use of org.orekit.propagation.conversion.NumericalPropagatorBuilder in project Orekit by CS-SI.
the class PVTest method testStateDerivatives.
@Test
public void testStateDerivatives() 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 range measurements
final Propagator propagator = EstimationTestUtils.createPropagator(context.initialOrbit, propagatorBuilder);
final List<ObservedMeasurement<?>> measurements = EstimationTestUtils.createMeasurements(propagator, new PVMeasurementCreator(), 1.0, 3.0, 300.0);
propagator.setSlaveMode();
double[] errorsP = new double[3 * 6 * measurements.size()];
double[] errorsV = new double[3 * 6 * measurements.size()];
int indexP = 0;
int indexV = 0;
for (final ObservedMeasurement<?> measurement : measurements) {
final AbsoluteDate date = measurement.getDate();
final SpacecraftState state = propagator.propagate(date);
final double[][] jacobian = measurement.estimate(0, 0, new SpacecraftState[] { state }).getStateDerivatives(0);
// compute a reference value using finite differences
final double[][] finiteDifferencesJacobian = Differentiation.differentiate(new StateFunction() {
public double[] value(final SpacecraftState state) throws OrekitException {
return measurement.estimate(0, 0, new SpacecraftState[] { state }).getEstimatedValue();
}
}, measurement.getDimension(), propagator.getAttitudeProvider(), OrbitType.CARTESIAN, PositionAngle.TRUE, 1.0, 3).value(state);
Assert.assertEquals(finiteDifferencesJacobian.length, jacobian.length);
Assert.assertEquals(finiteDifferencesJacobian[0].length, jacobian[0].length);
for (int i = 0; i < jacobian.length; ++i) {
for (int j = 0; j < jacobian[i].length; ++j) {
final double relativeError = FastMath.abs((finiteDifferencesJacobian[i][j] - jacobian[i][j]) / finiteDifferencesJacobian[i][j]);
if (j < 3) {
errorsP[indexP++] = relativeError;
} else {
errorsV[indexV++] = relativeError;
}
}
}
}
// median errors
Assert.assertEquals(0.0, new Median().evaluate(errorsP), 2.1e-10);
Assert.assertEquals(0.0, new Median().evaluate(errorsV), 2.1e-10);
}
use of org.orekit.propagation.conversion.NumericalPropagatorBuilder in project Orekit by CS-SI.
the class RangeAnalyticTest method genericTestValues.
/**
* Generic test function for values of the 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 range measurements
final Propagator propagator = EstimationTestUtils.createPropagator(context.initialOrbit, propagatorBuilder);
final List<ObservedMeasurement<?>> measurements = EstimationTestUtils.createMeasurements(propagator, new RangeMeasurementCreator(context), 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. If we had chosen the proper state date, the
// range would have depended only on the current position but
// not on the current 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 RangeAnalytic & errors
final double RangeObserved = measurement.getObservedValue()[0];
final double RangeEstimated = new RangeAnalytic((Range) measurement).theoreticalEvaluationAnalytic(0, 0, state).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();
String stationName = ((Range) measurement).getStation().getBaseFrame().getName();
System.out.format(Locale.US, "%-15s %-23s %-23s %19.6f %19.6f %13.6e %13.6e%n", stationName, 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, "%-15s %-23s %-23s %19s %19s %13s %13s%n", "Station", "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, 3.8e-08);
Assert.assertEquals(0.0, absErrorsMin, 2.0e-07);
Assert.assertEquals(0.0, absErrorsMax, 2.3e-07);
Assert.assertEquals(0.0, relErrorsMedian, 6.5e-15);
Assert.assertEquals(0.0, relErrorsMax, 2.4e-14);
}
use of org.orekit.propagation.conversion.NumericalPropagatorBuilder in project Orekit by CS-SI.
the class RangeRateTest method testStateDerivativesWithModifier.
@Test
public void testStateDerivativesWithModifier() 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 range rate measurements
final Propagator propagator = EstimationTestUtils.createPropagator(context.initialOrbit, propagatorBuilder);
final List<ObservedMeasurement<?>> measurements = EstimationTestUtils.createMeasurements(propagator, new RangeRateMeasurementCreator(context, false), 1.0, 3.0, 300.0);
propagator.setSlaveMode();
double maxRelativeError = 0;
for (final ObservedMeasurement<?> measurement : measurements) {
final RangeRateTroposphericDelayModifier modifier = new RangeRateTroposphericDelayModifier(SaastamoinenModel.getStandardModel(), true);
((RangeRate) measurement).addModifier(modifier);
//
// final AbsoluteDate date = measurement.getDate();
// measurement.getObservedValue()[0] / Constants.SPEED_OF_LIGHT;
final double meanDelay = 1;
final AbsoluteDate date = measurement.getDate().shiftedBy(-0.75 * meanDelay);
final SpacecraftState state = propagator.propagate(date);
final double[][] jacobian = measurement.estimate(0, 0, new SpacecraftState[] { state }).getStateDerivatives(0);
final double[][] finiteDifferencesJacobian = Differentiation.differentiate(new StateFunction() {
public double[] value(final SpacecraftState state) throws OrekitException {
return measurement.estimate(0, 0, new SpacecraftState[] { state }).getEstimatedValue();
}
}, 1, propagator.getAttitudeProvider(), OrbitType.CARTESIAN, PositionAngle.TRUE, 15.0, 3).value(state);
Assert.assertEquals(finiteDifferencesJacobian.length, jacobian.length);
Assert.assertEquals(finiteDifferencesJacobian[0].length, jacobian[0].length);
for (int i = 0; i < jacobian.length; ++i) {
for (int j = 0; j < jacobian[i].length; ++j) {
// check the values returned by getStateDerivatives() are correct
maxRelativeError = FastMath.max(maxRelativeError, FastMath.abs((finiteDifferencesJacobian[i][j] - jacobian[i][j]) / finiteDifferencesJacobian[i][j]));
}
}
}
Assert.assertEquals(0, maxRelativeError, 1.5e-7);
}
use of org.orekit.propagation.conversion.NumericalPropagatorBuilder in project Orekit by CS-SI.
the class RangeRateTest method testParameterDerivativesWithModifier.
