Examples with BoundedPropagator org.orekit.propagation.BoundedPropagator used on opensource projects

Example 1 with BoundedPropagator

use of org.orekit.propagation.BoundedPropagator in project Orekit by CS-SI.

the class OnBoardAntennaInterSatellitesRangeModifierTest method testPreliminary.

@Test
public void testPreliminary() throws OrekitException {
    // this test does not check OnBoardAntennaInterSatellitesRangeModifier at all,
    // it just checks InterSatellitesRangeMeasurementCreator behaves as necessary for the other test
    // the *real* test is testEffect below
    Context context = EstimationTestUtils.eccentricContext("regular-data:potential:tides");
    final NumericalPropagatorBuilder propagatorBuilder = context.createBuilder(OrbitType.KEPLERIAN, PositionAngle.TRUE, true, 1.0e-6, 60.0, 0.001);
    propagatorBuilder.setAttitudeProvider(new LofOffset(propagatorBuilder.getFrame(), LOFType.LVLH));
    // create perfect inter-satellites range measurements without antenna offset
    final TimeStampedPVCoordinates original = context.initialOrbit.getPVCoordinates();
    final Orbit closeOrbit = new CartesianOrbit(new TimeStampedPVCoordinates(context.initialOrbit.getDate(), original.getPosition().add(new Vector3D(1000, 2000, 3000)), original.getVelocity().add(new Vector3D(-0.03, 0.01, 0.02))), context.initialOrbit.getFrame(), context.initialOrbit.getMu());
    final Propagator closePropagator = EstimationTestUtils.createPropagator(closeOrbit, propagatorBuilder);
    closePropagator.setEphemerisMode();
    closePropagator.propagate(context.initialOrbit.getDate().shiftedBy(3.5 * closeOrbit.getKeplerianPeriod()));
    final BoundedPropagator ephemeris = closePropagator.getGeneratedEphemeris();
    final Propagator p1 = EstimationTestUtils.createPropagator(context.initialOrbit, propagatorBuilder);
    final List<ObservedMeasurement<?>> spacecraftCenteredMeasurements = EstimationTestUtils.createMeasurements(p1, new InterSatellitesRangeMeasurementCreator(ephemeris, Vector3D.ZERO, Vector3D.ZERO), 1.0, 3.0, 300.0);
    // create perfect inter-satellites range measurements with antenna offset
    final double xOffset1 = -2.5;
    final double yOffset2 = 0.8;
    final Propagator p2 = EstimationTestUtils.createPropagator(context.initialOrbit, propagatorBuilder);
    final List<ObservedMeasurement<?>> antennaCenteredMeasurements = EstimationTestUtils.createMeasurements(p2, new InterSatellitesRangeMeasurementCreator(ephemeris, new Vector3D(xOffset1, 0, 0), new Vector3D(0, yOffset2, 0)), 1.0, 3.0, 300.0);
    for (int i = 0; i < spacecraftCenteredMeasurements.size(); ++i) {
        InterSatellitesRange sr = (InterSatellitesRange) spacecraftCenteredMeasurements.get(i);
        InterSatellitesRange ar = (InterSatellitesRange) antennaCenteredMeasurements.get(i);
        Assert.assertEquals(0.0, sr.getDate().durationFrom(ar.getDate()), 2.0e-8);
        Assert.assertTrue(ar.getObservedValue()[0] - sr.getObservedValue()[0] >= -1.0);
        Assert.assertTrue(ar.getObservedValue()[0] - sr.getObservedValue()[0] <= -0.36);
    }
}

Example 2 with BoundedPropagator

use of org.orekit.propagation.BoundedPropagator in project Orekit by CS-SI.

the class HolmesFeatherstoneAttractionModelTest method testTimeDependentField.

