Package com.irurueta.navigation.inertial.calibration.noise

Class WindowedMeasurementNoiseEstimator<U extends Enum<?>,M extends com.irurueta.units.Measurement<U>,E extends WindowedMeasurementNoiseEstimator<U,M,E,L>,L extends WindowedMeasurementNoiseEstimatorListener<U,M,E>>

java.lang.Object
com.irurueta.navigation.inertial.calibration.noise.WindowedMeasurementNoiseEstimator<U,M,E,L>
Type Parameters:
U - a measurement unit type.
M - a measurement type.
E - an estimator type.
L - a listener type.
Direct Known Subclasses:
WindowedAccelerationMeasurementNoiseEstimator, WindowedAngularSpeedMeasurementNoiseEstimator, WindowedMagneticFluxDensityMeasurementNoiseEstimator
public abstract class WindowedMeasurementNoiseEstimator<U extends Enum<?>,M extends com.irurueta.units.Measurement<U>,E extends WindowedMeasurementNoiseEstimator<U,M,E,L>,L extends WindowedMeasurementNoiseEstimatorListener<U,M,E>> extends Object
Base class to estimate measurement noise variances and PSD's (Power Spectral Densities) along with average values for a windowed amount of samples. Implementations of this estimator may use norms of measurement triads to estimate noise levels. To compute PSD's, this estimator assumes that measurement samples are obtained at a constant provided rate equal to getTimeInterval() seconds. If not available, accelerometer sampling rate average can be estimated using TimeIntervalEstimator. Notice that if there are less than getWindowSize() processed samples in the window, this estimator will assume that the remaining ones until the window is completed have zero values.

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    private double
    avg
    Contains estimated average of measurement expressed in its default unit (m/s^2 for acceleration, rad/s for angular speed or T for magnetic flux density).
    static final double
    DEFAULT_TIME_INTERVAL_SECONDS
    Default time interval between accelerometer samples expressed in seconds (s).
    static final int
    DEFAULT_WINDOW_SIZE
    Number of samples to keep within the window by default.
    private int
    firstCursor
    Indicates position of first element in window.
    private int
    lastCursor
    Indicates position of last element in window.
    private L
    listener
    Listener to handle events raised by this estimator.
    static final int
    MIN_WINDOW_SIZE
    Minimum allowed window size.
    private int
    numberOfAddedSamples
    Number of added measurement samples.
    private int
    numberOfProcessedSamples
    Number of processed measurement samples.
    private boolean
    running
    Indicates whether estimator is running or not.
    private double
    timeInterval
    Time interval expressed in seconds (s) between consecutive measurements.
    private double
    variance
    Contains estimated variance of measurement expressed in its default squared unit (m^2/s^4 for acceleration, rad^2/s^2 for angular speed or T^2 for magnetic flux density).
    private double[]
    windowedMeasurements
    Keeps the window of measurements expressed in their default units.
    private int
    windowSize
    Length of number of samples to keep within the window being processed.

  • Constructor Summary

    Constructors
    Modifier
    Constructor
    Description
    protected
    WindowedMeasurementNoiseEstimator()
    Constructor.
    protected
    WindowedMeasurementNoiseEstimator(L listener)
    Constructor.

