Satellite

Satellite object belonging to satellite scenario

Description

Satellite defines a satellite object belonging to a satellite scenario.

Creation

You can create Satellite objects using the satellite function of satelliteScenario.

Properties

Name — Satellite name

"Satellite idx" (default) | string scalar | string vector | character vector | cell array of character vectors

You can set this property only when calling the satellite function. After you call satellite, this property is read-only.

Satellite name, specified as a comma-separated pair consisting of 'Name' and a string scalar, string vector, character vector or a cell array of character vectors.

• If only one Satellite is added, specify Name as a string scalar or a character vector.

• If multiple Satellites are added, specify Name as a string scalar, character vector, string vector or a cell array of character vectors. All Satellites added as a string scalar or a character vector are assigned the same specified name. The number of elements in the string vector or cell array of character vector must equal the number of Satellites being added. Each Satellite is assigned the corresponding name from the vector or cell array.

In the default value, idx is the ID of the Satellites added by the Satellite object function.

Data Types: char | string

ID — Satellite ID assigned by simulator

real positive scalar

This property is set internally by the simulator and is read-only.

Satellite ID assigned by the simulator, specified as a positive scalar.

ConicalSensors — Conical sensors

row vector of conical sensors

You can set this property only when calling conicalSensor. After you call conicalSensor, this property is read-only.

Conical sensors attached to the Satellite, specified as a row vector of conical sensors.

Gimbals — Gimbals

row vector of Gimbal objects

You can set this property only when calling gimbal. After you call gimbal, this property is read-only.

Gimbals attached to the Satellite, specified as the comma-separated pair consisting of 'Gimbals' and a row vector of Gimbal objects.

Transmitters — Transmitters attached to Satellite

row vector of Transmitter objects

You can set this property only when calling transmitter. After you call transmitter, this property is read-only.

Transmitters attached to the Satellite, specified as a row vector of Transmitter objects.

Receivers — Receivers attached to the satellite

row vector of Receiver objects

You can set this property only when calling receiver. After you call receiver, this property is read-only.

Receivers attached to the satellite, specified as a row vector of Receiver objects.

Accesses — Access analysis objects

row vector of Access objects

You can set this property only when calling Satellite. After you call Satellite, this property is read-only.

Access analysis objects, specified as a row vector of Access objects.

GroundTrack — Ground track of the Satellite

row vector of GroundTrack objects

You can set this property only when calling groundTrack. After you call groundTrack, this property is read-only.

Ground track of the Satellite, specified as a row vector of GroundTrack objects.

Orbit — Orbit graphic

Orbit object

Orbit object parameters for a satellite, specified as an orbit object. Only these object properties are relevant for this function.

LineColor — Color of orbit

[1,0,0] (default) | RGB triplet | hexadecimal color code | 'r' | 'g' | 'b'

Color of the orbit, specified as an RGB triplet, hexadecimal color code, a color name, or a short name.

For a custom color, specify an RGB triplet or a hexadecimal color code.

• An RGB triplet is a three-element row vector whose elements specify the intensities of the red, green, and blue components of the color. The intensities must be in the range [0,1]; for example, [0.4 0.6 0.7].

• A hexadecimal color code is a character vector or a string scalar that starts with a hash symbol (#) followed by three or six hexadecimal digits, which can range from 0 to F. The values are not case sensitive. Thus, the color codes '#FF8800', '#ff8800', '#F80', and '#f80' are equivalent.

Alternatively, you can specify some common colors by name. This table lists the named color options, the equivalent RGB triplets, and hexadecimal color codes.

Color Name	Short Name	RGB Triplet	Hexadecimal Color Code	Appearance
'red'	'r'	[1 0 0]	'#FF0000'
'green'	'g'	[0 1 0]	'#00FF00'
'blue'	'b'	[0 0 1]	'#0000FF'
'cyan'	'c'	[0 1 1]	'#00FFFF'
'magenta'	'm'	[1 0 1]	'#FF00FF'
'yellow'	'y'	[1 1 0]	'#FFFF00'
'black'	'k'	[0 0 0]	'#000000'
'white'	'w'	[1 1 1]	'#FFFFFF'
'none'	Not applicable	Not applicable	Not applicable	No color

Here are the RGB triplets and hexadecimal color codes for the default colors MATLAB^® uses in many types of plots.