@Test
public void testTimeDependentField() throws OrekitException {
    Utils.setDataRoot("regular-data:potential/icgem-format");
    GravityFieldFactory.addPotentialCoefficientsReader(new ICGEMFormatReader("eigen-6s-truncated", true));
    final Vector3D pos = new Vector3D(6.46885878304673824e+06, -1.88050918456274318e+06, -1.32931592294715829e+04);
    final Vector3D vel = new Vector3D(2.14718074509906819e+03, 7.38239351251748485e+03, -1.14097953925384523e+01);
    final SpacecraftState spacecraftState = new SpacecraftState(new CartesianOrbit(new PVCoordinates(pos, vel), FramesFactory.getGCRF(), new AbsoluteDate(2005, 3, 5, 0, 24, 0.0, TimeScalesFactory.getTAI()), GravityFieldFactory.getUnnormalizedProvider(1, 1).getMu()));
    double dP = 0.1;
    double duration = 3 * Constants.JULIAN_DAY;
    BoundedPropagator fixedFieldEphemeris = createEphemeris(dP, spacecraftState, duration, GravityFieldFactory.getConstantNormalizedProvider(8, 8));
    BoundedPropagator varyingFieldEphemeris = createEphemeris(dP, spacecraftState, duration, GravityFieldFactory.getNormalizedProvider(8, 8));
    double step = 60.0;
    double maxDeltaT = 0;
    double maxDeltaN = 0;
    double maxDeltaW = 0;
    for (AbsoluteDate date = fixedFieldEphemeris.getMinDate(); date.compareTo(fixedFieldEphemeris.getMaxDate()) < 0; date = date.shiftedBy(step)) {
        PVCoordinates pvFixedField = fixedFieldEphemeris.getPVCoordinates(date, FramesFactory.getGCRF());
        PVCoordinates pvVaryingField = varyingFieldEphemeris.getPVCoordinates(date, FramesFactory.getGCRF());
        Vector3D t = pvFixedField.getVelocity().normalize();
        Vector3D w = pvFixedField.getMomentum().normalize();
        Vector3D n = Vector3D.crossProduct(w, t);
        Vector3D delta = pvVaryingField.getPosition().subtract(pvFixedField.getPosition());
        maxDeltaT = FastMath.max(maxDeltaT, FastMath.abs(Vector3D.dotProduct(delta, t)));
        maxDeltaN = FastMath.max(maxDeltaN, FastMath.abs(Vector3D.dotProduct(delta, n)));
        maxDeltaW = FastMath.max(maxDeltaW, FastMath.abs(Vector3D.dotProduct(delta, w)));
    }
    Assert.assertTrue(maxDeltaT > 0.15);
    Assert.assertTrue(maxDeltaT < 0.25);
    Assert.assertTrue(maxDeltaN > 0.01);
    Assert.assertTrue(maxDeltaN < 0.02);
    Assert.assertTrue(maxDeltaW > 0.05);
    Assert.assertTrue(maxDeltaW < 0.10);
}

Example 3 with BoundedPropagator

use of org.orekit.propagation.BoundedPropagator in project Orekit by CS-SI.

the class InterSatellitesRangeTest method genericTestStateDerivatives.

