AbstractPropagatorBuilder.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.propagation.conversion;

  19. import org.hipparchus.exception.LocalizedCoreFormats;
  20. import org.hipparchus.util.FastMath;
  21. import org.orekit.attitudes.AttitudeProvider;
  22. import org.orekit.attitudes.FrameAlignedProvider;
  23. import org.orekit.errors.OrekitException;
  24. import org.orekit.errors.OrekitIllegalArgumentException;
  25. import org.orekit.errors.OrekitMessages;
  26. import org.orekit.forces.gravity.NewtonianAttraction;
  27. import org.orekit.frames.Frame;
  28. import org.orekit.orbits.Orbit;
  29. import org.orekit.orbits.OrbitType;
  30. import org.orekit.orbits.PositionAngleType;
  31. import org.orekit.propagation.Propagator;
  32. import org.orekit.propagation.integration.AdditionalDerivativesProvider;
  33. import org.orekit.time.AbsoluteDate;
  34. import org.orekit.utils.ParameterDriver;
  35. import org.orekit.utils.ParameterDriversList;
  36. import org.orekit.utils.ParameterDriversList.DelegatingDriver;
  37. import org.orekit.utils.ParameterObserver;
  38. import org.orekit.utils.TimeSpanMap;
  39. import org.orekit.utils.TimeSpanMap.Span;

  41. import java.util.ArrayList;
  42. import java.util.List;

  44. /** Base class for propagator builders.
  45.  * @author Pascal Parraud
  46.  * @since 7.1
  47.  */
  48. public abstract class AbstractPropagatorBuilder implements PropagatorBuilder {

  50.     /** Central attraction scaling factor.
  51.      * <p>
  52.      * We use a power of 2 to avoid numeric noise introduction
  53.      * in the multiplications/divisions sequences.
  54.      * </p>
  55.      */
  56.     private static final double MU_SCALE = FastMath.scalb(1.0, 32);

  58.     /** Date of the initial orbit. */
  59.     private AbsoluteDate initialOrbitDate;

  61.     /** Frame in which the orbit is propagated. */
  62.     private final Frame frame;

  64.     /** Central attraction coefficient (m³/s²). */
  65.     private double mu;

  67.     /** Initial mass. */
  68.     private double mass;

  70.     /** Drivers for orbital parameters. */
  71.     private final ParameterDriversList orbitalDrivers;

  73.     /** List of the supported parameters. */
  74.     private ParameterDriversList propagationDrivers;

  76.     /** Orbit type to use. */
  77.     private final OrbitType orbitType;

  79.     /** Position angle type to use. */
  80.     private final PositionAngleType positionAngleType;

  82.     /** Position scale to use for the orbital drivers. */
  83.     private final double positionScale;

  85.     /** Attitude provider for the propagator. */
  86.     private AttitudeProvider attitudeProvider;

  88.     /** Additional derivatives providers.
  89.      * @since 11.1
  90.      */
  91.     private List<AdditionalDerivativesProvider> additionalDerivativesProviders;

