FieldShiftingPVCoordinatesProvider.java

/* Copyright 2022-2025 Luc Maisonobe
 * Licensed to CS GROUP (CS) under one or more
 * 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
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.orekit.utils;

import org.hipparchus.CalculusFieldElement;
import org.orekit.frames.Frame;
import org.orekit.time.FieldAbsoluteDate;

/** Provider using simple {@link FieldPVCoordinates#shiftedBy(CalculusFieldElement)} shiftedBy} and frame transforms for evolution.
 * @param <T> the type of the field elements
 * @author Luc Maisonobe
 * @since 12.1
 */
public class FieldShiftingPVCoordinatesProvider<T extends CalculusFieldElement<T>>
    implements FieldPVCoordinatesProvider<T> {

    /** Reference coordinates. */
    private final TimeStampedFieldPVCoordinates<T> referencePV;

    /** Frame in which {@link #referencePV} is defined. */
    private final Frame referenceFrame;

    /** Simple constructor.
     * @param referencePV reference coordinates
     * @param referenceFrame frame in which {@code reference} is defined
     */
    public FieldShiftingPVCoordinatesProvider(final TimeStampedFieldPVCoordinates<T> referencePV,
                                              final Frame referenceFrame) {
        this.referencePV    = referencePV;
        this.referenceFrame = referenceFrame;
    }

    /** {@inheritDoc} */
    @Override
    public TimeStampedFieldPVCoordinates<T> getPVCoordinates(final FieldAbsoluteDate<T> date,
                                                             final Frame frame) {
        final TimeStampedFieldPVCoordinates<T> shifted = referencePV.shiftedBy(date.durationFrom(referencePV));
        return referenceFrame.getTransformTo(frame, date).transformPVCoordinates(shifted);
    }

}