void genericTestStateDerivatives(final boolean printResults, final int index, final double refErrorsPMedian, final double refErrorsPMean, final double refErrorsPMax, final double refErrorsVMedian, final double refErrorsVMean, final double refErrorsVMax) throws OrekitException {
    Context context = EstimationTestUtils.eccentricContext("regular-data:potential:tides");
    final NumericalPropagatorBuilder propagatorBuilder = context.createBuilder(OrbitType.KEPLERIAN, PositionAngle.TRUE, true, 1.0e-6, 60.0, 0.001);
    // Create perfect inter-satellites range measurements
    final TimeStampedPVCoordinates original = context.initialOrbit.getPVCoordinates();
    final Orbit closeOrbit = new CartesianOrbit(new TimeStampedPVCoordinates(context.initialOrbit.getDate(), original.getPosition().add(new Vector3D(1000, 2000, 3000)), original.getVelocity().add(new Vector3D(-0.03, 0.01, 0.02))), context.initialOrbit.getFrame(), context.initialOrbit.getMu());
    final Propagator closePropagator = EstimationTestUtils.createPropagator(closeOrbit, propagatorBuilder);
    closePropagator.setEphemerisMode();
    closePropagator.propagate(context.initialOrbit.getDate().shiftedBy(3.5 * closeOrbit.getKeplerianPeriod()));
    final BoundedPropagator ephemeris = closePropagator.getGeneratedEphemeris();
    final Propagator propagator = EstimationTestUtils.createPropagator(context.initialOrbit, propagatorBuilder);
    final List<ObservedMeasurement<?>> measurements = EstimationTestUtils.createMeasurements(propagator, new InterSatellitesRangeMeasurementCreator(ephemeris), 1.0, 3.0, 300.0);
    // Lists for results' storage - Used only for derivatives with respect to state
    // "final" value to be seen by "handleStep" function of the propagator
    final List<Double> errorsP = new ArrayList<Double>();
    final List<Double> errorsV = new ArrayList<Double>();
    // Set master mode
    // Use a lambda function to implement "handleStep" function
    propagator.setMasterMode((OrekitStepInterpolator interpolator, boolean isLast) -> {
        for (final ObservedMeasurement<?> measurement : measurements) {
            // Play test if the measurement date is between interpolator previous and current date
            if ((measurement.getDate().durationFrom(interpolator.getPreviousState().getDate()) > 0.) && (measurement.getDate().durationFrom(interpolator.getCurrentState().getDate()) <= 0.)) {
                // We intentionally propagate to a date which is close to the
                // real spacecraft state but is *not* the accurate date, by
                // compensating only part of the downlink delay. This is done
                // in order to validate the partial derivatives with respect
                // to velocity.
                final double meanDelay = measurement.getObservedValue()[0] / Constants.SPEED_OF_LIGHT;
                final AbsoluteDate date = measurement.getDate().shiftedBy(-0.75 * meanDelay);
                final SpacecraftState[] states = { interpolator.getInterpolatedState(date), ephemeris.propagate(date) };
                final double[][] jacobian = measurement.estimate(0, 0, states).getStateDerivatives(index);
                // Jacobian reference value
                final double[][] jacobianRef;
                // Compute a reference value using finite differences
                jacobianRef = Differentiation.differentiate(new StateFunction() {

