Merge branch 'issue-498' into develop

pom.xml

@@ -175,6 +175,9 @@
     <contributor>
       <name>Espen Bj&#248;rntvedt</name>
     </contributor>
+    <contributor>
+      <name>Bryan Cazabonne</name>
+    </contributor>
     <contributor>
       <name>Paul Cefola</name>
     </contributor>

src/main/java/org/orekit/errors/OrekitMessages.java

@@ -218,7 +218,10 @@ public enum OrekitMessages implements Localizable {
     DIMENSION_INCONSISTENT_WITH_PARAMETERS("dimension {0} is inconsistent with parameters list: {1}"),
     NOT_A_SUPPORTED_UNIX_COMPRESSED_FILE("file {0} is not a supported Unix-compressed file"),
     UNEXPECTED_END_OF_FILE("unexpected end of file {0}"),
-    CORRUPTED_FILE("file {0} is corrupted");
+    CORRUPTED_FILE("file {0} is corrupted"),
+    VIENNA_ACOEF_OR_ZENITH_DELAY_NOT_LOADED("Vienna coefficients ah or aw or zh or zw could not be loaded from {0}"),
+    VIENNA_ACOEF_OR_ZENITH_DELAY_NOT_AVAILABLE_FOR_DATE("Vienna coefficients ah or aw or zh or zw not available for date {0}"),
+    NO_VIENNA_ACOEF_OR_ZENITH_DELAY_IN_FILE("file {0} does not contain Vienna coefficients ah, aw, zh or zw");
 
 
     // CHECKSTYLE: resume JavadocVariable check

src/main/java/org/orekit/estimation/measurements/modifiers/AngularTroposphericDelayModifier.java

@@ -16,7 +16,6 @@
  */
 package org.orekit.estimation.measurements.modifiers;
 
-import java.util.Collections;
 import java.util.List;
 
 import org.hipparchus.geometry.euclidean.threed.Vector3D;
@@ -26,7 +25,7 @@ import org.orekit.estimation.measurements.EstimatedMeasurement;
 import org.orekit.estimation.measurements.EstimationModifier;
 import org.orekit.estimation.measurements.GroundStation;
 import org.orekit.frames.Frame;
-import org.orekit.models.earth.TroposphericModel;
+import org.orekit.models.earth.DiscreteTroposphericModel;
 import org.orekit.propagation.SpacecraftState;
 import org.orekit.time.AbsoluteDate;
 import org.orekit.utils.Constants;
@@ -47,13 +46,13 @@ import org.orekit.utils.ParameterDriver;
 public class AngularTroposphericDelayModifier implements EstimationModifier<AngularAzEl> {
 
     /** Tropospheric delay model. */
-    private final TroposphericModel tropoModel;
+    private final DiscreteTroposphericModel tropoModel;
 
     /** Constructor.
      *
      * @param model  Tropospheric delay model appropriate for the current angular measurement method.
      */
-    public AngularTroposphericDelayModifier(final TroposphericModel model) {
+    public AngularTroposphericDelayModifier(final DiscreteTroposphericModel model) {
         tropoModel = model;
     }
 
@@ -89,7 +88,7 @@ public class AngularTroposphericDelayModifier implements EstimationModifier<Angu
             final double height = getStationHeightAMSL(station);
 
             // delay in meters
-            final double delay = tropoModel.pathDelay(elevation, height);
+            final double delay = tropoModel.pathDelay(elevation, height, tropoModel.getParameters(), state.getDate());
 
             // one-way measurement.
             return delay;
@@ -101,7 +100,7 @@ public class AngularTroposphericDelayModifier implements EstimationModifier<Angu
     /** {@inheritDoc} */
     @Override
     public List<ParameterDriver> getParametersDrivers() {
-        return Collections.emptyList();
+        return tropoModel.getParametersDrivers();
     }
 
     @Override

src/main/java/org/orekit/frames/TopocentricFrame.java

@@ -16,19 +16,25 @@
  */
 package org.orekit.frames;
 
