/* 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.maneuvers;
import org.hipparchus.Field;
import org.hipparchus.analysis.differentiation.DSFactory;
import org.hipparchus.analysis.differentiation.DerivativeStructure;
import org.hipparchus.geometry.euclidean.threed.FieldVector3D;
import org.hipparchus.geometry.euclidean.threed.Rotation;
import org.hipparchus.geometry.euclidean.threed.Vector3D;
import org.hipparchus.ode.nonstiff.AdaptiveStepsizeFieldIntegrator;
import org.hipparchus.ode.nonstiff.AdaptiveStepsizeIntegrator;
import org.hipparchus.ode.nonstiff.DormandPrince853FieldIntegrator;
import org.hipparchus.ode.nonstiff.DormandPrince853Integrator;
import org.hipparchus.random.GaussianRandomGenerator;
import org.hipparchus.random.RandomGenerator;
import org.hipparchus.random.UncorrelatedRandomVectorGenerator;
import org.hipparchus.random.Well19937a;
import org.hipparchus.util.FastMath;
import org.hipparchus.util.MathUtils;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;
import org.orekit.Utils;
import org.orekit.attitudes.AttitudeProvider;
import org.orekit.attitudes.InertialProvider;
import org.orekit.errors.OrekitException;
import org.orekit.frames.Frame;
import org.orekit.frames.FramesFactory;
import org.orekit.orbits.CircularOrbit;
import org.orekit.orbits.FieldKeplerianOrbit;
import org.orekit.orbits.KeplerianOrbit;
import org.orekit.orbits.Orbit;
import org.orekit.orbits.OrbitType;
import org.orekit.orbits.PositionAngle;
import org.orekit.propagation.FieldSpacecraftState;
import org.orekit.propagation.SpacecraftState;
import org.orekit.propagation.events.EventDetector;
import org.orekit.propagation.numerical.FieldNumericalPropagator;
import org.orekit.propagation.numerical.NumericalPropagator;
import org.orekit.time.AbsoluteDate;
import org.orekit.time.DateComponents;
import org.orekit.time.FieldAbsoluteDate;
import org.orekit.time.TimeComponents;
import org.orekit.time.TimeScalesFactory;
import org.orekit.utils.Constants;
import org.orekit.utils.FieldPVCoordinates;
import org.orekit.utils.PVCoordinates;
public class ConstantThrustManeuverTest {
// Body mu
private double mu;
private CircularOrbit dummyOrbit(AbsoluteDate date) {
return new CircularOrbit(new PVCoordinates(Vector3D.PLUS_I, Vector3D.PLUS_J),
FramesFactory.getEME2000(), date, mu);
}
@Test
public void testPositiveDuration() throws OrekitException {
AbsoluteDate date = new AbsoluteDate(new DateComponents(2004, 01, 01),
new TimeComponents(23, 30, 00.000),
TimeScalesFactory.getUTC());
ConstantThrustManeuver maneuver =
new ConstantThrustManeuver(date, 10.0, 400.0, 300.0, Vector3D.PLUS_K);
EventDetector[] switches = maneuver.getEventsDetectors().toArray(EventDetector[]::new);
Orbit o1 = dummyOrbit(date.shiftedBy(- 1.0));
Assert.assertTrue(switches[0].g(new SpacecraftState(o1)) < 0);
Orbit o2 = dummyOrbit(date.shiftedBy( 1.0));
Assert.assertTrue(switches[0].g(new SpacecraftState(o2)) > 0);
Orbit o3 = dummyOrbit(date.shiftedBy( 9.0));
Assert.assertTrue(switches[1].g(new SpacecraftState(o3)) < 0);
Orbit o4 = dummyOrbit(date.shiftedBy( 11.0));
Assert.assertTrue(switches[1].g(new SpacecraftState(o4)) > 0);
}
@Test
public void testNegativeDuration() throws OrekitException {
