/* Copyright 2002-2025 CS GROUP
    * Licensed to CS GROUP (CS) under one or more
    * contributor license agreements.  See the NOTICE file distributed with
    * this work for additional information regarding copyright ownership.
    * CS licenses this file to You under the Apache License, Version 2.0
    * (the "License"); you may not use this file except in compliance with
    * the License.  You may obtain a copy of the License at
    *
    *   http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package org.orekit.propagation;
  
  import org.hipparchus.exception.LocalizedCoreFormats;
  import org.hipparchus.exception.MathIllegalStateException;
  import org.hipparchus.geometry.euclidean.threed.Vector3D;
  import org.hipparchus.util.FastMath;
  import org.orekit.attitudes.Attitude;
  import org.orekit.attitudes.AttitudeProvider;
  import org.orekit.attitudes.FrameAlignedProvider;
  import org.orekit.errors.OrekitException;
  import org.orekit.errors.OrekitIllegalArgumentException;
  import org.orekit.errors.OrekitIllegalStateException;
  import org.orekit.errors.OrekitMessages;
  import org.orekit.frames.Frame;
  import org.orekit.frames.StaticTransform;
  import org.orekit.frames.Transform;
  import org.orekit.orbits.Orbit;
  import org.orekit.propagation.numerical.NumericalPropagator;
  import org.orekit.time.AbsoluteDate;
  import org.orekit.time.TimeOffset;
  import org.orekit.time.TimeShiftable;
  import org.orekit.time.TimeStamped;
  import org.orekit.utils.AbsolutePVCoordinates;
  import org.orekit.utils.DataDictionary;
  import org.orekit.utils.DoubleArrayDictionary;
  import org.orekit.utils.TimeStampedPVCoordinates;
  
  /** This class is the representation of a complete state holding orbit, attitude
   * and mass information at a given date, meant primarily for propagation.
   *
   * <p>It contains an {@link Orbit}, or an {@link AbsolutePVCoordinates} if there
   * is no definite central body, plus the current mass and attitude at the intrinsic
   * {@link AbsoluteDate}. Quantities are guaranteed to be consistent in terms
   * of date and reference frame. The spacecraft state may also contain additional
   * data, which are simply named.
   * </p>
   * <p>
   * The state can be slightly shifted to close dates. This actual shift varies
   * between {@link Orbit} and {@link AbsolutePVCoordinates}.
   * For attitude it is a linear extrapolation taking the spin rate into account
   * and no mass change. It is <em>not</em> intended as a replacement for proper
   * orbit and attitude propagation but should be sufficient for either small
   * time shifts or coarse accuracy.
   * </p>
   * <p>
   * The instance <code>SpacecraftState</code> is guaranteed to be immutable.
   * </p>
   * @see NumericalPropagator
   * @author Fabien Maussion
   * @author V&eacute;ronique Pommier-Maurussane
   * @author Luc Maisonobe
   */
  public class SpacecraftState implements TimeStamped, TimeShiftable<SpacecraftState> {
  
      /** Default mass. */
      public static final double DEFAULT_MASS = 1000.0;
  
      /**
       * tolerance on date comparison in {@link #checkConsistency(Orbit, Attitude)}. 100 ns
       * corresponds to sub-mm accuracy at LEO orbital velocities.
       */
      private static final double DATE_INCONSISTENCY_THRESHOLD = 100e-9;
  
      /** Orbital state. */
      private final Orbit orbit;
  
      /** Trajectory state, when it is not an orbit. */
      private final AbsolutePVCoordinates absPva;
  
      /** Attitude. */
      private final Attitude attitude;
  
      /** Current mass (kg). */
      private final double mass;
  
      /** Additional data, can be any object (String, double[], etc.). */
      private final DataDictionary additional;
  
      /** Additional states derivatives.
       * @since 11.1
       */
      private final DoubleArrayDictionary additionalDot;
  
     /** Build a spacecraft state from orbit only.
      * <p>Attitude and mass are set to unspecified non-null arbitrary values.</p>
      * @param orbit the orbit
      */
     public SpacecraftState(final Orbit orbit) {
         this(orbit, getDefaultAttitudeProvider(orbit.getFrame())
                         .getAttitude(orbit, orbit.getDate(), orbit.getFrame()),
              DEFAULT_MASS, null, null);
     }
 