+import org.hipparchus.Field;
+import org.hipparchus.RealFieldElement;
 import org.hipparchus.analysis.UnivariateFunction;
 import org.hipparchus.analysis.solvers.BracketingNthOrderBrentSolver;
 import org.hipparchus.analysis.solvers.UnivariateSolver;
 import org.hipparchus.exception.MathRuntimeException;
+import org.hipparchus.geometry.euclidean.threed.FieldVector3D;
 import org.hipparchus.geometry.euclidean.threed.Rotation;
 import org.hipparchus.geometry.euclidean.threed.Vector3D;
 import org.hipparchus.util.FastMath;
 import org.hipparchus.util.MathUtils;
 import org.orekit.bodies.BodyShape;
+import org.orekit.bodies.FieldGeodeticPoint;
 import org.orekit.bodies.GeodeticPoint;
 import org.orekit.errors.OrekitException;
 import org.orekit.time.AbsoluteDate;
+import org.orekit.time.FieldAbsoluteDate;
 import org.orekit.utils.Constants;
+import org.orekit.utils.FieldPVCoordinates;
 import org.orekit.utils.PVCoordinates;
 import org.orekit.utils.PVCoordinatesProvider;
 import org.orekit.utils.TimeStampedPVCoordinates;
@@ -95,6 +101,19 @@ public class TopocentricFrame extends Frame implements PVCoordinatesProvider {
         return point;
     }
 
+    /** Get the surface point defining the origin of the frame.
+     * @param <T> tyoe of the elements
+     * @param field of the elements
+     * @return surface point defining the origin of the frame
+     * @since 9.3
+     */
+    public <T extends RealFieldElement<T>> FieldGeodeticPoint<T> getPoint(final Field<T> field) {
+        final T zero = field.getZero();
+        return new FieldGeodeticPoint<>(zero.add(point.getLatitude()),
+                                        zero.add(point.getLongitude()),
+                                        zero.add(point.getAltitude()));
+    }
+
     /** Get the zenith direction of topocentric frame, expressed in parent shape frame.
      * <p>The zenith direction is defined as the normal to local horizontal plane.</p>
      * @return unit vector in the zenith direction
@@ -170,6 +189,27 @@ public class TopocentricFrame extends Frame implements PVCoordinatesProvider {
         return extPointTopo.getDelta();
     }
 
+    /** Get the elevation of a point with regards to the local point.
+     * <p>The elevation is the angle between the local horizontal and
+     * the direction from local point to given point.</p>
+     * @param <T> type of the elements
+     * @param extPoint point for which elevation shall be computed
+     * @param frame frame in which the point is defined
+     * @param date computation date
+     * @return elevation of the point
+     * @since 9.3
+     */
+    public <T extends RealFieldElement<T>> T getElevation(final FieldVector3D<T> extPoint, final Frame frame,
+                                                          final FieldAbsoluteDate<T> date) {
+
+        // Transform given point from given frame to topocentric frame
+        final FieldTransform<T> t = frame.getTransformTo(this, date);
+        final FieldVector3D<T> extPointTopo = t.transformPosition(extPoint);
+
+        // Elevation angle is PI/2 - angle between zenith and given point direction
+        return extPointTopo.getDelta();
+    }
+
     /** Get the azimuth of a point with regards to the topocentric frame center point.
      * <p>The azimuth is the angle between the North direction at local point and
      * the projection in local horizontal plane of the direction from local point
@@ -195,6 +235,33 @@ public class TopocentricFrame extends Frame implements PVCoordinatesProvider {
 
