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Eclipse

Eclipse analysis object belonging to scenario

Since R2023b

    Description

    The Eclipse object defines an eclipse analysis object belonging to a Satellite or GroundStation object. Use the Eclipse object to calculate the fraction of the solar disk that is visible from the satellite or the ground station position.

    Creation

    Create an Eclipse object using the eclipse object function of GroundStation or Satellite object.

    Properties

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    Eclipse model to calculate solar occultation as observed from the position of the parent asset, specified as one of these values:

    • dual-cone — Calculate a fraction of the solar disk eclipsed while assuming that the occulting bodies and the Sun are spherical.

    • cylindrical — Calculate a fraction of the solar disk eclipsed while assuming that:

      • The Sun is infinitely far from the occulting bodies and the satellite.

      • All rays of sunlight are parallel.

    Option to include the lunar eclipse in the calculation of the solar occultation, specified as false or true. To include the lunar eclipse in the calculation, specify true. Otherwise, specify false.

    Object Functions

    eclipseIntervalsCalculate intervals of solar occultation
    eclipsePercentageCalculate percentage of time when solar occultation occurs

    Examples

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    Add an eclipse analysis object to a satellite, sat, and ground station, gs, and calculate the eclipse intervals, intvls.

    Create a satellite scenario object, sc.

    startTime = datetime(2023,4,20);
    stopTime = startTime + days(1);
    sampleTime = 10; % seconds
    sc = satelliteScenario(startTime,stopTime,sampleTime);

    Add a ground station, gs, to the scenario, sc.

    gs = groundStation(sc, ...
        1.038102, ... % latitude, degrees
        135.980085);  % longitude, degrees

    Add a satellite, sat, to the scenario, sc. Set the orbit propagator as a two-body-keplerian.

    sat = satellite(sc, ...
        10000000, ... % semimajor axis, meters
        0, ...        % eccentricity
        0, ...        % inclination, degrees
        0, ...        % right ascension of ascending node, degrees
        0, ...        % argument of periapsis, degrees
        0, ...        % true anomaly, degrees
        OrbitPropagator="two-body-keplerian");

    Add the eclipse analysis object to the ground station, gs. Include the lunar eclipse in the analysis. By default, the eclipse model is for a dual-cone.

    eclGs = eclipse(gs,IncludeLunarEclipse=true)
    eclGs = 
      Eclipse with properties:
    
               EclipseModel: "dual-cone"
        IncludeLunarEclipse: 1
    
    

    Add the eclipse analysis object to the satellite, sat. Include the lunar eclipse in the analysis. By default, the eclipse model is for a dual-cone.

    eclSat = eclipse(sat,IncludeLunarEclipse=true)
    eclSat = 
      Eclipse with properties:
    
               EclipseModel: "dual-cone"
        IncludeLunarEclipse: 1
    
    

    Inspect the satellite and ground station object properties. Note that their Eclipse properties are nonempty, which indicates that the eclipse analyses have been added.

    Eclipse: [1x1 Aero.satellitescenario.Eclipse]

    sat
    sat = 
      Satellite with properties:
    
                      Name:  Satellite 2
                        ID:  2
            ConicalSensors:  [1x0 matlabshared.satellitescenario.ConicalSensor]
                   Gimbals:  [1x0 matlabshared.satellitescenario.Gimbal]
              Transmitters:  [1x0 satcom.satellitescenario.Transmitter]
                 Receivers:  [1x0 satcom.satellitescenario.Receiver]
                  Accesses:  [1x0 matlabshared.satellitescenario.Access]
                   Eclipse:  [1x1 Aero.satellitescenario.Eclipse]
               GroundTrack:  [1x1 matlabshared.satellitescenario.GroundTrack]
                     Orbit:  [1x1 matlabshared.satellitescenario.Orbit]
            CoordinateAxes:  [1x1 matlabshared.satellitescenario.CoordinateAxes]
           OrbitPropagator:  two-body-keplerian
               MarkerColor:  [0.059 1 1]
                MarkerSize:  6
                 ShowLabel:  true
            LabelFontColor:  [1 1 1]
             LabelFontSize:  15
             Visual3DModel:  
        Visual3DModelScale:  1
    
    
    gs
    gs = 
      GroundStation with properties:
    
