FieldIntegratedEphemeris.java
- /* Copyright 2002-2021 CS GROUP
- * 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.propagation.integration;
- import java.util.Collections;
- import java.util.List;
- import java.util.Map;
- import org.hipparchus.CalculusFieldElement;
- import org.hipparchus.ode.FieldDenseOutputModel;
- import org.hipparchus.ode.FieldODEStateAndDerivative;
- import org.orekit.errors.OrekitException;
- import org.orekit.errors.OrekitMessages;
- import org.orekit.frames.Frame;
- import org.orekit.orbits.FieldOrbit;
- import org.orekit.propagation.FieldAdditionalStateProvider;
- import org.orekit.propagation.FieldBoundedPropagator;
- import org.orekit.propagation.FieldSpacecraftState;
- import org.orekit.propagation.PropagationType;
- import org.orekit.propagation.analytical.FieldAbstractAnalyticalPropagator;
- import org.orekit.time.FieldAbsoluteDate;
- import org.orekit.utils.ParameterDriver;
- import org.orekit.utils.TimeStampedFieldPVCoordinates;
- /** This class stores sequentially generated orbital parameters for
- * later retrieval.
- *
- * <p>
- * Instances of this class are built automatically when the {@link
- * org.orekit.propagation.FieldPropagator#getEphemerisGenerator()
- * getEphemerisGenerator} method has been called. They are created when propagation is over.
- * Random access to any intermediate state of the orbit throughout the propagation range is
- * possible afterwards through this object.
- * </p>
- * <p>
- * A typical use case is for numerically integrated orbits, which can be used by
- * algorithms that need to wander around according to their own algorithm without
- * cumbersome tight links with the integrator.
- * </p>
- * <p>
- * As this class implements the {@link org.orekit.propagation.Propagator Propagator}
- * interface, it can itself be used in batch mode to build another instance of the
- * same type. This is however not recommended since it would be a waste of resources.
- * </p>
- * <p>
- * Note that this class stores all intermediate states along with interpolation
- * models, so it may be memory intensive.
- * </p>
- *
- * @see org.orekit.propagation.numerical.NumericalPropagator
- * @author Mathieu Roméro
- * @author Luc Maisonobe
- * @author Véronique Pommier-Maurussane
- */
- public class FieldIntegratedEphemeris <T extends CalculusFieldElement<T>>
- extends FieldAbstractAnalyticalPropagator<T> implements FieldBoundedPropagator<T> {
- /** Event detection requires evaluating the state slightly before / past an event. */
- private static final double EXTRAPOLATION_TOLERANCE = 1.0;
- /** Mapper between raw double components and spacecraft state. */
- private final FieldStateMapper<T> mapper;
- /** Type of orbit to output (mean or osculating).
- * <p>
- * This is used only in the case of semianalitical propagators where there is a clear separation between
- * mean and short periodic elements. It is ignored by the Numerical propagator.
- * </p>
- */
- private PropagationType type;
- /** Start date of the integration (can be min or max). */
- private final FieldAbsoluteDate<T> startDate;
- /** First date of the range. */
- private final FieldAbsoluteDate<T> minDate;
- /** Last date of the range. */
- private final FieldAbsoluteDate<T> maxDate;
- /** Underlying raw mathematical model. */
- private FieldDenseOutputModel<T> model;
- /** Unmanaged additional states that must be simply copied. */
- private final Map<String, T[]> unmanaged;
- /** Creates a new instance of IntegratedEphemeris.
- * @param startDate Start date of the integration (can be minDate or maxDate)
- * @param minDate first date of the range
- * @param maxDate last date of the range
- * @param mapper mapper between raw double components and spacecraft state
- * @param type type of orbit to output (mean or osculating)
- * @param model underlying raw mathematical model
- * @param unmanaged unmanaged additional states that must be simply copied
- * @param providers providers for pre-integrated states
- * @param equations names of additional equations
- */
- public FieldIntegratedEphemeris(final FieldAbsoluteDate<T> startDate,
- final FieldAbsoluteDate<T> minDate, final FieldAbsoluteDate<T> maxDate,
- final FieldStateMapper<T> mapper, final PropagationType type,
- final FieldDenseOutputModel<T> model,
- final Map<String, T[]> unmanaged,
- final List<FieldAdditionalStateProvider<T>> providers,
- final String[] equations) {
- super(startDate.getField(), mapper.getAttitudeProvider());
- this.startDate = startDate;
- this.minDate = minDate;
- this.maxDate = maxDate;
- this.mapper = mapper;
- this.type = type;
- this.model = model;
- this.unmanaged = unmanaged;
- // set up the pre-integrated providers
- for (final FieldAdditionalStateProvider<T> provider : providers) {
- addAdditionalStateProvider(provider);
- }
- // set up providers to map the final elements of the model array to additional states
- for (int i = 0; i < equations.length; ++i) {
- addAdditionalStateProvider(new LocalProvider(equations[i], i));
- }
- }
- /** Interpolate the model at some date.
