Examples with Context org.orekit.estimation.Context used on opensource projects

Example 1 with Context

use of org.orekit.estimation.Context in project Orekit by CS-SI.

the class TurnAroundRangeAnalyticTest method genericTestParameterDerivatives.

/**
 * Generic test function for derivatives with respect to parameters (station's position in station's topocentric frame)
 * @param isModifier Use of atmospheric modifiers
 * @param isFiniteDifferences Finite differences reference calculation if true, TurnAroundRange class otherwise
 * @param printResults Print the results ?
 * @throws OrekitException
 */
void genericTestParameterDerivatives(final boolean isModifier, final boolean isFiniteDifferences, final boolean printResults, final double refErrorQMMedian, final double refErrorQMMean, final double refErrorQMMax, final double refErrorQSMedian, final double refErrorQSMean, final double refErrorQSMax) 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 TAR measurements
    for (Map.Entry<GroundStation, GroundStation> entry : context.TARstations.entrySet()) {
        final GroundStation masterStation = entry.getKey();
        final GroundStation slaveStation = entry.getValue();
        masterStation.getEastOffsetDriver().setSelected(true);
        masterStation.getNorthOffsetDriver().setSelected(true);
        masterStation.getZenithOffsetDriver().setSelected(true);
        slaveStation.getEastOffsetDriver().setSelected(true);
        slaveStation.getNorthOffsetDriver().setSelected(true);
        slaveStation.getZenithOffsetDriver().setSelected(true);
    }
    final Propagator propagator = EstimationTestUtils.createPropagator(context.initialOrbit, propagatorBuilder);
    final List<ObservedMeasurement<?>> measurements = EstimationTestUtils.createMeasurements(propagator, new TurnAroundRangeMeasurementCreator(context), 1.0, 3.0, 300.0);
    propagator.setSlaveMode();
    // Print results on console ? Header
    if (printResults) {
        System.out.format(Locale.US, "%-15s %-15s %-23s  %-23s  " + "%10s  %10s  %10s  " + "%10s  %10s  %10s  " + "%10s  %10s  %10s  " + "%10s  %10s  %10s%n", "Master Station", "Slave Station", "Measurement Date", "State Date", "ΔdQMx", "rel ΔdQMx", "ΔdQMy", "rel ΔdQMy", "ΔdQMz", "rel ΔdQMz", "ΔdQSx", "rel ΔdQSx", "ΔdQSy", "rel ΔdQSy", "ΔdQSz", "rel ΔdQSz");
    }
    // List to store the results for master and slave station
    final List<Double> relErrorQMList = new ArrayList<Double>();
    final List<Double> relErrorQSList = new ArrayList<Double>();
    // Loop on the measurements
    for (final ObservedMeasurement<?> measurement : measurements) {
        // Add modifiers if test implies it
        final TurnAroundRangeTroposphericDelayModifier modifier = new TurnAroundRangeTroposphericDelayModifier(SaastamoinenModel.getStandardModel());
        if (isModifier) {
            ((TurnAroundRange) measurement).addModifier(modifier);
        }
        // parameter corresponding to station position offset
        final GroundStation masterStationParameter = ((TurnAroundRange) measurement).getMasterStation();
        final GroundStation slaveStationParameter = ((TurnAroundRange) measurement).getSlaveStation();
        // 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[] { masterStationParameter.getEastOffsetDriver(), masterStationParameter.getNorthOffsetDriver(), masterStationParameter.getZenithOffsetDriver(), slaveStationParameter.getEastOffsetDriver(), slaveStationParameter.getNorthOffsetDriver(), slaveStationParameter.getZenithOffsetDriver() };
        // Print results on console ? Stations' names
        if (printResults) {
            String masterStationName = masterStationParameter.getBaseFrame().getName();
