Rectangular field of View

[YangYang]

hello
I now want to modify the sensor type of the satellite in the event detector code so that the observation task can be completed. The type of sensor is rectangular, while half vertical angle and horizontal angle are both 5deg. I know how to use the DoubleDihedraFieldOfView class, but I don’t know which method to use. How to call this method? I also hope you can teach me.
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package org.orekit.tutorials.propagation;

import java.io.File;
import java.util.Locale;

import org.hipparchus.geometry.euclidean.threed.Vector3D;
import org.hipparchus.ode.events.Action;
import org.hipparchus.util.FastMath;
import org.orekit.bodies.BodyShape;
import org.orekit.bodies.GeodeticPoint;
import org.orekit.bodies.OneAxisEllipsoid;
import org.orekit.data.DataContext;
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.TopocentricFrame;
import org.orekit.orbits.KeplerianOrbit;
import org.orekit.orbits.Orbit;
import org.orekit.propagation.Propagator;
import org.orekit.propagation.SpacecraftState;
import org.orekit.propagation.analytical.KeplerianPropagator;
import org.orekit.propagation.events.ElevationDetector;
import org.orekit.propagation.events.EventDetector;
import org.orekit.time.AbsoluteDate;
import org.orekit.time.TimeScalesFactory;
import org.orekit.utils.Constants;
import org.orekit.utils.IERSConventions;
import org.orekit.utils.PVCoordinates;

/** Orekit tutorial for special event detection.

• This tutorial shows how to easily check for visibility between a satellite and a ground station.

• @author Pascal Parraud
  */
  public class VisibilityCheck {

  /** Private constructor for utility class. */
  private VisibilityCheck() {
  // empty
  }

  /** Program entry point.

  • @param args program arguments (unused here)
    */
    public static void main(final String args) {
    try {

     // configure Orekit
     final File home       = new File(System.getProperty("user.home"));
     final File orekitData = new File(home, "orekit-data");
     if (!orekitData.exists()) {
         System.err.format(Locale.US, "Failed to find %s folder%n",
                           orekitData.getAbsolutePath());
         System.err.format(Locale.US, "You need to download %s from %s, unzip it in %s and rename it 'orekit-data' for this tutorial to work%n",
                           "orekit-data-master.zip", "https://gitlab.orekit.org/orekit/orekit-data/-/archive/master/orekit-data-master.zip",
                           home.getAbsolutePath());
         System.exit(1);
     }
     final DataProvidersManager manager = DataContext.getDefault().getDataProvidersManager();
     manager.addProvider(new DirectoryCrawler(orekitData));
    
     //  Initial state definition : date, orbit
     final AbsoluteDate initialDate = new AbsoluteDate(2004, 01, 01, 23, 30, 00.000, TimeScalesFactory.getUTC());
     final double mu =  3.986004415e+14; // gravitation coefficient
     final Frame inertialFrame = FramesFactory.getEME2000(); // inertial frame for orbit definition
     final Vector3D position  = new Vector3D(-6142438.668, 3492467.560, -25767.25680);
     final Vector3D velocity  = new Vector3D(505.8479685, 942.7809215, 7435.922231);
     final PVCoordinates pvCoordinates = new PVCoordinates(position, velocity);
     final Orbit initialOrbit = new KeplerianOrbit(pvCoordinates, inertialFrame, initialDate, mu);
    
     // Propagator : consider a simple Keplerian motion (could be more elaborate)
     final Propagator kepler = new KeplerianPropagator(initialOrbit);
    
     // Earth and frame
     final Frame earthFrame = FramesFactory.getITRF(IERSConventions.IERS_2010, true);
     final BodyShape earth = new OneAxisEllipsoid(Constants.WGS84_EARTH_EQUATORIAL_RADIUS,
                                                  Constants.WGS84_EARTH_FLATTENING,
                                                  earthFrame);
    
     // Station
     final double longitude = FastMath.toRadians(45.);
     final double latitude  = FastMath.toRadians(25.);
     final double altitude  = 0.;
     final GeodeticPoint station1 = new GeodeticPoint(latitude, longitude, altitude);
     final TopocentricFrame sta1Frame = new TopocentricFrame(earth, station1, "station1");
    
     // Event definition
     final double maxcheck  = 60.0;
     final double threshold =  0.001;
     final double elevation = FastMath.toRadians(5.0);
     final EventDetector sta1Visi =
             new ElevationDetector(maxcheck, threshold, sta1Frame).
             withConstantElevation(elevation).
             withHandler((s, detector, increasing) -> {
                 System.out.println(" Visibility on " +
                                    detector.getTopocentricFrame().getName() +
                                    (increasing ? " begins at " : " ends at ") +
                                    s.getDate());
                 return increasing ? Action.CONTINUE : Action.STOP;
             });
    
     // Add event to be detected
     kepler.addEventDetector(sta1Visi);
    
     // Propagate from the initial date to the first raising or for the fixed duration
     final SpacecraftState finalState = kepler.propagate(initialDate.shiftedBy(1500.));
    
     System.out.println(" Final state : " + finalState.getDate().durationFrom(initialDate));
    

    } catch (OrekitException oe) {
    System.err.println(oe.getLocalizedMessage());
    }
    }

}