                    public double[] value(final SpacecraftState state) throws OrekitException {
                        final SpacecraftState[] s = states.clone();
                        s[index] = state;
                        return measurement.estimate(0, 0, s).getEstimatedValue();
                    }
                }, measurement.getDimension(), propagator.getAttitudeProvider(), OrbitType.CARTESIAN, PositionAngle.TRUE, 2.0, 3).value(states[index]);
                Assert.assertEquals(jacobianRef.length, jacobian.length);
                Assert.assertEquals(jacobianRef[0].length, jacobian[0].length);
                // Errors & relative errors on the Jacobian
                double[][] dJacobian = new double[jacobian.length][jacobian[0].length];
                double[][] dJacobianRelative = new double[jacobian.length][jacobian[0].length];
                for (int i = 0; i < jacobian.length; ++i) {
                    for (int j = 0; j < jacobian[i].length; ++j) {
                        dJacobian[i][j] = jacobian[i][j] - jacobianRef[i][j];
                        dJacobianRelative[i][j] = FastMath.abs(dJacobian[i][j] / jacobianRef[i][j]);
                        if (j < 3) {
                            errorsP.add(dJacobianRelative[i][j]);
                        } else {
                            errorsV.add(dJacobianRelative[i][j]);
                        }
                    }
                }
                // Print values in console ?
                if (printResults) {
                    System.out.format(Locale.US, "%-23s  %-23s  " + "%10.3e  %10.3e  %10.3e  " + "%10.3e  %10.3e  %10.3e  " + "%10.3e  %10.3e  %10.3e  " + "%10.3e  %10.3e  %10.3e%n", measurement.getDate(), date, dJacobian[0][0], dJacobian[0][1], dJacobian[0][2], dJacobian[0][3], dJacobian[0][4], dJacobian[0][5], dJacobianRelative[0][0], dJacobianRelative[0][1], dJacobianRelative[0][2], dJacobianRelative[0][3], dJacobianRelative[0][4], dJacobianRelative[0][5]);
                }
            }
        // End if measurement date between previous and current interpolator step
        }
    // End for loop on the measurements
    });
    // Print results on console ?
    if (printResults) {
        System.out.format(Locale.US, "%-23s  %-23s  " + "%10s  %10s  %10s  " + "%10s  %10s  %10s  " + "%10s  %10s  %10s  " + "%10s  %10s  %10s%n", "Measurement Date", "State Date", "ΔdPx", "ΔdPy", "ΔdPz", "ΔdVx", "ΔdVy", "ΔdVz", "rel ΔdPx", "rel ΔdPy", "rel ΔdPz", "rel ΔdVx", "rel ΔdVy", "rel ΔdVz");
    }
    // Rewind the propagator to initial date
    propagator.propagate(context.initialOrbit.getDate());
    // Sort measurements chronologically
    measurements.sort(new ChronologicalComparator());
    // Propagate to final measurement's date
    propagator.propagate(measurements.get(measurements.size() - 1).getDate());
    // Convert lists to double[] and evaluate some statistics
    final double[] relErrorsP = errorsP.stream().mapToDouble(Double::doubleValue).toArray();
    final double[] relErrorsV = errorsV.stream().mapToDouble(Double::doubleValue).toArray();
    final double errorsPMedian = new Median().evaluate(relErrorsP);
    final double errorsPMean = new Mean().evaluate(relErrorsP);
    final double errorsPMax = new Max().evaluate(relErrorsP);
    final double errorsVMedian = new Median().evaluate(relErrorsV);
    final double errorsVMean = new Mean().evaluate(relErrorsV);
    final double errorsVMax = new Max().evaluate(relErrorsV);
    // Print the results on console ?
    if (printResults) {
        System.out.println();
        System.out.format(Locale.US, "Relative errors dR/dP -> Median: %6.3e / Mean: %6.3e / Max: %6.3e%n", errorsPMedian, errorsPMean, errorsPMax);
        System.out.format(Locale.US, "Relative errors dR/dV -> Median: %6.3e / Mean: %6.3e / Max: %6.3e%n", errorsVMedian, errorsVMean, errorsVMax);
    }
    Assert.assertEquals(0.0, errorsPMedian, refErrorsPMedian);
    Assert.assertEquals(0.0, errorsPMean, refErrorsPMean);
    Assert.assertEquals(0.0, errorsPMax, refErrorsPMax);
    Assert.assertEquals(0.0, errorsVMedian, refErrorsVMedian);
    Assert.assertEquals(0.0, errorsVMean, refErrorsVMean);
    Assert.assertEquals(0.0, errorsVMax, refErrorsVMax);
}

Example 4 with BoundedPropagator

use of org.orekit.propagation.BoundedPropagator in project Orekit by CS-SI.

the class InterSatellitesRangeTest method genericTestValues.

