AbstractPropagatorBuilder.java

  1. /* Copyright 2002-2020 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 java.util.ArrayList;
  20. import java.util.List;

  22. import org.hipparchus.exception.LocalizedCoreFormats;
  23. import org.hipparchus.util.FastMath;
  24. import org.orekit.attitudes.AttitudeProvider;
  25. import org.orekit.attitudes.InertialProvider;
  26. import org.orekit.errors.OrekitIllegalArgumentException;
  27. import org.orekit.forces.gravity.NewtonianAttraction;
  28. import org.orekit.frames.Frame;
  29. import org.orekit.orbits.Orbit;
  30. import org.orekit.orbits.OrbitType;
  31. import org.orekit.orbits.PositionAngle;
  32. import org.orekit.propagation.integration.AdditionalEquations;
  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;

  39. /** Base class for propagator builders.
  40.  * @author Pascal Parraud
  41.  * @since 7.1
  42.  */
  43. public abstract class AbstractPropagatorBuilder implements PropagatorBuilder {

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

  53.     /** Date of the initial orbit. */
  54.     private AbsoluteDate initialOrbitDate;

  56.     /** Frame in which the orbit is propagated. */
  57.     private final Frame frame;

  59.     /** Central attraction coefficient (m³/s²). */
  60.     private double mu;

  62.     /** Drivers for orbital parameters. */
  63.     private final ParameterDriversList orbitalDrivers;

  65.     /** List of the supported parameters. */
  66.     private ParameterDriversList propagationDrivers;

  68.     /** Orbit type to use. */
  69.     private final OrbitType orbitType;

  71.     /** Position angle type to use. */
  72.     private final PositionAngle positionAngle;

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

  77.     /** Attitude provider for the propagator. */
  78.     private AttitudeProvider attitudeProvider;

  80.     /** Additional equations. */
  81.     private List<AdditionalEquations> additionalEquations;

  83.     /** Build a new instance.
  84.      * <p>
  85.      * The template orbit is used as a model to {@link
  86.      * #createInitialOrbit() create initial orbit}. It defines the
  87.      * inertial frame, the central attraction coefficient, the orbit type, and is also
  88.      * used together with the {@code positionScale} to convert from the {@link
  89.      * ParameterDriver#setNormalizedValue(double) normalized} parameters used by the
  90.      * callers of this builder to the real orbital parameters. The initial attitude
  91.      * provider is aligned with the inertial frame.
  92.      * </p>
  93.      * <p>
  94.      * By default, all the {@link #getOrbitalParametersDrivers() orbital parameters drivers}
  95.      * are selected, which means that if the builder is used for orbit determination or
  96.      * propagator conversion, all orbital parameters will be estimated. If only a subset
  97.      * of the orbital parameters must be estimated, caller must retrieve the orbital
  98.      * parameters by calling {@link #getOrbitalParametersDrivers()} and then call
  99.      * {@link ParameterDriver#setSelected(boolean) setSelected(false)}.
  100.      * </p>
  101.      * @param templateOrbit reference orbit from which real orbits will be built
  102.      * @param positionAngle position angle type to use
  103.      * @param positionScale scaling factor used for orbital parameters normalization
  104.      * (typically set to the expected standard deviation of the position)
  105.      * @param addDriverForCentralAttraction if true, a {@link ParameterDriver} should
  106.      * be set up for central attraction coefficient
  107.      * @since 8.0
  108.      * @see #AbstractPropagatorBuilder(Orbit, PositionAngle, double, boolean,
  109.      * AttitudeProvider)
  110.      */
  111.     protected AbstractPropagatorBuilder(final Orbit templateOrbit, final PositionAngle positionAngle,
  112.                                         final double positionScale, final boolean addDriverForCentralAttraction) {
  113.         this(templateOrbit, positionAngle, positionScale, addDriverForCentralAttraction,
  114.                 new InertialProvider(templateOrbit.getFrame()));
  115.     }