            String slaveStationName = slaveStationParameter.getBaseFrame().getName();
            System.out.format(Locale.US, "%-15s %-15s %-23s  %-23s  ", masterStationName, slaveStationName, measurement.getDate(), date);
        }
        // Loop on the parameters
        for (int i = 0; i < 6; ++i) {
            // Analytical computation of the parameters derivatives
            final EstimatedMeasurement<TurnAroundRange> TAR = new TurnAroundRangeAnalytic((TurnAroundRange) measurement).theoreticalEvaluationAnalytic(0, 0, propagator.getInitialState(), state);
            // Optional modifier addition
            if (isModifier) {
                modifier.modify(TAR);
            }
            final double[] gradient = TAR.getParameterDerivatives(drivers[i]);
            Assert.assertEquals(1, measurement.getDimension());
            Assert.assertEquals(1, gradient.length);
            // Reference value
            double ref;
            if (isFiniteDifferences) {
                // Compute a reference value using finite differences
                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);
                ref = dMkdP.value(drivers[i]);
            } else {
                // Compute a reference value using TurnAroundRange function
                ref = measurement.estimate(0, 0, new SpacecraftState[] { state }).getParameterDerivatives(drivers[i])[0];
            }
            // Deltas
            double dGradient = gradient[0] - ref;
            double dGradientRelative = FastMath.abs(dGradient / ref);
            // Print results on console ? Gradient difference
            if (printResults) {
                System.out.format(Locale.US, "%10.3e  %10.3e  ", dGradient, dGradientRelative);
            }
            // Add relative error to the list
            if (i < 3) {
                relErrorQMList.add(dGradientRelative);
            } else {
                relErrorQSList.add(dGradientRelative);
            }
        }
        // End for loop on the parameters
        if (printResults) {
            System.out.format(Locale.US, "%n");
        }
    }
    // End for loop on the measurements
    // Convert error list to double[]
    final double[] relErrorQM = relErrorQMList.stream().mapToDouble(Double::doubleValue).toArray();
    final double[] relErrorQS = relErrorQSList.stream().mapToDouble(Double::doubleValue).toArray();
    // Compute statistics
    final double relErrorsQMMedian = new Median().evaluate(relErrorQM);
    final double relErrorsQMMean = new Mean().evaluate(relErrorQM);
    final double relErrorsQMMax = new Max().evaluate(relErrorQM);
    final double relErrorsQSMedian = new Median().evaluate(relErrorQS);
    final double relErrorsQSMean = new Mean().evaluate(relErrorQS);
    final double relErrorsQSMax = new Max().evaluate(relErrorQS);
    // Print the results on console ?
    if (printResults) {
        System.out.println();
        System.out.format(Locale.US, "Relative errors dR/dQ master station -> Median: %6.3e / Mean: %6.3e / Max: %6.3e%n", relErrorsQMMedian, relErrorsQMMean, relErrorsQMMax);
        System.out.format(Locale.US, "Relative errors dR/dQ slave station  -> Median: %6.3e / Mean: %6.3e / Max: %6.3e%n", relErrorsQSMedian, relErrorsQSMean, relErrorsQSMax);
    }
    // Check values
    Assert.assertEquals(0.0, relErrorsQMMedian, refErrorQMMedian);
    Assert.assertEquals(0.0, relErrorsQMMean, refErrorQMMean);
    Assert.assertEquals(0.0, relErrorsQMMax, refErrorQMMax);
    Assert.assertEquals(0.0, relErrorsQSMedian, refErrorQSMedian);
    Assert.assertEquals(0.0, relErrorsQSMean, refErrorQSMean);
    Assert.assertEquals(0.0, relErrorsQSMax, refErrorQSMax);
}

