Java tutorial
/* Copyright 2002-2015 CS Systmes d'Information * Licensed to CS Systmes 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 fr.cs.examples.attitude; import java.text.DecimalFormat; import java.text.DecimalFormatSymbols; import java.util.Locale; import java.util.SortedSet; import java.util.TreeSet; import org.apache.commons.math3.geometry.euclidean.threed.Rotation; import org.apache.commons.math3.geometry.euclidean.threed.RotationOrder; import org.apache.commons.math3.geometry.euclidean.threed.Vector3D; import org.apache.commons.math3.geometry.euclidean.threed.Vector3DFormat; import org.apache.commons.math3.util.FastMath; import org.orekit.attitudes.AttitudeProvider; import org.orekit.attitudes.AttitudesSequence; import org.orekit.attitudes.LofOffset; import org.orekit.bodies.CelestialBodyFactory; import org.orekit.errors.OrekitException; import org.orekit.errors.PropagationException; import org.orekit.frames.Frame; import org.orekit.frames.FramesFactory; import org.orekit.frames.LOFType; import org.orekit.orbits.KeplerianOrbit; import org.orekit.orbits.Orbit; import org.orekit.propagation.Propagator; import org.orekit.propagation.SpacecraftState; import org.orekit.propagation.analytical.EcksteinHechlerPropagator; import org.orekit.propagation.events.DateDetector; import org.orekit.propagation.events.EclipseDetector; import org.orekit.propagation.events.EventDetector; import org.orekit.propagation.events.handlers.EventHandler; import org.orekit.propagation.sampling.OrekitFixedStepHandler; import org.orekit.time.AbsoluteDate; import org.orekit.time.TimeScalesFactory; import org.orekit.utils.Constants; import org.orekit.utils.IERSConventions; import org.orekit.utils.PVCoordinates; import org.orekit.utils.PVCoordinatesProvider; import fr.cs.examples.Autoconfiguration; /** Orekit tutorial for Earth observation attitude sequence. * <p>This tutorial shows how to easily switch between day and night attitude modes.<p> * @author Luc Maisonobe */ public class EarthObservation_day_night_switch_with_fixed_transitions { /** Program entry point. * @param args program arguments (unused here) */ public static void main(String[] args) { try { // configure Orekit Autoconfiguration.configureOrekit(); final SortedSet<String> output = new TreeSet<String>(); //---------------------------------------- // Initial state definition : date, orbit //---------------------------------------- final AbsoluteDate initialDate = new AbsoluteDate(2004, 01, 02, 00, 00, 00.000, TimeScalesFactory.getUTC()); final Vector3D position = new Vector3D(-6142438.668, 3492467.560, -25767.25680); final Vector3D velocity = new Vector3D(505.8479685, 942.7809215, 7435.922231); final Orbit initialOrbit = new KeplerianOrbit(new PVCoordinates(position, velocity), FramesFactory.getEME2000(), initialDate, Constants.EIGEN5C_EARTH_MU); //------------------------------ // Attitudes sequence definition //------------------------------ final AttitudesSequence attitudesSequence = new AttitudesSequence(); // Attitude laws definition //------------------------- // Mode : day final AttitudeProvider dayObservationLaw = new LofOffset(initialOrbit.getFrame(), LOFType.VVLH, RotationOrder.XYZ, FastMath.toRadians(20), FastMath.toRadians(40), 0); // Mode : night final AttitudeProvider nightRestingLaw = new LofOffset(initialOrbit.getFrame(), LOFType.VVLH); // Mode : day-night rdv 1 final AttitudeProvider dayNightRdV1Law = new LofOffset(initialOrbit.getFrame(), LOFType.VVLH, RotationOrder.XYZ, FastMath.toRadians(20), FastMath.toRadians(20), 0); // Mode : day-night rdv 2 final AttitudeProvider dayNightRdV2Law = new LofOffset(initialOrbit.getFrame(), LOFType.VVLH, RotationOrder.XYZ, FastMath.toRadians(20), 0, 0); // Mode : night-day rdv 1 final AttitudeProvider nightDayRdV1Law = new LofOffset(initialOrbit.getFrame(), LOFType.VVLH, RotationOrder.XYZ, FastMath.toRadians(20), 0, 0); // Mode : night-day rdv 2 final AttitudeProvider nightDayRdV2Law = new LofOffset(initialOrbit.getFrame(), LOFType.VVLH, RotationOrder.XYZ, FastMath.toRadians(20), FastMath.toRadians(20), 0); // Event detectors definition //--------------------------- final PVCoordinatesProvider sun = CelestialBodyFactory.getSun(); final PVCoordinatesProvider earth = CelestialBodyFactory.getEarth(); // Detectors : end day-night rdv 2 final DateDetector endDayNightRdV2Event_increase = new DateDetector(10, 1e-04) .withHandler(new EventHandler<DateDetector>() { public Action eventOccurred(final SpacecraftState s, final DateDetector detector, final boolean increasing) { if (increasing) { output.add(s.getDate() + ": switching to night law"); System.out.println("# " + (s.getDate().durationFrom(AbsoluteDate.J2000_EPOCH) / Constants.JULIAN_DAY) + " end-day-night-2 night-mode"); } return Action.CONTINUE; } public SpacecraftState resetState(DateDetector detector, SpacecraftState oldState) { return oldState; } }); final DateDetector endDayNightRdV2Event_decrease = new DateDetector(10, 1e-04) .withHandler(new EventHandler<DateDetector>() { public Action eventOccurred(final SpacecraftState s, final DateDetector detector, final boolean increasing) { if (!increasing) { output.add(s.getDate() + ": switching to night law"); System.out.println("# " + (s.getDate().durationFrom(AbsoluteDate.J2000_EPOCH) / Constants.JULIAN_DAY) + " end-day-night-2 night-mode"); } return Action.CONTINUE; } public SpacecraftState resetState(DateDetector detector, SpacecraftState oldState) { return oldState; } }); // Detectors : end day-night rdv 1 final DateDetector endDayNightRdV1Event_increase = new DateDetector(10, 1e-04) .withHandler(new EventHandler<DateDetector>() { public Action eventOccurred(final SpacecraftState s, final DateDetector detector, final boolean increasing) { if (increasing) { output.add(s.getDate() + ": switching to day-night rdv 2 law"); System.out .println("# " + (s.getDate().durationFrom(AbsoluteDate.J2000_EPOCH) / Constants.JULIAN_DAY) + " end-day-night-1 day-night-rdv2-mode"); endDayNightRdV2Event_increase.addEventDate(s.getDate().shiftedBy(20)); endDayNightRdV2Event_decrease.addEventDate(s.getDate().shiftedBy(20)); } return Action.CONTINUE; } public SpacecraftState resetState(DateDetector detector, SpacecraftState oldState) { return oldState; } }); final DateDetector endDayNightRdV1Event_decrease = new DateDetector(10, 1e-04) .withHandler(new EventHandler<DateDetector>() { public Action eventOccurred(final SpacecraftState s, final DateDetector detector, final boolean increasing) { if (!increasing) { output.add(s.getDate() + ": switching to day-night rdv 2 law"); System.out .println("# " + (s.getDate().durationFrom(AbsoluteDate.J2000_EPOCH) / Constants.JULIAN_DAY) + " end-day-night-1 day-night-rdv2-mode"); endDayNightRdV2Event_increase.addEventDate(s.getDate().shiftedBy(20)); endDayNightRdV2Event_decrease.addEventDate(s.getDate().shiftedBy(20)); } return Action.CONTINUE; } public SpacecraftState resetState(DateDetector detector, SpacecraftState oldState) { return oldState; } }); // Detector : eclipse entry final EventDetector dayNightEvent = new EclipseDetector(sun, 