Class LMedSRobustRssiRadioSourceEstimator2D<S extends RadioSource>

java.lang.Object
com.irurueta.navigation.indoor.radiosource.RobustRadioSourceEstimator<com.irurueta.geometry.Point2D,RssiReadingLocated<S,com.irurueta.geometry.Point2D>,RobustRssiRadioSourceEstimatorListener<S,com.irurueta.geometry.Point2D>>
com.irurueta.navigation.indoor.radiosource.RobustRssiRadioSourceEstimator<S,com.irurueta.geometry.Point2D>
com.irurueta.navigation.indoor.radiosource.RobustRssiRadioSourceEstimator2D<S>
com.irurueta.navigation.indoor.radiosource.LMedSRobustRssiRadioSourceEstimator2D<S>
Type Parameters:
S - a RadioSource type.

public class LMedSRobustRssiRadioSourceEstimator2D<S extends RadioSource> extends RobustRssiRadioSourceEstimator2D<S>
Robustly estimate 2D position, transmitted power and path-loss exponent of a radio source (e.g. Wi-Fi access point or bluetooth beacon), by discarding outliers using LMedS algorithm and assuming that the radio source emits isotropically following the expression below: Pr = Pt*Gt*Gr*lambda^2 / (4*pi*d)^2, where Pr is the received power (expressed in mW), Gt is the Gain of the transmission antenna Gr is the Gain of the receiver antenna d is the distance between emitter and receiver and lambda is the wavelength and is equal to: lambda = c / f, where c is the speed of light and f is the carrier frequency of the radio signal. Because usually information about the antenna of the radio source cannot be retrieved (because many measurements are made on unknown devices where physical access is not possible), this implementation will estimate the equivalent transmitted power as: Pte = Pt * Gt * Gr. If RssiReadings contain RSSI standard deviations, those values will be used, otherwise it will be assumed an RSSI standard deviation of 1 dB. Implementations of this class should be able to detect and discard outliers in order to find the best solution.

IMPORTANT: When using this class estimation can be done using a combination of radio source position, transmitted power and path loss exponent. However enabling all three estimations usually achieves inaccurate results. When using this class, estimation must be of at least one parameter (position, transmitted power or path loss exponent) when initial values are provided for the other two, and at most it should consist of two parameters (either position and transmitted power, position and path loss exponent or transmitted power and path loss exponent), providing an initial value for the remaining parameter.

  • Field Details

    • DEFAULT_STOP_THRESHOLD

      public static final double DEFAULT_STOP_THRESHOLD
      Default value to be used for stop threshold. Stop threshold can be used to avoid keeping the algorithm unnecessarily iterating in case that best estimated threshold using median of residuals is not small enough. Once a solution is found that generates a threshold below this value, the algorithm will stop. The stop threshold can be used to prevent the LMedS algorithm iterating too many times in cases where samples have a very similar accuracy. For instance, in cases where proportion of outliers is very small (close to 0%), and samples are very accurate (i.e. 1e-6), the algorithm would iterate for a long time trying to find the best solution when indeed there is no need to do that if a reasonable threshold has already been reached. Because of this behaviour the stop threshold can be set to a value much lower than the one typically used in RANSAC, and yet the algorithm could still produce even smaller thresholds in estimated results.
      See Also:
    • MIN_STOP_THRESHOLD

      public static final double MIN_STOP_THRESHOLD
      Minimum allowed stop threshold value.
      See Also:
    • stopThreshold

      private double stopThreshold
      Threshold to be used to keep the algorithm iterating in case that best estimated threshold using median of residuals is not small enough. Once a solution is found that generates a threshold below this value, the algorithm will stop. The stop threshold can be used to prevent the LMedS algorithm iterating too many times in cases where samples have a very similar accuracy. For instance, in cases where proportion of outliers is very small (close to 0%), and samples are very accurate (i.e. 1e-6), the algorithm would iterate for a long time trying to find the best solution when indeed there is no need to do that if a reasonable threshold has already been reached. Because of this behaviour the stop threshold can be set to a value much lower than the one typically used in RANSAC, and yet the algorithm could still produce even smaller thresholds in estimated results.
  • Constructor Details