                     Name:  Ground station 1
                       ID:  1
                 Latitude:  1.0381 degrees
                Longitude:  135.98 degrees
                 Altitude:  0 meters
        MinElevationAngle:  0 degrees
           ConicalSensors:  [1x0 matlabshared.satellitescenario.ConicalSensor]
                  Gimbals:  [1x0 matlabshared.satellitescenario.Gimbal]
             Transmitters:  [1x0 satcom.satellitescenario.Transmitter]
                Receivers:  [1x0 satcom.satellitescenario.Receiver]
                 Accesses:  [1x0 matlabshared.satellitescenario.Access]
                  Eclipse:  [1x1 Aero.satellitescenario.Eclipse]
           CoordinateAxes:  [1x1 matlabshared.satellitescenario.CoordinateAxes]
              MarkerColor:  [1 0.4118 0.1608]
               MarkerSize:  6
                ShowLabel:  true
           LabelFontColor:  [1 1 1]
            LabelFontSize:  15
    
    

    Calculate the eclipse intervals for both eclipse objects, specified as the vector [eclGs eclSat].

    intvls = eclipseIntervals(eclSat)
    intvls=12×9 table
            Asset         EclipsingBody      IntervalNumber         StartTime                EndTime           Duration    MinimumEclipseStatus    StartOrbit    EndOrbit
        _____________    ________________    ______________    ____________________    ____________________    ________    ____________________    __________    ________
    
        "Satellite 2"    "Earth"                    1          20-Apr-2023 01:17:50    20-Apr-2023 01:53:10      2120                  0               1            1    
        "Satellite 2"    "Moon"                     2          20-Apr-2023 02:43:30    20-Apr-2023 02:56:40       790            0.87839               1            2    
        "Satellite 2"    "Earth"                    3          20-Apr-2023 04:03:50    20-Apr-2023 04:39:10      2120                  0               2            2    
        "Satellite 2"    "Moon"                     4          20-Apr-2023 05:53:50    20-Apr-2023 06:49:40      3350            0.17465               3            3    
        "Satellite 2"    "Earth and Moon"           5          20-Apr-2023 06:49:40    20-Apr-2023 06:51:20       100                  0               3            3    
        "Satellite 2"    "Earth"                    6          20-Apr-2023 06:51:20    20-Apr-2023 07:25:00      2020                  0               3            3    
        "Satellite 2"    "Earth"                    7          20-Apr-2023 09:35:40    20-Apr-2023 10:11:00      2120                  0               4            4    
        "Satellite 2"    "Earth"                    8          20-Apr-2023 12:21:30    20-Apr-2023 12:56:50      2120                  0               5            5    
        "Satellite 2"    "Earth"                    9          20-Apr-2023 15:07:30    20-Apr-2023 15:42:50      2120                  0               6            6    
        "Satellite 2"    "Earth"                   10          20-Apr-2023 17:53:20    20-Apr-2023 18:28:40      2120                  0               7            7    
        "Satellite 2"    "Earth"                   11          20-Apr-2023 20:39:20    20-Apr-2023 21:14:40      2120                  0               8            8    
        "Satellite 2"    "Earth"                   12          20-Apr-2023 23:25:10    21-Apr-2023 00:00:00      2090                  0               9            9    
    
    

    Limitations

    • When the AutoSimulate property of the satellite scenario is false, you can call eclipse only when SimulationStatus is NotStarted. Otherwise, you must call the restart function to reset SimulationStatus to NotStarted. Calling restart removes the simulation data.

    • The function ignores:

      • Atmospheric refractions.

      • Sunlight transit time delays.

    • The function assumes Earth, Moon, and Sun possess spherical geometries, with radii equal to their equatorial radii.

    • When the value of EclipsingBody from the solar occultation interval table is Earth and Moon, the predicted value of MinimumEclipseStatus is lower than the actual value.

    Version History

    Introduced in R2023b