gimbal
Description
gimbal(
adds a default parent
)Gimbal
object to each
parent in the parent
vector, which can be a satellite, a platform, or a
ground station. A gimbal can be added to satellites, platform, and ground stations, and
dynamically change orientation independent of the parent. Transmitters, receivers, and
conical sensors can be mounted on the gimbals.
gimbal(
adds gimbals to parents in parent
,Name=Value
)parent
using additional parameters specified
by optional name-value pairs.
gim
= gimbal(___)
returns the
added gimbals in the row vector gim
.
Examples
Calculate Maximum Revisit Time of Satellite
Create a satellite scenario with a start time of 15-June-2021 8:55:00 AM UTC and a stop time of five days later. Set the simulation sample time to 60
seconds.
startTime = datetime(2021,6,21,8,55,0);
stopTime = startTime + days(5);
sampleTime = 60; % seconds
sc = satelliteScenario(startTime,stopTime,sampleTime)
sc = satelliteScenario with properties: StartTime: 21-Jun-2021 08:55:00 StopTime: 26-Jun-2021 08:55:00 SampleTime: 60 AutoSimulate: 1 Satellites: [1×0 matlabshared.satellitescenario.Satellite] GroundStations: [1×0 matlabshared.satellitescenario.GroundStation] Platforms: [1×0 matlabshared.satellitescenario.Platform] Viewers: [0×0 matlabshared.satellitescenario.Viewer] AutoShow: 1
Add a satellite to the scenario using Keplerian orbital elements.
semiMajorAxis = 7878137; % meters eccentricity = 0; inclination = 50; % degrees rightAscensionOfAscendingNode = 0; % degrees argumentOfPeriapsis = 0; % degrees trueAnomaly = 50; % degrees sat = satellite(sc,semiMajorAxis,eccentricity,inclination,rightAscensionOfAscendingNode, ... argumentOfPeriapsis,trueAnomaly)
sat = Satellite with properties: Name: Satellite 1 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] Eclipse: [1x0 Aero.satellitescenario.Eclipse] GroundTrack: [1x1 matlabshared.satellitescenario.GroundTrack] Orbit: [1x1 matlabshared.satellitescenario.Orbit] CoordinateAxes: [1x1 matlabshared.satellitescenario.CoordinateAxes] OrbitPropagator: sgp4 MarkerColor: [0.059 1 1] MarkerSize: 6 ShowLabel: true LabelFontColor: [1 1 1] LabelFontSize: 15 Visual3DModel: Visual3DModelScale: 1
Add a ground station, which represents the location to be photographed, to the scenario.
gs = groundStation(sc,Name="Location to Photograph", ... Latitude=42.3001,Longitude=-71.3504) % degrees
gs = GroundStation with properties: Name: Location to Photograph ID: 2 Latitude: 42.3001 degrees Longitude: -71.3504 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: [1x0 Aero.satellitescenario.Eclipse] CoordinateAxes: [1x1 matlabshared.satellitescenario.CoordinateAxes] MarkerColor: [1 0.4118 0.1608] MarkerSize: 6 ShowLabel: true LabelFontColor: [1 1 1] LabelFontSize: 15
Add a gimbal to the satellite. You can steer this gimbal independently of the satellite.
g = gimbal(sat)
g = Gimbal with properties: Name: Gimbal 3 ID: 3 MountingLocation: [0; 0; 0] meters MountingAngles: [0; 0; 0] degrees ConicalSensors: [1x0 matlabshared.satellitescenario.ConicalSensor] Transmitters: [1x0 satcom.satellitescenario.Transmitter] Receivers: [1x0 satcom.satellitescenario.Receiver] CoordinateAxes: [1x1 matlabshared.satellitescenario.CoordinateAxes]
Track the location to be photographed using the gimbal.
pointAt(g,gs);
Add a conical sensor to the gimbal. This sensor represents the camera. Set the field of view to 60 degrees.