696000000., earth, Constants.WGS84_EARTH_EQUATORIAL_RADIUS).withHandler(new EventHandler<EclipseDetector>() { public Action eventOccurred(final SpacecraftState s, final EclipseDetector detector, final boolean increasing) { if (!increasing) { output.add(s.getDate() + ": switching to day-night rdv 1 law"); System.out .println("# " + (s.getDate().durationFrom(AbsoluteDate.J2000_EPOCH) / Constants.JULIAN_DAY) + " eclipse-entry day-night-rdv1-mode"); endDayNightRdV1Event_increase.addEventDate(s.getDate().shiftedBy(40)); endDayNightRdV1Event_decrease.addEventDate(s.getDate().shiftedBy(40)); } return Action.CONTINUE; } public SpacecraftState resetState(EclipseDetector detector, SpacecraftState oldState) { return oldState; } }); // Detectors : end night-day rdv 2 final DateDetector endNightDayRdV2Event_increase = new DateDetector(10, 1e-04) .withHandler(new EventHandler<DateDetector>() { public Action eventOccurred(final SpacecraftState s, final DateDetector detector, final boolean increasing) { if (increasing) { output.add(s.getDate() + ": switching to day law"); System.out.println("# " + (s.getDate().durationFrom(AbsoluteDate.J2000_EPOCH) / Constants.JULIAN_DAY) + " end-night-day-2 day-mode"); } return Action.CONTINUE; } public SpacecraftState resetState(DateDetector detector, SpacecraftState oldState) { return oldState; } }); final DateDetector endNightDayRdV2Event_decrease = new DateDetector(10, 1e-04) .withHandler(new EventHandler<DateDetector>() { public Action eventOccurred(final SpacecraftState s, final DateDetector detector, final boolean increasing) { if (!increasing) { output.add(s.getDate() + ": switching to day law"); System.out.println("# " + (s.getDate().durationFrom(AbsoluteDate.J2000_EPOCH) / Constants.JULIAN_DAY) + " end-night-day-2 day-mode"); } return Action.CONTINUE; } public SpacecraftState resetState(DateDetector detector, SpacecraftState oldState) { return oldState; } }); // Detectors : end night-day rdv 1 final DateDetector endNightDayRdV1Event_increase = new DateDetector(10, 1e-04) .withHandler(new EventHandler<DateDetector>() { public Action eventOccurred(final SpacecraftState s, final DateDetector detector, final boolean increasing) { if (increasing) { output.add(s.getDate() + ": switching to night-day rdv 2 law"); System.out .println("# " + (s.getDate().durationFrom(AbsoluteDate.J2000_EPOCH) / Constants.JULIAN_DAY) + " end-night-day-1 night-day-rdv2-mode"); endNightDayRdV2Event_increase.addEventDate(s.getDate().shiftedBy(40)); endNightDayRdV2Event_decrease.addEventDate(s.getDate().shiftedBy(40)); } return Action.CONTINUE; } public SpacecraftState resetState(DateDetector detector, SpacecraftState oldState) { return oldState; } }); final DateDetector endNightDayRdV1Event_decrease = new DateDetector(10, 1e-04) .withHandler(new EventHandler<DateDetector>() { public Action eventOccurred(final SpacecraftState s, final DateDetector detector, final boolean increasing) { if (!increasing) { output.add(s.getDate() + ": switching to night-day rdv 2 law"); System.out .println("# " + (s.getDate().durationFrom(AbsoluteDate.J2000_EPOCH) / Constants.JULIAN_DAY) + " end-night-day-1 night-day-rdv2-mode"); endNightDayRdV2Event_increase.addEventDate(s.getDate().shiftedBy(40)); endNightDayRdV2Event_decrease.addEventDate(s.getDate().shiftedBy(40)); } return Action.CONTINUE; } public SpacecraftState resetState(DateDetector detector, SpacecraftState oldState) { return oldState; } }); // Detector : eclipse exit final EventDetector nightDayEvent = new EclipseDetector(sun, 696000000., earth, Constants.WGS84_EARTH_EQUATORIAL_RADIUS).withHandler(new