PostSeismicDeformation.java

/* Copyright 2022-2025 Thales Alenia Space
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package org.orekit.models.earth.displacement;

import org.hipparchus.geometry.euclidean.threed.Vector3D;
import org.orekit.bodies.GeodeticPoint;
import org.orekit.data.BodiesElements;
import org.orekit.frames.Frame;
import org.orekit.utils.TimeSpanMap;

import java.util.List;

/** Modeling of displacement of one reference point due to post-seismic effects.
 * @see <a href="https://itrf.ign.fr/ftp/pub/itrf/itrf2020/ITRF2020-PSD-model-eqs-IGN.pdf">
 *     ITRF2020P: Equations of post-seismic deformation models</a>
 * @since 12.1
 * @author Luc Maisonobe
 */
public class PostSeismicDeformation implements StationDisplacement {

    /** Base point. */
    private final GeodeticPoint base;

    /** PSD corrections. */
    private final TimeSpanMap<List<PsdCorrection>> corrections;

    /** Simple constructor.
     * @param base base point
     * @param corrections Post-Seismic Deformation corrections
     */
    public PostSeismicDeformation(final GeodeticPoint base,
                                  final TimeSpanMap<List<PsdCorrection>> corrections) {
        this.base        = base;
        this.corrections = corrections;
    }

    /** {@inheritDoc} */
    @Override
    public Vector3D displacement(final BodiesElements elements, final Frame earthFrame, final Vector3D referencePoint) {

        // initialize displacement with zero correction
        Vector3D cumulativeCorrection = Vector3D.ZERO;

        // apply all relevant Post-Seismic Deformation corrections
        final List<PsdCorrection> correctionsAtDate = corrections.get(elements.getDate());
        if (correctionsAtDate != null) {
            for (final PsdCorrection correction : correctionsAtDate) {
                cumulativeCorrection = cumulativeCorrection.add(correction.displacement(elements.getDate(), base));
            }
        }

        return cumulativeCorrection;

    }

}