     /** Build a spacecraft state from orbit and attitude. Kept for performance.
      * <p>Mass is set to an unspecified non-null arbitrary value.</p>
      * @param orbit the orbit
      * @param attitude attitude
      * @exception IllegalArgumentException if orbit and attitude dates
      * or frames are not equal
      */
     public SpacecraftState(final Orbit orbit, final Attitude attitude)
         throws IllegalArgumentException {
         this(orbit, attitude, DEFAULT_MASS, null, null);
     }
 
     /** Create a new instance from orbit and mass.
      * <p>Attitude law is set to an unspecified default attitude.</p>
      * @param orbit the orbit
      * @param mass the mass (kg)
      * @deprecated since 13.0, use withXXX
      */
     @Deprecated
     public SpacecraftState(final Orbit orbit, final double mass) {
         this(orbit, getDefaultAttitudeProvider(orbit.getFrame())
                         .getAttitude(orbit, orbit.getDate(), orbit.getFrame()),
              mass, null, null);
     }
 
     /** Build a spacecraft state from orbit, attitude and mass.
      * @param orbit the orbit
      * @param attitude attitude
      * @param mass the mass (kg)
      * @exception IllegalArgumentException if orbit and attitude dates
      * or frames are not equal
      * @deprecated since 13.0, use withXXX
      */
     @Deprecated
     public SpacecraftState(final Orbit orbit, final Attitude attitude, final double mass)
         throws IllegalArgumentException {
         this(orbit, attitude, mass, null, null);
     }
 
     /** Build a spacecraft state from orbit, attitude, mass, additional states and derivatives.
      * @param orbit the orbit
      * @param attitude attitude
      * @param mass the mass (kg)
      * @param additional additional data (may be null if no additional states are available)
      * @param additionalDot additional states derivatives (may be null if no additional states derivatives are available)
      * @exception IllegalArgumentException if orbit and attitude dates
      * or frames are not equal
      * @since 13.0
      */
     public SpacecraftState(final Orbit orbit, final Attitude attitude, final double mass,
                            final DataDictionary additional, final DoubleArrayDictionary additionalDot)
         throws IllegalArgumentException {
         checkConsistency(orbit, attitude);
         this.orbit      = orbit;
         this.absPva     = null;
         this.attitude   = attitude;
         this.mass       = mass;
         this.additional = additional == null ? new DataDictionary() : additional;
         this.additionalDot = additionalDot == null ? new DoubleArrayDictionary() : new DoubleArrayDictionary(additionalDot);
     }
 
     /** Build a spacecraft state from position-velocity-acceleration only.
      * <p>Attitude and mass are set to unspecified non-null arbitrary values.</p>
      * @param absPva position-velocity-acceleration
      */
     public SpacecraftState(final AbsolutePVCoordinates absPva) {
         this(absPva, getDefaultAttitudeProvider(absPva.getFrame())
                         .getAttitude(absPva, absPva.getDate(), absPva.getFrame()),
              DEFAULT_MASS, null, null);
     }
 
     /** Build a spacecraft state from position-velocity-acceleration and attitude. Kept for performance.
      * <p>Mass is set to an unspecified non-null arbitrary value.</p>
      * @param absPva position-velocity-acceleration
      * @param attitude attitude
      * @exception IllegalArgumentException if orbit and attitude dates
      * or frames are not equal
      */
     public SpacecraftState(final AbsolutePVCoordinates absPva, final Attitude attitude)
         throws IllegalArgumentException {
         this(absPva, attitude, DEFAULT_MASS, null, null);
     }
 
     /** Create a new instance from position-velocity-acceleration and mass.
      * <p>Attitude law is set to an unspecified default attitude.</p>
      * @param absPva position-velocity-acceleration
      * @param mass the mass (kg)
      * @deprecated since 13.0, use withXXX
      */
     @Deprecated
     public SpacecraftState(final AbsolutePVCoordinates absPva, final double mass) {
         this(absPva, getDefaultAttitudeProvider(absPva.getFrame())
                         .getAttitude(absPva, absPva.getDate(), absPva.getFrame()),
              mass,  null, null);
     }
 