RGB Triplet	Hexadecimal Color Code	Appearance
[0 0.4470 0.7410]	'#0072BD'
[0.8500 0.3250 0.0980]	'#D95319'
[0.9290 0.6940 0.1250]	'#EDB120'
[0.4940 0.1840 0.5560]	'#7E2F8E'
[0.4660 0.6740 0.1880]	'#77AC30'
[0.3010 0.7450 0.9330]	'#4DBEEE'
[0.6350 0.0780 0.1840]	'#A2142F'

Example: 'blue'

Example: [0 0 1]

Example: '#0000FF'

LineWidth — Visual width of orbit

1 (default) | scalar in the range (0, 10)

Visual width of orbit in pixels, specified as a scalar in the range (0, 10).

The line width cannot be thinner than the width of a pixel. If you set the line width to a value that is less than the width of a pixel on your system, the line displays as one pixel wide.

VisibilityMode — Visibility mode of orbit graphic

'inherit' (default) | 'manual'

Visibility mode of orbit graphic, specified as one of these values:

• 'inherit' — Visibility of the graphic matches that of the parent

• 'manual' — Visibility of the graphic is not inherited and is independent of that of the parent

Data Types: char | string

OrbitPropagator — Name of orbit propagator

"sgp4" | "sdp4" | "two-body-keplerian" | "ephemeris" | "gps"

This property is read-only.

Set OrbitPropagator on satellite object creation.

Name of the orbit propagator used for propagating the satellite position and velocity, specified as "sgp4", "sdp4", "two-body-keplerian", "ephemeris", or "gps". The value depends on how you specify the satellite.

• Timetable, table, timeseries, or tscollection — OrbitPropagator is "ephemeris".

• SEM almanac file — OrbitPropagator can be any value except "ephemeris". The initialization is performed using the "gps" orbit propagator.

• TLE file — OrbitPropagator can be "two-body-keplerian", "sgp4", or "sdp4". If the orbital period is less than 225 minutes, the initialization is performed using "sgp4". Otherwise, the initialization is performed using "sdp4".

• Keplerian elements — OrbitPropagator can be "two-body-keplerian", "sgp4", or "sdp4".

If the satellite is initialized using a timetable, table, timeseries object, or tscollection object, the default propagator is "ephemeris". If the initialization is performed using a SEM almanac file, the default propagator is "gps". Otherwise, if the orbital period is less than 225 minutes, the default propagator is "sgp4", else "sdp4".

OrbitPropagator is not available for ephemeris data inputs (timetable or timeseries). In these cases, satellite automatically selects "ephemeris" orbit propagator.

MarkerColor — Color of marker

[1 0 0] (default) | RGB triplet | string scalar of color name | character vector of color name

Color of the marker, specified as a comma-separated pair consisting of 'MarkerColor' and either an RGB triplet or a string or character vector of a color name.

For a custom color, specify an RGB triplet or a hexadecimal color code.

• An RGB triplet is a three-element row vector whose elements specify the intensities of the red, green, and blue components of the color. The intensities must be in the range [0,1]; for example, [0.4 0.6 0.7].

• A hexadecimal color code is a character vector or a string scalar that starts with a hash symbol (#) followed by three or six hexadecimal digits, which can range from 0 to F. The values are not case sensitive. Thus, the color codes '#FF8800', '#ff8800', '#F80', and '#f80' are equivalent.

Alternatively, you can specify some common colors by name. This table lists the named color options, the equivalent RGB triplets, and hexadecimal color codes.

Color Name	Short Name	RGB Triplet	Hexadecimal Color Code	Appearance
'red'	'r'	[1 0 0]	'#FF0000'
'green'	'g'	[0 1 0]	'#00FF00'
'blue'	'b'	[0 0 1]	'#0000FF'
'cyan'	'c'	[0 1 1]	'#00FFFF'
'magenta'	'm'	[1 0 1]	'#FF00FF'
'yellow'	'y'	[1 1 0]	'#FFFF00'
'black'	'k'	[0 0 0]	'#000000'
'white'	'w'	[1 1 1]	'#FFFFFF'
'none'	Not applicable	Not applicable	Not applicable	No color

Here are the RGB triplets and hexadecimal color codes for the default colors MATLAB uses in many types of plots.