AbsoluteDate date = new AbsoluteDate(new DateComponents(2004, 01, 01),
new TimeComponents(23, 30, 00.000),
TimeScalesFactory.getUTC());
ConstantThrustManeuver maneuver =
new ConstantThrustManeuver(date, -10.0, 400.0, 300.0, Vector3D.PLUS_K);
EventDetector[] switches = maneuver.getEventsDetectors().toArray(EventDetector[]::new);
Orbit o1 = dummyOrbit(date.shiftedBy(-11.0));
Assert.assertTrue(switches[0].g(new SpacecraftState(o1)) < 0);
Orbit o2 = dummyOrbit(date.shiftedBy( -9.0));
Assert.assertTrue(switches[0].g(new SpacecraftState(o2)) > 0);
Orbit o3 = dummyOrbit(date.shiftedBy( -1.0));
Assert.assertTrue(switches[1].g(new SpacecraftState(o3)) < 0);
Orbit o4 = dummyOrbit(date.shiftedBy( 1.0));
Assert.assertTrue(switches[1].g(new SpacecraftState(o4)) > 0);
}
@Test
public void testRoughBehaviour() throws OrekitException {
final double isp = 318;
final double mass = 2500;
final double a = 24396159;
final double e = 0.72831215;
final double i = FastMath.toRadians(7);
final double omega = FastMath.toRadians(180);
final double OMEGA = FastMath.toRadians(261);
final double lv = 0;
final double duration = 3653.99;
final double f = 420;
final double delta = FastMath.toRadians(-7.4978);
final double alpha = FastMath.toRadians(351);
final AttitudeProvider law = new InertialProvider(new Rotation(new Vector3D(alpha, delta), Vector3D.PLUS_I));
final AbsoluteDate initDate = new AbsoluteDate(new DateComponents(2004, 01, 01),
new TimeComponents(23, 30, 00.000),
TimeScalesFactory.getUTC());
final Orbit orbit =
new KeplerianOrbit(a, e, i, omega, OMEGA, lv, PositionAngle.TRUE,
FramesFactory.getEME2000(), initDate, mu);
final SpacecraftState initialState =
new SpacecraftState(orbit, law.getAttitude(orbit, orbit.getDate(), orbit.getFrame()), mass);
final AbsoluteDate fireDate = new AbsoluteDate(new DateComponents(2004, 01, 02),
new TimeComponents(04, 15, 34.080),
TimeScalesFactory.getUTC());
final ConstantThrustManeuver maneuver =
new ConstantThrustManeuver(fireDate, duration, f, isp, Vector3D.PLUS_I);
Assert.assertEquals(f, maneuver.getThrust(), 1.0e-10);
Assert.assertEquals(isp, maneuver.getISP(), 1.0e-10);
double[] absTolerance = {
0.001, 1.0e-9, 1.0e-9, 1.0e-6, 1.0e-6, 1.0e-6, 0.001
};
double[] relTolerance = {
1.0e-7, 1.0e-4, 1.0e-4, 1.0e-7, 1.0e-7, 1.0e-7, 1.0e-7
};
AdaptiveStepsizeIntegrator integrator =
new DormandPrince853Integrator(0.001, 1000, absTolerance, relTolerance);
integrator.setInitialStepSize(60);
final NumericalPropagator propagator = new NumericalPropagator(integrator);
propagator.setInitialState(initialState);
propagator.setAttitudeProvider(law);
propagator.addForceModel(maneuver);
final SpacecraftState finalorb = propagator.propagate(fireDate.shiftedBy(3800));
final double massTolerance =
FastMath.abs(maneuver.getFlowRate()) * maneuver.getEventsDetectors().findFirst().get().getThreshold();
Assert.assertEquals(2007.8824544261233, finalorb.getMass(), massTolerance);
Assert.assertEquals(2.6872, FastMath.toDegrees(MathUtils.normalizeAngle(finalorb.getI(), FastMath.PI)), 1e-4);
Assert.assertEquals(28970, finalorb.getA()/1000, 1);
}
/**Testing if the propagation between the FieldPropagation and the propagation
* is equivalent.