     }
 
+    /** Get the azimuth of a point with regards to the topocentric frame center point.
+     * <p>The azimuth is the angle between the North direction at local point and
+     * the projection in local horizontal plane of the direction from local point
+     * to given point. Azimuth angles are counted clockwise, i.e positive towards the East.</p>
+     * @param <T> type of the elements
+     * @param extPoint point for which elevation shall be computed
+     * @param frame frame in which the point is defined
+     * @param date computation date
+     * @return azimuth of the point
+     * @since 9.3
+     */
+    public <T extends RealFieldElement<T>> T getAzimuth(final FieldVector3D<T> extPoint, final Frame frame,
+                                                        final FieldAbsoluteDate<T> date) {
+
+        // Transform given point from given frame to topocentric frame
+        final FieldTransform<T> t = getTransformTo(frame, date).getInverse();
+        final FieldVector3D<T> extPointTopo = t.transformPosition(extPoint);
+
+        // Compute azimuth
+        T azimuth = FastMath.atan2(extPointTopo.getX(), extPointTopo.getY());
+        if (azimuth.getReal() < 0.) {
+            azimuth = azimuth.add(MathUtils.TWO_PI);
+        }
+        return azimuth;
+
+    }
+
     /** Get the range of a point with regards to the topocentric frame center point.
      * @param extPoint point for which range shall be computed
      * @param frame frame in which the point is defined
@@ -213,6 +280,26 @@ public class TopocentricFrame extends Frame implements PVCoordinatesProvider {
 
     }
 
+    /** Get the range of a point with regards to the topocentric frame center point.
+     * @param <T> type of the elements
+     * @param extPoint point for which range shall be computed
+     * @param frame frame in which the point is defined
+     * @param date computation date
+     * @return range (distance) of the point
+     * @since 9.3
+     */
+    public <T extends RealFieldElement<T>> T getRange(final FieldVector3D<T> extPoint, final Frame frame,
+                                                      final FieldAbsoluteDate<T> date) {
+
+        // Transform given point from given frame to topocentric frame
+        final FieldTransform<T> t = frame.getTransformTo(this, date);
+        final FieldVector3D<T> extPointTopo = t.transformPosition(extPoint);
+
+        // Compute range
+        return extPointTopo.getNorm();
+
+    }
+
     /** Get the range rate of a point with regards to the topocentric frame center point.
      * @param extPV point/velocity for which range rate shall be computed
      * @param frame frame in which the point is defined
@@ -232,6 +319,27 @@ public class TopocentricFrame extends Frame implements PVCoordinatesProvider {
 
     }
 
+    /** Get the range rate of a point with regards to the topocentric frame center point.
+     * @param <T> type of the elements
+     * @param extPV point/velocity for which range rate shall be computed
+     * @param frame frame in which the point is defined
+     * @param date computation date
+     * @return range rate of the point (positive if point departs from frame)
+     * @since 9.3
+     */
+    public <T extends RealFieldElement<T>> T getRangeRate(final FieldPVCoordinates<T> extPV, final Frame frame,
+                                                          final FieldAbsoluteDate<T> date) {
+
+        // Transform given point from given frame to topocentric frame
+        final FieldTransform<T> t = frame.getTransformTo(this, date);
+        final FieldPVCoordinates<T> extPVTopo = t.transformPVCoordinates(extPV);
+
+        // Compute range rate (doppler) : relative rate along the line of sight
+        return FieldVector3D.dotProduct(extPVTopo.getPosition(), extPVTopo.getVelocity()).divide(
+               extPVTopo.getPosition().getNorm());
+
+    }
+
     /**
      * Compute the limit visibility point for a satellite in a given direction.
      * <p>