  93.     /** Build a new instance.
  94.      * <p>
  95.      * The template orbit is used as a model to {@link
  96.      * #createInitialOrbit() create initial orbit}. It defines the
  97.      * inertial frame, the central attraction coefficient, the orbit type, and is also
  98.      * used together with the {@code positionScale} to convert from the {@link
  99.      * ParameterDriver#setNormalizedValue(double) normalized} parameters used by the
  100.      * callers of this builder to the real orbital parameters. The default attitude
  101.      * provider is aligned with the orbit's inertial frame.
  102.      * </p>
  103.      * <p>
  104.      * By default, all the {@link #getOrbitalParametersDrivers() orbital parameters drivers}
  105.      * are selected, which means that if the builder is used for orbit determination or
  106.      * propagator conversion, all orbital parameters will be estimated. If only a subset
  107.      * of the orbital parameters must be estimated, caller must retrieve the orbital
  108.      * parameters by calling {@link #getOrbitalParametersDrivers()} and then call
  109.      * {@link ParameterDriver#setSelected(boolean) setSelected(false)}.
  110.      * </p>
  111.      * @param templateOrbit reference orbit from which real orbits will be built
  112.      * @param positionAngleType position angle type to use
  113.      * @param positionScale scaling factor used for orbital parameters normalization
  114.      * (typically set to the expected standard deviation of the position)
  115.      * @param addDriverForCentralAttraction if true, a {@link ParameterDriver} should
  116.      * be set up for central attraction coefficient
  117.      * @since 8.0
  118.      * @see #AbstractPropagatorBuilder(Orbit, PositionAngleType, double, boolean,
  119.      * AttitudeProvider)
  120.      */
  121.     protected AbstractPropagatorBuilder(final Orbit templateOrbit, final PositionAngleType positionAngleType,
  122.                                         final double positionScale, final boolean addDriverForCentralAttraction) {
  123.         this(templateOrbit, positionAngleType, positionScale, addDriverForCentralAttraction,
  124.              new FrameAlignedProvider(templateOrbit.getFrame()), Propagator.DEFAULT_MASS);
  125.     }
  126.     /** Build a new instance.
  127.      * <p>
  128.      * The template orbit is used as a model to {@link
  129.      * #createInitialOrbit() create initial orbit}. It defines the
  130.      * inertial frame, the central attraction coefficient, the orbit type, and is also
  131.      * used together with the {@code positionScale} to convert from the {@link
  132.      * ParameterDriver#setNormalizedValue(double) normalized} parameters used by the
  133.      * callers of this builder to the real orbital parameters.
  134.      * </p>
  135.      * <p>
  136.      * By default, all the {@link #getOrbitalParametersDrivers() orbital parameters drivers}
  137.      * are selected, which means that if the builder is used for orbit determination or
  138.      * propagator conversion, all orbital parameters will be estimated. If only a subset
  139.      * of the orbital parameters must be estimated, caller must retrieve the orbital
  140.      * parameters by calling {@link #getOrbitalParametersDrivers()} and then call
  141.      * {@link ParameterDriver#setSelected(boolean) setSelected(false)}.
  142.      * </p>
  143.      * @param templateOrbit reference orbit from which real orbits will be built
  144.      * @param positionAngleType position angle type to use
  145.      * @param positionScale scaling factor used for orbital parameters normalization
  146.      * (typically set to the expected standard deviation of the position)
  147.      * @param addDriverForCentralAttraction if true, a {@link ParameterDriver} should
  148.      * be set up for central attraction coefficient
  149.      * @param attitudeProvider for the propagator.
  150.      * @since 10.1
  151.      * @see #AbstractPropagatorBuilder(Orbit, PositionAngleType, double, boolean)
  152.      */
  153.     protected AbstractPropagatorBuilder(final Orbit templateOrbit,
  154.                                         final PositionAngleType positionAngleType,
  155.                                         final double positionScale,
  156.                                         final boolean addDriverForCentralAttraction,
  157.                                         final AttitudeProvider attitudeProvider) {
  158.         this(templateOrbit, positionAngleType, positionScale, addDriverForCentralAttraction, attitudeProvider,
  159.                 Propagator.DEFAULT_MASS);
  160.     }