* Also testing if propagating X+dX with the propagation is equivalent to
* propagation X with the FieldPropagation and then applying the taylor
* expansion of dX to the result.*/
@Test
public void RealFieldTest() throws OrekitException {
DSFactory factory = new DSFactory(6, 5);
DerivativeStructure a_0 = factory.variable(0, 7e7);
DerivativeStructure e_0 = factory.variable(1, 0.4);
DerivativeStructure i_0 = factory.variable(2, 85 * FastMath.PI / 180);
DerivativeStructure R_0 = factory.variable(3, 0.7);
DerivativeStructure O_0 = factory.variable(4, 0.5);
DerivativeStructure n_0 = factory.variable(5, 0.1);
Field<DerivativeStructure> field = a_0.getField();
DerivativeStructure zero = field.getZero();
FieldAbsoluteDate<DerivativeStructure> J2000 = new FieldAbsoluteDate<DerivativeStructure>(field);
Frame EME = FramesFactory.getEME2000();
FieldKeplerianOrbit<DerivativeStructure> FKO = new FieldKeplerianOrbit<DerivativeStructure>(a_0, e_0, i_0, R_0, O_0, n_0,
PositionAngle.MEAN,
EME,
J2000,
Constants.EIGEN5C_EARTH_MU);
FieldSpacecraftState<DerivativeStructure> initialState = new FieldSpacecraftState<DerivativeStructure>(FKO);
SpacecraftState iSR = initialState.toSpacecraftState();
final OrbitType type = OrbitType.KEPLERIAN;
double[][] tolerance = NumericalPropagator.tolerances(10.0, FKO.toOrbit(), type);
AdaptiveStepsizeFieldIntegrator<DerivativeStructure> integrator =
new DormandPrince853FieldIntegrator<DerivativeStructure>(field, 0.001, 200, tolerance[0], tolerance[1]);
integrator.setInitialStepSize(zero.add(60));
AdaptiveStepsizeIntegrator RIntegrator =
new DormandPrince853Integrator(0.001, 200, tolerance[0], tolerance[1]);
RIntegrator.setInitialStepSize(60);
FieldNumericalPropagator<DerivativeStructure> FNP = new FieldNumericalPropagator<>(field, integrator);
FNP.setOrbitType(type);
FNP.setInitialState(initialState);
NumericalPropagator NP = new NumericalPropagator(RIntegrator);
NP.setOrbitType(type);
NP.setInitialState(iSR);
final ConstantThrustManeuver forceModel = new ConstantThrustManeuver(J2000.toAbsoluteDate().shiftedBy(100), 100.0, 400.0, 300.0, Vector3D.PLUS_K);
FNP.addForceModel(forceModel);
NP.addForceModel(forceModel);
FieldAbsoluteDate<DerivativeStructure> target = J2000.shiftedBy(10000.);
FieldSpacecraftState<DerivativeStructure> finalState_DS = FNP.propagate(target);
SpacecraftState finalState_R = NP.propagate(target.toAbsoluteDate());
FieldPVCoordinates<DerivativeStructure> finPVC_DS = finalState_DS.getPVCoordinates();
PVCoordinates finPVC_R = finalState_R.getPVCoordinates();
Assert.assertEquals(finPVC_DS.toPVCoordinates().getPosition().getX(), finPVC_R.getPosition().getX(), FastMath.abs(finPVC_R.getPosition().getX()) * 1e-11);
Assert.assertEquals(finPVC_DS.toPVCoordinates().getPosition().getY(), finPVC_R.getPosition().getY(), FastMath.abs(finPVC_R.getPosition().getY()) * 1e-11);
Assert.assertEquals(finPVC_DS.toPVCoordinates().getPosition().getZ(), finPVC_R.getPosition().getZ(), FastMath.abs(finPVC_R.getPosition().getZ()) * 1e-11);
long number = 23091991;
RandomGenerator RG = new Well19937a(number);
GaussianRandomGenerator NGG = new GaussianRandomGenerator(RG);
UncorrelatedRandomVectorGenerator URVG = new UncorrelatedRandomVectorGenerator(new double[] {0.0 , 0.0 , 0.0 , 0.0 , 0.0 , 0.0 },
new double[] {1e3, 0.01, 0.01, 0.01, 0.01, 0.01},
NGG);
double a_R = a_0.getReal();
double e_R = e_0.getReal();
double i_R = i_0.getReal();
double R_R = R_0.getReal();