     /** Build a spacecraft state from position-velocity-acceleration, attitude and mass.
      * @param absPva position-velocity-acceleration
      * @param attitude attitude
      * @param mass the mass (kg)
      * @exception IllegalArgumentException if orbit and attitude dates
      * or frames are not equal
      * @deprecated since 13.0, use withXXX
      */
     @Deprecated
     public SpacecraftState(final AbsolutePVCoordinates absPva, final Attitude attitude, final double mass)
         throws IllegalArgumentException {
         this(absPva, attitude, mass, null, null);
     }
 
     /** Build a spacecraft state from position-velocity-acceleration, attitude, mass and additional states and derivatives.
      * @param absPva position-velocity-acceleration
      * @param attitude attitude
      * @param mass the mass (kg)
      * @param additional additional data (may be null if no additional data are available)
      * @param additionalDot additional states derivatives(may be null if no additional states derivatives are available)
      * @exception IllegalArgumentException if orbit and attitude dates
      * or frames are not equal
      * @since 13.0
      */
     public SpacecraftState(final AbsolutePVCoordinates absPva, final Attitude attitude, final double mass,
                            final DataDictionary additional, final DoubleArrayDictionary additionalDot)
         throws IllegalArgumentException {
         checkConsistency(absPva, attitude);
         this.orbit      = null;
         this.absPva     = absPva;
         this.attitude   = attitude;
         this.mass       = mass;
         this.additional = additional == null ? new DataDictionary() : new DataDictionary(additional);
         this.additionalDot = additionalDot == null ? new DoubleArrayDictionary() : new DoubleArrayDictionary(additionalDot);
     }
 
     /**
      * Create a new instance with input mass.
      * @param newMass mass
      * @return new state
      * @since 13.0
      */
     public SpacecraftState withMass(final double newMass) {
         if (isOrbitDefined()) {
             return new SpacecraftState(orbit, attitude, newMass, additional, additionalDot);
         } else {
             return new SpacecraftState(absPva, attitude, newMass, additional, additionalDot);
         }
     }
 
     /**
      * Create a new instance with input attitude.
      * @param newAttitude attitude
      * @return new state
      * @since 13.0
      */
     public SpacecraftState withAttitude(final Attitude newAttitude) {
         if (isOrbitDefined()) {
             return new SpacecraftState(orbit, newAttitude, mass, additional, additionalDot);
         } else {
             return new SpacecraftState(absPva, newAttitude, mass, additional, additionalDot);
         }
     }
 
     /**
      * Create a new instance with input additional data.
      * @param dataDictionary additional data
      * @return new state
      * @since 13.0
      */
     public SpacecraftState withAdditionalData(final DataDictionary dataDictionary) {
         if (isOrbitDefined()) {
             return new SpacecraftState(orbit, attitude, mass, dataDictionary, additionalDot);
         } else {
             return new SpacecraftState(absPva, attitude, mass, dataDictionary, additionalDot);
         }
     }
 
     /**
      * Create a new instance with input additional data.
      * @param additionalStateDerivatives additional state derivatives
      * @return new state
      * @since 13.0
      */
     public SpacecraftState withAdditionalStatesDerivatives(final DoubleArrayDictionary additionalStateDerivatives) {
         if (isOrbitDefined()) {
             return new SpacecraftState(orbit, attitude, mass, additional, additionalStateDerivatives);
         } else {
             return new SpacecraftState(absPva, attitude, mass, additional, additionalStateDerivatives);
         }
     }
 
     /** Add an additional data.
      * <p>
      * {@link SpacecraftState SpacecraftState} instances are immutable,
      * so this method does <em>not</em> change the instance, but rather
      * creates a new instance, which has the same orbit, attitude, mass
      * and additional states as the original instance, except it also
      * has the specified state. If the original instance already had an
      * additional data with the same name, it will be overridden. If it
      * did not have any additional state with that name, the new instance
      * will have one more additional state than the original instance.
      * </p>
      * @param name name of the additional data (names containing "orekit"
      * with any case are reserved for the library internal use)
      * @param value value of the additional data
      * @return a new instance, with the additional data added
      * @see #hasAdditionalData(String)
      * @see #getAdditionalData(String)
      * @see #getAdditionalDataValues()
      * @since 13.0
      */
     public SpacecraftState addAdditionalData(final String name, final Object value) {
         final DataDictionary newDict = new DataDictionary(additional);
         if (value instanceof double[]) {
             newDict.put(name, ((double[]) value).clone());
         } else if (value instanceof Double) {
             newDict.put(name, new double[] {(double) value});
         } else {
             newDict.put(name, value);
         }
         return withAdditionalData(newDict);
     }
 