- * @param date desired interpolation date
- * @return state interpolated at date
- * of supported range
- */
- private FieldODEStateAndDerivative<T> getInterpolatedState(final FieldAbsoluteDate<T> date) {
- // compare using double precision instead of FieldAbsoluteDate<T>.compareTo(...)
- // because time is expressed as a double when searching for events
- if (date.compareTo(minDate.shiftedBy(-EXTRAPOLATION_TOLERANCE)) < 0) {
- // date is outside of supported range
- throw new OrekitException(OrekitMessages.OUT_OF_RANGE_EPHEMERIDES_DATE_BEFORE,
- date, minDate, maxDate, minDate.durationFrom(date).getReal());
- }
- if (date.compareTo(maxDate.shiftedBy(EXTRAPOLATION_TOLERANCE)) > 0) {
- // date is outside of supported range
- throw new OrekitException(OrekitMessages.OUT_OF_RANGE_EPHEMERIDES_DATE_AFTER,
- date, minDate, maxDate, date.durationFrom(maxDate).getReal());
- }
- return model.getInterpolatedState(date.durationFrom(startDate));
- }
- /** {@inheritDoc} */
- @Override
- protected FieldSpacecraftState<T> basicPropagate(final FieldAbsoluteDate<T> date) {
- final FieldODEStateAndDerivative<T> os = getInterpolatedState(date);
- FieldSpacecraftState<T> state = mapper.mapArrayToState(mapper.mapDoubleToDate(os.getTime(), date),
- os.getPrimaryState(), os.getPrimaryDerivative(),
- type);
- for (Map.Entry<String, T[]> initial : unmanaged.entrySet()) {
- state = state.addAdditionalState(initial.getKey(), initial.getValue());
- }
- return state;
- }
- /** {@inheritDoc} */
- @Override
- protected FieldOrbit<T> propagateOrbit(final FieldAbsoluteDate<T> date, final T[] parameters) {
- return basicPropagate(date).getOrbit();
- }
- /** {@inheritDoc} */
- @Override
- protected T getMass(final FieldAbsoluteDate<T> date) {
- return basicPropagate(date).getMass();
- }
- /** {@inheritDoc} */
- @Override
- public TimeStampedFieldPVCoordinates<T> getPVCoordinates(final FieldAbsoluteDate<T> date, final Frame frame) {
- return propagate(date).getPVCoordinates(frame);
- }
- /** Get the first date of the range.
- * @return the first date of the range
- */
- @Override
- public FieldAbsoluteDate<T> getMinDate() {
- return minDate;
- }
- /** Get the last date of the range.
- * @return the last date of the range
- */
- @Override
- public FieldAbsoluteDate<T> getMaxDate() {
- return maxDate;
- }
- @Override
- public Frame getFrame() {
- return this.mapper.getFrame();
- }
- /** {@inheritDoc} */
- @Override
- public void resetInitialState(final FieldSpacecraftState<T> state) {
- throw new OrekitException(OrekitMessages.NON_RESETABLE_STATE);
- }
- /** {@inheritDoc} */
- @Override
- protected void resetIntermediateState(final FieldSpacecraftState<T> state, final boolean forward) {
- throw new OrekitException(OrekitMessages.NON_RESETABLE_STATE);
- }
- /** {@inheritDoc} */
- @Override
- public FieldSpacecraftState<T> getInitialState() {
- return updateAdditionalStates(basicPropagate(getMinDate()));
- }
- /** Local provider for additional state data. */
- private class LocalProvider implements FieldAdditionalStateProvider<T> {
- /** Name of the additional state. */
- private final String name;
- /** Index of the additional state. */
- private final int index;
- /** Simple constructor.
- * @param name name of the additional state
- * @param index index of the additional state
- */
- LocalProvider(final String name, final int index) {
- this.name = name;
- this.index = index;
- }
- /** {@inheritDoc} */
- @Override
- public String getName() {
- return name;
- }
- /** {@inheritDoc} */
- @Override
- public T[] getAdditionalState(final FieldSpacecraftState<T> state) {
- // extract the part of the interpolated array corresponding to the additional state
- return getInterpolatedState(state.getDate()).getSecondaryState(index + 1);
- }
- }
- /** {@inheritDoc} */
- @Override
- protected List<ParameterDriver> getParametersDrivers() {
- // Integrated Ephemeris propagation model does not have parameter drivers.
- return Collections.emptyList();
- }
- }