  162.     /** Build a new instance.
  163.      * <p>
  164.      * The template orbit is used as a model to {@link
  165.      * #createInitialOrbit() create initial orbit}. It defines the
  166.      * inertial frame, the central attraction coefficient, the orbit type, and is also
  167.      * used together with the {@code positionScale} to convert from the {@link
  168.      * ParameterDriver#setNormalizedValue(double) normalized} parameters used by the
  169.      * callers of this builder to the real orbital parameters.
  170.      * </p>
  171.      * <p>
  172.      * By default, all the {@link #getOrbitalParametersDrivers() orbital parameters drivers}
  173.      * are selected, which means that if the builder is used for orbit determination or
  174.      * propagator conversion, all orbital parameters will be estimated. If only a subset
  175.      * of the orbital parameters must be estimated, caller must retrieve the orbital
  176.      * parameters by calling {@link #getOrbitalParametersDrivers()} and then call
  177.      * {@link ParameterDriver#setSelected(boolean) setSelected(false)}.
  178.      * </p>
  179.      * @param templateOrbit reference orbit from which real orbits will be built
  180.      * @param positionAngleType position angle type to use
  181.      * @param positionScale scaling factor used for orbital parameters normalization
  182.      * (typically set to the expected standard deviation of the position)
  183.      * @param addDriverForCentralAttraction if true, a {@link ParameterDriver} should
  184.      * be set up for central attraction coefficient
  185.      * @param attitudeProvider for the propagator.
  186.      * @param initialMass mass
  187.      * @since 12.2
  188.      * @see #AbstractPropagatorBuilder(Orbit, PositionAngleType, double, boolean)
  189.      */
  190.     protected AbstractPropagatorBuilder(final Orbit templateOrbit,
  191.                                         final PositionAngleType positionAngleType,
  192.                                         final double positionScale,
  193.                                         final boolean addDriverForCentralAttraction,
  194.                                         final AttitudeProvider attitudeProvider, final double initialMass) {

  196.         this.initialOrbitDate    = templateOrbit.getDate();
  197.         this.frame               = templateOrbit.getFrame();
  198.         this.mu                  = templateOrbit.getMu();
  199.         this.propagationDrivers  = new ParameterDriversList();
  200.         this.orbitType           = templateOrbit.getType();
  201.         this.positionAngleType = positionAngleType;
  202.         this.positionScale       = positionScale;
  203.         this.orbitalDrivers      = orbitType.getDrivers(positionScale, templateOrbit, positionAngleType);
  204.         this.attitudeProvider = attitudeProvider;
  205.         this.mass         = initialMass;
  206.         for (final DelegatingDriver driver : orbitalDrivers.getDrivers()) {
  207.             driver.setSelected(true);
  208.         }

  210.         this.additionalDerivativesProviders  = new ArrayList<>();

  212.         if (addDriverForCentralAttraction) {
  213.             final ParameterDriver muDriver = new ParameterDriver(NewtonianAttraction.CENTRAL_ATTRACTION_COEFFICIENT,
  214.                                                                  mu, MU_SCALE, 0, Double.POSITIVE_INFINITY);
  215.             muDriver.addObserver(new ParameterObserver() {
  216.                 /** {@inheridDoc} */
  217.                 @Override
  218.                 public void valueChanged(final double previousValue, final ParameterDriver driver, final AbsoluteDate date) {
  219.                     // getValue(), can be called without argument as mu driver should have only one span
  220.                     AbstractPropagatorBuilder.this.mu = driver.getValue();
  221.                 }

  223.                 @Override
  224.                 public void valueSpanMapChanged(final TimeSpanMap<Double> previousValueSpanMap, final ParameterDriver driver) {
  225.                     // getValue(), can be called without argument as mu driver should have only one span
  226.                     AbstractPropagatorBuilder.this.mu = driver.getValue();
  227.                 }
  228.             });
  229.             propagationDrivers.add(muDriver);
  230.         }

  232.     }

  234.     /** Get the mass.
  235.      * @return the mass
  236.      * @since 9.2
  237.      */
  238.     public double getMass()
  239.     {
  240.         return mass;
  241.     }

  243.     /** Set the initial mass.
  244.      * @param mass the mass (kg)
  245.      */
  246.     public void setMass(final double mass) {
  247.         this.mass = mass;
  248.     }

  250.     /** {@inheritDoc} */
  251.     public OrbitType getOrbitType() {
  252.         return orbitType;
  253.     }

  255.     /** {@inheritDoc} */
  256.     public PositionAngleType getPositionAngleType() {
  257.         return positionAngleType;
  258.     }

  260.     /** {@inheritDoc} */
  261.     public AbsoluteDate getInitialOrbitDate() {
  262.         return initialOrbitDate;
  263.     }

  265.     /** {@inheritDoc} */
  266.     public Frame getFrame() {
  267.         return frame;
  268.     }

  270.     /** {@inheritDoc} */
  271.     public ParameterDriversList getOrbitalParametersDrivers() {
  272.         return orbitalDrivers;
  273.     }