double O_R = O_0.getReal();
double n_R = n_0.getReal();
for (int ii = 0; ii < 1; ii++){
double[] rand_next = URVG.nextVector();
double a_shift = a_R + rand_next[0];
double e_shift = e_R + rand_next[1];
double i_shift = i_R + rand_next[2];
double R_shift = R_R + rand_next[3];
double O_shift = O_R + rand_next[4];
double n_shift = n_R + rand_next[5];
KeplerianOrbit shiftedOrb = new KeplerianOrbit(a_shift, e_shift, i_shift, R_shift, O_shift, n_shift,
PositionAngle.MEAN,
EME,
J2000.toAbsoluteDate(),
Constants.EIGEN5C_EARTH_MU
);
SpacecraftState shift_iSR = new SpacecraftState(shiftedOrb);
NumericalPropagator shift_NP = new NumericalPropagator(RIntegrator);
shift_NP.setInitialState(shift_iSR);
shift_NP.addForceModel(forceModel);
SpacecraftState finalState_shift = shift_NP.propagate(target.toAbsoluteDate());
PVCoordinates finPVC_shift = finalState_shift.getPVCoordinates();
//position check
FieldVector3D<DerivativeStructure> pos_DS = finPVC_DS.getPosition();
double x_DS = pos_DS.getX().taylor(rand_next[0],rand_next[1],rand_next[2],rand_next[3],rand_next[4],rand_next[5]);
double y_DS = pos_DS.getY().taylor(rand_next[0],rand_next[1],rand_next[2],rand_next[3],rand_next[4],rand_next[5]);
double z_DS = pos_DS.getZ().taylor(rand_next[0],rand_next[1],rand_next[2],rand_next[3],rand_next[4],rand_next[5]);
//System.out.println(pos_DS.getX().getPartialDerivative(1));
double x = finPVC_shift.getPosition().getX();
double y = finPVC_shift.getPosition().getY();
double z = finPVC_shift.getPosition().getZ();
Assert.assertEquals(x_DS, x, FastMath.abs(x - pos_DS.getX().getReal()) * 1e-8);
Assert.assertEquals(y_DS, y, FastMath.abs(y - pos_DS.getY().getReal()) * 1e-8);
Assert.assertEquals(z_DS, z, FastMath.abs(z - pos_DS.getZ().getReal()) * 1e-8);
//velocity check
FieldVector3D<DerivativeStructure> vel_DS = finPVC_DS.getVelocity();
double vx_DS = vel_DS.getX().taylor(rand_next[0],rand_next[1],rand_next[2],rand_next[3],rand_next[4],rand_next[5]);
double vy_DS = vel_DS.getY().taylor(rand_next[0],rand_next[1],rand_next[2],rand_next[3],rand_next[4],rand_next[5]);
double vz_DS = vel_DS.getZ().taylor(rand_next[0],rand_next[1],rand_next[2],rand_next[3],rand_next[4],rand_next[5]);
double vx = finPVC_shift.getVelocity().getX();
double vy = finPVC_shift.getVelocity().getY();
double vz = finPVC_shift.getVelocity().getZ();
Assert.assertEquals(vx_DS, vx, FastMath.abs(vx) * 1e-9);
Assert.assertEquals(vy_DS, vy, FastMath.abs(vy) * 1e-9);
Assert.assertEquals(vz_DS, vz, FastMath.abs(vz) * 1e-9);
//acceleration check
FieldVector3D<DerivativeStructure> acc_DS = finPVC_DS.getAcceleration();
double ax_DS = acc_DS.getX().taylor(rand_next[0],rand_next[1],rand_next[2],rand_next[3],rand_next[4],rand_next[5]);
double ay_DS = acc_DS.getY().taylor(rand_next[0],rand_next[1],rand_next[2],rand_next[3],rand_next[4],rand_next[5]);
double az_DS = acc_DS.getZ().taylor(rand_next[0],rand_next[1],rand_next[2],rand_next[3],rand_next[4],rand_next[5]);
double ax = finPVC_shift.getAcceleration().getX();
double ay = finPVC_shift.getAcceleration().getY();
double az = finPVC_shift.getAcceleration().getZ();
Assert.assertEquals(ax_DS, ax, FastMath.abs(ax) * 1e-8);
Assert.assertEquals(ay_DS, ay, FastMath.abs(ay) * 1e-8);
Assert.assertEquals(az_DS, az, FastMath.abs(az) * 1e-8);
}
}
/**Same test as the previous one but not adding the ForceModel to the NumericalPropagator
it is a test to validate the previous test.