/**
 * Generic test function for values of the inter-satellites range
 * @param printResults Print the results ?
 * @throws OrekitException
 */
void genericTestValues(final boolean printResults) throws OrekitException {
    Context context = EstimationTestUtils.eccentricContext("regular-data:potential:tides");
    final NumericalPropagatorBuilder propagatorBuilder = context.createBuilder(OrbitType.KEPLERIAN, PositionAngle.TRUE, true, 1.0e-6, 60.0, 0.001);
    // Create perfect inter-satellites range measurements
    final TimeStampedPVCoordinates original = context.initialOrbit.getPVCoordinates();
    final Orbit closeOrbit = new CartesianOrbit(new TimeStampedPVCoordinates(context.initialOrbit.getDate(), original.getPosition().add(new Vector3D(1000, 2000, 3000)), original.getVelocity().add(new Vector3D(-0.03, 0.01, 0.02))), context.initialOrbit.getFrame(), context.initialOrbit.getMu());
    final Propagator closePropagator = EstimationTestUtils.createPropagator(closeOrbit, propagatorBuilder);
    closePropagator.setEphemerisMode();
    closePropagator.propagate(context.initialOrbit.getDate().shiftedBy(3.5 * closeOrbit.getKeplerianPeriod()));
    final BoundedPropagator ephemeris = closePropagator.getGeneratedEphemeris();
    final Propagator propagator = EstimationTestUtils.createPropagator(context.initialOrbit, propagatorBuilder);
    final List<ObservedMeasurement<?>> measurements = EstimationTestUtils.createMeasurements(propagator, new InterSatellitesRangeMeasurementCreator(ephemeris), 1.0, 3.0, 300.0);
    // Lists for results' storage - Used only for derivatives with respect to state
    // "final" value to be seen by "handleStep" function of the propagator
    final List<Double> absoluteErrors = new ArrayList<Double>();
    final List<Double> relativeErrors = new ArrayList<Double>();
    // Set master mode
    // Use a lambda function to implement "handleStep" function
    propagator.setMasterMode((OrekitStepInterpolator interpolator, boolean isLast) -> {
        for (final ObservedMeasurement<?> measurement : measurements) {
            // Play test if the measurement date is between interpolator previous and current date
            if ((measurement.getDate().durationFrom(interpolator.getPreviousState().getDate()) > 0.) && (measurement.getDate().durationFrom(interpolator.getCurrentState().getDate()) <= 0.)) {
                // We intentionally propagate to a date which is close to the
                // real spacecraft state but is *not* the accurate date, by
                // compensating only part of the downlink delay. This is done
                // in order to validate the partial derivatives with respect
                // to velocity.
                final double meanDelay = measurement.getObservedValue()[0] / Constants.SPEED_OF_LIGHT;
                final AbsoluteDate date = measurement.getDate().shiftedBy(-0.75 * meanDelay);
                final SpacecraftState state = interpolator.getInterpolatedState(date);
                // Values of the Range & errors
                final double RangeObserved = measurement.getObservedValue()[0];
                final EstimatedMeasurement<?> estimated = measurement.estimate(0, 0, new SpacecraftState[] { state, ephemeris.propagate(state.getDate()) });
                // the real state used for estimation is adjusted according to downlink delay
                double adjustment = state.getDate().durationFrom(estimated.getStates()[0].getDate());
                Assert.assertTrue(adjustment > 0.000006);
                Assert.assertTrue(adjustment < 0.0003);
                final double RangeEstimated = estimated.getEstimatedValue()[0];
                final double absoluteError = RangeEstimated - RangeObserved;
                absoluteErrors.add(absoluteError);
                relativeErrors.add(FastMath.abs(absoluteError) / FastMath.abs(RangeObserved));
                // Print results on console ?
                if (printResults) {
                    final AbsoluteDate measurementDate = measurement.getDate();
                    System.out.format(Locale.US, "%-23s  %-23s  %19.6f  %19.6f  %13.6e  %13.6e%n", measurementDate, date, RangeObserved, RangeEstimated, FastMath.abs(RangeEstimated - RangeObserved), FastMath.abs((RangeEstimated - RangeObserved) / RangeObserved));
                }
            }
        // End if measurement date between previous and current interpolator step
        }
    // End for loop on the measurements
    });
    // Print results on console ? Header
    if (printResults) {
        System.out.format(Locale.US, "%-23s  %-23s  %19s  %19s  %13s  %13s%n", "Measurement Date", "State Date", "Range observed [m]", "Range estimated [m]", "ΔRange [m]", "rel ΔRange");
    }
    // Rewind the propagator to initial date
    propagator.propagate(context.initialOrbit.getDate());
    // Sort measurements chronologically
    measurements.sort(new ChronologicalComparator());
    // Propagate to final measurement's date
    propagator.propagate(measurements.get(measurements.size() - 1).getDate());
    // Convert lists to double array
    final double[] absErrors = absoluteErrors.stream().mapToDouble(Double::doubleValue).toArray();
    final double[] relErrors = relativeErrors.stream().mapToDouble(Double::doubleValue).toArray();
    // Statistics' assertion
    final double absErrorsMedian = new Median().evaluate(absErrors);
    final double absErrorsMin = new Min().evaluate(absErrors);
    final double absErrorsMax = new Max().evaluate(absErrors);
    final double relErrorsMedian = new Median().evaluate(relErrors);
    final double relErrorsMax = new Max().evaluate(relErrors);
    // Print the results on console ? Final results
    if (printResults) {
        System.out.println();
        System.out.println("Absolute errors median: " + absErrorsMedian);
        System.out.println("Absolute errors min   : " + absErrorsMin);
        System.out.println("Absolute errors max   : " + absErrorsMax);
        System.out.println("Relative errors median: " + relErrorsMedian);
        System.out.println("Relative errors max   : " + relErrorsMax);
    }
    Assert.assertEquals(0.0, absErrorsMedian, 1.3e-7);
    Assert.assertEquals(0.0, absErrorsMin, 7.3e-7);
    Assert.assertEquals(0.0, absErrorsMax, 1.8e-7);
    Assert.assertEquals(0.0, relErrorsMedian, 1.0e-12);
    Assert.assertEquals(0.0, relErrorsMax, 3.2e-12);
}

