IsotropicRadiationClassicalConvention.java
- /* Copyright 2002-2016 CS Systèmes d'Information
- * Licensed to CS Systèmes d'Information (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.apache.commons.math3.analysis.differentiation.DerivativeStructure;
- import org.apache.commons.math3.geometry.euclidean.threed.FieldRotation;
- import org.apache.commons.math3.geometry.euclidean.threed.FieldVector3D;
- import org.apache.commons.math3.geometry.euclidean.threed.Rotation;
- import org.apache.commons.math3.geometry.euclidean.threed.Vector3D;
- import org.orekit.errors.OrekitException;
- import org.orekit.errors.OrekitMessages;
- import org.orekit.forces.radiation.RadiationSensitive;
- import org.orekit.frames.Frame;
- import org.orekit.time.AbsoluteDate;
- /** This class represents the features of a simplified spacecraft.
- * <p>This model uses the classical thermo-optical coefficients
- * Ca for absorption, Cs for specular reflection and Kd for diffuse
- * reflection. The equation Ca + Cs + Cd = 1 always holds.
- * </p>
- * <p>
- * A less standard set of coefficients α = Ca for absorption and
- * τ = Cs/(1-Ca) for specular reflection is implemented in the sister
- * class {@link IsotropicRadiationCNES95Convention}.
- * </p>
- *
- * @see org.orekit.forces.BoxAndSolarArraySpacecraft
- * @see org.orekit.forces.drag.IsotropicDrag
- * @see IsotropicRadiationCNES95Convention
- * @author Luc Maisonobe
- * @since 7.1
- */
- public class IsotropicRadiationClassicalConvention implements RadiationSensitive {
- /** Cross section (m²). */
- private final double crossSection;
- /** Absorption coefficient. */
- private double ca;
- /** Specular reflection coefficient. */
- private double cs;
- /** Simple constructor.
- * @param crossSection Surface (m²)
- * @param ca absorption coefficient Ca between 0.0 an 1.0
- * @param cs specular reflection coefficient Cs between 0.0 an 1.0
- */
- public IsotropicRadiationClassicalConvention(final double crossSection, final double ca, final double cs) {
- this.crossSection = crossSection;
- this.ca = ca;
- this.cs = cs;
- }
- /** {@inheritDoc} */
- public Vector3D radiationPressureAcceleration(final AbsoluteDate date, final Frame frame, final Vector3D position,
- final Rotation rotation, final double mass, final Vector3D flux) {
- final double kP = crossSection * (1 + 4 * (1.0 - ca - cs) / 9.0);
- return new Vector3D(kP / mass, flux);
- }
- /** {@inheritDoc} */
- public FieldVector3D<DerivativeStructure> radiationPressureAcceleration(final AbsoluteDate date, final Frame frame, final FieldVector3D<DerivativeStructure> position,
- final FieldRotation<DerivativeStructure> rotation, final DerivativeStructure mass,
- final FieldVector3D<DerivativeStructure> flux) {
- final double kP = crossSection * (1 + 4 * (1.0 - ca - cs) / 9.0);
- return new FieldVector3D<DerivativeStructure>(mass.reciprocal().multiply(kP), flux);
- }
- /** {@inheritDoc} */
- public FieldVector3D<DerivativeStructure> radiationPressureAcceleration(final AbsoluteDate date, final Frame frame, final Vector3D position,
- final Rotation rotation, final double mass,
- final Vector3D flux, final String paramName)
- throws OrekitException {
- final DerivativeStructure caDS;
- final DerivativeStructure csDS;
- if (ABSORPTION_COEFFICIENT.equals(paramName)) {
- caDS = new DerivativeStructure(1, 1, 0, ca);
- csDS = new DerivativeStructure(1, 1, cs);
- } else if (REFLECTION_COEFFICIENT.equals(paramName)) {
- caDS = new DerivativeStructure(1, 1, ca);
- csDS = new DerivativeStructure(1, 1, 0, cs);
- } else {
- throw new OrekitException(OrekitMessages.UNSUPPORTED_PARAMETER_NAME, paramName,
- ABSORPTION_COEFFICIENT + ", " + REFLECTION_COEFFICIENT);
- }
- final DerivativeStructure kP =
- caDS.add(csDS).subtract(1).multiply(-4.0 / 9.0).add(1).multiply(crossSection);
- return new FieldVector3D<DerivativeStructure>(kP.divide(mass), flux);
- }
- /** {@inheritDoc} */
- public void setAbsorptionCoefficient(final double value) {
- ca = value;
- }
- /** {@inheritDoc} */
- public double getAbsorptionCoefficient() {
- return ca;
- }
- /** {@inheritDoc} */
- public void setReflectionCoefficient(final double value) {
- cs = value;
- }
- /** {@inheritDoc} */
- public double getReflectionCoefficient() {
- return cs;
- }
- }