EventHandler<EclipseDetector>() { public Action eventOccurred(final SpacecraftState s, final EclipseDetector detector, final boolean increasing) { if (increasing) { output.add(s.getDate() + ": switching to night-day rdv 1 law"); System.out .println("# " + (s.getDate().durationFrom(AbsoluteDate.J2000_EPOCH) / Constants.JULIAN_DAY) + " eclipse-exit night-day-rdv1-mode"); endNightDayRdV1Event_increase.addEventDate(s.getDate().shiftedBy(20)); endNightDayRdV1Event_decrease.addEventDate(s.getDate().shiftedBy(20)); } return Action.CONTINUE; } public SpacecraftState resetState(EclipseDetector detector, SpacecraftState oldState) { return oldState; } }); // Attitude sequences definition //------------------------------ attitudesSequence.addSwitchingCondition(dayObservationLaw, dayNightEvent, false, true, dayNightRdV1Law); attitudesSequence.addSwitchingCondition(dayNightRdV1Law, endDayNightRdV1Event_increase, true, false, dayNightRdV2Law); attitudesSequence.addSwitchingCondition(dayNightRdV1Law, endDayNightRdV1Event_decrease, false, true, dayNightRdV2Law); attitudesSequence.addSwitchingCondition(dayNightRdV2Law, endDayNightRdV2Event_increase, true, false, nightRestingLaw); attitudesSequence.addSwitchingCondition(dayNightRdV2Law, endDayNightRdV2Event_decrease, false, true, nightRestingLaw); attitudesSequence.addSwitchingCondition(nightRestingLaw, nightDayEvent, true, false, nightDayRdV1Law); attitudesSequence.addSwitchingCondition(nightDayRdV1Law, endNightDayRdV1Event_increase, true, false, nightDayRdV2Law); attitudesSequence.addSwitchingCondition(nightDayRdV1Law, endNightDayRdV1Event_decrease, false, true, nightDayRdV2Law); attitudesSequence.addSwitchingCondition(nightDayRdV2Law, endNightDayRdV2Event_increase, true, false, dayObservationLaw); attitudesSequence.addSwitchingCondition(nightDayRdV2Law, endNightDayRdV2Event_decrease, false, true, dayObservationLaw); // Initialisation //--------------- if (dayNightEvent.g(new SpacecraftState(initialOrbit)) >= 0) { // initial position is in daytime attitudesSequence.resetActiveProvider(dayObservationLaw); System.out .println("# " + (initialDate.durationFrom(AbsoluteDate.J2000_EPOCH) / Constants.JULIAN_DAY) + " begin with day law"); } else { // initial position is in nighttime attitudesSequence.resetActiveProvider(nightRestingLaw); System.out .println("# " + (initialDate.durationFrom(AbsoluteDate.J2000_EPOCH) / Constants.JULIAN_DAY) + " begin with night law"); } //---------------------- // Propagator definition //---------------------- // Propagator : consider the analytical Eckstein-Hechler model final Propagator propagator = new EcksteinHechlerPropagator(initialOrbit, attitudesSequence, Constants.EIGEN5C_EARTH_EQUATORIAL_RADIUS, Constants.EIGEN5C_EARTH_MU, Constants.EIGEN5C_EARTH_C20, Constants.EIGEN5C_EARTH_C30, Constants.EIGEN5C_EARTH_C40, Constants.EIGEN5C_EARTH_C50, Constants.EIGEN5C_EARTH_C60); // Register the switching events to the propagator attitudesSequence.registerSwitchEvents(propagator); propagator.setMasterMode(10.0, new OrekitFixedStepHandler() { private DecimalFormat f1 = new DecimalFormat("0.0000000000000000E00", new DecimalFormatSymbols(Locale.US)); private Vector3DFormat f2 = new Vector3DFormat(" ", " ", " ", f1); private PVCoordinatesProvider sun = CelestialBodyFactory.getSun(); private PVCoordinatesProvider moon = CelestialBodyFactory.getMoon(); private Frame eme2000 = FramesFactory.getEME2000(); private Frame itrf2005 = FramesFactory.getITRF(IERSConventions.IERS_2010, true); private String printVector3D(final String name, final