Examples with UpdatableFrame org.orekit.frames.UpdatableFrame used on opensource projects

Example 1 with UpdatableFrame

use of org.orekit.frames.UpdatableFrame in project Orekit by CS-SI.

the class Frames2 method main.

public static void main(String[] args) {
    try {
        // configure Orekit
        File home = new File(System.getProperty("user.home"));
        File orekitData = new File(home, "orekit-data");
        if (!orekitData.exists()) {
            System.err.format(Locale.US, "Failed to find %s folder%n", orekitData.getAbsolutePath());
            System.err.format(Locale.US, "You need to download %s from the %s page and unzip it in %s for this tutorial to work%n", "orekit-data.zip", "https://www.orekit.org/forge/projects/orekit/files", home.getAbsolutePath());
            System.exit(1);
        }
        DataProvidersManager manager = DataProvidersManager.getInstance();
        manager.addProvider(new DirectoryCrawler(orekitData));
        // Considering the following Computing/Measurement date in UTC time scale
        TimeScale utc = TimeScalesFactory.getUTC();
        AbsoluteDate date = new AbsoluteDate(2008, 10, 01, 12, 00, 00.000, utc);
        // The Center of Gravity frame has its origin at the satellite center of gravity (CoG)
        // and its axes parallel to EME2000. It is derived from EME2000 frame at any moment
        // by an unknown transform which depends on the current position and the velocity.
        // Let's initialize this transform by the identity transform.
        UpdatableFrame cogFrame = new UpdatableFrame(FramesFactory.getEME2000(), Transform.IDENTITY, "LOF", false);
        // The satellite frame, with origin also at the CoG, depends on attitude.
        // For the sake of this tutorial, we consider a simple inertial attitude here
        Transform cogToSat = new Transform(date, new Rotation(0.6, 0.48, 0, 0.64, false));
        Frame satFrame = new Frame(cogFrame, cogToSat, "sat", false);
        // Finally, the GPS antenna frame can be defined from the satellite frame by 2 transforms:
        // a translation and a rotation
        Transform translateGPS = new Transform(date, new Vector3D(0, 0, 1));
        Transform rotateGPS = new Transform(date, new Rotation(new Vector3D(0, 1, 3), FastMath.toRadians(10), RotationConvention.VECTOR_OPERATOR));
        Frame gpsFrame = new Frame(satFrame, new Transform(date, translateGPS, rotateGPS), "GPS", false);
        // Let's get the satellite position and velocity in ITRF as measured by GPS antenna at this moment:
        final Vector3D position = new Vector3D(-6142438.668, 3492467.560, -25767.25680);
        final Vector3D velocity = new Vector3D(505.8479685, 942.7809215, 7435.922231);
        System.out.format(Locale.US, "GPS antenna position in ITRF:    %12.3f %12.3f %12.3f%n", position.getX(), position.getY(), position.getZ());
        System.out.format(Locale.US, "GPS antenna velocity in ITRF:    %12.7f %12.7f %12.7f%n", velocity.getX(), velocity.getY(), velocity.getZ());
        // The transform from GPS frame to ITRF frame at this moment is defined by
        // a translation and a rotation. The translation is directly provided by the
        // GPS measurement above. The rotation is extracted from the existing tree, where
        // we know all rotations are already up to date, even if one translation is still
        // unknown. We combine the extracted rotation and the measured translation by
        // applying the rotation first because the position/velocity vector are given in
        // ITRF frame not in GPS antenna frame:
        Transform measuredTranslation = new Transform(date, position, velocity);
        Transform formerTransform = gpsFrame.getTransformTo(FramesFactory.getITRF(IERSConventions.IERS_2010, true), date);
        Transform preservedRotation = new Transform(date, formerTransform.getRotation(), formerTransform.getRotationRate());
        Transform gpsToItrf = new Transform(date, preservedRotation, measuredTranslation);
        // So we can update the transform from EME2000 to CoG frame
        cogFrame.updateTransform(gpsFrame, FramesFactory.getITRF(IERSConventions.IERS_2010, true), gpsToItrf, date);
        // And we can get the position and velocity of satellite CoG in EME2000 frame
        PVCoordinates origin = PVCoordinates.ZERO;
        Transform cogToItrf = cogFrame.getTransformTo(FramesFactory.getITRF(IERSConventions.IERS_2010, true), date);
        PVCoordinates satItrf = cogToItrf.transformPVCoordinates(origin);
        System.out.format(Locale.US, "Satellite   position in ITRF:    %12.3f %12.3f %12.3f%n", satItrf.getPosition().getX(), satItrf.getPosition().getY(), satItrf.getPosition().getZ());
        System.out.format(Locale.US, "Satellite   velocity in ITRF:    %12.7f %12.7f %12.7f%n", satItrf.getVelocity().getX(), satItrf.getVelocity().getY(), satItrf.getVelocity().getZ());
        Transform cogToEme2000 = cogFrame.getTransformTo(FramesFactory.getEME2000(), date);
        PVCoordinates satEME2000 = cogToEme2000.transformPVCoordinates(origin);
        System.out.format(Locale.US, "Satellite   position in EME2000: %12.3f %12.3f %12.3f%n", satEME2000.getPosition().getX(), satEME2000.getPosition().getY(), satEME2000.getPosition().getZ());
        System.out.format(Locale.US, "Satellite   velocity in EME2000: %12.7f %12.7f %12.7f%n", satEME2000.getVelocity().getX(), satEME2000.getVelocity().getY(), satEME2000.getVelocity().getZ());
    } catch (OrekitException oe) {
        System.err.println(oe.getMessage());
    }
}