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    addMeasurement(double value)
    Adds a measurement value expressed in its default unit (m/s^2 for acceleration, rad/s for angular speed or T for magnetic flux density).
    void
    addMeasurement(M value)
    Adds a measurement.
    void
    addMeasurementAndProcess(double value)
    Adds a measurement value expressed in its default unit (m/s^2 for acceleration, rad/s for angular speed or T for magnetic flux density) and processes current window.
    void
    addMeasurementAndProcess(M value)
    Adds a measurement and processes current window.
    protected abstract double
    convertToDefaultUnit(M value)
    Converts provided measurement into default unit.
    protected abstract M
    createMeasurement(double value, U unit)
    Creates a measurement with provided value and unit.
    double
    getAvg()
    Gets estimated average of measurement expressed in its default unit (m/s^2 for acceleration, rad/s for angular speed or T for magnetic flux density).
    M
    getAvgAsMeasurement()
    Gets estimated average of measurement within current window.
    void
    getAvgAsMeasurement(M result)
    Gets estimated average of measurement within current window.
    protected abstract U
    getDefaultUnit()
    Gets default unit for a measurement.
    M
    getFirstWindowedMeasurement()
    Gets first provided measurement within the window.
    boolean
    getFirstWindowedMeasurement(M result)
    Gets first provided measurement within the window.
    Double
    getFirstWindowedMeasurementValue()
    Gets first provided measurement value expressed in its default units.
    M
    getLastWindowedMeasurement()
    Gets last provided measurement within the window.
    boolean
    getLastWindowedMeasurement(M result)
    Gets last provided measurement within the window.
    Double
    getLastWindowedMeasurementValue()
    Gets las provided measurement value expressed in its default units.
    L
    getListener()
    Gets listener to handle events raised by this estimator.
    int
    getNumberOfAddedSamples()
    Gets number of samples that have been added so far.
    int
    getNumberOfProcessedSamples()
    Gets number of samples that have been processed so far.
    int
    getNumberOfSamplesInWindow()
    Gets number of currently windowed samples.
    double
    getPsd()
    Gets measurement noise PSD (Power Spectral Density) expressed in (m^2 * s^-3) for accelerometer, (rad^2/s) for gyroscope or (T^2 * s) for magnetometer.
    double
    getRootPsd()
    Gets measurement noise root PSD (Power Spectral Density) expressed in (m * s^-1.5) for accelerometer, (rad * s^-0.5) for gyroscope or (T * s^0.5) for magnetometer.
    double
    getStandardDeviation()
    Gets estimated standard deviation of measurement within current window and expressed in its default unit (m/s^2 for acceleration, rad/s for angular speed or T for magnetic flux density).
    M
    getStandardDeviationAsMeasurement()
    Gets estimated standard deviation of measurement within current window.
    void
    getStandardDeviationAsMeasurement(M result)
    Gets estimated standard deviation of measurement within current window.
    double
    getTimeInterval()
    Gets time interval between accelerometer triad samples expressed in seconds (s).
    com.irurueta.units.Time
    getTimeIntervalAsTime()
    Gets time interval between accelerometer triad samples.
    void
    getTimeIntervalAsTime(com.irurueta.units.Time result)
    Gets time interval between accelerometer triad samples.
    double
    getVariance()
    Gets estimated variance of measurement within current window expressed in its default squared unit (m^2/s^4 for acceleration, rad^2/s^2 for angular speed or T^2 for magnetic flux density).
    int
    getWindowSize()
    Gets length of number of samples to keep within the window being processed.
    private void
    internalAdd(double value, boolean process)
    Internally adds a measurement value and processes current window if indicated.
    boolean
    isRunning()
    Indicates whether estimator is currently running or not.
    boolean
    isWindowFilled()
    Indicates whether window of samples is filled or not.
    private void
    processWindow()
    Processes current windowed samples.
    boolean
    reset()
    Resets current estimator.
    void
    setListener(L listener)
    Sets listener to handle events raised by this estimator.
    void
    setTimeInterval(double timeInterval)
    Sets time interval between accelerometer triad samples expressed in seconds (s).
    void
    setTimeInterval(com.irurueta.units.Time timeInterval)
    Sets time interval between accelerometer triad samples.
    void
    setWindowSize(int windowSize)
    Sets length of number of samples to keep within the window being processed.