RGB Triplet	Hexadecimal Color Code	Appearance
[0 0.4470 0.7410]	'#0072BD'
[0.8500 0.3250 0.0980]	'#D95319'
[0.9290 0.6940 0.1250]	'#EDB120'
[0.4940 0.1840 0.5560]	'#7E2F8E'
[0.4660 0.6740 0.1880]	'#77AC30'
[0.3010 0.7450 0.9330]	'#4DBEEE'
[0.6350 0.0780 0.1840]	'#A2142F'

MarkerSize — Size of marker

10 (default) | positive scalar less than 30

Size of the marker, specified as a comma-separated pair consisting of 'MarkerSize' and a real positive scalar less than 30. The unit is in pixels.

ShowLabel — State of Satellite label visibility

true or 1 (default) | false or 0

State of Satellite label visibility, specified as a comma-separated pair consisting of 'ShowLabel' and numerical or logical value of 1 (true) or 0 (false).

Data Types: logical

LabelFontColor — Font color of Satellite label

[1,0,0] (default) | RGB triplet | string scalar of color name | character vector of color name

Font color of the Satellitelabel, specified as a comma-separated pair consisting of 'LabelFontColor' and either an RGB triplet or a string or character vector of a color name.

For a custom color, specify an RGB triplet or a hexadecimal color code.

• An RGB triplet is a three-element row vector whose elements specify the intensities of the red, green, and blue components of the color. The intensities must be in the range [0,1]; for example, [0.4 0.6 0.7].

• A hexadecimal color code is a character vector or a string scalar that starts with a hash symbol (#) followed by three or six hexadecimal digits, which can range from 0 to F. The values are not case sensitive. Thus, the color codes '#FF8800', '#ff8800', '#F80', and '#f80' are equivalent.

Alternatively, you can specify some common colors by name. This table lists the named color options, the equivalent RGB triplets, and hexadecimal color codes.

Color Name	Short Name	RGB Triplet	Hexadecimal Color Code	Appearance
'red'	'r'	[1 0 0]	'#FF0000'
'green'	'g'	[0 1 0]	'#00FF00'
'blue'	'b'	[0 0 1]	'#0000FF'
'cyan'	'c'	[0 1 1]	'#00FFFF'
'magenta'	'm'	[1 0 1]	'#FF00FF'
'yellow'	'y'	[1 1 0]	'#FFFF00'
'black'	'k'	[0 0 0]	'#000000'
'white'	'w'	[1 1 1]	'#FFFFFF'
'none'	Not applicable	Not applicable	Not applicable	No color

Here are the RGB triplets and hexadecimal color codes for the default colors MATLAB uses in many types of plots.

RGB Triplet	Hexadecimal Color Code	Appearance
[0 0.4470 0.7410]	'#0072BD'
[0.8500 0.3250 0.0980]	'#D95319'
[0.9290 0.6940 0.1250]	'#EDB120'
[0.4940 0.1840 0.5560]	'#7E2F8E'
[0.4660 0.6740 0.1880]	'#77AC30'
[0.3010 0.7450 0.9330]	'#4DBEEE'
[0.6350 0.0780 0.1840]	'#A2142F'

LabelFontSize — Font size of Satellite label

15 (default) | positive scalar less than 30

Font size of the Satellite label, specified as a comma-separated pair consisting of 'LabelFontSize' and a positive scalar less than 30.

Object Functions

access	Add access analysis objects to satellite scenario
aer	Calculate azimuth angle, elevation angle, and range of another satellite or ground station in NED frame
conicalSensor	Add conical sensor to satellite scenario
gimbal	Add gimbal to satellite or ground station
groundTrack	Add ground track object to satellite in scenario
orbitalElements	Orbital elements of satellites in scenario
pointAt	Specify the target at which the satellite is pointed
receiver	Add receiver to satellite scenario
transmitter	Add transmitter to satellite scenario
states	Obtain position and velocity of satellite
show	Show object in satellite scenario viewer
hide	Hides satellite scenario entity from viewer

Examples

Visualize Line of Sight Between Two Satellites

Create a satellite scenario object.

startTime = datetime(2020,5,5,0,0,0);
stopTime = startTime + days(1);
sampleTime = 60;                                      %seconds
sc = satelliteScenario(startTime,stopTime,sampleTime);

Add a satellite from a TLE file to the scenario.

tleFile = "eccentricOrbitSatellite.tle";
sat1 = satellite(sc,tleFile,"Name","Sat1")

sat1 = 
  Satellite with properties:

