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GPS

Simulate GPS sensor readings with noise

  • Library:
  • UAV Toolbox / UAV Scenario and Sensor Modeling

    Navigation Toolbox / Multisensor Positioning / Sensor Models

    Sensor Fusion and Tracking Toolbox / Multisensor Positioning / Sensor Models

  • GPS Block

Description

The block outputs noise-corrupted GPS measurements based on the input position and velocity in the local coordinate frame or geodetic frame. It uses the WGS84 earth model to convert local coordinates to latitude-longitude-altitude LLA coordinates.

Ports

Input

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Specify the input position of the GPS receiver in the navigation coordinate system as a real, finite N-by-3 matrix. N is the number of samples in the current frame. The format of the matrix rows differs depending on the value of the Position input format parameter.

  • If the value of the Position input format parameter is Local, specify each row of the Position as Cartesian coordinates in meters with respect to the local navigation reference frame, specified by the Reference frame parameter, with the origin specified by the Reference location parameter.

  • If the value of the Position input format parameter is Geodetic, specify each row of the Position input as geodetic coordinates of the form [latitude longitude altitude]. The values of latitude and longitude are in degrees. Altitude is the height above the WGS84 ellipsoid model in meters.

Data Types: single | double

Specify the input velocity of the GPS receiver in the navigation coordinate system in meters per second as a real, finite N-by-3 matrix. N is the number of samples in the current frame. The format of the matrix rows differs depending on the value of the Position input format parameter.

  • If the value of the Position input format parameter is Local, specify each row of the Velocity with respect to the local navigation reference frame (NED or ENU), specified by the Reference frame parameter, with the origin specified by the Reference location parameter.

  • If the value of the Position input format parameter is Geodetic, specify each row of the Velocity with respect to the navigation reference frame (NED or ENU), specified by the Reference frame parameter, with the origin specified by Position.

Data Types: single | double

Output

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Position of the GPS receiver in the geodetic latitude, longitude, and altitude (LLA) coordinate system, returned as a real, finite N-by-3 array. Latitude and longitude are in degrees with North and East being positive. Altitude is in meters.

N is the number of samples in the current frame.

Data Types: single | double

Velocity of the GPS receiver in the local navigation coordinate system in meters per second, returned as a real, finite N-by-3 matrix. N is the number of samples in the current frame. The format of the matrix rows differs depending on the value of the Position input format parameter.

  • If the value of the Position input format parameter is Local, the Velocity output is with respect to the local navigation reference frame (NED or ENU), specified by the Reference frame parameter, with the origin specified by the Reference location parameter.

  • If the value of the Position input format parameter is Geodetic, the Velocity output is with respect to the navigation reference frame (NED or ENU), specified by the Reference frame parameter, with the origin specified by LLA.

Data Types: single | double

Magnitude of the horizontal velocity of the GPS receiver in the local navigation coordinate system in meters per second, returned as a real, finite N-element column vector.

N is the number of samples in the current frame.

Data Types: single | double

Direction of the horizontal velocity of the GPS receiver in the local navigation coordinate system, in degrees, returned as a real, finite N-element column vector of values from 0 to 360. North corresponds to 0 degrees and East corresponds to 90 degrees.

N is the number of samples in the current frame.

Data Types: single | double

Parameters

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Specify the reference frame as NED (North-East-Down) or ENU(East-North-Up).

Specify the position coordinate input format as Local or Geodetic.

  • If you set this parameter to Local, then the input to the Position port must be in the form of Cartesian coordinates with respect to the local navigation frame, specified by the Reference Frame parameter, with the origin fixed and defined by the Reference location parameter. The input to the Velocity input port must also be with respect to this local navigation frame.

  • If you set this parameter to Geodetic, then the input to the Position port must be geodetic coordinates in [latitude longitude altitude]. The input to the Velocity input port must also be with respect to the navigation frame specified by the Reference frame parameter, with the origin corresponding to the Position port.

Specify the origin of the local reference frame as a three-element row vector in geodetic coordinates [latitude longitude altitude], where altitude is the height above the reference ellipsoid model WGS84. The reference location values are in degrees, degrees, and meters, respectively. The degree format is decimal degrees (DD).

Dependencies

To enable this parameter, set the Position input format parameter to Local.

Specify horizontal position accuracy as a nonnegative real scalar in meters. The horizontal position accuracy specifies the standard deviation of the noise in the horizontal position measurement. Increasing this value adds noise to the measurement, decreasing its accuracy.

Tunable: Yes

Specify vertical position accuracy as a nonnegative real scalar in meters. The vertical position accuracy specifies the standard deviation of the noise in the vertical position measurement. Increasing this value adds noise to the measurement, decreasing its accuracy.

Tunable: Yes

Specify velocity accuracy per second as a nonnegative real scalar in meters. The velocity accuracy specifies the standard deviation of the noise in the velocity measurement. Increasing this value adds noise to the measurement, decreasing its accuracy.

Tunable: Yes

Specify the global position noise decay factor as a numeric scalar in the range [0, 1]. A decay factor of 0 models the global position noise as a white noise process. A decay factor of 1 models the global position noise as a random walk process.

Tunable: Yes

Specify the initial seed of an mt19937ar random number generator algorithm as a nonnegative integer.

Select the type of simulation to run from these options:

  • Interpreted execution — Simulate the model using the MATLAB® interpreter. For more information, see Simulation Modes.

  • Code generation — Simulate the model using generated C code. The first time you run a simulation, Simulink® generates C code for the block. The C code is reused for subsequent simulations, as long as the model does not change.

See Also

Objects

Introduced in R2021b