/* Copyright 2002-2017 CS Systèmes d'Information
* Licensed to CS Systèmes d'Information (CS) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* CS licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
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package org.orekit.estimation.measurements;
import java.util.List;
import org.hipparchus.util.MathUtils;
import org.hipparchus.util.Precision;
import org.junit.After;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;
import org.orekit.errors.OrekitException;
import org.orekit.estimation.Context;
import org.orekit.estimation.EstimationTestUtils;
import org.orekit.estimation.measurements.modifiers.AngularRadioRefractionModifier;
import org.orekit.estimation.measurements.modifiers.AngularTroposphericDelayModifier;
import org.orekit.estimation.measurements.modifiers.RangeRateTroposphericDelayModifier;
import org.orekit.estimation.measurements.modifiers.RangeTroposphericDelayModifier;
import org.orekit.estimation.measurements.modifiers.TurnAroundRangeTroposphericDelayModifier;
import org.orekit.models.earth.EarthITU453AtmosphereRefraction;
import org.orekit.models.earth.SaastamoinenModel;
import org.orekit.orbits.OrbitType;
import org.orekit.orbits.PositionAngle;
import org.orekit.propagation.Propagator;
import org.orekit.propagation.SpacecraftState;
import org.orekit.propagation.conversion.NumericalPropagatorBuilder;
import org.orekit.time.AbsoluteDate;
public class TropoModifierTest {
@Before
public void setUp() throws Exception {
}
@After
public void tearDown() {
}
@Test
public void testRangeTropoModifier() throws OrekitException {
Context context = EstimationTestUtils.eccentricContext();
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 RangeMeasurementCreator(context),
1.0, 3.0, 300.0);
propagator.setSlaveMode();
final RangeTroposphericDelayModifier modifier = new RangeTroposphericDelayModifier(SaastamoinenModel.getStandardModel());
for (final ObservedMeasurement<?> measurement : measurements) {
final AbsoluteDate date = measurement.getDate();
final SpacecraftState refstate = propagator.propagate(date);
Range range = (Range) measurement;
EstimatedMeasurement<Range> evalNoMod = range.estimate(0, 0, refstate);
// add modifier
range.addModifier(modifier);
EstimatedMeasurement<Range> eval = range.estimate(0, 0, refstate);
final double diffMeters = eval.getEstimatedValue()[0] - evalNoMod.getEstimatedValue()[0];
final double epsilon = 1e-6;
Assert.assertTrue(Precision.compareTo(diffMeters, 12., epsilon) < 0);
Assert.assertTrue(Precision.compareTo(diffMeters, 0., epsilon) > 0);
}
}
@Test
public void testTurnAroundRangeTropoModifier() throws OrekitException {
Context context = EstimationTestUtils.eccentricContext();
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 TurnAroundRangeMeasurementCreator(context),
1.0, 3.0, 300.0);
propagator.setSlaveMode();
final TurnAroundRangeTroposphericDelayModifier modifier = new TurnAroundRangeTroposphericDelayModifier(SaastamoinenModel.getStandardModel());
for (final ObservedMeasurement<?> measurement : measurements) {
final AbsoluteDate date = measurement.getDate();
final SpacecraftState refstate = propagator.propagate(date);
TurnAroundRange turnAroundRange = (TurnAroundRange) measurement;
EstimatedMeasurement<TurnAroundRange> evalNoMod = turnAroundRange.estimate(0, 0, refstate);
// add modifier
turnAroundRange.addModifier(modifier);
//
EstimatedMeasurement<TurnAroundRange> eval = turnAroundRange.estimate(0, 0, refstate);
final double diffMeters = eval.getEstimatedValue()[0] - evalNoMod.getEstimatedValue()[0];
final double epsilon = 1e-6;