Example 2 with Context

use of org.orekit.estimation.Context in project Orekit by CS-SI.

the class TurnAroundRangeAnalyticTest method genericTestValues.

/**
 * Generic test function for values of the TAR
 * @param printResults Print the results ?
 * @throws OrekitException
 */
void genericTestValues(final boolean printResults) throws OrekitException {
    Context context = EstimationTestUtils.eccentricContext("regular-data:potential:tides");
    // Context context = EstimationTestUtils.geoStationnaryContext();
    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 TurnAroundRangeMeasurementCreator(context), 1.0, 3.0, 300.0);
    propagator.setSlaveMode();
    double[] absoluteErrors = new double[measurements.size()];
    double[] relativeErrors = new double[measurements.size()];
    int index = 0;
    // Print the results ? Header
    if (printResults) {
        System.out.format(Locale.US, "%-15s  %-15s  %-23s  %-23s  %17s  %17s  %13s %13s%n", "Master Station", "Slave Station", "Measurement Date", "State Date", "TAR observed [m]", "TAR estimated [m]", "|ΔTAR| [m]", "rel |ΔTAR|");
    }
    // Loop on the measurements
    for (final ObservedMeasurement<?> measurement : measurements) {
        final double meanDelay = measurement.getObservedValue()[0] / Constants.SPEED_OF_LIGHT;
        final AbsoluteDate date = measurement.getDate().shiftedBy(meanDelay);
        final SpacecraftState state = propagator.propagate(date);
        // Values of the TAR & errors
        final double TARobserved = measurement.getObservedValue()[0];
        final double TARestimated = new TurnAroundRangeAnalytic((TurnAroundRange) measurement).theoreticalEvaluationAnalytic(0, 0, propagator.getInitialState(), state).getEstimatedValue()[0];
        absoluteErrors[index] = TARestimated - TARobserved;
        relativeErrors[index] = FastMath.abs(absoluteErrors[index]) / FastMath.abs(TARobserved);
        index++;
        // Print results ? Values
        if (printResults) {
            final AbsoluteDate measurementDate = measurement.getDate();
            String masterStationName = ((TurnAroundRange) measurement).getMasterStation().getBaseFrame().getName();
            String slaveStationName = ((TurnAroundRange) measurement).getSlaveStation().getBaseFrame().getName();
            System.out.format(Locale.US, "%-15s  %-15s  %-23s  %-23s  %17.6f  %17.6f  %13.6e %13.6e%n", masterStationName, slaveStationName, measurementDate, date, TARobserved, TARestimated, FastMath.abs(TARestimated - TARobserved), FastMath.abs((TARestimated - TARobserved) / TARobserved));
        }
    }
    // Compute some statistics
    final double absErrorsMedian = new Median().evaluate(absoluteErrors);
    final double absErrorsMin = new Min().evaluate(absoluteErrors);
    final double absErrorsMax = new Max().evaluate(absoluteErrors);
    final double relErrorsMedian = new Median().evaluate(relativeErrors);
    final double relErrorsMax = new Max().evaluate(relativeErrors);
    // 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 statistical errors
    Assert.assertEquals(0.0, absErrorsMedian, 8.4e-08);
    Assert.assertEquals(0.0, absErrorsMin, 9.0e-08);
    Assert.assertEquals(0.0, absErrorsMax, 2.0e-07);
    Assert.assertEquals(0.0, relErrorsMedian, 5.1e-15);
    Assert.assertEquals(0.0, relErrorsMax, 1.2e-14);
}

Example 3 with Context

use of org.orekit.estimation.Context in project Orekit by CS-SI.

the class TurnAroundRangeTest method genericTestValues.