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Field Details

    • DEFAULT_WINDOW_SIZE

      public static final int DEFAULT_WINDOW_SIZE
      Number of samples to keep within the window by default. For an accelerometer generating 100 samples/second, this is equivalent to 1 second. For an accelerometer generating 50 samples/second, this is equivalent to 2 seconds.
      See Also:

    • MIN_WINDOW_SIZE

      public static final int MIN_WINDOW_SIZE
      Minimum allowed window size.
      See Also:

    • DEFAULT_TIME_INTERVAL_SECONDS

      public static final double DEFAULT_TIME_INTERVAL_SECONDS
      Default time interval between accelerometer samples expressed in seconds (s).
      See Also:

    • windowSize

      private int windowSize
      Length of number of samples to keep within the window being processed. Window size must always be larger than allowed minimum value and must have and odd value.

    • timeInterval

      private double timeInterval
      Time interval expressed in seconds (s) between consecutive measurements.

    • windowedMeasurements

      private double[] windowedMeasurements
      Keeps the window of measurements expressed in their default units. (m/s^2 for acceleration, rad/s for angular speed or T for magnetic flux density).

    • listener

      private L extends WindowedMeasurementNoiseEstimatorListener<U,M,E> listener
      Listener to handle events raised by this estimator.

    • avg

      private double avg
      Contains estimated average of measurement expressed in its default unit (m/s^2 for acceleration, rad/s for angular speed or T for magnetic flux density).

    • variance

      private double variance
      Contains estimated variance of measurement expressed in its default squared unit (m^2/s^4 for acceleration, rad^2/s^2 for angular speed or T^2 for magnetic flux density).

    • firstCursor

      private int firstCursor
      Indicates position of first element in window.

    • lastCursor

      private int lastCursor
      Indicates position of last element in window.

    • numberOfProcessedSamples

      private int numberOfProcessedSamples
      Number of processed measurement samples.

    • numberOfAddedSamples

      private int numberOfAddedSamples
      Number of added measurement samples.

    • running

      private boolean running
      Indicates whether estimator is running or not.

  • Constructor Details

    • WindowedMeasurementNoiseEstimator

      protected WindowedMeasurementNoiseEstimator()
      Constructor.

    • WindowedMeasurementNoiseEstimator

      protected WindowedMeasurementNoiseEstimator(L listener)
      Constructor.
      Parameters:
      listener - listener to handle events raised by this estimator.

  • Method Details

    • getWindowSize

      public int getWindowSize()
      Gets length of number of samples to keep within the window being processed. Window size must always be larger than allowed minimum value and must have and odd value.
      Returns:
      length of number of samples to keep within the window.

    • setWindowSize

      public void setWindowSize(int windowSize) throws com.irurueta.navigation.LockedException
      Sets length of number of samples to keep within the window being processed. Window size must always be larger than allowed minimum value and must have an odd value.
      Parameters:
      windowSize - length of number of samples to keep within the window.
      Throws:
      IllegalArgumentException - if provided value is not valid.
      com.irurueta.navigation.LockedException - if estimator is currently running.

    • getTimeInterval

      public double getTimeInterval()
      Gets time interval between accelerometer triad samples expressed in seconds (s).
      Returns:
      time interval between accelerometer triad samples.

    • setTimeInterval

      public void setTimeInterval(double timeInterval) throws com.irurueta.navigation.LockedException
      Sets time interval between accelerometer triad samples expressed in seconds (s).
      Parameters:
      timeInterval - time interval between accelerometer triad samples.
      Throws:
      IllegalArgumentException - if provided value is negative.
      com.irurueta.navigation.LockedException - if estimator is currently running.

    • getTimeIntervalAsTime

      public com.irurueta.units.Time getTimeIntervalAsTime()
      Gets time interval between accelerometer triad samples.
      Returns:
      time interval between accelerometer triad samples.

    • getTimeIntervalAsTime

      public void getTimeIntervalAsTime(com.irurueta.units.Time result)
      Gets time interval between accelerometer triad samples.
      Parameters:
      result - instance where time interval will be stored.

    • setTimeInterval

      public void setTimeInterval(com.irurueta.units.Time timeInterval) throws com.irurueta.navigation.LockedException
      Sets time interval between accelerometer triad samples.
      Parameters:
      timeInterval - time interval between accelerometer triad samples.
      Throws:
      com.irurueta.navigation.LockedException - if estimator is currently running.