     /** Add an additional state derivative.
      * <p>
      * {@link SpacecraftState SpacecraftState} instances are immutable,
      * so this method does <em>not</em> change the instance, but rather
      * creates a new instance, which has the same components as the original
      * instance, except it also has the specified state derivative. If the
      * original instance already had an additional state derivative with the
      * same name, it will be overridden. If it did not have any additional
      * state derivative with that name, the new instance will have one more
      * additional state derivative than the original instance.
      * </p>
      * @param name name of the additional state derivative (names containing "orekit"
      * with any case are reserved for the library internal use)
      * @param value value of the additional state derivative
      * @return a new instance, with the additional state added
      * @see #hasAdditionalStateDerivative(String)
      * @see #getAdditionalStateDerivative(String)
      * @see #getAdditionalStatesDerivatives()
      * @since 11.1
      */
     public SpacecraftState addAdditionalStateDerivative(final String name, final double... value) {
         final DoubleArrayDictionary newDict = new DoubleArrayDictionary(additionalDot);
         newDict.put(name, value.clone());
         return withAdditionalStatesDerivatives(newDict);
     }
 
     /** Check orbit and attitude dates are equal.
      * @param orbit the orbit
      * @param attitude attitude
      * @exception IllegalArgumentException if orbit and attitude dates
      * are not equal
      */
     private static void checkConsistency(final Orbit orbit, final Attitude attitude)
         throws IllegalArgumentException {
         checkDateAndFrameConsistency(attitude, orbit.getDate(), orbit.getFrame());
     }
 
     /** Defines provider for default Attitude when not passed to constructor.
      * Currently chosen arbitrarily as aligned with input frame.
      * It is also used in {@link FieldSpacecraftState}.
      * @param frame reference frame
      * @return default attitude provider
      * @since 12.0
      */
     static AttitudeProvider getDefaultAttitudeProvider(final Frame frame) {
         return new FrameAlignedProvider(frame);
     }
 
     /** Check if the state contains an orbit part.
      * <p>
      * A state contains either an {@link AbsolutePVCoordinates absolute
      * position-velocity-acceleration} or an {@link Orbit orbit}.
      * </p>
      * @return true if state contains an orbit (in which case {@link #getOrbit()}
      * will not throw an exception), or false if the state contains an
      * absolut position-velocity-acceleration (in which case {@link #getAbsPVA()}
      * will not throw an exception)
      */
     public boolean isOrbitDefined() {
         return orbit != null;
     }
 
     /** Check AbsolutePVCoordinates and attitude dates are equal.
      * @param absPva position-velocity-acceleration
      * @param attitude attitude
      * @exception IllegalArgumentException if orbit and attitude dates
      * are not equal
      */
     private static void checkConsistency(final AbsolutePVCoordinates absPva, final Attitude attitude)
         throws IllegalArgumentException {
         checkDateAndFrameConsistency(attitude, absPva.getDate(), absPva.getFrame());
     }
 
     /** Check attitude frame and epoch.
      * @param attitude attitude
      * @param date epoch to verify
      * @param frame frame to verify
      */
     private static void checkDateAndFrameConsistency(final Attitude attitude, final AbsoluteDate date, final Frame frame) {
         if (FastMath.abs(date.durationFrom(attitude.getDate())) >
                 DATE_INCONSISTENCY_THRESHOLD) {
             throw new OrekitIllegalArgumentException(OrekitMessages.ORBIT_AND_ATTITUDE_DATES_MISMATCH,
                     date, attitude.getDate());
         }
         if (frame != attitude.getReferenceFrame()) {
             throw new OrekitIllegalArgumentException(OrekitMessages.FRAMES_MISMATCH,
                     frame.getName(),
                     attitude.getReferenceFrame().getName());
         }
     }
 
