ProfileThrustPropulsionModel.java

  1. /* Copyright 2022-2025 Luc Maisonobe
  2.  * Licensed to CS GROUP (CS) under one or more
  3.  * contributor license agreements.  See the NOTICE file distributed with
  4.  * this work for additional information regarding copyright ownership.
  5.  * CS licenses this file to You under the Apache License, Version 2.0
  6.  * (the "License"); you may not use this file except in compliance with
  7.  * the License.  You may obtain a copy of the License at
  8.  *
  9.  *   http://www.apache.org/licenses/LICENSE-2.0
  10.  *
  11.  * Unless required by applicable law or agreed to in writing, software
  12.  * distributed under the License is distributed on an "AS IS" BASIS,
  13.  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  14.  * See the License for the specific language governing permissions and
  15.  * limitations under the License.
  16.  */

  18. package org.orekit.forces.maneuvers.propulsion;

  20. import java.util.ArrayList;
  21. import java.util.Collections;
  22. import java.util.List;
  23. import java.util.stream.Stream;

  25. import org.hipparchus.CalculusFieldElement;
  26. import org.hipparchus.Field;
  27. import org.hipparchus.geometry.euclidean.threed.FieldVector3D;
  28. import org.hipparchus.geometry.euclidean.threed.Vector3D;
  29. import org.orekit.forces.maneuvers.Control3DVectorCostType;
  30. import org.orekit.propagation.FieldSpacecraftState;
  31. import org.orekit.propagation.SpacecraftState;
  32. import org.orekit.propagation.events.DateDetector;
  33. import org.orekit.propagation.events.EventDetector;
  34. import org.orekit.propagation.events.FieldDateDetector;
  35. import org.orekit.propagation.events.FieldEventDetector;
  36. import org.orekit.time.AbsoluteDate;
  37. import org.orekit.time.TimeStamped;
  38. import org.orekit.utils.ParameterDriver;
  39. import org.orekit.utils.TimeSpanMap;

  41. /** Thrust propulsion model based on segmented profile.
  42.  * @author Luc Maisonobe
  43.  * @since 12.0
  44.  */
  45. public class ProfileThrustPropulsionModel implements ThrustPropulsionModel {

  47.     /** Thrust profile. */
  48.     private final TimeSpanMap<ThrustVectorProvider> profile;

  50.     /** Specific impulse. */
  51.     private final double isp;

  53.     /** Name of the maneuver. */
  54.     private final String name;

  56.     /** Type of norm linking thrust vector to mass flow rate. */
  57.     private final Control3DVectorCostType control3DVectorCostType;

  59.     /** Constructor with default cost type.
  60.      * @param profile thrust profile (N)
  61.      * @param isp specific impulse (s)
  62.      * @param name name of the maneuver
  63.      * @since 13.0
  64.      */
  65.     public ProfileThrustPropulsionModel(final TimeSpanMap<ThrustVectorProvider> profile, final double isp,
  66.                                         final String name) {
  67.         this(profile, isp, Control3DVectorCostType.TWO_NORM, name);
  68.     }

  70.     /** Generic constructor.
  71.      * @param profile thrust profile (N)
  72.      * @param isp specific impulse (s)
  73.      * @param control3DVectorCostType control vector's cost type
  74.      * @param name name of the maneuver
  75.      * @since 13.0
  76.      */
  77.     public ProfileThrustPropulsionModel(final TimeSpanMap<ThrustVectorProvider> profile, final double isp,
  78.                                         final Control3DVectorCostType control3DVectorCostType, final String name) {
  79.         this.name    = name;
  80.         this.isp     = isp;
  81.         this.profile = profile;
  82.         this.control3DVectorCostType = control3DVectorCostType;
  83.     }

  85.     /** Build with customized profile.
  86.      * @param profile thrust profile (N)
  87.      * @param isp specific impulse (s)
  88.      * @param name name of the maneuver
  89.      * @param control3DVectorCostType control vector's cost type
  90.      * @param <T> segment type
  91.      * @return propulsion model
  92.      * @since 13.0
  93.      */
  94.     public static <T extends ThrustVectorProvider> ProfileThrustPropulsionModel of(final TimeSpanMap<T> profile,
  95.                                                                                    final double isp,
  96.                                                                                    final Control3DVectorCostType control3DVectorCostType,
  97.                                                                                    final String name) {
  98.         return new ProfileThrustPropulsionModel(buildSegments(profile), isp, control3DVectorCostType, name);
  99.     }

  101.     /**
  102.      * Method building a map of generic segments from customized ones.
  103.      * @param timeSpanMap input profile
  104.      * @param <T> segment type
  105.      * @return generic profile
  106.      * @since 13.0
  107.      */
  108.     private static <T extends ThrustVectorProvider> TimeSpanMap<ThrustVectorProvider> buildSegments(final TimeSpanMap<T> timeSpanMap) {
  109.         TimeSpanMap.Span<T> span = timeSpanMap.getFirstSpan();
  110.         final TimeSpanMap<ThrustVectorProvider> segments = new TimeSpanMap<>(null);
  111.         while (span != null) {
  112.             segments.addValidBetween(span.getData(), span.getStart(), span.getEnd());
  113.             span = span.next();
  114.         }
  115.         return segments;
  116.     }