  117.     /** Build a new instance.
  118.      * <p>
  119.      * The template orbit is used as a model to {@link
  120.      * #createInitialOrbit() create initial orbit}. It defines the
  121.      * inertial frame, the central attraction coefficient, the orbit type, and is also
  122.      * used together with the {@code positionScale} to convert from the {@link
  123.      * ParameterDriver#setNormalizedValue(double) normalized} parameters used by the
  124.      * callers of this builder to the real orbital parameters.
  125.      * </p>
  126.      * <p>
  127.      * By default, all the {@link #getOrbitalParametersDrivers() orbital parameters drivers}
  128.      * are selected, which means that if the builder is used for orbit determination or
  129.      * propagator conversion, all orbital parameters will be estimated. If only a subset
  130.      * of the orbital parameters must be estimated, caller must retrieve the orbital
  131.      * parameters by calling {@link #getOrbitalParametersDrivers()} and then call
  132.      * {@link ParameterDriver#setSelected(boolean) setSelected(false)}.
  133.      * </p>
  134.      * @param templateOrbit reference orbit from which real orbits will be built
  135.      * @param positionAngle position angle type to use
  136.      * @param positionScale scaling factor used for orbital parameters normalization
  137.      * (typically set to the expected standard deviation of the position)
  138.      * @param addDriverForCentralAttraction if true, a {@link ParameterDriver} should
  139.      * be set up for central attraction coefficient
  140.      * @param attitudeProvider for the propagator.
  141.      * @since 10.1
  142.      * @see #AbstractPropagatorBuilder(Orbit, PositionAngle, double, boolean)
  143.      */
  144.     protected AbstractPropagatorBuilder(final Orbit templateOrbit,
  145.                                         final PositionAngle positionAngle,
  146.                                         final double positionScale,
  147.                                         final boolean addDriverForCentralAttraction,
  148.                                         final AttitudeProvider attitudeProvider) {

  150.         this.initialOrbitDate    = templateOrbit.getDate();
  151.         this.frame               = templateOrbit.getFrame();
  152.         this.mu                  = templateOrbit.getMu();
  153.         this.propagationDrivers  = new ParameterDriversList();
  154.         this.orbitType           = templateOrbit.getType();
  155.         this.positionAngle       = positionAngle;
  156.         this.positionScale       = positionScale;
  157.         this.orbitalDrivers      = orbitType.getDrivers(positionScale, templateOrbit, positionAngle);
  158.         this.attitudeProvider = attitudeProvider;
  159.         for (final DelegatingDriver driver : orbitalDrivers.getDrivers()) {
  160.             driver.setSelected(true);
  161.         }

  163.         this.additionalEquations  = new ArrayList<AdditionalEquations>();

  165.         if (addDriverForCentralAttraction) {
  166.             final ParameterDriver muDriver = new ParameterDriver(NewtonianAttraction.CENTRAL_ATTRACTION_COEFFICIENT,
  167.                                                                  mu, MU_SCALE, 0, Double.POSITIVE_INFINITY);
  168.             muDriver.addObserver(new ParameterObserver() {
  169.                 /** {@inheridDoc} */
  170.                 @Override
  171.                 public void valueChanged(final double previousValue, final ParameterDriver driver) {
  172.                     AbstractPropagatorBuilder.this.mu = driver.getValue();
  173.                 }
  174.             });
  175.             propagationDrivers.add(muDriver);
  176.         }

  178.     }

  180.     /** {@inheritDoc} */
  181.     public OrbitType getOrbitType() {
  182.         return orbitType;
  183.     }

  185.     /** {@inheritDoc} */
  186.     public PositionAngle getPositionAngle() {
  187.         return positionAngle;
  188.     }

  190.     /** {@inheritDoc} */
  191.     public AbsoluteDate getInitialOrbitDate() {
  192.         return initialOrbitDate;
  193.     }

  195.     /** {@inheritDoc} */
  196.     public Frame getFrame() {
  197.         return frame;
  198.     }

  200.     /** {@inheritDoc} */
  201.     public ParameterDriversList getOrbitalParametersDrivers() {
  202.         return orbitalDrivers;
  203.     }

  205.     /** {@inheritDoc} */
  206.     public ParameterDriversList getPropagationParametersDrivers() {
  207.         return propagationDrivers;
  208.     }

  210.     /**
  211.      * Get the attitude provider.
  212.      *
  213.      * @return the attitude provider
  214.      * @since 10.1
  215.      */
  216.     public AttitudeProvider getAttitudeProvider() {
  217.         return attitudeProvider;
  218.     }

  220.     /**
  221.      * Set the attitude provider.
  222.      *
  223.      * @param attitudeProvider attitude provider
  224.      * @since 10.1
  225.      */
  226.     public void setAttitudeProvider(final AttitudeProvider attitudeProvider) {
  227.         this.attitudeProvider = attitudeProvider;
  228.     }

  230.     /** Get the position scale.
  231.      * @return the position scale used to scale the orbital drivers
  232.      */
  233.     public double getPositionScale() {
  234.         return positionScale;
  235.     }

  237.     /** Get the central attraction coefficient (µ - m³/s²) value.
  238.      * @return the central attraction coefficient (µ - m³/s²) value
  239.      * @since 9.2
  240.      */
  241.     public double getMu() {
  242.         return mu;
  243.     }

  245.     /** Get the number of selected parameters.
  246.      * @return number of selected parameters
  247.      */
  248.     private int getNbSelected() {

  250.         int count = 0;

  252.         // count orbital parameters
  253.         for (final ParameterDriver driver : orbitalDrivers.getDrivers()) {
  254.             if (driver.isSelected()) {
  255.                 ++count;
  256.             }
  257.         }