     /** Get a time-shifted state.
      * <p>
      * The state can be slightly shifted to close dates. This shift is based on
      * simple models. For orbits, the model is a Keplerian one if no derivatives
      * are available in the orbit, or Keplerian plus quadratic effect of the
      * non-Keplerian acceleration if derivatives are available. For attitude,
      * a polynomial model is used. Neither mass nor additional states change.
      * Shifting is <em>not</em> intended as a replacement for proper orbit
      * and attitude propagation but should be sufficient for small time shifts
      * or coarse accuracy.
      * </p>
      * <p>
      * As a rough order of magnitude, the following table shows the extrapolation
      * errors obtained between this simple shift method and an {@link
      * NumericalPropagator numerical
      * propagator} for a low Earth Sun Synchronous Orbit, with a 20x20 gravity field,
      * Sun and Moon third bodies attractions, drag and solar radiation pressure.
      * Beware that these results will be different for other orbits.
      * </p>
      * <table border="1">
      * <caption>Extrapolation Error</caption>
      * <tr style="background-color: #ccccff"><th>interpolation time (s)</th>
      * <th>position error without derivatives (m)</th><th>position error with derivatives (m)</th></tr>
      * <tr><td style="background-color: #eeeeff; padding:5px"> 60</td><td>  18</td><td> 1.1</td></tr>
      * <tr><td style="background-color: #eeeeff; padding:5px">120</td><td>  72</td><td> 9.1</td></tr>
      * <tr><td style="background-color: #eeeeff; padding:5px">300</td><td> 447</td><td> 140</td></tr>
      * <tr><td style="background-color: #eeeeff; padding:5px">600</td><td>1601</td><td>1067</td></tr>
      * <tr><td style="background-color: #eeeeff; padding:5px">900</td><td>3141</td><td>3307</td></tr>
      * </table>
      * @param dt time shift in seconds
      * @return a new state, shifted with respect to the instance (which is immutable)
      * except for the mass and additional states which stay unchanged
      */
     @Override
     public SpacecraftState shiftedBy(final double dt) {
         if (isOrbitDefined()) {
             return new SpacecraftState(orbit.shiftedBy(dt), attitude.shiftedBy(dt),
                                        mass, shiftAdditional(dt), additionalDot);
         } else {
             return new SpacecraftState(absPva.shiftedBy(dt), attitude.shiftedBy(dt),
                                        mass, shiftAdditional(dt), additionalDot);
         }
     }
 
     /** Get a time-shifted state.
      * <p>
      * The state can be slightly shifted to close dates. This shift is based on
      * simple models. For orbits, the model is a Keplerian one if no derivatives
      * are available in the orbit, or Keplerian plus quadratic effect of the
      * non-Keplerian acceleration if derivatives are available. For attitude,
      * a polynomial model is used. Neither mass nor additional states change.
      * Shifting is <em>not</em> intended as a replacement for proper orbit
      * and attitude propagation but should be sufficient for small time shifts
      * or coarse accuracy.
      * </p>
      * <p>
      * As a rough order of magnitude, the following table shows the extrapolation
      * errors obtained between this simple shift method and an {@link
      * NumericalPropagator numerical
      * propagator} for a low Earth Sun Synchronous Orbit, with a 20x20 gravity field,
      * Sun and Moon third bodies attractions, drag and solar radiation pressure.
      * Beware that these results will be different for other orbits.
      * </p>
      * <table border="1">
      * <caption>Extrapolation Error</caption>
      * <tr style="background-color: #ccccff"><th>interpolation time (s)</th>
      * <th>position error without derivatives (m)</th><th>position error with derivatives (m)</th></tr>
      * <tr><td style="background-color: #eeeeff; padding:5px"> 60</td><td>  18</td><td> 1.1</td></tr>
      * <tr><td style="background-color: #eeeeff; padding:5px">120</td><td>  72</td><td> 9.1</td></tr>
      * <tr><td style="background-color: #eeeeff; padding:5px">300</td><td> 447</td><td> 140</td></tr>
      * <tr><td style="background-color: #eeeeff; padding:5px">600</td><td>1601</td><td>1067</td></tr>
      * <tr><td style="background-color: #eeeeff; padding:5px">900</td><td>3141</td><td>3307</td></tr>
      * </table>
      * @param dt time shift in seconds
      * @return a new state, shifted with respect to the instance (which is immutable)
      * except for the mass and additional states which stay unchanged
      * @since 13.0
      */
     @Override
     public SpacecraftState shiftedBy(final TimeOffset dt) {
         if (isOrbitDefined()) {
             return new SpacecraftState(orbit.shiftedBy(dt), attitude.shiftedBy(dt),
                                        mass, shiftAdditional(dt.toDouble()), additionalDot);
         } else {
             return new SpacecraftState(absPva.shiftedBy(dt), attitude.shiftedBy(dt),
                                        mass, shiftAdditional(dt.toDouble()), additionalDot);
         }
     }
 