    • getListener

      public L getListener()
      Gets listener to handle events raised by this estimator.
      Returns:
      listener to handle events raised by this estimator.

    • setListener

      public void setListener(L listener) throws com.irurueta.navigation.LockedException
      Sets listener to handle events raised by this estimator.
      Parameters:
      listener - listener to handle events raised by this estimator.
      Throws:
      com.irurueta.navigation.LockedException - if this estimator is running.

    • getFirstWindowedMeasurementValue

      public Double getFirstWindowedMeasurementValue()
      Gets first provided measurement value expressed in its default units. (m/s^2 for acceleration, rad/s for angular speed or T for magnetic flux density).
      Returns:
      first provided measurement value or null if not available.

    • getLastWindowedMeasurementValue

      public Double getLastWindowedMeasurementValue()
      Gets las provided measurement value expressed in its default units. (m/s^2 for acceleration, rad/s for angular speed or T for magnetic flux density).
      Returns:
      last provided measurement value or null if not available.

    • getFirstWindowedMeasurement

      public M getFirstWindowedMeasurement()
      Gets first provided measurement within the window.
      Returns:
      first provided measurement within the window or null if not available.

    • getFirstWindowedMeasurement

      public boolean getFirstWindowedMeasurement(M result)
      Gets first provided measurement within the window.
      Parameters:
      result - instance where first provided measurement will be stored.
      Returns:
      true if result was updated, false if first measurement is not available.

    • getLastWindowedMeasurement

      public M getLastWindowedMeasurement()
      Gets last provided measurement within the window.
      Returns:
      last provided measurement within the window or null if not available.

    • getLastWindowedMeasurement

      public boolean getLastWindowedMeasurement(M result)
      Gets last provided measurement within the window.
      Parameters:
      result - instance where last provided measurement will be stored.
      Returns:
      true if result was updated, false if last measurement is not available.

    • getAvg

      public double getAvg()
      Gets estimated average of measurement expressed in its default unit (m/s^2 for acceleration, rad/s for angular speed or T for magnetic flux density).
      Returns:
      average of measurement in current window.

    • getAvgAsMeasurement

      public M getAvgAsMeasurement()
      Gets estimated average of measurement within current window.
      Returns:
      average of measurement in current window

    • getAvgAsMeasurement

      public void getAvgAsMeasurement(M result)
      Gets estimated average of measurement within current window.
      Parameters:
      result - instance where average of measurement will be stored.

    • getVariance

      public double getVariance()
      Gets estimated variance of measurement within current window expressed in its default squared unit (m^2/s^4 for acceleration, rad^2/s^2 for angular speed or T^2 for magnetic flux density).
      Returns:
      estimated variance of measurement within current window.

    • getStandardDeviation

      public double getStandardDeviation()
      Gets estimated standard deviation of measurement within current window and expressed in its default unit (m/s^2 for acceleration, rad/s for angular speed or T for magnetic flux density).
      Returns:
      estimated standard of measurement.

    • getStandardDeviationAsMeasurement

      public M getStandardDeviationAsMeasurement()
      Gets estimated standard deviation of measurement within current window.
      Returns:
      estimated standard deviation of measurement.

    • getStandardDeviationAsMeasurement

      public void getStandardDeviationAsMeasurement(M result)
      Gets estimated standard deviation of measurement within current window.
      Parameters:
      result - instance where estimated standard deviation of measurement will be stored.

    • getPsd

      public double getPsd()
      Gets measurement noise PSD (Power Spectral Density) expressed in (m^2 * s^-3) for accelerometer, (rad^2/s) for gyroscope or (T^2 * s) for magnetometer.
      Returns:
      measurement noise PSD.

    • getRootPsd

      public double getRootPsd()
      Gets measurement noise root PSD (Power Spectral Density) expressed in (m * s^-1.5) for accelerometer, (rad * s^-0.5) for gyroscope or (T * s^0.5) for magnetometer.
      Returns:
      measurement noise root PSD.

