CustomSensor

Custom sensor specification

Since R2025a

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    Description

    A CustomSensor object contains a custom sensor specification. You can modify this specification by defining its measurement model, detectability model, clutter model, and birth model. Use this object as an input to the multiSensorTargetTracker function.

    Creation

    To create a CustomSensor object, use the trackerSensorSpec function with the input argument "custom". For example:

    spec = trackerSensorSpec("custom")

    Properties

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    Sensor Models

    Measurement model for the sensor, specified as a sensor measurement model object. You can use the sensorMeasurementModel function to generate the object. The model defines what the sensor measures and how it relates to the state of the target.

    Detectability model for the sensor, specified as a sensor detectability model object. You can use the sensorDetectabilityModel function to generate the object. The model defines the sensor's fields of view and the probability of detecting a target at a given state within each field of view.

    Clutter model for the sensor, specified as a sensor clutter model object. You can use the sensorClutterModel function to generate the object. The model defines the distribution of clutter in the measurement space.

    Birth model for the sensor, specified as a sensor birth model object. You can use the sensorBirthModel function to generate the object. The model defines the distribution of newly appearing targets in the measurement space.

    General Properties

    Maximum number of measurements per update, specified as a positive integer.

    Example: 5

    Data Types: single | double

    Option to enable updating sensor models with time and measurements, specified as true or false. When you set this property to true, you can use the ModelUpdateFcn property to update the specification.

    Example: true

    Data Types: logical

    Maximum number of timestamps per update, specified as a positive integer. This property allows you to send time-varying data from the sensor to update the models.

    To enable this property, set the UpdateModels property to true.

    Example: 64

    Data Types: single | double

    Model update function, specified as a function handle. This property defines how to update the specification based on time and measurement. The function signature is spec = ModelUpdateFcn(spec,data).

    data is a subset of the input data. You provide this subset as an input to the tracker. The tracker selects appropriate timestamps and measurements from the data and calls the function. Use the dataFormat function of the specification to understand the data format required by the sensor.

    To enable this property, set the UpdateModels property to true.

    Object Functions

    dataFormatStructure for data format required by task-oriented tracker

    Examples

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    Open Live Script

    Create a specification for a marine radar. The radar of interest is on top of a stationary tower.

    radarPosition = [0;0;35]; % radar's relative position to the tower origin.
towerPosition = [3800;15200;110]; % tower origin location in scenario coordinate.
radarOrientation = [0 1 0;-1 0 0;0 0 1]; % radar's relative orientation to the tower origin.
towerOrientation = [-0.2 0.6 0.7;0.9 0.3 0;-0.2 0.7 -0.6]; % tower orientation in scenario coordinate.
marineRadarSpec = trackerSensorSpec("custom")
    marineRadarSpec = 
  CustomSensor with properties:

    MaxNumMeasurements: 32

      MeasurementModel: []
    DetectabilityModel: []
          ClutterModel: []
            BirthModel: []

          UpdateModels: 0

    Define the measurement, detectability, clutter, and birth model of the marine radar specification. For measurement, specify that the radar of interest reports the position in the scenario coordinates. 

    measurementModel = sensorMeasurementModel("position");
measurementModel.OriginPosition = zeros(3,1);
measurementModel.Orientation = eye(3);

    For detectability, specify that the radar detects targets within its field of view around a center beam.

    detectabilityModel = sensorDetectabilityModel("field-of-view");
detectabilityModel.AzimuthLimits = [-10 10];
detectabilityModel.ElevationLimits = [-15 15];
detectabilityModel.RangeLimits = [0 10000];
detectabilityModel.OriginPosition = cat(2,radarPosition,towerPosition);
detectabilityModel.Orientation = cat(3,radarOrientation,towerOrientation);
detectabilityModel.DetectionProbability = 0.95;

    For clutter, specify that the radar assumes a uniform Poisson clutter model, which assumes false measurements or noise (referred to as "clutter") in radar data are uniformly distributed across the observation space.

    clutterModel = sensorClutterModel("uniform-poisson");
clutterModel.ClutterDensity = 5e-9;

    For birth, specify that the radar assumes a uniform Poisson birth model, which assumes new targets can appear uniformly across the entire observation space.

    birthModel = sensorBirthModel("uniform-poisson");
birthModel.BirthDensity = 5e-9;

    Configure the marine radar specification using these models.

    marineRadarSpec.MeasurementModel = measurementModel;
marineRadarSpec.DetectabilityModel = detectabilityModel;
marineRadarSpec.ClutterModel = clutterModel;
marineRadarSpec.BirthModel = birthModel;

    To update the specification based on time or measurement, you can set the UpdateModels property to true and specify the ModelUpdateFcn function handle of the specification. For example, the following model update function allows you to update the radar center beam orientation with time, and update the position variance with measurement.

    marineRadarSpec.UpdateModels = true;
marineRadarSpec.ModelUpdateFcn = @updateRadarSpec;
function spec = updateRadarSpec(spec, data)
if ~isempty(data.Time)
    spec.DetectabilityModel.Orientation(:,:,1) = data.TimeVaryingModelData.BeamOrientation;
end
if ~isempty(data.MeasurementTime)
    spec.MeasurementModel.PositionVariance = data.MeasurementVaryingModelData.PositionVariance;
end
end

    More About

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    Version History

    Introduced in R2025a

    See Also

    Functions

    Objects