     /** Shift additional states.
      * @param dt time shift in seconds
      * @return shifted additional states
      * @since 11.1.1
      */
     private DataDictionary shiftAdditional(final double dt) {
 
         // fast handling when there are no derivatives at all
         if (additionalDot.size() == 0) {
             return additional;
         }
 
         // there are derivatives, we need to take them into account in the additional state
         final DataDictionary shifted = new DataDictionary(additional);
         for (final DoubleArrayDictionary.Entry dotEntry : additionalDot.getData()) {
             final DataDictionary.Entry entry = shifted.getEntry(dotEntry.getKey());
             if (entry != null) {
                 entry.scaledIncrement(dt, dotEntry);
             }
         }
 
         return shifted;
 
     }
 
     /** Get the absolute position-velocity-acceleration.
      * <p>
      * A state contains either an {@link AbsolutePVCoordinates absolute
      * position-velocity-acceleration} or an {@link Orbit orbit}. Which
      * one is present can be checked using {@link #isOrbitDefined()}.
      * </p>
      * @return absolute position-velocity-acceleration
      * @exception OrekitIllegalStateException if position-velocity-acceleration is null,
      * which mean the state rather contains an {@link Orbit}
      * @see #isOrbitDefined()
      * @see #getOrbit()
      */
     public AbsolutePVCoordinates getAbsPVA() throws OrekitIllegalStateException {
         if (isOrbitDefined()) {
             throw new OrekitIllegalStateException(OrekitMessages.UNDEFINED_ABSOLUTE_PVCOORDINATES);
         }
         return absPva;
     }
 
     /** Get the current orbit.
      * <p>
      * A state contains either an {@link AbsolutePVCoordinates absolute
      * position-velocity-acceleration} or an {@link Orbit orbit}. Which
      * one is present can be checked using {@link #isOrbitDefined()}.
      * </p>
      * @return the orbit
      * @exception OrekitIllegalStateException if orbit is null,
      * which means the state rather contains an {@link AbsolutePVCoordinates absolute
      * position-velocity-acceleration}
      * @see #isOrbitDefined()
      * @see #getAbsPVA()
      */
     public Orbit getOrbit() throws OrekitIllegalStateException {
         if (orbit == null) {
             throw new OrekitIllegalStateException(OrekitMessages.UNDEFINED_ORBIT);
         }
         return orbit;
     }
 
     /** {@inheritDoc} */
     @Override
     public AbsoluteDate getDate() {
         return (absPva == null) ? orbit.getDate() : absPva.getDate();
     }
 
     /** Get the defining frame.
      * @return the frame in which state is defined
      */
     public Frame getFrame() {
         return isOrbitDefined() ? orbit.getFrame() : absPva.getFrame();
     }
 
     /** Check if an additional data is available.
      * @param name name of the additional data
      * @return true if the additional data is available
      * @see #addAdditionalData(String, Object)
      * @see #getAdditionalState(String)
      * @see #getAdditionalData(String)
      * @see #getAdditionalDataValues()
      */
     public boolean hasAdditionalData(final String name) {
         return additional.getEntry(name) != null;
     }
 
     /** Check if an additional state derivative is available.
      * @param name name of the additional state derivative
      * @return true if the additional state derivative is available
      * @see #addAdditionalStateDerivative(String, double[])
      * @see #getAdditionalStateDerivative(String)
      * @see #getAdditionalStatesDerivatives()
      * @since 11.1
      */
     public boolean hasAdditionalStateDerivative(final String name) {
         return additionalDot.getEntry(name) != null;
     }
 
