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Commit 624c926c authored by Guylaine Prat's avatar Guylaine Prat
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Source code for Wiki page tutorial InverseLocation

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/* Copyright 2013-2015 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 fr.cs.examples;
import java.io.File;
import java.util.ArrayList;
import java.util.List;
import java.util.Locale;
import org.apache.commons.math3.geometry.euclidean.threed.Rotation;
import org.apache.commons.math3.geometry.euclidean.threed.Vector3D;
import org.apache.commons.math3.util.FastMath;
import org.orekit.bodies.GeodeticPoint;
import org.orekit.data.DataProvidersManager;
import org.orekit.data.DirectoryCrawler;
import org.orekit.errors.OrekitException;
import org.orekit.frames.Frame;
import org.orekit.frames.FramesFactory;
import org.orekit.frames.Transform;
import org.orekit.rugged.api.AlgorithmId;
import org.orekit.rugged.api.BodyRotatingFrameId;
import org.orekit.rugged.api.EllipsoidId;
import org.orekit.rugged.api.InertialFrameId;
import org.orekit.rugged.api.Rugged;
import org.orekit.rugged.api.RuggedBuilder;
import org.orekit.rugged.errors.RuggedException;
import org.orekit.rugged.linesensor.LineSensor;
import org.orekit.rugged.linesensor.LinearLineDatation;
import org.orekit.rugged.linesensor.SensorPixel;
import org.orekit.rugged.los.LOSBuilder;
import org.orekit.rugged.los.FixedRotation;
import org.orekit.rugged.los.TimeDependentLOS;
import org.orekit.rugged.utils.ParameterType;
import org.orekit.time.AbsoluteDate;
import org.orekit.time.TimeScale;
import org.orekit.time.TimeScalesFactory;
import org.orekit.utils.AngularDerivativesFilter;
import org.orekit.utils.CartesianDerivativesFilter;
import org.orekit.utils.IERSConventions;
import org.orekit.utils.PVCoordinates;
import org.orekit.utils.TimeStampedAngularCoordinates;
import org.orekit.utils.TimeStampedPVCoordinates;
public class InverseLocation {
public static void main(String[] args) {
try {
// Initialize Orekit, assuming an orekit-data folder is in user home directory
File home = new File(System.getProperty("user.home"));
File orekitData = new File(home, "orekit-data");
DataProvidersManager.getInstance().addProvider(new DirectoryCrawler(orekitData));
// The raw viewing direction of pixel i with respect to the instrument is defined by the vector:
List<Vector3D> rawDirs = new ArrayList<Vector3D>();
for (int i = 0; i < 2000; i++) {
//20° field of view, 2000 pixels
rawDirs.add(new Vector3D(0d, i*FastMath.toRadians(20)/2000d, 1d));
}
// The instrument is oriented 10° off nadir around the X-axis, we need to rotate the viewing
// direction to obtain the line of sight in the satellite frame
LOSBuilder losBuilder = new LOSBuilder(rawDirs);
losBuilder.addTransform(new FixedRotation(ParameterType.FIXED, Vector3D.PLUS_I, FastMath.toRadians(10)));
TimeDependentLOS lineOfSight = losBuilder.build();
// We use Orekit for handling time and dates, and Rugged for defining the datation model:
TimeScale gps = TimeScalesFactory.getGPS();
AbsoluteDate absDate = new AbsoluteDate("2009-12-11T16:59:30.0", gps);
LinearLineDatation lineDatation = new LinearLineDatation(absDate, 1d, 20);
// With the LOS and the datation now defined , we can initialize a line sensor object in Rugged:
String sensorName = "mySensor";
LineSensor lineSensor = new LineSensor(sensorName, lineDatation, Vector3D.ZERO, lineOfSight);
// In our application, we simply need to know the name of the frames we are working with. Positions and
// velocities are given in the ITRF terrestrial frame, while the quaternions are given in EME2000
// inertial frame.