(to test if the ForceModel it's actually
doing something in the Propagator and the FieldPropagator)*/
@Test
public void RealFieldExpectErrorTest() throws OrekitException {
DSFactory factory = new DSFactory(6, 0);
DerivativeStructure a_0 = factory.variable(0, 7e7);
DerivativeStructure e_0 = factory.variable(1, 0.4);
DerivativeStructure i_0 = factory.variable(2, 85 * FastMath.PI / 180);
DerivativeStructure R_0 = factory.variable(3, 0.7);
DerivativeStructure O_0 = factory.variable(4, 0.5);
DerivativeStructure n_0 = factory.variable(5, 0.1);
Field<DerivativeStructure> field = a_0.getField();
DerivativeStructure zero = field.getZero();
FieldAbsoluteDate<DerivativeStructure> J2000 = new FieldAbsoluteDate<DerivativeStructure>(field);
Frame EME = FramesFactory.getEME2000();
FieldKeplerianOrbit<DerivativeStructure> FKO = new FieldKeplerianOrbit<DerivativeStructure>(a_0, e_0, i_0, R_0, O_0, n_0,
PositionAngle.MEAN,
EME,
J2000,
Constants.EIGEN5C_EARTH_MU);
FieldSpacecraftState<DerivativeStructure> initialState = new FieldSpacecraftState<DerivativeStructure>(FKO);
SpacecraftState iSR = initialState.toSpacecraftState();
final OrbitType type = OrbitType.KEPLERIAN;
double[][] tolerance = NumericalPropagator.tolerances(10.0, FKO.toOrbit(), type);
AdaptiveStepsizeFieldIntegrator<DerivativeStructure> integrator =
new DormandPrince853FieldIntegrator<DerivativeStructure>(field, 0.001, 200, tolerance[0], tolerance[1]);
integrator.setInitialStepSize(zero.add(60));
AdaptiveStepsizeIntegrator RIntegrator =
new DormandPrince853Integrator(0.001, 200, tolerance[0], tolerance[1]);
RIntegrator.setInitialStepSize(60);
FieldNumericalPropagator<DerivativeStructure> FNP = new FieldNumericalPropagator<>(field, integrator);
FNP.setOrbitType(type);
FNP.setInitialState(initialState);
NumericalPropagator NP = new NumericalPropagator(RIntegrator);
NP.setInitialState(iSR);
final ConstantThrustManeuver forceModel = new ConstantThrustManeuver(J2000.toAbsoluteDate().shiftedBy(100), 100.0, 400.0, 300.0, Vector3D.PLUS_K);
FNP.addForceModel(forceModel);
//NOT ADDING THE FORCE MODEL TO THE NUMERICAL PROPAGATOR NP.addForceModel(forceModel);
FieldAbsoluteDate<DerivativeStructure> target = J2000.shiftedBy(10000.);
FieldSpacecraftState<DerivativeStructure> finalState_DS = FNP.propagate(target);
SpacecraftState finalState_R = NP.propagate(target.toAbsoluteDate());
FieldPVCoordinates<DerivativeStructure> finPVC_DS = finalState_DS.getPVCoordinates();
PVCoordinates finPVC_R = finalState_R.getPVCoordinates();
Assert.assertFalse(FastMath.abs(finPVC_DS.toPVCoordinates().getPosition().getX() - finPVC_R.getPosition().getX()) < FastMath.abs(finPVC_R.getPosition().getX()) * 1e-11);
Assert.assertFalse(FastMath.abs(finPVC_DS.toPVCoordinates().getPosition().getY() - finPVC_R.getPosition().getY()) < FastMath.abs(finPVC_R.getPosition().getY()) * 1e-11);