src/main/java/org/orekit/models/earth/DiscreteTroposphericModel.java

+/* Copyright 2011-2012 Space Applications Services
+ * Licensed to CS Communication & Systèmes (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.
+ */
+package org.orekit.models.earth;
+
+import org.hipparchus.RealFieldElement;
+import org.orekit.time.AbsoluteDate;
+import org.orekit.time.FieldAbsoluteDate;
+
+/** Defines a tropospheric model, used to calculate the path delay imposed to
+ * electro-magnetic signals between an orbital satellite and a ground station.
+ * <p>
+ * Models that implement this interface split the delay into hydrostatic
+ * and non-hydrostatic part:
+ * </p>
+ * <pre>
+ * δ = δ<sub>h</sub> + δ<sub>nh</sub>
+ * </pre>
+ * With:
+ * <ul>
+ * <li> δ<sub>h</sub>  =  hydrostatic delay </li>
+ * <li> δ<sub>nh</sub> =  non-hydrostatic (or wet) delay </li>
+ * </ul>
+ * @author Bryan Cazabonne
+ */
+public interface DiscreteTroposphericModel extends MappingFunction {
+
+    /** Calculates the tropospheric path delay for the signal path from a ground
+     * station to a satellite.
+     *
+     * @param elevation the elevation of the satellite, in radians
+     * @param height the height of the station in m above sea level
+     * @param parameters tropospheric model parameters.
+     * @param date current date
+     * @return the path delay due to the troposphere in m
+     */
+    double pathDelay(double elevation, double height, double[] parameters, AbsoluteDate date);
+
+    /** Calculates the tropospheric path delay for the signal path from a ground
+     * station to a satellite.
+     *
+     * @param <T> type of the elements
+     * @param elevation the elevation of the satellite, in radians
+     * @param height the height of the station in m above sea level
+     * @param parameters tropospheric model parameters.
+     * @param date current date
+     * @return the path delay due to the troposphere in m
+     */
+    <T extends RealFieldElement<T>> T pathDelay(T elevation, T height, T[] parameters, FieldAbsoluteDate<T> date);
+
+    /** This method allows the  computation of the zenith hydrostatic and
+     * zenith wet delay. The resulting element is an array having the following form:
+     * <ul>
+     * <li>double[0] = D<sub>hz</sub> -&gt zenith hydrostatic delay
+     * <li>double[1] = D<sub>wz</sub> -&gt zenith wet delay
+     * </ul>
+     * @param height the height of the station in m above sea level.
+     * @param parameters tropospheric model parameters.
+     * @param date current date
+     * @return a two components array containing the zenith hydrostatic and wet delays.
+     */
+     double[] computeZenithDelay(double height, double[] parameters, AbsoluteDate date);
+
+    /** This method allows the  computation of the zenith hydrostatic and
+     * zenith wet delay. The resulting element is an array having the following form:
+     * <ul>
+     * <li>T[0] = D<sub>hz</sub> -&gt zenith hydrostatic delay
+     * <li>T[1] = D<sub>wz</sub> -&gt zenith wet delay
+     * </ul>
+     * @param <T> type of the elements
+     * @param height the height of the station in m above sea level.
+     * @param parameters tropospheric model parameters.
+     * @param date current date
+     * @return a two components array containing the zenith hydrostatic and wet delays.
+     */
+    <T extends RealFieldElement<T>> T[] computeZenithDelay(T height, T[] parameters, FieldAbsoluteDate<T> date);
+
+}