Example 5 with BoundedPropagator

use of org.orekit.propagation.BoundedPropagator in project Orekit by CS-SI.

the class StreamingOemWriterTest method testWriteOemStepHandler.

/**
 * Check reading and writing an OEM both with and without using the step handler
 * methods.
 *
 * @throws Exception on error.
 */
@Test
public void testWriteOemStepHandler() throws Exception {
    // setup
    TimeScale utc = TimeScalesFactory.getUTC();
    List<String> files = Arrays.asList("/ccsds/OEMExample5.txt", "/ccsds/OEMExample4.txt");
    for (String ex : files) {
        InputStream inEntry = getClass().getResourceAsStream(ex);
        OEMParser parser = new OEMParser().withMu(CelestialBodyFactory.getEarth().getGM()).withConventions(IERSConventions.IERS_2010);
        OEMFile oemFile = parser.parse(inEntry, "OEMExample.txt");
        OemSatelliteEphemeris satellite = oemFile.getSatellites().values().iterator().next();
        EphemeridesBlock ephemerisBlock = satellite.getSegments().get(0);
        Frame frame = ephemerisBlock.getFrame();
        double step = ephemerisBlock.getStopTime().durationFrom(ephemerisBlock.getStartTime()) / (ephemerisBlock.getCoordinates().size() - 1);
        String originator = oemFile.getOriginator();
        EphemeridesBlock block = oemFile.getEphemeridesBlocks().get(0);
        String objectName = block.getMetaData().getObjectName();
        String objectID = block.getMetaData().getObjectID();
        Map<Keyword, String> metadata = new LinkedHashMap<>();
        metadata.put(Keyword.ORIGINATOR, originator);
        metadata.put(Keyword.OBJECT_NAME, "will be overwritten");
        metadata.put(Keyword.OBJECT_ID, objectID);
        Map<Keyword, String> segmentData = new LinkedHashMap<>();
        segmentData.put(Keyword.OBJECT_NAME, objectName);
        // check using the Propagator / StepHandler interface
        StringBuilder buffer = new StringBuilder();
        StreamingOemWriter writer = new StreamingOemWriter(buffer, utc, metadata);
        writer.writeHeader();
        Segment segment = writer.newSegment(frame, segmentData);
        BoundedPropagator propagator = satellite.getPropagator();
        propagator.setMasterMode(step, segment);
        propagator.propagate(propagator.getMinDate(), propagator.getMaxDate());
        // verify
        BufferedReader reader = new BufferedReader(new StringReader(buffer.toString()));
        OEMFile generatedOemFile = parser.parse(reader, "buffer");
        compareOemFiles(oemFile, generatedOemFile, 1e-7, 1e-7);
        // check calling the methods directly
        buffer = new StringBuilder();
        writer = new StreamingOemWriter(buffer, utc, metadata);
        writer.writeHeader();
        // set start and stop date manually
        segmentData.put(Keyword.START_TIME, StreamingOemWriter.dateToString(block.getStart().getComponents(utc)));
        segmentData.put(Keyword.STOP_TIME, StreamingOemWriter.dateToString(block.getStop().getComponents(utc)));
        segment = writer.newSegment(frame, segmentData);
        segment.writeMetadata();
        for (TimeStampedPVCoordinates coordinate : block.getCoordinates()) {
            segment.writeEphemerisLine(coordinate);
        }
        // verify
        reader = new BufferedReader(new StringReader(buffer.toString()));
        generatedOemFile = parser.parse(reader, "buffer");
        compareOemFiles(oemFile, generatedOemFile, 1e-7, 1e-7);
    }
}