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2020-08-17T09:06:59Z

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<syntaxhighlight lang="java">
public class NumericalPropagationWithAttitudeSequence {

public static void main(String[] args) throws PatriusException, IOException, URISyntaxException {

// Patrius Dataset initialization (needed for example to get the UTC time
PatriusDataset.addResourcesFromPatriusDataset() ;

// Recovery of the UTC time scale using a "factory" (not to duplicate such unique object)
final TimeScale TUC = TimeScalesFactory.getUTC();

// Date of the orbit given in UTC time scale)
final AbsoluteDate date = new AbsoluteDate("2010-01-01T12:00:00.000", TUC);

// Getting the frame with wich will defined the orbit parameters
// As for time scale, we will use also a "factory".
final Frame GCRF = FramesFactory.getGCRF();

// Initial orbit
final double sma = 7200.e+3;
final double exc = 0.01;
final double per = sma*(1.-exc);
final double apo = sma*(1.+exc);
final double inc = FastMath.toRadians(98.);
final double pa = FastMath.toRadians(0.);
final double raan = FastMath.toRadians(0.);
final double anm = FastMath.toRadians(0.);
final double MU = Constants.WGS84_EARTH_MU;

final ApsisRadiusParameters par = new ApsisRadiusParameters(per, apo, inc, pa, raan, anm, PositionAngle.MEAN, MU);
final Orbit iniOrbit = new ApsisOrbit(par, GCRF, date);

// We create a spacecratftstate
final SpacecraftState iniState = new SpacecraftState(iniOrbit);

// Initialization of the Runge Kutta integrator with a 2 s step
final double pasRk = 2.;
final FirstOrderIntegrator integrator = new ClassicalRungeKuttaIntegrator(pasRk);

// Initialization of the propagator
final NumericalPropagator propagator = new NumericalPropagator(integrator);
propagator.resetInitialState(iniState);

// Forcing integration using cartesian equations
propagator.setOrbitType(OrbitType.CARTESIAN);

//SPECIFIC
// Adding attitude sequence
final AttitudesSequence seqAtt = new AttitudesSequence();

// Laws to be taken into account in the sequence
final AttitudeLaw law1 = new ConstantAttitudeLaw(GCRF, new Rotation(RotationOrder.ZYX, 0., 0., 0.));
final AttitudeLaw law2 = new ConstantAttitudeLaw(GCRF, new Rotation(RotationOrder.ZYX, FastMath.toRadians(45.), FastMath.toRadians(45.), FastMath.toRadians(45.)));

// Events that will switch from a law to another
final double maxCheck = 10.;
final double threshold = 1.e-3;
final EventDetector event1 = new AOLDetector(0., PositionAngle.MEAN, GCRF, maxCheck, threshold, Action.RESET_STATE);
final EventDetector event2 = new AOLDetector(FastMath.toRadians(180.), PositionAngle.MEAN, GCRF, maxCheck, threshold, Action.RESET_STATE);

//Adding switches
seqAtt.addSwitchingCondition(law1, event1, true, false, law2);
seqAtt.addSwitchingCondition(law2, event2, true, false, law1);

propagator.setAttitudeProvider(seqAtt);
seqAtt.registerSwitchEvents(propagator);
//SPECIFIC

// Propagating 100s
final double dt = 0.25*iniOrbit.getKeplerianPeriod();
System.out.println(dt);
final AbsoluteDate finalDate = date.shiftedBy(dt);
final SpacecraftState finalState = propagator.propagate(finalDate);
final Orbit finalOrbit = finalState.getOrbit();

// Printing new date and true latitude argument
System.out.println();
System.out.println("Initial true latitude argument = "+FastMath.toDegrees(iniOrbit.getLv())+" deg");
System.out.println("New date = "+finalOrbit.getDate().toString(TUC)+" deg");
System.out.println("True latitude argument = "+FastMath.toDegrees(finalOrbit.getLv())+" deg");
// Printing attitude
final double psi = finalState.getAttitude().getRotation().getAngles(RotationOrder.ZYX)[0];
final double teta = finalState.getAttitude().getRotation().getAngles(RotationOrder.ZYX)[1];
final double phi = finalState.getAttitude().getRotation().getAngles(RotationOrder.ZYX)[2];
System.out.println("Psi / GCRF = "+FastMath.toDegrees(psi)+" deg");
System.out.println("Teta / GCRF = "+FastMath.toDegrees(teta)+" deg");
System.out.println("Phi / GCRF = "+FastMath.toDegrees(phi)+" deg");

}

}
</syntaxhighlight>

NumericalPropagationWithAttitudeSequence 4.5.1 - Historique des versions

Admin : Page créée avec « public class NumericalPropagationWithAttitudeSequence { public static void main(String[] args) throws PatriusException, IOException, URI... »

Admin : Page créée avec « public class NumericalPropagationWithAttitudeSequence { public static void main(String[] args) throws PatriusException, IOException, URI... »