               Name:  Sat1
                 ID:  1
     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]
        GroundTrack:  [1x1 matlabshared.satellitescenario.GroundTrack]
              Orbit:  [1x1 matlabshared.satellitescenario.Orbit]
    OrbitPropagator:  sdp4
        MarkerColor:  [1 0 0]
         MarkerSize:  10
          ShowLabel:  true
     LabelFontColor:  [1 0 0]
      LabelFontSize:  15

Add a satellite from Keplerian elements to the scenario and specify its orbit propagator to be "two-body-keplerian".

semiMajorAxis = 6878137;                                                                    %m
eccentricity = 0;
inclination = 20;                                                                           %degrees
rightAscensionOfAscendingNode = 0;                                                          %degrees
argumentOfPeriapsis = 0;                                                                    %degrees
trueAnomaly = 0;                                                                            %degrees
sat2 = satellite(sc,semiMajorAxis,eccentricity,inclination,rightAscensionOfAscendingNode,...
    argumentOfPeriapsis,trueAnomaly,"OrbitPropagator","two-body-keplerian","Name","Sat2")

sat2 = 
  Satellite with properties:

               Name:  Sat2
                 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]
        GroundTrack:  [1x1 matlabshared.satellitescenario.GroundTrack]
              Orbit:  [1x1 matlabshared.satellitescenario.Orbit]
    OrbitPropagator:  two-body-keplerian
        MarkerColor:  [1 0 0]
         MarkerSize:  10
          ShowLabel:  true
     LabelFontColor:  [1 0 0]
      LabelFontSize:  15

Add access analysis between the two satellites.

ac = access(sat1,sat2);

Determine the times when there is line of sight between the two satellites.

accessIntervals(ac)

ans=15×8 table
    Source    Target    IntervalNumber         StartTime                EndTime           Duration    StartOrbit    EndOrbit
    ______    ______    ______________    ____________________    ____________________    ________    __________    ________

    "Sat1"    "Sat2"           1          05-May-2020 00:09:00    05-May-2020 01:08:00      3540          1            1    
    "Sat1"    "Sat2"           2          05-May-2020 01:50:00    05-May-2020 02:47:00      3420          1            1    
    "Sat1"    "Sat2"           3          05-May-2020 03:45:00    05-May-2020 04:05:00      1200          1            1    
    "Sat1"    "Sat2"           4          05-May-2020 04:32:00    05-May-2020 05:26:00      3240          1            1    
    "Sat1"    "Sat2"           5          05-May-2020 06:13:00    05-May-2020 07:10:00      3420          1            1    
    "Sat1"    "Sat2"           6          05-May-2020 07:52:00    05-May-2020 08:50:00      3480          1            1    
    "Sat1"    "Sat2"           7          05-May-2020 09:30:00    05-May-2020 10:29:00      3540          1            1    
    "Sat1"    "Sat2"           8          05-May-2020 11:09:00    05-May-2020 12:07:00      3480          1            2    
    "Sat1"    "Sat2"           9          05-May-2020 12:48:00    05-May-2020 13:46:00      3480          2            2    
    "Sat1"    "Sat2"          10          05-May-2020 14:31:00    05-May-2020 15:27:00      3360          2            2    
    "Sat1"    "Sat2"          11          05-May-2020 17:12:00    05-May-2020 18:08:00      3360          2            2    
    "Sat1"    "Sat2"          12          05-May-2020 18:52:00    05-May-2020 19:49:00      3420          2            2    
    "Sat1"    "Sat2"          13          05-May-2020 20:30:00    05-May-2020 21:29:00      3540          2            2    
    "Sat1"    "Sat2"          14          05-May-2020 22:08:00    05-May-2020 23:07:00      3540          2            2    
    "Sat1"    "Sat2"          15          05-May-2020 23:47:00    06-May-2020 00:00:00       780          2            2    

Visualize the line of sight between the satellites.

play(sc);

Visualize GPS Constellation

Set up the satellite scenario.

startTime = datetime(2021,8,5);
stopTime = startTime + days(1);
sampleTime = 60;                                      % seconds
sc = satelliteScenario(startTime,stopTime,sampleTime);

Add satellites to the scenario from a SEM almanac file.

sat = satellite(sc,"gpsAlmanac.txt","OrbitPropagator","gps");

Visualize the GPS constellation.

v = satelliteScenarioViewer(sc);

References

[1] Hoots, Felix R., and Ronald L. Roehrich. Models for propagation of NORAD element sets. Aerospace Defense Command Peterson AFB CO Office of Astrodynamics, 1980.

Version History

Introduced in R2021a