/**
 * Generic test function for values of the TAR
 * @param printResults Print the results ?
 * @throws OrekitException
 */
void genericTestValues(final boolean printResults) throws OrekitException {
    Context context = EstimationTestUtils.eccentricContext("regular-data:potential:tides");
    // Context context = EstimationTestUtils.geoStationnaryContext();
    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 TurnAroundRangeMeasurementCreator(context), 1.0, 3.0, 300.0);
    propagator.setSlaveMode();
    double[] absoluteErrors = new double[measurements.size()];
    double[] relativeErrors = new double[measurements.size()];
    int index = 0;
    // Print the results ? Header
    if (printResults) {
        System.out.format(Locale.US, "%-15s  %-15s  %-23s  %-23s  %17s  %17s  %13s %13s%n", "Master Station", "Slave Station", "Measurement Date", "State Date", "TAR observed [m]", "TAR estimated [m]", "|ΔTAR| [m]", "rel |ΔTAR|");
    }
    // Loop on the measurements
    for (final ObservedMeasurement<?> measurement : measurements) {
        final double meanDelay = measurement.getObservedValue()[0] / Constants.SPEED_OF_LIGHT;
        final AbsoluteDate date = measurement.getDate().shiftedBy(meanDelay);
        final SpacecraftState state = propagator.propagate(date);
        // Values of the TAR & errors
        final double TARobserved = measurement.getObservedValue()[0];
        final EstimatedMeasurement<?> estimated = measurement.estimate(0, 0, new SpacecraftState[] { state });
        final double TARestimated = estimated.getEstimatedValue()[0];
        final TimeStampedPVCoordinates[] participants = estimated.getParticipants();
        Assert.assertEquals(5, participants.length);
        Assert.assertEquals(0.5 * Constants.SPEED_OF_LIGHT * participants[4].getDate().durationFrom(participants[0].getDate()), estimated.getEstimatedValue()[0], 2.0e-8);
        absoluteErrors[index] = TARestimated - TARobserved;
        relativeErrors[index] = FastMath.abs(absoluteErrors[index]) / FastMath.abs(TARobserved);
        index++;
        // Print results ? Values
        if (printResults) {
            final AbsoluteDate measurementDate = measurement.getDate();
            String masterStationName = ((TurnAroundRange) measurement).getMasterStation().getBaseFrame().getName();
            String slaveStationName = ((TurnAroundRange) measurement).getSlaveStation().getBaseFrame().getName();
            System.out.format(Locale.US, "%-15s  %-15s  %-23s  %-23s  %17.6f  %17.6f  %13.6e %13.6e%n", masterStationName, slaveStationName, measurementDate, date, TARobserved, TARestimated, FastMath.abs(TARestimated - TARobserved), FastMath.abs((TARestimated - TARobserved) / TARobserved));
        }
    }
    // Compute some statistics
    final double absErrorsMedian = new Median().evaluate(absoluteErrors);
    final double absErrorsMin = new Min().evaluate(absoluteErrors);
    final double absErrorsMax = new Max().evaluate(absoluteErrors);
    final double relErrorsMedian = new Median().evaluate(relativeErrors);
    final double relErrorsMax = new Max().evaluate(relativeErrors);
    // 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 statistical errors
    Assert.assertEquals(0.0, absErrorsMedian, 1.4e-7);
    Assert.assertEquals(0.0, absErrorsMin, 5.0e-7);
    Assert.assertEquals(0.0, absErrorsMax, 4.9e-7);
    Assert.assertEquals(0.0, relErrorsMedian, 8.9e-15);
    Assert.assertEquals(0.0, relErrorsMax, 2.9e-14);
}

Example 4 with Context

use of org.orekit.estimation.Context in project Orekit by CS-SI.

the class TurnAroundRangeTest method genericTestStateDerivatives.

