eclipseIntervals

Calculate intervals of solar occultation

Since R2023b

Syntax

interval_table = eclipseIntervals(eclipse_objects)

Description

interval_table = eclipseIntervals(eclipse_objects) returns a table, interval_table, of solar occultation intervals. During each interval, the eclipse status corresponding to each eclipse object in the input vector eclipse_objects is nonzero.

Examples

Add Eclipse Analysis Object to Satellite and Ground Station

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
    MaskElevationAngle:  0 degrees
      MaskAzimuthEdges:  [0 360]
        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    

Input Arguments

eclipse_objects — Vector of eclipse objects

vector

Vector of eclipse objects, specified as a vector of Eclipse objects.

Example: eclSat, where eclSat is a vector eclipse objects added to satellites.

Output Arguments

interval_table — Solar occultation interval table

table

Solar occultation interval table, returned as a table. Each row of the table denotes a specific interval.

Column	Description
Asset	Name of Satellite or GroundStation object to which the solar occultation is observed.
EclipsingBody	Name of body (Earth, Moon, or Earth and Moon) occulting the Sun.
IntervalNumber	Eclipse interval number for Asset.
StartTime	Start time of the interval.
EndTime	End time of the interval.
Duration	Duration of the interval, returned in seconds.
MinimumEclipseStatus	Minimum eclipse status in the interval, returned as a value between 0 and 1.
StartOrbit	Orbit number counted from scenario start time that corresponds to the interval start time. For ground stations, this value is NaN.
EndOrbit	Orbit number counted from scenario start time corresponding to the interval end time. For ground stations, this value is NaN.

Limitations

• 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