LOFOffsetAttitudeLaw

LOFOffsetAttitudeLaw

public class LOFOffsetAttitudeLaw {
 
    public static void main(String[] args) throws PatriusException {
 
        // 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 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 KeplerianParameters par = new KeplerianParameters(sma, exc, inc, pa, raan, anm, PositionAngle.MEAN, MU);
        final Orbit iniOrbit = new KeplerianOrbit(par, GCRF, date);
 
        // Building a first attitude law
        final AttitudeLaw attitudeLaw0= new LofOffset(LOFType.TNW);
        final Attitude att0 = attitudeLaw0.getAttitude(iniOrbit);
 
        // Building a second attitude law with a 45 deg rotation on Z axis
        final double psi  = FastMath.toRadians(45.);
        final double teta = 0.;
        final double phi  = 0.;
        final AttitudeLaw attitudeLaw = new LofOffset(LOFType.TNW, RotationOrder.ZYX, psi, teta, phi);
        final Attitude att = attitudeLaw.getAttitude(iniOrbit);
 
        // Rotation of the X axis
        Vector3D vec0 = att0.getRotation().applyTo(Vector3D.PLUS_I);
        Vector3D vec  = att.getRotation().applyTo(Vector3D.PLUS_I);
        double cos = vec.dotProduct(vec0);
        double ang = FastMath.acos(cos);
        System.out.println(FastMath.toDegrees(ang));
 
        // Rotation of the Y axis
        vec0 = att0.getRotation().applyTo(Vector3D.PLUS_J);
        vec  = att.getRotation().applyTo(Vector3D.PLUS_J);
        cos = vec.dotProduct(vec0);
        ang = FastMath.acos(cos);
        System.out.println(FastMath.toDegrees(ang));
 
        // Z axis comparison
        vec0 = att0.getRotation().applyTo(Vector3D.PLUS_K);
        vec  = att.getRotation().applyTo(Vector3D.PLUS_K);
        final Vector3D dVec = vec.subtract(vec0);
        final double norm = dVec.getNorm();
        System.out.println(norm);
 
    }
 
}