states

Obtain position and velocity of satellite or platform

Since R2021a

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    Syntax

    pos = states(sat)
    pos = states(pltf)
    [pos,velocity] = states(sat)
    [pos,velocity] = states(pltf)
    [___] = states(sat,timeIn)
    [___] = states(pltf,timeIn)
    [___] = states(___,CoordinateFrame=c)
    [pos,velocity,timeOut] = states(___)

    Description

    pos = states(sat) returns a 3-by-n-by-m array of the position history pos of each satellite in the vector sat, where n is the number of time samples and m is the number of satellites. The rows represent the x, y, and z coordinates of the satellite in the Geocentric Celestial Reference Frame (GCRF).

    pos = states(pltf) returns a 3-by-n-by-p array of the position history pos of each platform in the vector pltf, where n is the number of time samples and p is the number of platform. The rows represent the x, y, and z coordinates of the platform in the Geocentric Celestial Reference Frame (GCRF).

    [pos,velocity] = states(sat) returns a 3-by-n-by-m array of the inertial velocity velocity of each satellite in the vector sat in the GCRF.

    example

    [pos,velocity] = states(pltf) returns a 3-by-n-by-p array of the inertial velocity velocity of each platform in the vector pltf in the GCRF.

    [___] = states(sat,timeIn) returns one or both of the outputs as 3-by-1-by-m arrays in addition to the position at the specified datetime timeIn. If no time zone is specified in timeIn, the time zone is assumed to be Coordinated Universal Time (UTC).

    [___] = states(pltf,timeIn) returns one or both of the outputs as 3-by-1-by-p arrays in addition to the position at the specified datetime timeIn. If no time zone is specified in timeIn, the time zone is assumed to be Coordinated Universal Time (UTC).

    [___] = states(___,CoordinateFrame=c) returns the outputs in the coordinates specified by c.

    [pos,velocity,timeOut] = states(___) returns the position, velocity history, and the corresponding datetime in UTC for satellites or platforms.

    Examples

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    Open Live Script

    Create a satellite scenario object.

    startTime = datetime(2021,5,25);                      % May 25, 2021, 12:00 AM UTC
stopTime = datetime(2021,5,26);                       % May 26, 2021, 12:00 AM UTC
sampleTime = 60;                                      % In seconds
sc = satelliteScenario(startTime,stopTime,sampleTime);

    Add a satellite to the scenario.

    tleFile = "eccentricOrbitSatellite.tle";
sat = satellite(sc,tleFile);

    Obtain the position and velocity of the satellite in the Earth-centered Earth-fixed (ECEF) frame corresponding to May 25, 2021, 10:30 PM UTC.

    time = datetime(2021,5,25,22,30,0);
[position,velocity] = states(sat,time,"CoordinateFrame","ecef")
    position = 3×1
107 ×

   -0.9001
   -3.0897
    2.6716


    velocity = 3×1
103 ×

   -1.2151
    0.4417
   -1.7198

    Input Arguments

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    Satellite, specified as a row vector of Satellite objects.

    Platform, specified as a row vector of Platform objects.

    Time at which the output is calculated, specified as a datetime scalar. If no time zone is specified in timeIn, the time zone is assumed to be UTC.

    Coordinate frame in which the outputs are returned, specified as 'inertial', 'ecef', or 'geographic'.

    • The 'inertial' option returns the position and velocity coordinates in the GCRF.

    • The 'ecef' option returns the position and velocity coordinates in the ECEF frame. For more information on ECEF frames, see Earth-Centered Earth-Fixed Coordinates.

    • The 'geographic' option returns the position as [lat; lon; altitude], where lat and lon are latitude and longitude in degrees and altitude is the height above the surface of the Earth in meters. The velocity returned is in the North-East-Down (NED) frame.

    Output Arguments

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    Position history of the satellites in meters, returned as a 3-by-n-by-m array. n is the number of time samples and m is the number of satellites. The position value type depends on the coordinate frame input value.

    When the AutoSimulate property of the satellite scenario is true, the position history from StartTime to StopTime is returned. Otherwise, the position history from StartTime to SimulationTime is returned.

    Velocity history of the satellites in meters per second, returned as a 3-by-n-by-m array. n is the number of time samples and m is the number of satellites. The velocity value type depends on the coordinate frame input value.

    Time samples of the position and velocity of the satellites, returned as a scalar or vector. If time histories of the position and velocity of the satellite are returned, timeOut is a row vector.

    Version History

    Introduced in R2021a

    See Also

    Objects

    Functions

    Topics