Assert.assertFalse(FastMath.abs(finPVC_DS.toPVCoordinates().getPosition().getZ() - finPVC_R.getPosition().getZ()) < FastMath.abs(finPVC_R.getPosition().getZ()) * 1e-11);
}
@Test
public void testForwardAndBackward() throws OrekitException {
final double isp = 318;
final double mass = 2500;
final double a = 24396159;
final double e = 0.72831215;
final double i = FastMath.toRadians(7);
final double omega = FastMath.toRadians(180);
final double OMEGA = FastMath.toRadians(261);
final double lv = 0;
final double duration = 3653.99;
final double f = 420;
final double delta = FastMath.toRadians(-7.4978);
final double alpha = FastMath.toRadians(351);
final AttitudeProvider law = new InertialProvider(new Rotation(new Vector3D(alpha, delta), Vector3D.PLUS_I));
final AbsoluteDate initDate = new AbsoluteDate(new DateComponents(2004, 01, 01),
new TimeComponents(23, 30, 00.000),
TimeScalesFactory.getUTC());
final Orbit orbit =
new KeplerianOrbit(a, e, i, omega, OMEGA, lv, PositionAngle.TRUE,
FramesFactory.getEME2000(), initDate, mu);
final SpacecraftState initialState =
new SpacecraftState(orbit, law.getAttitude(orbit, orbit.getDate(), orbit.getFrame()), mass);
final AbsoluteDate fireDate = new AbsoluteDate(new DateComponents(2004, 01, 02),
new TimeComponents(04, 15, 34.080),
TimeScalesFactory.getUTC());
final ConstantThrustManeuver maneuver =
new ConstantThrustManeuver(fireDate, duration, f, isp, Vector3D.PLUS_I);
Assert.assertEquals(f, maneuver.getThrust(), 1.0e-10);
Assert.assertEquals(isp, maneuver.getISP(), 1.0e-10);
double[][] tol = NumericalPropagator.tolerances(1.0, orbit, OrbitType.KEPLERIAN);
AdaptiveStepsizeIntegrator integrator1 =
new DormandPrince853Integrator(0.001, 1000, tol[0], tol[1]);
integrator1.setInitialStepSize(60);
final NumericalPropagator propagator1 = new NumericalPropagator(integrator1);
propagator1.setInitialState(initialState);
propagator1.setAttitudeProvider(law);
propagator1.addForceModel(maneuver);
final SpacecraftState finalState = propagator1.propagate(fireDate.shiftedBy(3800));
AdaptiveStepsizeIntegrator integrator2 =
new DormandPrince853Integrator(0.001, 1000, tol[0], tol[1]);
integrator2.setInitialStepSize(60);
final NumericalPropagator propagator2 = new NumericalPropagator(integrator2);
propagator2.setInitialState(finalState);
propagator2.setAttitudeProvider(law);
propagator2.addForceModel(maneuver);
final SpacecraftState recoveredState = propagator2.propagate(orbit.getDate());
final Vector3D refPosition = initialState.getPVCoordinates().getPosition();
final Vector3D recoveredPosition = recoveredState.getPVCoordinates().getPosition();
Assert.assertEquals(0.0, Vector3D.distance(refPosition, recoveredPosition), 30.0);
Assert.assertEquals(initialState.getMass(), recoveredState.getMass(), 1.5e-10);
}
@Before
public void setUp() {
Utils.setDataRoot("regular-data");
// Body mu
mu = 3.9860047e14;
}
}