    • getNumberOfProcessedSamples

      public int getNumberOfProcessedSamples()
      Gets number of samples that have been processed so far.
      Returns:
      number of samples that have been processed so far.

    • getNumberOfAddedSamples

      public int getNumberOfAddedSamples()
      Gets number of samples that have been added so far.
      Returns:
      number of samples that have been added so far.

    • getNumberOfSamplesInWindow

      public int getNumberOfSamplesInWindow()
      Gets number of currently windowed samples.
      Returns:
      number of samples within the window.

    • isWindowFilled

      public boolean isWindowFilled()
      Indicates whether window of samples is filled or not.
      Returns:
      true if window is filled, false otherwise.

    • isRunning

      public boolean isRunning()
      Indicates whether estimator is currently running or not.
      Returns:
      true if estimator is running, false otherwise.

    • addMeasurementAndProcess

      public void addMeasurementAndProcess(double value) throws com.irurueta.navigation.LockedException
      Adds a measurement value expressed in its default unit (m/s^2 for acceleration, rad/s for angular speed or T for magnetic flux density) and processes current window. Notice that if there are less than getWindowSize() processed samples in the window, the remaining ones are considered to be zero when average values and standard deviation is estimated.
      Parameters:
      value - value to be added.
      Throws:
      com.irurueta.navigation.LockedException - if estimator is currently running.

    • addMeasurementAndProcess

      public void addMeasurementAndProcess(M value) throws com.irurueta.navigation.LockedException
      Adds a measurement and processes current window. Notice that if there are less than getWindowSize() processed samples in the window, the remaining ones are considered to be zero when average values and standard deviation is estimated.
      Parameters:
      value - value to be added.
      Throws:
      com.irurueta.navigation.LockedException - if estimator is currently running.

    • addMeasurement

      public void addMeasurement(double value) throws com.irurueta.navigation.LockedException
      Adds a measurement value expressed in its default unit (m/s^2 for acceleration, rad/s for angular speed or T for magnetic flux density). Notice that if there are less than getWindowSize() processed samples in the window, the remaining ones are considered to be zero when average values and standard deviation is estimated.
      Parameters:
      value - value to be added.
      Throws:
      com.irurueta.navigation.LockedException - if estimator is currently running.

    • addMeasurement

      public void addMeasurement(M value) throws com.irurueta.navigation.LockedException
      Adds a measurement. Notice that if there are less than getWindowSize() processed samples in the window, the remaining ones are considered to be zero when average values and standard deviation is estimated.
      Parameters:
      value - value to be added.
      Throws:
      com.irurueta.navigation.LockedException - if estimator is currently running

    • reset

      public boolean reset() throws com.irurueta.navigation.LockedException
      Resets current estimator.
      Returns:
      true if estimator was successfully reset, false if no reset was needed.
      Throws:
      com.irurueta.navigation.LockedException - if estimator is currently running.

    • getDefaultUnit

      protected abstract U getDefaultUnit()
      Gets default unit for a measurement.
      Returns:
      default unit for a measurement.

    • createMeasurement

      protected abstract M createMeasurement(double value, U unit)
      Creates a measurement with provided value and unit.
      Parameters:
      value - value to be set.
      unit - unit to be set.
      Returns:
      created measurement.

    • convertToDefaultUnit

      protected abstract double convertToDefaultUnit(M value)
      Converts provided measurement into default unit.
      Parameters:
      value - measurement to be converted.
      Returns:
      converted value.

    • internalAdd

      private void internalAdd(double value, boolean process) throws com.irurueta.navigation.LockedException
      Internally adds a measurement value and processes current window if indicated.
      Parameters:
      value - measurement value to be added.
      process - true if window of samples must also be processed, false otherwise.
      Throws:
      com.irurueta.navigation.LockedException - if estimator is currently running.

    • processWindow

      private void processWindow()
      Processes current windowed samples.