Frame eme2000 = FramesFactory.getEME2000();
boolean simpleEOP = true; // we don't want to compute tiny tidal effects at millimeter level
Frame itrf = FramesFactory.getITRF(IERSConventions.IERS_2010, simpleEOP);
ArrayList<TimeStampedAngularCoordinates> satelliteQList = new ArrayList<TimeStampedAngularCoordinates>();
ArrayList<TimeStampedPVCoordinates> satellitePVList = new ArrayList<TimeStampedPVCoordinates>();
addSatelliteQ(gps, satelliteQList, "2009-12-11T16:58:42.592937", -0.340236d, 0.333952d, -0.844012d, -0.245684d);
addSatelliteQ(gps, satelliteQList, "2009-12-11T16:59:06.592937", -0.354773d, 0.329336d, -0.837871d, -0.252281d);
addSatelliteQ(gps, satelliteQList, "2009-12-11T16:59:30.592937", -0.369237d, 0.324612d, -0.831445d, -0.258824d);
addSatelliteQ(gps, satelliteQList, "2009-12-11T16:59:54.592937", -0.3836d, 0.319792d, -0.824743d, -0.265299d);
addSatelliteQ(gps, satelliteQList, "2009-12-11T17:00:18.592937", -0.397834d, 0.314883d, -0.817777d, -0.271695d);
addSatelliteQ(gps, satelliteQList, "2009-12-11T17:00:42.592937", -0.411912d, 0.309895d, -0.810561d, -0.278001d);
addSatelliteQ(gps, satelliteQList, "2009-12-11T17:01:06.592937", -0.42581d, 0.304838d, -0.803111d, -0.284206d);
addSatelliteQ(gps, satelliteQList, "2009-12-11T17:01:30.592937", -0.439505d, 0.299722d, -0.795442d, -0.290301d);
addSatelliteQ(gps, satelliteQList, "2009-12-11T17:01:54.592937", -0.452976d, 0.294556d, -0.787571d, -0.296279d);
addSatelliteQ(gps, satelliteQList, "2009-12-11T17:02:18.592937", -0.466207d, 0.28935d, -0.779516d, -0.302131d);
addSatellitePV(gps, eme2000, itrf, satellitePVList, "2009-12-11T16:58:42.592937", -726361.466d, -5411878.485d, 4637549.599d, -2463.635d, -4447.634d, -5576.736d);
addSatellitePV(gps, eme2000, itrf, satellitePVList, "2009-12-11T16:59:04.192937", -779538.267d, -5506500.533d, 4515934.894d, -2459.848d, -4312.676d, -5683.906d);
addSatellitePV(gps, eme2000, itrf, satellitePVList, "2009-12-11T16:59:25.792937", -832615.368d, -5598184.195d, 4392036.13d, -2454.395d, -4175.564d, -5788.201d);
addSatellitePV(gps, eme2000, itrf, satellitePVList, "2009-12-11T16:59:47.392937", -885556.748d, -5686883.696d, 4265915.971d, -2447.273d, -4036.368d, -5889.568d);
addSatellitePV(gps, eme2000, itrf, satellitePVList, "2009-12-11T17:00:08.992937", -938326.32d, -5772554.875d, 4137638.207d, -2438.478d, -3895.166d, -5987.957d);
addSatellitePV(gps, eme2000, itrf, satellitePVList, "2009-12-11T17:00:30.592937", -990887.942d, -5855155.21d, 4007267.717d, -2428.011d, -3752.034d, -6083.317d);
addSatellitePV(gps, eme2000, itrf, satellitePVList, "2009-12-11T17:00:52.192937", -1043205.448d, -5934643.836d, 3874870.441d, -2415.868d, -3607.05d, -6175.6d);
addSatellitePV(gps, eme2000, itrf, satellitePVList, "2009-12-11T17:01:13.792937", -1095242.669d, -6010981.571d, 3740513.34d, -2402.051d, -3460.291d, -6264.76d);
addSatellitePV(gps, eme2000, itrf, satellitePVList, "2009-12-11T17:01:35.392937", -1146963.457d, -6084130.93d, 3604264.372d, -2386.561d, -3311.835d, -6350.751d);
addSatellitePV(gps, eme2000, itrf, satellitePVList, "2009-12-11T17:01:56.992937", -1198331.706d, -6154056.146d, 3466192.446d, -2369.401d, -3161.764d, -6433.531d);
addSatellitePV(gps, eme2000, itrf, satellitePVList, "2009-12-11T17:02:18.592937", -1249311.381d, -6220723.191d, 3326367.397d, -2350.574d, -3010.159d, -6513.056d);
Rugged rugged = new RuggedBuilder().
