TLEPropagatorBuilder.java

  1. /* Copyright 2002-2025 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.orekit.annotation.DefaultDataContext;
  20. import org.orekit.attitudes.AttitudeProvider;
  21. import org.orekit.attitudes.FrameAlignedProvider;
  22. import org.orekit.data.DataContext;
  23. import org.orekit.frames.Frame;
  24. import org.orekit.orbits.Orbit;
  25. import org.orekit.orbits.PositionAngleType;
  26. import org.orekit.propagation.Propagator;
  27. import org.orekit.propagation.SpacecraftState;
  28. import org.orekit.propagation.analytical.tle.TLE;
  29. import org.orekit.propagation.analytical.tle.TLEPropagator;
  30. import org.orekit.propagation.analytical.tle.generation.TleGenerationAlgorithm;
  31. import org.orekit.utils.ParameterDriver;
  32. import org.orekit.utils.ParameterDriversList;

  34. import java.util.List;

  36. /** Builder for TLEPropagator.
  37.  * @author Pascal Parraud
  38.  * @author Thomas Paulet
  39.  * @since 6.0
  40.  */
  41. public class TLEPropagatorBuilder extends AbstractAnalyticalPropagatorBuilder<TLEPropagator> {

  43.     /** Data context used to access frames and time scales. */
  44.     private final DataContext dataContext;

  46.     /** Template TLE. */
  47.     private final TLE templateTLE;

  49.     /** TLE generation algorithm. */
  50.     private final TleGenerationAlgorithm generationAlgorithm;

  52.     /** Build a new instance. This constructor uses the {@link DataContext#getDefault()
  53.      * default data context}.
  54.      * <p>
  55.      * The template TLE is used as a model to {@link
  56.      * #createInitialOrbit() create initial orbit}. It defines the
  57.      * inertial frame, the central attraction coefficient, orbit type, satellite number,
  58.      * classification, .... and is also used together with the {@code positionScale} to
  59.      * convert from the {@link ParameterDriver#setNormalizedValue(double) normalized}
  60.      * parameters used by the callers of this builder to the real orbital parameters.
  61.      * </p>
  62.      * @param templateTLE reference TLE from which real orbits will be built
  63.      * @param positionAngleType position angle type to use
  64.      * @param positionScale scaling factor used for orbital parameters normalization
  65.      * (typically set to the expected standard deviation of the position)
  66.      * @param generationAlgorithm TLE generation algorithm
  67.      * @since 12.0
  68.      * @see #TLEPropagatorBuilder(TLE, PositionAngleType, double, DataContext, TleGenerationAlgorithm)
  69.      * @see #TLEPropagatorBuilder(TLE, PositionAngleType, double, DataContext, TleGenerationAlgorithm, AttitudeProvider)
  70.      */
  71.     @DefaultDataContext
  72.     public TLEPropagatorBuilder(final TLE templateTLE, final PositionAngleType positionAngleType,
  73.                                 final double positionScale, final TleGenerationAlgorithm generationAlgorithm) {
  74.         this(templateTLE, positionAngleType, positionScale, DataContext.getDefault(), generationAlgorithm);
  75.     }

  77.     /** Build a new instance.
  78.      * <p>
  79.      * The template TLE is used as a model to {@link
  80.      * #createInitialOrbit() create initial orbit}. It defines the
  81.      * inertial frame, the central attraction coefficient, orbit type, satellite number,
  82.      * classification, .... and is also used together with the {@code positionScale} to
  83.      * convert from the {@link ParameterDriver#setNormalizedValue(double) normalized}
  84.      * parameters used by the callers of this builder to the real orbital parameters.
  85.      * The default attitude provider is aligned with the orbit's inertial frame.
  86.      * </p>
  87.      * @param templateTLE reference TLE from which real orbits will be built
  88.      * @param positionAngleType position angle type to use
  89.      * @param positionScale scaling factor used for orbital parameters normalization
  90.      * (typically set to the expected standard deviation of the position)
  91.      * @param dataContext used to access frames and time scales.
  92.      * @param generationAlgorithm TLE generation algorithm
  93.      * @since 12.0
  94.      * @see #TLEPropagatorBuilder(TLE, PositionAngleType, double, DataContext, TleGenerationAlgorithm, AttitudeProvider)
  95.      */
  96.     public TLEPropagatorBuilder(final TLE templateTLE, final PositionAngleType positionAngleType,
  97.                                 final double positionScale, final DataContext dataContext,
  98.                                 final TleGenerationAlgorithm generationAlgorithm) {
  99.         this(templateTLE, positionAngleType, positionScale, dataContext, generationAlgorithm, FrameAlignedProvider.of(dataContext.getFrames().getTEME()));
  100.     }