  118.     /** {@inheritDoc} */
  119.     @Override
  120.     public String getName() {
  121.         return name;
  122.     }

  124.     /** {@inheritDoc} */
  125.     @Override
  126.     public Control3DVectorCostType getControl3DVectorCostType() {
  127.         return control3DVectorCostType;
  128.     }

  130.     /**
  131.      * Getter for active provider at input date.
  132.      * @param date date
  133.      * @return active segment
  134.      * @since 13.0
  135.      */
  136.     public ThrustVectorProvider getActiveProvider(final AbsoluteDate date) {
  137.         return profile.get(date);
  138.     }

  140.     /** {@inheritDoc} */
  141.     @Override
  142.     public Vector3D getThrustVector(final SpacecraftState s) {
  143.         return getThrustVector(s, getParameters());
  144.     }

  146.     /** {@inheritDoc} */
  147.     @Override
  148.     public double getFlowRate(final SpacecraftState s) {
  149.         return getFlowRate(s, getParameters());
  150.     }

  152.     /** {@inheritDoc} */
  153.     @Override
  154.     public double getFlowRate(final SpacecraftState s, final double[] parameters) {
  155.         return -control3DVectorCostType.evaluate(getThrustVector(s, parameters)) / ThrustPropulsionModel.getExhaustVelocity(isp);
  156.     }

  158.     /** {@inheritDoc} */
  159.     @Override
  160.     public Vector3D getThrustVector(final SpacecraftState s, final double[] parameters) {
  161.         final ThrustVectorProvider active = getActiveProvider(s.getDate());
  162.         return active == null ? Vector3D.ZERO : active.getThrustVector(s.getDate(), s.getMass());
  163.     }

  165.     /** {@inheritDoc} */
  166.     public <T extends CalculusFieldElement<T>> FieldVector3D<T> getThrustVector(final FieldSpacecraftState<T> s,
  167.                                                                                 final T[] parameters) {
  168.         final ThrustVectorProvider active = getActiveProvider(s.getDate().toAbsoluteDate());
  169.         return active == null ? FieldVector3D.getZero(s.getDate().getField()) :
  170.                 active.getThrustVector(s.getDate(), s.getMass());
  171.     }

  173.     /** {@inheritDoc} */
  174.     public <T extends CalculusFieldElement<T>> T getFlowRate(final FieldSpacecraftState<T> s, final T[] parameters) {
  175.         return control3DVectorCostType.evaluate(getThrustVector(s, parameters)).divide(-ThrustPropulsionModel.getExhaustVelocity(isp));
  176.     }

  178.     /** {@inheritDoc}.
  179.      * <p>
  180.      * The single detector returned triggers {@link org.hipparchus.ode.events.Action#RESET_DERIVATIVES} events
  181.      * at every {@link ThrustVectorProvider} boundaries.
  182.      * </p>
  183.      */
  184.     @Override
  185.     public Stream<EventDetector> getEventDetectors() {

  187.         final List<AbsoluteDate> transitionDates = new ArrayList<>();
  188.         for (TimeSpanMap.Transition<ThrustVectorProvider> transition = profile.getFirstTransition();
  189.              transition != null;
  190.              transition = transition.next()) {
  191.             transitionDates.add(transition.getDate());
  192.         }
  193.         final DateDetector detector = getDateDetector(transitionDates.toArray(new TimeStamped[0]));
  194.         return Stream.of(detector);
  195.     }

  197.     /** {@inheritDoc}.
  198.      * <p>
  199.      * The single detector returned triggers {@link org.hipparchus.ode.events.Action#RESET_DERIVATIVES} events
  200.      * at every {@link ThrustVectorProvider} boundaries.
  201.      * </p>
  202.      */
  203.     @Override
  204.     public <T extends CalculusFieldElement<T>> Stream<FieldEventDetector<T>> getFieldEventDetectors(final Field<T> field) {
  205.         final List<AbsoluteDate> transitionDates = new ArrayList<>();
  206.         for (TimeSpanMap.Transition<ThrustVectorProvider> transition = profile.getFirstTransition();
  207.              transition != null;
  208.              transition = transition.next()) {
  209.             transitionDates.add(transition.getDate());
  210.         }
  211.         final FieldDateDetector<T> detector = getFieldDateDetector(field, transitionDates.toArray(new AbsoluteDate[0]));
  212.         return Stream.of(detector);
  213.     }

  215.     /** {@inheritDoc} */
  216.     @Override
  217.     public List<ParameterDriver> getParametersDrivers() {
  218.         return Collections.emptyList();
  219.     }
  220. }
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