setAlgorithm(AlgorithmId.IGNORE_DEM_USE_ELLIPSOID).
setEllipsoid(EllipsoidId.WGS84, BodyRotatingFrameId.ITRF).
setTimeSpan(absDate, absDate.shiftedBy(60.0), 0.01, 5 / lineSensor.getRate(0)).
setTrajectory(InertialFrameId.EME2000,
satellitePVList, 4, CartesianDerivativesFilter.USE_P,
satelliteQList, 4, AngularDerivativesFilter.USE_R).
addLineSensor(lineSensor).
build();
// Point defined by its latitude, longitude and altitude
double latitude = FastMath.toRadians(37.585);
double longitude = FastMath.toRadians(-96.949);
double altitude = 0.0d;
GeodeticPoint gp = new GeodeticPoint(latitude, longitude, altitude);
// Search the sensor pixel seeing point
int minLine = 0;
int maxLine = 100;
SensorPixel sensorPixel = rugged.inverseLocation(sensorName, gp, minLine, maxLine);
// we need to test if the sensor pixel is found in the prescribed lines otherwise the sensor pixel is null
if (sensorPixel != null){
System.out.format(Locale.US, "Sensor Pixel found : line = %5.3f, pixel = %5.3f %n", sensorPixel.getLineNumber(), sensorPixel.getPixelNumber());
} else {
System.out.println("Sensor Pixel is null: point cannot be seen between the prescribed line numbers\n");
}
// Find the date at which the sensor sees the ground point
AbsoluteDate dateLine = rugged.dateLocation(sensorName, gp, minLine, maxLine);
System.out.println("Date at which the sensor sees the ground point : " + dateLine);
} catch (OrekitException oe) {
System.err.println(oe.getLocalizedMessage());
System.exit(1);
} catch (RuggedException re) {
System.err.println(re.getLocalizedMessage());
System.exit(1);
}
}
private static void addSatellitePV(TimeScale gps, Frame eme2000, Frame itrf,
ArrayList<TimeStampedPVCoordinates> satellitePVList,
String absDate,
double px, double py, double pz, double vx, double vy, double vz)
throws OrekitException {
AbsoluteDate ephemerisDate = new AbsoluteDate(absDate, gps);
Vector3D position = new Vector3D(px, py, pz);
Vector3D velocity = new Vector3D(vx, vy, vz);
PVCoordinates pvITRF = new PVCoordinates(position, velocity);
Transform transform = itrf.getTransformTo(eme2000, ephemerisDate);
PVCoordinates pvEME2000 = transform.transformPVCoordinates(pvITRF);
satellitePVList.add(new TimeStampedPVCoordinates(ephemerisDate, pvEME2000.getPosition(), pvEME2000.getVelocity(), Vector3D.ZERO));
}
private static void addSatelliteQ(TimeScale gps, ArrayList<TimeStampedAngularCoordinates> satelliteQList, String absDate,
double q0, double q1, double q2, double q3) {
AbsoluteDate attitudeDate = new AbsoluteDate(absDate, gps);
Rotation rotation = new Rotation(q0, q1, q2, q3, true);
TimeStampedAngularCoordinates pair =
new TimeStampedAngularCoordinates(attitudeDate, rotation, Vector3D.ZERO, Vector3D.ZERO);
satelliteQList.add(pair);
}
}
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