ConstantSphericalHarmonics.java
- /* Copyright 2002-2017 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.gravity.potential;
- import org.orekit.errors.OrekitException;
- import org.orekit.errors.OrekitMessages;
- import org.orekit.time.AbsoluteDate;
- /** Simple implementation of {@link RawSphericalHarmonicsProvider} for constant gravity fields.
- * @author Luc Maisonobe
- * @since 6.0
- */
- class ConstantSphericalHarmonics implements RawSphericalHarmonicsProvider {
- /** Central body reference radius. */
- private final double ae;
- /** Central body attraction coefficient. */
- private final double mu;
- /** Tide system. */
- private final TideSystem tideSystem;
- /** Raw tesseral-sectorial coefficients matrix. */
- private final double[][] rawC;
- /** Raw tesseral-sectorial coefficients matrix. */
- private final double[][] rawS;
- /** Simple constructor.
- * @param ae central body reference radius
- * @param mu central body attraction coefficient
- * @param tideSystem tide system
- * @param rawC raw tesseral-sectorial coefficients
- * @param rawS raw tesseral-sectorial coefficients
- */
- ConstantSphericalHarmonics(final double ae, final double mu,
- final TideSystem tideSystem,
- final double[][] rawC, final double[][] rawS) {
- this.ae = ae;
- this.mu = mu;
- this.tideSystem = tideSystem;
- this.rawC = rawC;
- this.rawS = rawS;
- }
- /** {@inheritDoc} */
- public int getMaxDegree() {
- return rawC.length - 1;
- }
- /** {@inheritDoc} */
- public int getMaxOrder() {
- return rawC[rawC.length - 1].length - 1;
- }
- /** {@inheritDoc} */
- public double getMu() {
- return mu;
- }
- /** {@inheritDoc} */
- public double getAe() {
- return ae;
- }
- /** {@inheritDoc}
- * <p>
- * For a constant field, null is always returned.
- * </p>
- */
- public AbsoluteDate getReferenceDate() {
- return null;
- }
- /** {@inheritDoc} */
- public double getOffset(final AbsoluteDate date) {
- return 0.0;
- }
- /** {@inheritDoc} */
- public TideSystem getTideSystem() {
- return tideSystem;
- }
- @Override
- public RawSphericalHarmonics onDate(final AbsoluteDate date) {
- return new RawSphericalHarmonics() {
- @Override
- public AbsoluteDate getDate() {
- return date;
- }
- /** {@inheritDoc} */
- public double getRawCnm(final int n, final int m)
- throws OrekitException {
- checkLimits(n, m);
- return rawC[n][m];
- }
- /** {@inheritDoc} */
- public double getRawSnm(final int n, final int m)
- throws OrekitException {
- checkLimits(n, m);
- return rawS[n][m];
- }
- };
- }
- /** Check limits.
- * @param degree degree
- * @param order order
- * @exception OrekitException if indices are out of bound
- */
- private void checkLimits(final int degree, final int order)
- throws OrekitException {
- if (degree >= rawC.length) {
- throw new OrekitException(OrekitMessages.TOO_LARGE_DEGREE_FOR_GRAVITY_FIELD,
- degree, rawC.length - 1);
- }
- if (order >= rawC[degree].length) {
- throw new OrekitException(OrekitMessages.TOO_LARGE_ORDER_FOR_GRAVITY_FIELD,
- order, rawC[degree].length - 1);
- }
- }
- }