camSensor = conicalSensor(g,MaxViewAngle=60)
camSensor = ConicalSensor with properties: Name: Conical sensor 4 ID: 4 MountingLocation: [0; 0; 0] meters MountingAngles: [0; 0; 0] degrees MaxViewAngle: 60 degrees Accesses: [1x0 matlabshared.satellitescenario.Access] FieldOfView: [0x0 matlabshared.satellitescenario.FieldOfView] CoordinateAxes: [1x1 matlabshared.satellitescenario.CoordinateAxes]
Add access analysis to the conical sensor between the camera and the location to be photographed.
ac = access(camSensor,gs)
ac = Access with properties: Sequence: [4 2] LineWidth: 3 LineColor: [0.3922 0.8314 0.0745]
Visualize the field of view of the camera by using the Satellite Scenario Viewer.
v = satelliteScenarioViewer(sc); fieldOfView(camSensor);
Determine the intervals during which the camera can see the geographical site.
t = accessIntervals(ac)
t=35×8 table
Source Target IntervalNumber StartTime EndTime Duration StartOrbit EndOrbit
__________________ ________________________ ______________ ____________________ ____________________ ________ __________ ________
"Conical sensor 4" "Location to Photograph" 1 21-Jun-2021 10:38:00 21-Jun-2021 10:55:00 1020 1 2
"Conical sensor 4" "Location to Photograph" 2 21-Jun-2021 12:36:00 21-Jun-2021 12:58:00 1320 2 3
"Conical sensor 4" "Location to Photograph" 3 21-Jun-2021 14:37:00 21-Jun-2021 15:01:00 1440 3 4
"Conical sensor 4" "Location to Photograph" 4 21-Jun-2021 16:41:00 21-Jun-2021 17:04:00 1380 5 5
"Conical sensor 4" "Location to Photograph" 5 21-Jun-2021 18:44:00 21-Jun-2021 19:07:00 1380 6 6
"Conical sensor 4" "Location to Photograph" 6 21-Jun-2021 20:46:00 21-Jun-2021 21:08:00 1320 7 7
"Conical sensor 4" "Location to Photograph" 7 21-Jun-2021 22:50:00 21-Jun-2021 23:04:00 840 8 8
"Conical sensor 4" "Location to Photograph" 8 22-Jun-2021 09:51:00 22-Jun-2021 10:02:00 660 13 13
"Conical sensor 4" "Location to Photograph" 9 22-Jun-2021 11:46:00 22-Jun-2021 12:07:00 1260 14 15
"Conical sensor 4" "Location to Photograph" 10 22-Jun-2021 13:46:00 22-Jun-2021 14:10:00 1440 15 16
"Conical sensor 4" "Location to Photograph" 11 22-Jun-2021 15:49:00 22-Jun-2021 16:13:00 1440 16 17
"Conical sensor 4" "Location to Photograph" 12 22-Jun-2021 17:53:00 22-Jun-2021 18:16:00 1380 18 18
"Conical sensor 4" "Location to Photograph" 13 22-Jun-2021 19:55:00 22-Jun-2021 20:18:00 1380 19 19
"Conical sensor 4" "Location to Photograph" 14 22-Jun-2021 21:58:00 22-Jun-2021 22:16:00 1080 20 20
"Conical sensor 4" "Location to Photograph" 15 23-Jun-2021 10:56:00 23-Jun-2021 11:16:00 1200 26 27
"Conical sensor 4" "Location to Photograph" 16 23-Jun-2021 12:56:00 23-Jun-2021 13:19:00 1380 27 28
⋮
Calculate the maximum revisit time in hours.
startTimes = t.StartTime;
endTimes = t.EndTime;
revisitTimes = hours(startTimes(2:end) - endTimes(1:end-1));
maxRevisitTime = max(revisitTimes) % hours
maxRevisitTime = 12.666666666666666
Visualize the revisit times that the camera photographs of the location.
play(sc);
Input Arguments
parent
— Element of scenario to which you add gimbal
scalar | vector
Element of scenario to which you add the gimbal, specified as a scalar or vector of satellites, platforms, or ground stations. The number of gimbals specified is determined by the size of the inputs.
If
parent
is a scalar, all gimbals are added to the parent.If
parent
is a vector and the number of gimbals specified is one, that gimbal is added to each parent.If
parent
is a vector and the number of gimbals specified is more than one, the number of gimbals must equal the number ofparent
s and eachparent
gets one gimbal.