src/main/java/org/orekit/models/earth/EstimatedTroposphericModel.java

+/* Copyright 2002-2019 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.
+ */
+package org.orekit.models.earth;
+
+import java.util.Collections;
+import java.util.List;
+
+import org.hipparchus.Field;
+import org.hipparchus.RealFieldElement;
+import org.hipparchus.util.FastMath;
+import org.hipparchus.util.MathArrays;
+import org.orekit.time.AbsoluteDate;
+import org.orekit.time.FieldAbsoluteDate;
+import org.orekit.utils.ParameterDriver;
+
+/** An estimated tropospheric model. The tropospheric delay is computed according to the formula:
+ * <pre>
+ * δ = δ<sub>h</sub> * m<sub>h</sub> + (δ<sub>t</sub> - δ<sub>h</sub>) * m<sub>w</sub>
+ * </pre>
+ * With:
+ * <ul>
+ * <li>δ<sub>h</sub>: Tropospheric zenith hydro-static delay.</li>
+ * <li>δ<sub>t</sub>: Tropospheric total zenith delay.</li>
+ * <li>m<sub>h</sub>: Hydro-static mapping function.</li>
+ * <li>m<sub>w</sub>: Wet mapping function.</li>
+ * </ul>
+ * <p>
+ * The mapping functions m<sub>h</sub>(e) and m<sub>w</sub>(e) are
+ * computed thanks to a {@link #model} initialized by the user.
+ * The user has the possiblility to use several mapping function models for the computations:
+ * the {@link GlobalMappingFunctionModel Global Mapping Function}, or
+ * the {@link NiellMappingFunctionModel Niell Mapping Function}
+ * </p> <p>
+ * The tropospheric zenith delay δ<sub>h</sub> is computed empirically with a {@link SaastamoinenModel}
+ * while the tropospheric total zenith delay δ<sub>t</sub> is estimated as a {@link ParameterDriver}
+ */
+public class EstimatedTroposphericModel implements DiscreteTroposphericModel {
+
+    /** Name of the parameter of this model: the total zenith delay. */
+    public static final String TOTAL_ZENITH_DELAY = "total zenith delay";
+
+    /** Serializable UID. */
+    private static final long serialVersionUID = 3550108249909528948L;
+
+    /** Mapping Function model. */
+    private final MappingFunction model;
+
+    /** Driver for the tropospheric zenith total delay.*/
+    private final ParameterDriver totalZenithDelay;
+
+    /** The temperature at the station [K]. */
+    private double t0;
+
+    /** The atmospheric pressure [mbar]. */
+    private double p0;
+
+    /** Build a new instance using the given environmental conditions.
+     * @param t0 the temperature at the station [K]
+     * @param p0 the atmospheric pressure at the station [mbar]
+     * @param model mapping function model (NMF or GMF).
+     * @param totalDelay initial value for the tropospheric zenith total delay [m]
+     */
+    public EstimatedTroposphericModel(final double t0, final double p0,
+                                      final MappingFunction model, final double totalDelay) {
+
+        totalZenithDelay = new ParameterDriver(EstimatedTroposphericModel.TOTAL_ZENITH_DELAY,
+                                               totalDelay, FastMath.scalb(1.0, 0), 0.0, Double.POSITIVE_INFINITY);
+
+        this.t0    = t0;
+        this.p0    = p0;
+        this.model = model;
+    }
+
+    /** Build a new instance using a standard atmosphere model.
+     * <ul>
+     * <li>temperature: 18 degree Celsius
+     * <li>pressure: 1013.25 mbar
+     * </ul>
+     * @param model mapping function model (NMF or GMF).
+     * @param totalDelay initial value for the tropospheric zenith total delay [m]
+     */
+    public EstimatedTroposphericModel(final MappingFunction model, final double totalDelay) {
+        this(273.15 + 18.0, 1013.25, model, totalDelay);
+    }
+
+    @Override
+    public double[] mappingFactors(final double elevation, final double height,
+                                   final double[] parameters, final AbsoluteDate date) {
+        return model.mappingFactors(elevation, height, parameters, date);
+    }
+
+    @Override
+    public <T extends RealFieldElement<T>> T[] mappingFactors(final T elevation, final T height,
+                                                              final T[] parameters, final FieldAbsoluteDate<T> date) {
+        return model.mappingFactors(elevation, height, parameters, date);
+    }
+
+    @Override
+    public List<ParameterDriver> getParametersDrivers() {
