TLEPropagatorBuilder.java

/* Copyright 2002-2026 CS GROUP
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 * 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
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package org.orekit.propagation.conversion;

import org.orekit.annotation.DefaultDataContext;
import org.orekit.attitudes.AttitudeProvider;
import org.orekit.attitudes.FrameAlignedProvider;
import org.orekit.data.DataContext;
import org.orekit.propagation.Propagator;
import org.orekit.propagation.analytical.tle.TLE;
import org.orekit.propagation.analytical.tle.TLEPropagator;
import org.orekit.propagation.analytical.tle.generation.TleGenerationAlgorithm;
import org.orekit.utils.ParameterDriversList;

/** Builder for TLEPropagator.
 * @author Pascal Parraud
 * @author Thomas Paulet
 * @since 6.0
 */
public class TLEPropagatorBuilder
    extends AbstractAnalyticalPropagatorBuilder<TLEPropagator, TLE, TleGenerationAlgorithm> {

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

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

    /** Build a new instance. This constructor uses the {@link DataContext#getDefault()
     * default data context}.
     * @param generationAlgorithm TLE generation algorithm
     * @see #TLEPropagatorBuilder(DataContext, TleGenerationAlgorithm)
     * @see #TLEPropagatorBuilder(DataContext, TleGenerationAlgorithm, AttitudeProvider)
     * @since 14.0
     */
    @DefaultDataContext
    public TLEPropagatorBuilder(final TleGenerationAlgorithm generationAlgorithm) {
        this(DataContext.getDefault(), generationAlgorithm);
    }

    /** Build a new instance.
     * @param dataContext used to access frames and time scales.
     * @param generationAlgorithm TLE generation algorithm
     * @see #TLEPropagatorBuilder(DataContext, TleGenerationAlgorithm, AttitudeProvider)
     * @since 14.0
     */
    public TLEPropagatorBuilder(final DataContext dataContext,
                                final TleGenerationAlgorithm generationAlgorithm) {
        this(dataContext, generationAlgorithm,
             FrameAlignedProvider.of(dataContext.getFrames().getTEME()));
    }

    /** Build a new instance.
     * @param dataContext used to access frames and time scales.
     * @param generationAlgorithm TLE generation algorithm
     * @param attitudeProvider attitude law to use
     * @since 14.0
     */
    public TLEPropagatorBuilder(final DataContext dataContext,
                                final TleGenerationAlgorithm generationAlgorithm,
                                final AttitudeProvider attitudeProvider) {
        super(generationAlgorithm, false, attitudeProvider, Propagator.DEFAULT_MASS);
        this.dataContext         = dataContext;
        this.generationAlgorithm = generationAlgorithm;
    }

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

        // Use cloned builder to unlink orbital drivers
        final TLEPropagatorBuilder builder =
            new TLEPropagatorBuilder(clonedBuilder.dataContext,
                                     clonedBuilder.generationAlgorithm.clone(),
                                     clonedBuilder.getAttitudeProvider());

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

        // Ensure drivers' selection consistency
        final ParameterDriversList propDrivers = clonedBuilder.getPropagationParametersDrivers();
        builder.getPropagationParametersDrivers().getDrivers().
                        forEach(driver -> driver.setSelected(propDrivers.findByName(driver.getName()).isSelected()));
        return builder;
    }

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

        // set all parameters (including both orbital parameters and propagation parameters)
        setParameters(normalizedParameters);

        // TLE related to the orbit
        final TLE tle = getOrbitalParameterFactory().createFromDrivers();

        // propagator
        final TLEPropagator propagator = TLEPropagator.selectExtrapolator(tle, getAttitudeProvider(), getMass(),
                                                                          getOrbitalParameterFactory().getFrame());

        final boolean bStarSelected = this.getPropagationParametersDrivers().getDrivers().getFirst().isSelected();
        propagator.getParametersDrivers().getFirst().setSelected(bStarSelected);
        propagator.setTleGenerationAlgorithm(generationAlgorithm);
        getImpulseManeuvers().forEach(propagator::addEventDetector);
        return propagator;
    }

}