Name-Value Arguments
Specify optional pairs of arguments as
Name1=Value1,...,NameN=ValueN
, where Name
is
the argument name and Value
is the corresponding value.
Name-value arguments must appear after other arguments, but the order of the
pairs does not matter.
Before R2021a, use commas to separate each name and value, and enclose
Name
in quotes.
Example: 'MountingAngle'=[20;35;10]
sets the yaw, pitch, and roll
angles of the gimbal to 20, 35, and 10 degrees, respectively.
Note
The size of the name-value arguments defines the number of gimbals that you can specify. To understand how to specify multiple gimbals, refer to these properties.
Name
— Gimbal name
"Gimbal idx"
(default) | string scalar | string vector | character vector | cell array of character vectors
You can set this property only when calling the gimbal
function. After you call the gimbal
function, this property is
read-only.
Gimbal name, specified as a name-value argument consisting of
'Name'
and a string scalar, string vector, character vector, or
a cell array of character vectors.
If you are adding only one gimbal, specify
Name
as a string scalar or a character vector.If you are adding multiple gimbals, specify
Name
as a string scalar, character vector, string vector, or a cell array of character vectors. All gimbals that you add 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 vectors must equal the number of gimbals that you are adding. Each gimbal is assigned the corresponding name from the vector or cell array.
In the default value, idx is the ID assigned by the satellite scenario.
Data Types: char
| string
MountingLocation
— Mounting location with respect to parent
[0; 0; 0]
(default) | three-element vector | matrix
Mounting location with respect to the parent object in meters, specified as a three-element vector or a matrix. The position vector is specified in the body frame of the input parent
.
If you are adding one gimbal,
MountingLocation
is a three-element vector. The elements specify the x, y, and z components of the Cartesian coordinates in the body frame of gimbal.If you are adding multiple gimbals,
MountingLocation
can be a three-element vector or a matrix. When specified as a vector, the same set of mounting locations are assigned to all specified gimbals. When specified as a matrix,MountingLocation
must contain three rows and the same number of columns as the gimbals. The columns correspond to the mounting location of each specified gimbal and the rows correspond to the mounting location coordinates in the parent body frame.
When the AutoSimulate
property of the satellite scenario is
false
, you can modify the MountingLocation
property only when SimulationStatus
is NotStarted
. You can use the
restart
function to
reset SimulationStatus
to NotStarted
, but doing
so erases the simulation data.
Data Types: double
MountingAngles
— Mounting orientation with respect to parent object
[0; 0; 0]
(default) | three-element row vector of positive numbers | matrix
Mounting orientation with respect to parent object in degrees, specified as a three-element row vector of positive numbers. The elements of the vector correspond to yaw, pitch, and roll, in that order. Yaw, pitch, and roll are positive rotations about the z-axis, intermediate y-axis, and intermediate x-axis of the parent.
If you are adding one gimbal, the
MountingAngles
property is a three-element vector.If you are adding multiple gimbals the
MountingAngles
property can be a three-element vector or a matrix. When specified as a vector, the same set of mounting angles are assigned to all specified gimbals. When specified as a matrix,MountingAngles
must contain three rows and the same number of columns as the gimbals. The columns correspond to the mounting angles of each specified gimbal and the rows correspond to the yaw, pitch, and roll angles in the parent body frame.
When the AutoSimulate
property of the satellite scenario is
false
, you can modify the MountingAngles
property only when SimulationStatus
is NotStarted
. You can use the
restart
function to
reset SimulationStatus
to NotStarted
, but doing
so erases the simulation data.
Example: [0; 30; 60]
Data Types: double
Output Arguments
gim
— Gimbal
scalar | vector
Gimbal object attached to parent
, returned as either a scalar
or a vector.
When the AutoSimulate
property of the satellite scenario is
false
, you can call the gimbal
function
only when SimulationStatus
is NotStarted
. You can use the
restart
function to
reset SimulationStatus
to NotStarted
, but doing so erases the
simulation data.
Version History
Introduced in R2021a
See Also
Objects
Functions
show
|play
|access
|groundStation
|satellite
|conicalSensor
|hide
|platform
(Satellite Communications Toolbox)
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