Satellite

Satellite in satellite scenario

Since R2021a

Description

Satellite defines a satellite in satellite scenario object.

Creation

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

Properties

Name — Satellite name

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 function, 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.

The default value when satellite is added to the satellite scenario using

• Keplerian orbital elements, TLE file, timeseries, or timetable — "Satellite ID", where ID is assigned by the satellite scenario.

• SEM almanac file or RINEX GPS navigation data — "PRN:prnValue", where prnValue is an integer denoting the pseudorandom noise code of the satellite as specified in the SEM almanac file.

• RINEX Galileo navigation data — "GAL Sat IF: id", where "id" is the satellite ID of the Galileo satellite defined in the RINEX navigation data.

Data Types: 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 the conicalSensor. After you call the conicalSensor function, 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.

Accesses — Access analysis objects

row vector of Access objects

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

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

Eclipse — Eclipse analysis objects

empty | scalar

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

Eclipse analysis object, specified as an empty or a scalar Eclipse object.

CoordinateAxes — Coordinate axes triad graphic object

CoordinateAxes object (default)

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

Coordinate axes triad graphic object, specified as CoordinateAxes object.

Orbit — Orbit visualization

Orbit object

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

Orbit visualization parameters for a satellite, specified as an Orbit object.

Data Types: char | string

OrbitPropagator — Name of orbit propagator

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

You can set this property on satellite object creation and then this property becomes read-only.

Name of the orbit propagator used for propagating the satellite position and velocity, specified as one of these options.

• If you specify the satellite using timetable, table, timeseries, or tscollection, the OrbitPropagator value is "ephemeris".

• If you specify the satellite using a SEM almanac file or RINEX data containing a GPS navigation message, the OrbitPropagator value can take one of these options.

  • "gps" (default)

  • "sgp4"

  • "sdp4"

  • "two-body-keplerian"

  • "numerical"

• If you specify the satellite using the RINEX data containing a Galileo navigation message, the OrbitPropagator value can take one of these options.

  • "galileo" (default)

  • "sgp4"

  • "sdp4"

  • "two-body-keplerian"

  • "numerical"

• If you specify the satellite is added using Keplerian elements, OrbitPropagator value can take one of these options.

  • "two-body-keplerian"

  • "sgp4"

  • "sdp4"

  • "numerical"

  Additionally, if semimajor axis is negative, OrbitPropagator value can only be "numerical". If semimajor axis is positive, default value is "sgp4" for periods less than 225 min and "sdp4" for periods greater than or equal to 225 minutes.

• If you specify the satellite using a TLE or OMM file, the OrbitPropagator value can take one of these options.

  • "two-body-keplerian"

  • "sgp4"

  • "sdp4"

  • "numerical"

  If the orbital period is less than 225 minutes, the default OrbitPropagator value is "sgp4". Otherwise, the default OrbitPropagator value is "sdp4".

• If you specify the satellite using Keplerian elements, the OrbitPropagator value can take one of these options.

  • "two-body-keplerian"

  • "sgp4"

  • "sdp4"

If the RINEX data contains both valid GPS and Galileo navigation messages, you cannot specify OrbitPropagator as "gps" or "galileo" using a name-value argument. However, you can still specify it as "two-body-keplerian", "sgp4", "sdp4", or "numerical".

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 string scalar or character vector 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. Therefore, 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"

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 string scalar or character vector 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. Therefore, 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"

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 in the range [6 30]

Font size of the Satellite label, specified as a comma-separated pair consisting of 'LabelFontSize' and a positive scalar in the range [6 30].

Visual3DModel — Name of 3-D model file

zero-length string (default)

Name of the visual 3-D model file that you want to render in the viewer, specified as a string with .GLTF, .GLB, or .STL extension. For GLB and GLTF models, gITF uses a right-hand coordinate system. gITF defines +Y as up, and +Z as forward, and -X as right. A gITF asset faces +Z. For more information, see https://registry.khronos.org/glTF/specs/2.0/glTF-2.0.html#coordinate-system-and-units. The mesh of the GLB is in meters.

Data Types: string

Visual3DModelScale — Linear scaling of 3-D model

1 (default) | nonnegative integer

Linear scaling of the visual 3-D model rendered in the viewer, specified as a nonnegative integer. The scaling assumes that the GLB model is in meters.

Data Types: double

PhysicalProperties — Physical properties of satellite used by numerical propagator

PhysicalProperties object

Physical properties of satellite used by numerical propagator, specified as a Aero.spacecraft.PhysicalProperties object. To modify these options, use the physicalProperties function.

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
eclipse	Add eclipse analysis object to satellite or ground station
gimbal	Add gimbal to satellite, platform, or ground station
groundTrack	Add ground track object to satellite or platform in scenario
orbitalElements	Orbital elements of satellites in scenario
coordinateAxes	Visualize coordinate axes triad of satellite scenario assets
pointAt	Point satellite at target
states	Obtain position and velocity of satellite or platform
show	Show object in satellite scenario viewer
hide	Hide satellite scenario entity from viewer
physicalProperties	Retrieve or modify physical properties of satellite object

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:  [0.059 1 1]
         MarkerSize:  6
          ShowLabel:  true
     LabelFontColor:  [1 1 1]
      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:  [0.059 1 1]
         MarkerSize:  6
          ShowLabel:  true
     LabelFontColor:  [1 1 1]
      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.

[2] Vallado, David, et al. “Revisiting Spacetrack Report #3.” AIAA/AAS Astrodynamics Specialist Conference and Exhibit, American Institute of Aeronautics and Astronautics, 2006, https://doi.org/10.2514/6.2006-6753

Version History

Introduced in R2021a