AbstractLightFluxModel.java
- /* Copyright 2022-2024 Romain Serra
- * 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.forces.radiation;
- import org.hipparchus.CalculusFieldElement;
- import org.hipparchus.geometry.euclidean.threed.FieldVector3D;
- import org.hipparchus.geometry.euclidean.threed.Vector3D;
- import org.orekit.frames.Frame;
- import org.orekit.propagation.FieldSpacecraftState;
- import org.orekit.propagation.SpacecraftState;
- import org.orekit.time.AbsoluteDate;
- import org.orekit.time.FieldAbsoluteDate;
- import org.orekit.utils.ExtendedPositionProvider;
- /**
- * Abstract class for light flux models.
- * Via the definition of the lighting ratio and the unocculted flux vector, derives the final value.
- *
- * @author Romain Serra
- * @see LightFluxModel
- * @since 12.1
- */
- public abstract class AbstractLightFluxModel implements LightFluxModel {
- /** Direction provider for the occulted body e.g. the Sun. */
- private final ExtendedPositionProvider occultedBody;
- /**
- * Constructor.
- * @param occultedBody position provider for light source
- */
- protected AbstractLightFluxModel(final ExtendedPositionProvider occultedBody) {
- this.occultedBody = occultedBody;
- }
- /**
- * Getter for the occulted body's position provider.
- * @return occulted body
- */
- public ExtendedPositionProvider getOccultedBody() {
- return occultedBody;
- }
- /** {@inheritDoc} */
- @Override
- public Vector3D getLightFluxVector(final SpacecraftState state) {
- final Vector3D position = state.getPosition();
- final Vector3D lightSourcePosition = getOccultedBodyPosition(state.getDate(), state.getFrame());
- final double lightingRatio = getLightingRatio(position, lightSourcePosition);
- if (lightingRatio != 0.) {
- final Vector3D relativePosition = position.subtract(lightSourcePosition);
- final Vector3D unoccultedFlux = getUnoccultedFluxVector(relativePosition);
- return unoccultedFlux.scalarMultiply(lightingRatio);
- } else {
- return Vector3D.ZERO;
- }
- }
- /** {@inheritDoc} */
- @Override
- public <T extends CalculusFieldElement<T>> FieldVector3D<T> getLightFluxVector(final FieldSpacecraftState<T> state) {
- final FieldVector3D<T> position = state.getPosition();
- final FieldVector3D<T> lightSourcePosition = getOccultedBodyPosition(state.getDate(), state.getFrame());
- final T lightingRatio = getLightingRatio(position, lightSourcePosition);
- final FieldVector3D<T> relativePosition = position.subtract(lightSourcePosition);
- final FieldVector3D<T> unoccultedFlux = getUnoccultedFluxVector(relativePosition);
- return unoccultedFlux.scalarMultiply(lightingRatio);
- }
- /**
- * Method computing the occulted body's position at a given date and frame.
- * @param date date
- * @param frame frame
- * @return position
- */
- protected Vector3D getOccultedBodyPosition(final AbsoluteDate date, final Frame frame) {
- return occultedBody.getPosition(date, frame);
- }
- /**
- * Method computing the occulted body's position at a given date and frame. Field version.
- * @param date date
- * @param frame frame
- * @param <T> field type
- * @return position
- */
- protected <T extends CalculusFieldElement<T>> FieldVector3D<T> getOccultedBodyPosition(final FieldAbsoluteDate<T> date,
- final Frame frame) {
- return occultedBody.getPosition(date, frame);
- }
- /** Get the light flux vector, not considering any shadowing effect.
- * @param relativePosition relative position w.r.t. light source
- * @return unocculted flux
- */
- protected abstract Vector3D getUnoccultedFluxVector(Vector3D relativePosition);
- /** Get the light flux vector, not considering any shadowing effect. Field version.
- * @param relativePosition relative position w.r.t. light source
- * @param <T> field type
- * @return unocculted flux
- */
- protected abstract <T extends CalculusFieldElement<T>> FieldVector3D<T> getUnoccultedFluxVector(FieldVector3D<T> relativePosition);
- /** Get the lighting ratio ([0-1]).
- * @param position object's position
- * @param occultedBodyPosition occulted body position in same frame
- * @return lighting ratio
- */
- protected abstract double getLightingRatio(Vector3D position, Vector3D occultedBodyPosition);
- /** Get the lighting ratio ([0-1]). Field version.
- * @param position object's position
- * @param occultedBodyPosition occulted body position in same frame
- * @param <T> field type
- * @return lighting ratio
- */
- protected abstract <T extends CalculusFieldElement<T>> T getLightingRatio(FieldVector3D<T> position,
- FieldVector3D<T> occultedBodyPosition);
- }