void genericTestStateDerivatives(final boolean isModifier, final boolean printResults, 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");
    // Context context = EstimationTestUtils.geoStationnaryContext();
    final NumericalPropagatorBuilder propagatorBuilder = context.createBuilder(OrbitType.KEPLERIAN, PositionAngle.TRUE, true, 1.0e-6, 60.0, 0.001);
    // create perfect range2 measurements
    final Propagator propagator = EstimationTestUtils.createPropagator(context.initialOrbit, propagatorBuilder);
    final List<ObservedMeasurement<?>> measurements = EstimationTestUtils.createMeasurements(propagator, new TurnAroundRangeMeasurementCreator(context), 1.0, 3.0, 300.0);
    propagator.setSlaveMode();
    double[] errorsP = new double[3 * measurements.size()];
    double[] errorsV = new double[3 * measurements.size()];
    int indexP = 0;
    int indexV = 0;
    // Print the results ? Header
    if (printResults) {
        System.out.format(Locale.US, "%-15s  %-15s  %-23s  %-23s  " + "%10s  %10s  %10s  " + "%10s  %10s  %10s  " + "%10s  %10s  %10s  " + "%10s  %10s  %10s%n", "Master Station", "Slave Station", "Measurement Date", "State Date", "ΔdPx", "ΔdPy", "ΔdPz", "ΔdVx", "ΔdVy", "ΔdVz", "rel ΔdPx", "rel ΔdPy", "rel ΔdPz", "rel ΔdVx", "rel ΔdVy", "rel ΔdVz");
    }
    // Loop on the measurements
    for (final ObservedMeasurement<?> measurement : measurements) {
        // Add modifiers if test implies it
        final TurnAroundRangeTroposphericDelayModifier modifier = new TurnAroundRangeTroposphericDelayModifier(SaastamoinenModel.getStandardModel());
        if (isModifier) {
            ((TurnAroundRange) measurement).addModifier(modifier);
        }
        // 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 double[][] jacobian = measurement.estimate(0, 0, new SpacecraftState[] { state }).getStateDerivatives(0);
        // 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 {
                return measurement.estimate(0, 0, new SpacecraftState[] { state }).getEstimatedValue();
            }
        }, measurement.getDimension(), propagator.getAttitudeProvider(), OrbitType.CARTESIAN, PositionAngle.TRUE, 2.0, 3).value(state);
        Assert.assertEquals(jacobianRef.length, jacobian.length);
        Assert.assertEquals(jacobianRef[0].length, jacobian[0].length);
        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[indexP++] = dJacobianRelative[i][j];
                } else {
                    errorsV[indexV++] = dJacobianRelative[i][j];
                }
            }
        }
        // Print results on the console ? Print the Jacobian
        if (printResults) {
            String masterStationName = ((TurnAroundRange) measurement).getMasterStation().getBaseFrame().getName();
            String slaveStationName = ((TurnAroundRange) measurement).getSlaveStation().getBaseFrame().getName();
            System.out.format(Locale.US, "%-15s  %-15s  %-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", masterStationName, slaveStationName, 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 loop on the measurements
    // Compute some statistics
    final double errorsPMedian = new Median().evaluate(errorsP);
    final double errorsPMean = new Mean().evaluate(errorsP);
    final double errorsPMax = new Max().evaluate(errorsP);
    final double errorsVMedian = new Median().evaluate(errorsV);
    final double errorsVMean = new Mean().evaluate(errorsV);
    final double errorsVMax = new Max().evaluate(errorsV);
    // Print the results on console ? Final results
    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 5 with Context

use of org.orekit.estimation.Context in project Orekit by CS-SI.

the class IonoModifierTest method testRangeRateIonoModifier.

@Test
public void testRangeRateIonoModifier() 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
    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();
    final RangeRateIonosphericDelayModifier modifier = new RangeRateIonosphericDelayModifier(model, true);
    for (final ObservedMeasurement<?> measurement : measurements) {
        final AbsoluteDate date = measurement.getDate();
        final SpacecraftState refstate = propagator.propagate(date);
        RangeRate rangeRate = (RangeRate) measurement;
        EstimatedMeasurement<RangeRate> evalNoMod = rangeRate.estimate(0, 0, new SpacecraftState[] { refstate });
        // add modifier
        rangeRate.addModifier(modifier);
        // 
        EstimatedMeasurement<RangeRate> eval = rangeRate.estimate(0, 0, new SpacecraftState[] { refstate });
        final double diffMetersSec = eval.getEstimatedValue()[0] - evalNoMod.getEstimatedValue()[0];
        // TODO: check threshold
        Assert.assertEquals(0.0, diffMetersSec, 0.016);
    }
}