     /** Check if two instances have the same set of additional states available.
      * <p>
      * Only the names and dimensions of the additional states are compared,
      * not their values.
      * </p>
      * @param state state to compare to instance
      * @exception MathIllegalStateException if an additional state does not have
      * the same dimension in both states
      */
     public void ensureCompatibleAdditionalStates(final SpacecraftState state)
         throws MathIllegalStateException {
 
         // check instance additional states is a subset of the other one
         for (final DataDictionary.Entry entry : additional.getData()) {
             final Object other = state.additional.get(entry.getKey());
             if (other == null || !entry.getValue().getClass().equals(other.getClass())) {
                 throw new OrekitException(OrekitMessages.UNKNOWN_ADDITIONAL_DATA,
                                           entry.getKey());
             }
             if (other instanceof double[] && ((double[]) other).length != ((double[]) entry.getValue()).length) {
                 throw new MathIllegalStateException(LocalizedCoreFormats.DIMENSIONS_MISMATCH,
                                                     ((double[]) other).length, ((double[]) entry.getValue()).length);
             }
         }
 
         // check instance additional states derivatives is a subset of the other one
         for (final DoubleArrayDictionary.Entry entry : additionalDot.getData()) {
             final double[] other = state.additionalDot.get(entry.getKey());
             if (other == null) {
                 throw new OrekitException(OrekitMessages.UNKNOWN_ADDITIONAL_DATA,
                                           entry.getKey());
             }
             if (other.length != entry.getValue().length) {
                 throw new MathIllegalStateException(LocalizedCoreFormats.DIMENSIONS_MISMATCH,
                                                     other.length, entry.getValue().length);
             }
         }
 
         if (state.additional.size() > additional.size()) {
             // the other state has more additional states
             for (final DataDictionary.Entry entry : state.additional.getData()) {
                 if (additional.getEntry(entry.getKey()) == null) {
                     throw new OrekitException(OrekitMessages.UNKNOWN_ADDITIONAL_DATA,
                                               entry.getKey());
                 }
             }
         }
 
         if (state.additionalDot.size() > additionalDot.size()) {
             // the other state has more additional states
             for (final DoubleArrayDictionary.Entry entry : state.additionalDot.getData()) {
                 if (additionalDot.getEntry(entry.getKey()) == null) {
                     throw new OrekitException(OrekitMessages.UNKNOWN_ADDITIONAL_DATA,
                                               entry.getKey());
                 }
             }
         }
 
     }
 
     /**
      * Get an additional state.
      *
      * @param name name of the additional state
      * @return value of the additional state
      * @see #hasAdditionalData(String)
      * @see #getAdditionalDataValues()
      */
     public double[] getAdditionalState(final String name) {
         final Object data = getAdditionalData(name);
         if (!(data instanceof double[])) {
             if (data instanceof Double) {
                 return new double[] {(double) data};
             } else {
                 throw new OrekitException(OrekitMessages.ADDITIONAL_STATE_BAD_TYPE, name);
             }
         }
         return (double[]) data;
     }
 
     /**
      * Get an additional data.
      *
      * @param name name of the additional state
      * @return value of the additional state
      * @see #addAdditionalData(String, Object)
      * @see #hasAdditionalData(String)
      * @see #getAdditionalDataValues()
      * @since 13.0
      */
     public Object getAdditionalData(final String name) {
         final DataDictionary.Entry entry = additional.getEntry(name);
         if (entry == null) {
             throw new OrekitException(OrekitMessages.UNKNOWN_ADDITIONAL_DATA, name);
         }
         return entry.getValue();
     }
 
     /** Get an additional state derivative.
      * @param name name of the additional state derivative
      * @return value of the additional state derivative
      * @see #addAdditionalStateDerivative(String, double[])
      * @see #hasAdditionalStateDerivative(String)
      * @see #getAdditionalStatesDerivatives()
      * @since 11.1
      */
     public double[] getAdditionalStateDerivative(final String name) {
         final DoubleArrayDictionary.Entry entry = additionalDot.getEntry(name);
         if (entry == null) {
             throw new OrekitException(OrekitMessages.UNKNOWN_ADDITIONAL_DATA, name);
         }
         return entry.getValue();
     }
 
