FixedRate.java
- /* Copyright 2002-2019 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.attitudes;
- import org.hipparchus.Field;
- import org.hipparchus.RealFieldElement;
- import org.orekit.frames.Frame;
- import org.orekit.time.AbsoluteDate;
- import org.orekit.time.FieldAbsoluteDate;
- import org.orekit.utils.FieldPVCoordinatesProvider;
- import org.orekit.utils.PVCoordinatesProvider;
- /**
- * This class handles a simple attitude provider at constant rate around a fixed axis.
- * <p>This attitude provider is a simple linear extrapolation from an initial
- * orientation, a rotation axis and a rotation rate. All this elements can be
- * specified as a simple {@link Attitude reference attitude}.</p>
- * <p>Instances of this class are guaranteed to be immutable.</p>
- * @author Luc Maisonobe
- */
- public class FixedRate implements AttitudeProvider {
- /** Reference attitude. */
- private final Attitude referenceAttitude;
- /** Creates a new instance.
- * @param referenceAttitude attitude at reference date
- */
- public FixedRate(final Attitude referenceAttitude) {
- this.referenceAttitude = referenceAttitude;
- }
- /** {@inheritDoc} */
- public Attitude getAttitude(final PVCoordinatesProvider pvProv,
- final AbsoluteDate date, final Frame frame) {
- final double timeShift = date.durationFrom(referenceAttitude.getDate());
- final Attitude shifted = referenceAttitude.shiftedBy(timeShift);
- return shifted.withReferenceFrame(frame);
- }
- /** {@inheritDoc} */
- public <T extends RealFieldElement<T>> FieldAttitude<T> getAttitude(final FieldPVCoordinatesProvider<T> pvProv,
- final FieldAbsoluteDate<T> date,
- final Frame frame) {
- final Field<T> field = date.getField();
- final T timeShift = date.durationFrom(referenceAttitude.getDate());
- final FieldAttitude<T> shifted = new FieldAttitude<>(field, referenceAttitude).shiftedBy(timeShift);
- return shifted.withReferenceFrame(frame);
- }
- /** Get the reference attitude.
- * @return reference attitude
- */
- public Attitude getReferenceAttitude() {
- return referenceAttitude;
- }
- }