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2019-10-03T13:01:29Z

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

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);

//SPECIFIC
// Creating a mass model (see also specific example)
final AssemblyBuilder builder = new AssemblyBuilder();

// Main part
final double iniMass = 900.;
builder.addMainPart("MAIN");
builder.addProperty(new MassProperty(iniMass), "MAIN");

// Tank part (ergols mass)
final double ergolsMass = 100.;
final TankProperty tank = new TankProperty(ergolsMass);
builder.addPart("TANK", "MAIN", Transform.IDENTITY);
builder.addProperty(tank, "TANK");

// Engine part
final double isp = 300.;
final double thrust = 400.;
final PropulsiveProperty prop = new PropulsiveProperty(thrust, isp); // au lieu de new PropulsiveProperty("PROP", thrust, isp);
builder.addPart("PROP", "MAIN", Transform.IDENTITY);
builder.addProperty(prop, "PROP");

final Assembly assembly = builder.returnAssembly();
final MassProvider mm = new MassModel(assembly);

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

// 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
// Duration of the maneuver to get a 20 m/S boost
final double G0 = 9.80665;
final double duration = G0*isp*iniMass*(1. - FastMath.exp(-20/(G0*isp)))/thrust;
// Start and end thrust events
final EventDetector eventStart = new DateDetector(date.shiftedBy(10.));
final EventDetector eventEnd = new DateDetector(date.shiftedBy(10.+duration));
// Creation of the continuous thrust maneuver
final Vector3D direction = new Vector3D(1., 0., 0.);
final ContinuousThrustManeuver man = new ContinuousThrustManeuver(eventStart, eventEnd, prop, direction, mm, tank);
// Adding a continuous thrust maneuver
propagator.addForceModel(man);
// Adding additional state (change name add to set for V3.3)
propagator.setMassProviderEquation(mm);

// Adding an attitude law (or attitude sequence : mandatory)
final AttitudeLaw attitudeLaw = new LofOffset(LOFType.TNW, RotationOrder.ZYX, 0., 0., 0.);
propagator.setAttitudeProvider(attitudeLaw);

//SPECIFIC

// Propagating 100s
final double dt = 100.;
final AbsoluteDate finalDate = date.shiftedBy(dt);
final SpacecraftState finalState = propagator.propagate(finalDate);
final Orbit finalOrbit = finalState.getOrbit();

// Printing new date and semi major axis
System.out.println();
System.out.println("Initial semi major axis = "+iniOrbit.getA()/1000.+" km");
System.out.println("New date = "+finalOrbit.getDate().toString(TUC)+" deg");
System.out.println("Final semi major axis = "+finalOrbit.getA()/1000.+" km");
// Printing mass
System.out.println();
System.out.println("Dry Mass = "+finalState.getMass("MAIN")+" kg");
System.out.println("Ergols Mass = "+finalState.getMass("TANK")+" kg");

}

}
</syntaxhighlight>

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

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