+        return Collections.singletonList(totalZenithDelay);
+    }
+
+    @Override
+    public double pathDelay(final double elevation, final double height,
+                            final double[] parameters, final AbsoluteDate date) {
+
+        // Mapping functions
+        final double[] mf = mappingFactors(elevation, height, parameters, date);
+        // Zenith delays
+        final double[] delays = computeZenithDelay(height, parameters, date);
+        // Total delay
+        return mf[0] * delays[0] + mf[1] * (delays[1] - delays[0]);
+    }
+
+    @Override
+    public <T extends RealFieldElement<T>> T pathDelay(final T elevation, final T height,
+                                                       final T[] parameters, final FieldAbsoluteDate<T> date) {
+
+        // Mapping functions
+        final T[] mf = mappingFactors(elevation, height, parameters, date);
+        // Zenith delays
+        final T[] delays = computeZenithDelay(height, parameters, date);
+        // Total delay
+        return mf[0].multiply(delays[0]).add(mf[1].multiply(delays[1].subtract(delays[0])));
+    }
+
+    /** This method allows the computation of the zenith hydrostatic and zenith total delays.
+     *  The resulting element is an array having the following form:
+     * <ul>
+     * <li>double[0] = D<sub>hz</sub> -&gt zenith hydrostatic delay
+     * <li>double[1] = D<sub>tz</sub> -&gt zenith total delay
+     * </ul>
+     * <p>
+     * The user have to be careful because the others tropospheric models in Orekit
+     * compute the zenith wet delay instead of the total zenith delay.
+     * </p>
+     * @param height the height of the station in m above sea level.
+     * @param parameters tropospheric model parameters.
+     * @param date current date
+     * @return a two components array containing the zenith hydrostatic and wet delays.
+     */
+    public double[] computeZenithDelay(final double height, final double[] parameters,
+                                       final AbsoluteDate date) {
+
+        // Use an empirical model for tropospheric zenith hydro-static delay : Saastamoinen model
+        final SaastamoinenModel saastamoinen = new SaastamoinenModel(t0, p0, 0.0, (String) null);
+
+        // elevation = pi/2 because we compute the delay in the zenith direction
+        final double zhd = saastamoinen.pathDelay(0.5 * FastMath.PI, height, parameters, date);
+        final double ztd = parameters[0];
+
+        return new double[] {
+            zhd,
+            ztd
+        };
+    }
+
+    /** This method allows the computation of the zenith hydrostatic and zenith total delays.
+     *  The resulting element is an array having the following form:
+     * <ul>
+     * <li>double[0] = D<sub>hz</sub> -&gt zenith hydrostatic delay
+     * <li>double[1] = D<sub>tz</sub> -&gt zenith total delay
+     * </ul>
+     * <p>
+     * The user have to be careful because the others tropospheric models in Orekit
+     * compute the zenith wet delay instead of the total zenith delay.
+     * </p>
+     * @param <T> type of the elements
+     * @param height the height of the station in m above sea level.
+     * @param parameters tropospheric model parameters.
+     * @param date current date
+     * @return a two components array containing the zenith hydrostatic and wet delays.
+     */
+    public <T extends RealFieldElement<T>> T[] computeZenithDelay(final T height, final T[] parameters,
+                                                                  final FieldAbsoluteDate<T> date) {
+
+        // Field
+        final Field<T> field = date.getField();
+        final T zero         = field.getZero();
+
+        // Use an empirical model for tropospheric zenith hydro-static delay : Saastamoinen model
+        final SaastamoinenModel saastamoinen = new SaastamoinenModel(t0, p0, 0.0, (String) null);
+
+        // elevation = pi/2 because we compute the delay in the zenith direction
+        final T zhd = saastamoinen.pathDelay(zero.add(0.5 * FastMath.PI), height, parameters, date);
+        final T ztd = parameters[0];
+
+        final T[] delays = MathArrays.buildArray(field, 2);
+        delays[0] = zhd;
+        delays[1] = ztd;
+
+        return delays;
+    }
+
+}