     /** Get an unmodifiable map of additional data.
      * @return unmodifiable map of additional data
      * @see #addAdditionalData(String, Object)
      * @see #hasAdditionalData(String)
      * @see #getAdditionalState(String)
      * @since 11.1
      */
     public DataDictionary getAdditionalDataValues() {
         return additional;
     }
 
     /** Get an unmodifiable map of additional states derivatives.
      * @return unmodifiable map of additional states derivatives
      * @see #addAdditionalStateDerivative(String, double[])
      * @see #hasAdditionalStateDerivative(String)
      * @see #getAdditionalStateDerivative(String)
      * @since 11.1
      */
     public DoubleArrayDictionary getAdditionalStatesDerivatives() {
         return additionalDot;
     }
 
     /** Compute the transform from state defining frame to spacecraft frame.
      * <p>The spacecraft frame origin is at the point defined by the orbit
      * (or absolute position-velocity-acceleration), and its orientation is
      * defined by the attitude.</p>
      * @return transform from specified frame to current spacecraft frame
      */
     public Transform toTransform() {
         final TimeStampedPVCoordinates pv = getPVCoordinates();
         return new Transform(pv.getDate(), pv.negate(), attitude.getOrientation());
     }
 
     /** Compute the static transform from state defining frame to spacecraft frame.
      * @return static transform from specified frame to current spacecraft frame
      * @see #toTransform()
      * @since 12.0
      */
     public StaticTransform toStaticTransform() {
         return StaticTransform.of(getDate(), getPosition().negate(), attitude.getRotation());
     }
 
     /** Get the position in orbit definition frame.
      * @return position in orbit definition frame
      * @since 12.0
      * @see #getPVCoordinates()
      */
     public Vector3D getPosition() {
         return isOrbitDefined() ? orbit.getPosition() : absPva.getPosition();
     }
 
     /** Get the {@link TimeStampedPVCoordinates} in orbit definition frame.
      * <p>
      * Compute the position and velocity of the satellite. This method caches its
      * results, and recompute them only when the method is called with a new value
      * for mu. The result is provided as a reference to the internally cached
      * {@link TimeStampedPVCoordinates}, so the caller is responsible to copy it in a separate
      * {@link TimeStampedPVCoordinates} if it needs to keep the value for a while.
      * </p>
      * @return pvCoordinates in orbit definition frame
      */
     public TimeStampedPVCoordinates getPVCoordinates() {
         return isOrbitDefined() ? orbit.getPVCoordinates() : absPva.getPVCoordinates();
     }
 
     /** Get the position in given output frame.
      * @param outputFrame frame in which position should be defined
      * @return position in given output frame
      * @since 12.0
      * @see #getPVCoordinates(Frame)
      */
     public Vector3D getPosition(final Frame outputFrame) {
         return isOrbitDefined() ? orbit.getPosition(outputFrame) : absPva.getPosition(outputFrame);
     }
 
     /** Get the {@link TimeStampedPVCoordinates} in given output frame.
      * <p>
      * Compute the position and velocity of the satellite. This method caches its
      * results, and recompute them only when the method is called with a new value
      * for mu. The result is provided as a reference to the internally cached
      * {@link TimeStampedPVCoordinates}, so the caller is responsible to copy it in a separate
      * {@link TimeStampedPVCoordinates} if it needs to keep the value for a while.
      * </p>
      * @param outputFrame frame in which coordinates should be defined
      * @return pvCoordinates in given output frame
      */
     public TimeStampedPVCoordinates getPVCoordinates(final Frame outputFrame) {
         return isOrbitDefined() ? orbit.getPVCoordinates(outputFrame) : absPva.getPVCoordinates(outputFrame);
     }
 
     /** Get the attitude.
      * @return the attitude.
      */
     public Attitude getAttitude() {
         return attitude;
     }
 
     /** Gets the current mass.
      * @return the mass (kg)
      */
     public double getMass() {
         return mass;
     }
 
     @Override
     public String toString() {
         return "SpacecraftState{" +
                 "orbit=" + orbit +
                 ", attitude=" + attitude +
                 ", mass=" + mass +
                 ", additional=" + additional +
                 ", additionalDot=" + additionalDot +
                 '}';
     }
 }