(a5.multiply(v5.getX()));
  827.         row[j + 1] = a1.linearCombination(a1, v1.getY(), a2, v2.getY(), a3, v3.getY(), a4, v4.getY()).add(a5.multiply(v5.getY()));
  828.         row[j + 2] = a1.linearCombination(a1, v1.getZ(), a2, v2.getZ(), a3, v3.getZ(), a4, v4.getZ()).add(a5.multiply(v5.getZ()));

  830.     }

  832.     /** Fill a Jacobian half row with a linear combination of vectors.
  833.      * @param a1 coefficient of the first vector
  834.      * @param v1 first vector
  835.      * @param a2 coefficient of the second vector
  836.      * @param v2 second vector
  837.      * @param a3 coefficient of the third vector
  838.      * @param v3 third vector
  839.      * @param a4 coefficient of the fourth vector
  840.      * @param v4 fourth vector
  841.      * @param a5 coefficient of the fifth vector
  842.      * @param v5 fifth vector
  843.      * @param a6 coefficient of the sixth vector
  844.      * @param v6 sixth vector
  845.      * @param row Jacobian matrix row
  846.      * @param j index of the first element to set (row[j], row[j+1] and row[j+2] will all be set)
  847.      */
  848.     protected void fillHalfRow(final T a1, final FieldVector3D<T> v1, final T a2, final FieldVector3D<T> v2,
  849.                                       final T a3, final FieldVector3D<T> v3, final T a4, final FieldVector3D<T> v4,
  850.                                       final T a5, final FieldVector3D<T> v5, final T a6, final FieldVector3D<T> v6,
  851.                                       final T[] row, final int j) {
  852.         row[j]     = a1.linearCombination(a1, v1.getX(), a2, v2.getX(), a3, v3.getX(), a4, v4.getX()).add(a1.linearCombination(a5, v5.getX(), a6, v6.getX()));
  853.         row[j + 1] = a1.linearCombination(a1, v1.getY(), a2, v2.getY(), a3, v3.getY(), a4, v4.getY()).add(a1.linearCombination(a5, v5.getY(), a6, v6.getY()));
  854.         row[j + 2] = a1.linearCombination(a1, v1.getZ(), a2, v2.getZ(), a3, v3.getZ(), a4, v4.getZ()).add(a1.linearCombination(a5, v5.getZ(), a6, v6.getZ()));

  856.     }


  859. }
Created with JaCoCo 0.8.12.202403310830