  275.     /** {@inheritDoc} */
  276.     public ParameterDriversList getPropagationParametersDrivers() {
  277.         return propagationDrivers;
  278.     }

  280.     @Override
  281.     public AbstractPropagatorBuilder clone() {
  282.         try {
  283.             return (AbstractPropagatorBuilder) super.clone();
  284.         } catch (CloneNotSupportedException cnse) {
  285.             throw new OrekitException(OrekitMessages.PROPAGATOR_BUILDER_NOT_CLONEABLE);
  286.         }
  287.     }

  289.     /**
  290.      * Get the attitude provider.
  291.      *
  292.      * @return the attitude provider
  293.      * @since 10.1
  294.      */
  295.     public AttitudeProvider getAttitudeProvider() {
  296.         return attitudeProvider;
  297.     }

  299.     /**
  300.      * Set the attitude provider.
  301.      *
  302.      * @param attitudeProvider attitude provider
  303.      * @since 10.1
  304.      */
  305.     public void setAttitudeProvider(final AttitudeProvider attitudeProvider) {
  306.         this.attitudeProvider = attitudeProvider;
  307.     }

  309.     /** Get the position scale.
  310.      * @return the position scale used to scale the orbital drivers
  311.      */
  312.     public double getPositionScale() {
  313.         return positionScale;
  314.     }

  316.     /** {@inheritDoc} */
  317.     @Override
  318.     public double getMu() {
  319.         return mu;
  320.     }

  322.     /** Get the number of estimated values for selected parameters.
  323.      * @return number of estimated values for selected parameters
  324.      */
  325.     private int getNbValuesForSelected() {

  327.         int count = 0;

  329.         // count orbital parameters
  330.         for (final ParameterDriver driver : orbitalDrivers.getDrivers()) {
  331.             if (driver.isSelected()) {
  332.                 count += driver.getNbOfValues();
  333.             }
  334.         }

  336.         // count propagation parameters
  337.         for (final ParameterDriver driver : propagationDrivers.getDrivers()) {
  338.             if (driver.isSelected()) {
  339.                 count += driver.getNbOfValues();
  340.             }
  341.         }

  343.         return count;

  345.     }

  347.     /** {@inheritDoc} */
  348.     public double[] getSelectedNormalizedParameters() {

  350.         // allocate array
  351.         final double[] selected = new double[getNbValuesForSelected()];

  353.         // fill data
  354.         int index = 0;
  355.         for (final ParameterDriver driver : orbitalDrivers.getDrivers()) {
  356.             if (driver.isSelected()) {
  357.                 for (int spanNumber = 0; spanNumber < driver.getNbOfValues(); ++spanNumber ) {
  358.                     selected[index++] = driver.getNormalizedValue(AbsoluteDate.ARBITRARY_EPOCH);
  359.                 }
  360.             }
  361.         }
  362.         for (final ParameterDriver driver : propagationDrivers.getDrivers()) {
  363.             if (driver.isSelected()) {
  364.                 for (int spanNumber = 0; spanNumber < driver.getNbOfValues(); ++spanNumber ) {
  365.                     selected[index++] = driver.getNormalizedValue(AbsoluteDate.ARBITRARY_EPOCH);
  366.                 }
  367.             }
  368.         }

  370.         return selected;

  372.     }

  374.     /** Build an initial orbit using the current selected parameters.
  375.      * <p>
  376.      * This method is a stripped down version of {@link #buildPropagator(double[])}
  377.      * that only builds the initial orbit and not the full propagator.
  378.      * </p>
  379.      * @return an initial orbit
  380.      * @since 8.0
  381.      */
  382.     protected Orbit createInitialOrbit() {
  383.         final double[] unNormalized = new double[orbitalDrivers.getNbParams()];
  384.         for (int i = 0; i < unNormalized.length; ++i) {
  385.             unNormalized[i] = orbitalDrivers.getDrivers().get(i).getValue(initialOrbitDate);
  386.         }
  387.         return getOrbitType().mapArrayToOrbit(unNormalized, null, positionAngleType, initialOrbitDate, mu, frame);
  388.     }