Assert.assertTrue(Precision.compareTo(diffMeters, 12., epsilon) < 0);
Assert.assertTrue(Precision.compareTo(diffMeters, 0., epsilon) > 0);
}
}
@Test
public void testRangeRateTropoModifier() throws OrekitException {
Context context = EstimationTestUtils.eccentricContext();
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 RangeRateTroposphericDelayModifier modifier = new RangeRateTroposphericDelayModifier(SaastamoinenModel.getStandardModel(), false);
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, refstate);
// add modifier
rangeRate.addModifier(modifier);
//
EstimatedMeasurement<RangeRate> eval = rangeRate.estimate(0, 0, refstate);
final double diffMetersSec = eval.getEstimatedValue()[0] - evalNoMod.getEstimatedValue()[0];
final double epsilon = 1e-6;
Assert.assertTrue(Precision.compareTo(diffMetersSec, 0.01, epsilon) < 0);
Assert.assertTrue(Precision.compareTo(diffMetersSec, -0.01, epsilon) > 0);
}
}
@Test
public void testAngularTropoModifier() throws OrekitException {
Context context = EstimationTestUtils.eccentricContext();
final NumericalPropagatorBuilder propagatorBuilder =
context.createBuilder(OrbitType.KEPLERIAN, PositionAngle.TRUE, true,
1.0e-6, 60.0, 0.001);
// create perfect angular 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 AngularMeasurementCreator(context),
1.0, 3.0, 300.0);
propagator.setSlaveMode();
final AngularTroposphericDelayModifier modifier = new AngularTroposphericDelayModifier(SaastamoinenModel.getStandardModel());
for (final ObservedMeasurement<?> measurement : measurements) {
final AbsoluteDate date = measurement.getDate();
final SpacecraftState refstate = propagator.propagate(date);
Angular angular = (Angular) measurement;
EstimatedMeasurement<Angular> evalNoMod = angular.estimate(0, 0, refstate);
// add modifier
angular.addModifier(modifier);
//
EstimatedMeasurement<Angular> eval = angular.estimate(0, 0, refstate);
final double diffAz = MathUtils.normalizeAngle(eval.getEstimatedValue()[0], evalNoMod.getEstimatedValue()[0]) - evalNoMod.getEstimatedValue()[0];
final double diffEl = MathUtils.normalizeAngle(eval.getEstimatedValue()[1], evalNoMod.getEstimatedValue()[1]) - evalNoMod.getEstimatedValue()[1];
// TODO: check threshold
Assert.assertEquals(0.0, diffAz, 5.0e-5);
Assert.assertEquals(0.0, diffEl, 5.0e-6);
}
}
@Test
public void testAngularRadioRefractionModifier() throws OrekitException {
Context context = EstimationTestUtils.eccentricContext();
final NumericalPropagatorBuilder propagatorBuilder =
context.createBuilder(OrbitType.KEPLERIAN, PositionAngle.TRUE, true,
1.0e-6, 60.0, 0.001);
// create perfect angular 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 AngularMeasurementCreator(context),
1.0, 3.0, 300.0);
propagator.setSlaveMode();
for (final ObservedMeasurement<?> measurement : measurements) {
final AbsoluteDate date = measurement.getDate();
final SpacecraftState refstate = propagator.propagate(date);
Angular angular = (Angular) measurement;
EstimatedMeasurement<Angular> evalNoMod = angular.estimate(0, 0, refstate);
// get the altitude of the station (in kilometers)
final double altitude = angular.getStation().getBaseFrame().getPoint().getAltitude() / 1000.;
final AngularRadioRefractionModifier modifier = new AngularRadioRefractionModifier(new EarthITU453AtmosphereRefraction(altitude));
// add modifier
angular.addModifier(modifier);
//
EstimatedMeasurement<Angular> eval = angular.estimate(0, 0, refstate);
final double diffEl = MathUtils.normalizeAngle(eval.getEstimatedValue()[1], evalNoMod.getEstimatedValue()[1]) - evalNoMod.getEstimatedValue()[1];
// TODO: check threshold
Assert.assertEquals(0.0, diffEl, 1.0e-3);
}
}
}