  102.     /** Build a new instance.
  103.      * <p>
  104.      * The template TLE is used as a model to {@link
  105.      * #createInitialOrbit() create initial orbit}. It defines the
  106.      * inertial frame, the central attraction coefficient, orbit type, satellite number,
  107.      * classification, .... and is also used together with the {@code positionScale} to
  108.      * convert from the {@link ParameterDriver#setNormalizedValue(double) normalized}
  109.      * parameters used by the callers of this builder to the real orbital parameters.
  110.      * </p>
  111.      * @param templateTLE reference TLE 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 dataContext used to access frames and time scales.
  116.      * @param generationAlgorithm TLE generation algorithm
  117.      * @param attitudeProvider attitude law to use
  118.      * @since 12.2
  119.      */
  120.     public TLEPropagatorBuilder(final TLE templateTLE, final PositionAngleType positionAngleType,
  121.                                 final double positionScale, final DataContext dataContext,
  122.                                 final TleGenerationAlgorithm generationAlgorithm, final AttitudeProvider attitudeProvider) {
  123.         super(TLEPropagator.selectExtrapolator(templateTLE, dataContext.getFrames().getTEME(), attitudeProvider).getInitialState().getOrbit(),
  124.               positionAngleType, positionScale, false, attitudeProvider, Propagator.DEFAULT_MASS);

  126.         // Supported parameters: Bstar
  127.         addSupportedParameters(templateTLE.getParametersDrivers());

  129.         this.templateTLE         = templateTLE;
  130.         this.dataContext         = dataContext;
  131.         this.generationAlgorithm = generationAlgorithm;
  132.     }

  134.     /** Copy constructor.
  135.      * @param builder builder to copy from
  136.      */
  137.     private TLEPropagatorBuilder(final TLEPropagatorBuilder builder) {
  138.         this(builder.getTemplateTLE(), builder.getPositionAngleType(),
  139.              builder.getPositionScale(), builder.dataContext,
  140.              builder.generationAlgorithm, builder.getAttitudeProvider());
  141.     }

  143.     /** {@inheritDoc}. */
  144.     @Override
  145.     public TLEPropagatorBuilder clone() {
  146.         // Call to super clone() method to avoid warning
  147.         final TLEPropagatorBuilder clonedBuilder = (TLEPropagatorBuilder) super.clone();

  149.         // Use copy constructor to unlink orbital drivers
  150.         final TLEPropagatorBuilder builder = new TLEPropagatorBuilder(clonedBuilder);

  152.         // Set mass
  153.         builder.setMass(getMass());

  155.         // Ensure drivers' selection consistency
  156.         final ParameterDriversList propDrivers = clonedBuilder.getPropagationParametersDrivers();
  157.         builder.getPropagationParametersDrivers().getDrivers().
  158.                         forEach(driver -> driver.setSelected(propDrivers.findByName(driver.getName()).isSelected()));
  159.         return new TLEPropagatorBuilder(clonedBuilder);
  160.     }

  162.     /** {@inheritDoc} */
  163.     @Override
  164.     public TLEPropagator buildPropagator(final double[] normalizedParameters) {

  166.         // create the orbit
  167.         setParameters(normalizedParameters);
  168.         final Orbit           orbit = createInitialOrbit();
  169.         final SpacecraftState state = new SpacecraftState(orbit);
  170.         final Frame           teme  = dataContext.getFrames().getTEME();

  172.         // TLE related to the orbit
  173.         final TLE tle = generationAlgorithm.generate(state, templateTLE);
  174.         final List<ParameterDriver> drivers = templateTLE.getParametersDrivers();
  175.         for (int index = 0; index < drivers.size(); index++) {
  176.             if (drivers.get(index).isSelected()) {
  177.                 tle.getParametersDrivers().get(index).setSelected(true);
  178.             }
  179.         }

  181.         // propagator
  182.         final TLEPropagator propagator = TLEPropagator.selectExtrapolator(tle, getAttitudeProvider(), getMass(), teme);
  183.         getImpulseManeuvers().forEach(propagator::addEventDetector);
  184.         return propagator;
  185.     }

  187.     /** Getter for the template TLE.
  188.      * @return the template TLE
  189.      */
  190.     public TLE getTemplateTLE() {
  191.         return templateTLE;
  192.     }
  193. }
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