src/main/java/org/orekit/models/earth/MappingFunction.java

+/* Copyright 2011-2012 Space Applications Services
+ * Licensed to CS Communication & Systèmes (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.
+ */
+package org.orekit.models.earth;
+
+import java.io.Serializable;
+import java.util.List;
+
+import org.hipparchus.Field;
+import org.hipparchus.RealFieldElement;
+import org.hipparchus.util.MathArrays;
+import org.orekit.time.AbsoluteDate;
+import org.orekit.time.FieldAbsoluteDate;
+import org.orekit.utils.ParameterDriver;
+
+/** Interface for mapping functions used in the tropospheric delay computation.
+ * @author Bryan Cazabonne
+ */
+public interface MappingFunction extends Serializable {
+
+    /** This method allows the computation of the hydrostatic and
+     * wet mapping functions. The resulting element is an array having the following form:
+     * <ul>
+     * <li>double[0] = m<sub>h</sub>(e) -&gt hydrostatic mapping function
+     * <li>double[1] = m<sub>w</sub>(e) -&gt wet mapping function
+     * </ul>
+     * @param elevation the elevation of the satellite, in radians.
+     * @param height the height of the station in m above sea level.
+     * @param parameters tropospheric model parameters.
+     * @param date current date
+     * @return a two components array containing the hydrostatic and wet mapping functions.
+     */
+    double[] mappingFactors(double elevation, double height, double[] parameters, AbsoluteDate date);
+
+    /** This method allows the computation of the hydrostatic and
+     * wet mapping functions. The resulting element is an array having the following form:
+     * <ul>
+     * <li>T[0] = m<sub>h</sub>(e) -&gt hydrostatic mapping function
+     * <li>T[1] = m<sub>w</sub>(e) -&gt wet mapping function
+     * </ul>
+     * @param elevation the elevation of the satellite, in radians.
+     * @param height the height of the station in m above sea level.
+     * @param parameters tropospheric model parameters.
+     * @param date current date
+     * @param <T> type of the elements
+     * @return a two components array containing the hydrostatic and wet mapping functions.
+     */
+    <T extends RealFieldElement<T>> T[] mappingFactors(T elevation, T height, T[] parameters, FieldAbsoluteDate<T> date);
+
+    /** Get the drivers for tropospheric model parameters.
+     * @return drivers for tropospheric model parameters
+     */
+    List<ParameterDriver> getParametersDrivers();
+
+    /** Get tropospheric model parameters.
+     * @return tropospheric model parameters
+     */
+    default double[] getParameters() {
+        final List<ParameterDriver> drivers = getParametersDrivers();
+        final double[] parameters = new double[drivers.size()];
+        for (int i = 0; i < drivers.size(); ++i) {
+            parameters[i] = drivers.get(i).getValue();
+        }
+        return parameters;
+    }
+
+    /** Get tropospheric model parameters.
+     * @param field field to which the elements belong
+     * @param <T> type of the elements
+     * @return tropospheric model parameters
+     */
+    default <T extends RealFieldElement<T>> T[] getParameters(final Field<T> field) {
+        final List<ParameterDriver> drivers = getParametersDrivers();
+        final T[] parameters = MathArrays.buildArray(field, drivers.size());
+        for (int i = 0; i < drivers.size(); ++i) {
+            parameters[i] = field.getZero().add(drivers.get(i).getValue());
+        }
+        return parameters;
+    }
+}

src/main/java/org/orekit/models/earth/MariniMurrayModel.java

@@ -75,7 +75,7 @@ public class MariniMurrayModel implements TroposphericModel {
      * @param latitude site latitude
      * @param lambda laser wavelength (c/f), nm
      *
-     * @return a Saastamoinen model with standard environmental values
+     * @return a Marini-Murray model with standard environmental values
      */
     public static MariniMurrayModel getStandardModel(final double latitude, final double lambda) {
         return new MariniMurrayModel(273.15 + 20, 1013.25, 0.5, latitude, lambda);

src/main/java/org/orekit/models/earth/TroposphericModel.java

@@ -16,14 +16,27 @@
  */
 package org.orekit.models.earth;
 
-import java.io.Serializable;
+import java.util.Collections;
+import java.util.List;
+
+import org.hipparchus.Field;
+import org.hipparchus.RealFieldElement;
+import org.hipparchus.util.FastMath;
+import org.hipparchus.util.MathArrays;
+import org.orekit.time.AbsoluteDate;
+import org.orekit.time.FieldAbsoluteDate;
+import org.orekit.utils.ParameterDriver;
 
 /** Defines a tropospheric model, used to calculate the path delay imposed to
  * electro-magnetic signals between