  390.     /** Set the selected parameters.
  391.      * @param normalizedParameters normalized values for the selected parameters
  392.      */
  393.     protected void setParameters(final double[] normalizedParameters) {


  396.         if (normalizedParameters.length != getNbValuesForSelected()) {
  397.             throw new OrekitIllegalArgumentException(LocalizedCoreFormats.DIMENSIONS_MISMATCH,
  398.                                                      normalizedParameters.length,
  399.                                                      getNbValuesForSelected());
  400.         }

  402.         int index = 0;

  404.         // manage orbital parameters
  405.         for (final ParameterDriver driver : orbitalDrivers.getDrivers()) {
  406.             if (driver.isSelected()) {
  407.                 // If the parameter driver contains only 1 value to estimate over the all time range, which
  408.                 // is normally always the case for orbital drivers
  409.                 if (driver.getNbOfValues() == 1) {
  410.                     driver.setNormalizedValue(normalizedParameters[index++], null);

  412.                 } else {

  414.                     for (Span<Double> span = driver.getValueSpanMap().getFirstSpan(); span != null; span = span.next()) {
  415.                         driver.setNormalizedValue(normalizedParameters[index++], span.getStart());
  416.                     }
  417.                 }
  418.             }
  419.         }

  421.         // manage propagation parameters
  422.         for (final ParameterDriver driver : propagationDrivers.getDrivers()) {

  424.             if (driver.isSelected()) {

  426.                 for (Span<Double> span = driver.getValueSpanMap().getFirstSpan(); span != null; span = span.next()) {
  427.                     driver.setNormalizedValue(normalizedParameters[index++], span.getStart());
  428.                 }
  429.             }
  430.         }
  431.     }

  433.     /**
  434.      * Add supported parameters.
  435.      *
  436.      * @param drivers drivers for the parameters
  437.      */
  438.     protected void addSupportedParameters(final List<ParameterDriver> drivers) {
  439.         drivers.forEach(propagationDrivers::add);
  440.         propagationDrivers.sort();
  441.     }

  443.     /** Reset the orbit in the propagator builder.
  444.      * @param newOrbit New orbit to set in the propagator builder
  445.      */
  446.     public void resetOrbit(final Orbit newOrbit) {

  448.         // Map the new orbit in an array of double
  449.         final double[] orbitArray = new double[6];
  450.         orbitType.mapOrbitToArray(newOrbit, getPositionAngleType(), orbitArray, null);

  452.         // Update all the orbital drivers, selected or unselected
  453.         // Reset values and reference values
  454.         final List<DelegatingDriver> orbitalDriversList = getOrbitalParametersDrivers().getDrivers();
  455.         int i = 0;
  456.         for (DelegatingDriver driver : orbitalDriversList) {
  457.             driver.setReferenceValue(orbitArray[i]);
  458.             driver.setValue(orbitArray[i++], newOrbit.getDate());
  459.         }

  461.         // Change the initial orbit date in the builder
  462.         this.initialOrbitDate = newOrbit.getDate();
  463.     }

  465.     /** Add a set of user-specified equations to be integrated along with the orbit propagation (author Shiva Iyer).
  466.      * @param provider provider for additional derivatives
  467.      * @since 11.1
  468.      */
  469.     public void addAdditionalDerivativesProvider(final AdditionalDerivativesProvider provider) {
  470.         additionalDerivativesProviders.add(provider);
  471.     }

  473.     /** Get the list of additional equations.
  474.      * @return the list of additional equations
  475.      * @since 11.1
  476.      */
  477.     protected List<AdditionalDerivativesProvider> getAdditionalDerivativesProviders() {
  478.         return additionalDerivativesProviders;
  479.     }

  481.     /** Deselects orbital and propagation drivers. */
  482.     public void deselectDynamicParameters() {
  483.         for (ParameterDriver driver : getPropagationParametersDrivers().getDrivers()) {
  484.             driver.setSelected(false);
  485.         }
  486.         for (ParameterDriver driver : getOrbitalParametersDrivers().getDrivers()) {
  487.             driver.setSelected(false);
  488.         }
  489.     }

  491. }
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