@Test
public void testParameterDerivativesWithModifier() 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 range rate measurements
for (final GroundStation station : context.stations) {
station.getEastOffsetDriver().setSelected(true);
station.getNorthOffsetDriver().setSelected(true);
station.getZenithOffsetDriver().setSelected(true);
}
final Propagator propagator = EstimationTestUtils.createPropagator(context.initialOrbit, propagatorBuilder);
final List<ObservedMeasurement<?>> measurements = EstimationTestUtils.createMeasurements(propagator, new RangeRateMeasurementCreator(context, false), 1.0, 3.0, 300.0);
propagator.setSlaveMode();
double maxRelativeError = 0;
for (final ObservedMeasurement<?> measurement : measurements) {
final RangeRateTroposphericDelayModifier modifier = new RangeRateTroposphericDelayModifier(SaastamoinenModel.getStandardModel(), true);
((RangeRate) measurement).addModifier(modifier);
// parameter corresponding to station position offset
final GroundStation stationParameter = ((RangeRate) measurement).getStation();
// 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. If we had chosen the proper state date, the
// range would have depended only on the current position but
// not on the current velocity.
final double meanDelay = measurement.getObservedValue()[0] / Constants.SPEED_OF_LIGHT;
final AbsoluteDate date = measurement.getDate().shiftedBy(-0.75 * meanDelay);
final SpacecraftState state = propagator.propagate(date);
final ParameterDriver[] drivers = new ParameterDriver[] { stationParameter.getEastOffsetDriver(), stationParameter.getNorthOffsetDriver(), stationParameter.getZenithOffsetDriver() };
for (int i = 0; i < 3; ++i) {
final double[] gradient = measurement.estimate(0, 0, new SpacecraftState[] { state }).getParameterDerivatives(drivers[i]);
Assert.assertEquals(1, measurement.getDimension());
Assert.assertEquals(1, gradient.length);
final ParameterFunction dMkdP = Differentiation.differentiate(new ParameterFunction() {
/**
* {@inheritDoc}
*/
@Override
public double value(final ParameterDriver parameterDriver) throws OrekitException {
return measurement.estimate(0, 0, new SpacecraftState[] { state }).getEstimatedValue()[0];
}
}, drivers[i], 3, 20.0);
final double ref = dMkdP.value(drivers[i]);
maxRelativeError = FastMath.max(maxRelativeError, FastMath.abs((ref - gradient[0]) / ref));
}
}
Assert.assertEquals(0, maxRelativeError, 1.2e-6);
}
use of org.orekit.propagation.conversion.NumericalPropagatorBuilder in project Orekit by CS-SI.
the class RangeRateTest method testStateDerivativesTwoWays.
@Test
public void testStateDerivativesTwoWays() 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 range rate measurements
final Propagator propagator = EstimationTestUtils.createPropagator(context.initialOrbit, propagatorBuilder);
final List<ObservedMeasurement<?>> measurements = EstimationTestUtils.createMeasurements(propagator, new RangeRateMeasurementCreator(context, true), 1.0, 3.0, 300.0);
for (final ObservedMeasurement<?> m : measurements) {
Assert.assertTrue(((RangeRate) m).isTwoWay());
}
propagator.setSlaveMode();
double maxRelativeError = 0;
for (final ObservedMeasurement<?> measurement : measurements) {
//
// final AbsoluteDate date = measurement.getDate();
// measurement.getObservedValue()[0] / Constants.SPEED_OF_LIGHT;
final double meanDelay = 1;
final AbsoluteDate date = measurement.getDate().shiftedBy(-0.75 * meanDelay);
final SpacecraftState state = propagator.propagate(date);
final EstimatedMeasurement<?> estimated = measurement.estimate(0, 0, new SpacecraftState[] { state });
Assert.assertEquals(3, estimated.getParticipants().length);
final double[][] jacobian = estimated.getStateDerivatives(0);
final double[][] finiteDifferencesJacobian = Differentiation.differentiate(new StateFunction() {
public double[] value(final SpacecraftState state) throws OrekitException {
return measurement.estimate(0, 0, new SpacecraftState[] { state }).getEstimatedValue();
}
}, 1, propagator.getAttitudeProvider(), OrbitType.CARTESIAN, PositionAngle.TRUE, 15.0, 3).value(state);
Assert.assertEquals(finiteDifferencesJacobian.length, jacobian.length);
Assert.assertEquals(finiteDifferencesJacobian[0].length, jacobian[0].length);
for (int i = 0; i < jacobian.length; ++i) {
for (int j = 0; j < jacobian[i].length; ++j) {
// check the values returned by getStateDerivatives() are correct
maxRelativeError = FastMath.max(maxRelativeError, FastMath.abs((finiteDifferencesJacobian[i][j] - jacobian[i][j]) / finiteDifferencesJacobian[i][j]));
}
}
}
Assert.assertEquals(0, maxRelativeError, 2.6e-5);
}
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