  259.         // count propagation parameters
  260.         for (final ParameterDriver driver : propagationDrivers.getDrivers()) {
  261.             if (driver.isSelected()) {
  262.                 ++count;
  263.             }
  264.         }

  266.         return count;

  268.     }

  270.     /** {@inheritDoc} */
  271.     public double[] getSelectedNormalizedParameters() {

  273.         // allocate array
  274.         final double[] selected = new double[getNbSelected()];

  276.         // fill data
  277.         int index = 0;
  278.         for (final ParameterDriver driver : orbitalDrivers.getDrivers()) {
  279.             if (driver.isSelected()) {
  280.                 selected[index++] = driver.getNormalizedValue();
  281.             }
  282.         }
  283.         for (final ParameterDriver driver : propagationDrivers.getDrivers()) {
  284.             if (driver.isSelected()) {
  285.                 selected[index++] = driver.getNormalizedValue();
  286.             }
  287.         }

  289.         return selected;

  291.     }

  293.     /** Build an initial orbit using the current selected parameters.
  294.      * <p>
  295.      * This method is a stripped down version of {@link #buildPropagator(double[])}
  296.      * that only builds the initial orbit and not the full propagator.
  297.      * </p>
  298.      * @return an initial orbit
  299.      * @since 8.0
  300.      */
  301.     protected Orbit createInitialOrbit() {
  302.         final double[] unNormalized = new double[orbitalDrivers.getNbParams()];
  303.         for (int i = 0; i < unNormalized.length; ++i) {
  304.             unNormalized[i] = orbitalDrivers.getDrivers().get(i).getValue();
  305.         }
  306.         return getOrbitType().mapArrayToOrbit(unNormalized, null, positionAngle, initialOrbitDate, mu, frame);
  307.     }

  309.     /** Set the selected parameters.
  310.      * @param normalizedParameters normalized values for the selected parameters
  311.      */
  312.     protected void setParameters(final double[] normalizedParameters) {


  315.         if (normalizedParameters.length != getNbSelected()) {
  316.             throw new OrekitIllegalArgumentException(LocalizedCoreFormats.DIMENSIONS_MISMATCH,
  317.                                                      normalizedParameters.length,
  318.                                                      getNbSelected());
  319.         }

  321.         int index = 0;

  323.         // manage orbital parameters
  324.         for (final ParameterDriver driver : orbitalDrivers.getDrivers()) {
  325.             if (driver.isSelected()) {
  326.                 driver.setNormalizedValue(normalizedParameters[index++]);
  327.             }
  328.         }

  330.         // manage propagation parameters
  331.         for (final ParameterDriver driver : propagationDrivers.getDrivers()) {
  332.             if (driver.isSelected()) {
  333.                 driver.setNormalizedValue(normalizedParameters[index++]);
  334.             }
  335.         }

  337.     }

  339.     /** Add a supported parameter.
  340.      * @param driver driver for the parameter
  341.      */
  342.     protected void addSupportedParameter(final ParameterDriver driver) {
  343.         propagationDrivers.add(driver);
  344.         propagationDrivers.sort();
  345.     }

  347.     /** Reset the orbit in the propagator builder.
  348.      * @param newOrbit New orbit to set in the propagator builder
  349.      */
  350.     public void resetOrbit(final Orbit newOrbit) {

  352.         // Map the new orbit in an array of double
  353.         final double[] orbitArray = new double[6];
  354.         orbitType.mapOrbitToArray(newOrbit, getPositionAngle(), orbitArray, null);

  356.         // Update all the orbital drivers, selected or unselected
  357.         // Reset values and reference values
  358.         final List<DelegatingDriver> orbitalDriversList = getOrbitalParametersDrivers().getDrivers();
  359.         int i = 0;
  360.         for (DelegatingDriver driver : orbitalDriversList) {
  361.             driver.setReferenceValue(orbitArray[i]);
  362.             driver.setValue(orbitArray[i++]);
  363.         }

  365.         // Change the initial orbit date in the builder
  366.         this.initialOrbitDate = newOrbit.getDate();
  367.     }

  369.     /** Add a set of user-specified equations to be integrated along with the orbit propagation (author Shiva Iyer).
  370.      * @param additional additional equations
  371.      * @since 10.1
  372.      */
  373.     public void addAdditionalEquations(final AdditionalEquations additional) {

  375.         additionalEquations.add(additional);

  377.     }

  379.     /** Get the list of additional equations.
  380.      * @return the list of additional equations
  381.      * @since 10.1
  382.      */
  383.     protected List<AdditionalEquations> getAdditionalEquations() {
  384.         return additionalEquations;
  385.     }

  387. }
Created with JaCoCo 0.8.6.202009150832