Vector3D v) { return name + " " + f2.format(v); } private String printRotation(final String name, final Rotation r) { return name + " " + f1.format(r.getQ1()) + " " + f1.format(r.getQ2()) + " " + f1.format(r.getQ3()) + " " + f1.format(r.getQ0()); } private String printRotation2(final String name, final Rotation r) { return name + " " + f1.format(-r.getQ1()) + " " + f1.format(-r.getQ2()) + " " + f1.format(-r.getQ3()) + " " + f1.format(-r.getQ0()); } public void init(final SpacecraftState s0, final AbsoluteDate t) { } public void handleStep(SpacecraftState currentState, boolean isLast) throws PropagationException { try { // the Earth position in spacecraft should be along spacecraft Z axis // during nigthtime and away from it during daytime due to roll and pitch offsets final Vector3D earth = currentState.toTransform().transformPosition(Vector3D.ZERO); final double pointingOffset = Vector3D.angle(earth, Vector3D.PLUS_K); // the g function is the eclipse indicator, its an angle between Sun and Earth limb, // positive when Sun is outside of Earth limb, negative when Sun is hidden by Earth limb final double eclipseAngle = dayNightEvent.g(currentState); final double endNightDayTimer1 = endNightDayRdV1Event_decrease.g(currentState); final double endNightDayTimer2 = endNightDayRdV2Event_decrease.g(currentState); final double endDayNightTimer1 = endDayNightRdV1Event_decrease.g(currentState); final double endDayNightTimer2 = endDayNightRdV2Event_decrease.g(currentState); output.add(currentState.getDate() + " " + FastMath.toDegrees(eclipseAngle) + " " + endNightDayTimer1 + " " + endNightDayTimer2 + " " + endDayNightTimer1 + " " + endDayNightTimer2 + " " + FastMath.toDegrees(pointingOffset)); final AbsoluteDate date = currentState.getDate(); final PVCoordinates pv = currentState.getPVCoordinates(eme2000); final Rotation lvlhRot = new Rotation(pv.getPosition(), pv.getMomentum(), Vector3D.MINUS_K, Vector3D.MINUS_J); final Rotation earthRot = eme2000.getTransformTo(itrf2005, date).getRotation(); System.out.println("Scenario::setVectorMap 0x960b7e0 " + (date.durationFrom(AbsoluteDate.J2000_EPOCH) / Constants.JULIAN_DAY) + " " + printVector3D("sun", sun.getPVCoordinates(date, eme2000).getPosition()) + " " + printVector3D("moon", moon.getPVCoordinates(date, eme2000).getPosition()) + " " + printVector3D("satPos", pv.getPosition()) + " " + printVector3D("satVel", pv.getVelocity()) + " " + printVector3D("orbMom", pv.getMomentum())); System.out.println("Scenario::setQuatMap 0x960b7e0 " + (date.durationFrom(AbsoluteDate.J2000_EPOCH) / Constants.JULIAN_DAY) + " " + printRotation("earthFrame", earthRot) + " " + printRotation("LVLHFrame", lvlhRot)); System.out.println("Scenario::computeStep 0x960b7e0 " + (date.durationFrom(AbsoluteDate.J2000_EPOCH) / Constants.JULIAN_DAY)); System.out.println(" -> " + printRotation2("", currentState.getAttitude().getRotation()) + " " + printVector3D("", currentState.getAttitude().getSpin())); } catch (OrekitException oe) { throw new PropagationException(oe); } } }); //---------- // Propagate //---------- // Propagate from the initial date for the fixed duration propagator.propagate(initialDate.shiftedBy(1.75 * 3600.)); //-------------- // Print results //-------------- // we print the lines according to lexicographic order, which is chronological order here // to make sure out of orders calls between step handler and event handlers don't mess things up for (final String line : output) { System.out.println(line); } } catch (OrekitException oe) { System.err.println(oe.getMessage()); } } }