    • LMedSRobustRssiRadioSourceEstimator2D

      public LMedSRobustRssiRadioSourceEstimator2D()
      Constructor.
    • LMedSRobustRssiRadioSourceEstimator2D

      public LMedSRobustRssiRadioSourceEstimator2D(List<? extends RssiReadingLocated<S,com.irurueta.geometry.Point2D>> readings)
      Constructor. Sets signal readings belonging to the same radio source.
      Parameters:
      readings - signal readings belonging to the same radio source.
      Throws:
      IllegalArgumentException - if readings are not valid.
    • LMedSRobustRssiRadioSourceEstimator2D

      public LMedSRobustRssiRadioSourceEstimator2D(RobustRssiRadioSourceEstimatorListener<S,com.irurueta.geometry.Point2D> listener)
      Constructor.
      Parameters:
      listener - listener in charge of attending events raised by this instance.
    • LMedSRobustRssiRadioSourceEstimator2D

      public LMedSRobustRssiRadioSourceEstimator2D(List<? extends RssiReadingLocated<S,com.irurueta.geometry.Point2D>> readings, RobustRssiRadioSourceEstimatorListener<S,com.irurueta.geometry.Point2D> listener)
      Constructor. Sets signal readings belonging to the same radio source.
      Parameters:
      readings - signal readings belonging to the same radio source.
      listener - listener in charge of attending events raised by this instance.
      Throws:
      IllegalArgumentException - if readings are not valid.
    • LMedSRobustRssiRadioSourceEstimator2D

      public LMedSRobustRssiRadioSourceEstimator2D(List<? extends RssiReadingLocated<S,com.irurueta.geometry.Point2D>> readings, com.irurueta.geometry.Point2D initialPosition)
      Constructor. Sets signal readings belonging to the same radio source.
      Parameters:
      readings - signal readings belonging to the same radio source.
      initialPosition - initial position to start the estimation of radio source position.
      Throws:
      IllegalArgumentException - if readings are not valid.
    • LMedSRobustRssiRadioSourceEstimator2D

      public LMedSRobustRssiRadioSourceEstimator2D(com.irurueta.geometry.Point2D initialPosition)
      Constructor.
      Parameters:
      initialPosition - initial position to start the estimation of radio source position.
    • LMedSRobustRssiRadioSourceEstimator2D

      public LMedSRobustRssiRadioSourceEstimator2D(com.irurueta.geometry.Point2D initialPosition, RobustRssiRadioSourceEstimatorListener<S,com.irurueta.geometry.Point2D> listener)
      Constructor.
      Parameters:
      initialPosition - initial position to start the estimation of radio source position.
      listener - listener in charge of attending events raised by this instance.
    • LMedSRobustRssiRadioSourceEstimator2D

      public LMedSRobustRssiRadioSourceEstimator2D(List<? extends RssiReadingLocated<S,com.irurueta.geometry.Point2D>> readings, com.irurueta.geometry.Point2D initialPosition, RobustRssiRadioSourceEstimatorListener<S,com.irurueta.geometry.Point2D> listener)
      Constructor. Sets signal readings belonging to the same radio source.
      Parameters:
      readings - signal readings belonging to the same radio source.
      initialPosition - initial position to start the estimation of radio source position.
      listener - listener in charge of attending events raised by this instance.
      Throws:
      IllegalArgumentException - if readings are not valid.
    • LMedSRobustRssiRadioSourceEstimator2D

      public LMedSRobustRssiRadioSourceEstimator2D(Double initialTransmittedPowerdBm)
      Constructor.
      Parameters:
      initialTransmittedPowerdBm - initial transmitted power to start the estimation of radio source transmitted power (expressed in dBm's)
    • LMedSRobustRssiRadioSourceEstimator2D

      public LMedSRobustRssiRadioSourceEstimator2D(List<? extends RssiReadingLocated<S,com.irurueta.geometry.Point2D>> readings, Double initialTransmittedPowerdBm)
      Constructor. Sets signal readings belonging to the same radio source.
      Parameters:
      readings - signal readings belonging to the same radio source.
      initialTransmittedPowerdBm - initial transmitted power to start the estimation of radio source transmitted power (expressed in dBm's)
      Throws:
      IllegalArgumentException - if readings are not valid.
    • LMedSRobustRssiRadioSourceEstimator2D

      public LMedSRobustRssiRadioSourceEstimator2D(Double initialTransmittedPowerdBm, RobustRssiRadioSourceEstimatorListener<S,com.irurueta.geometry.Point2D> listener)
      Constructor.
      Parameters:
      initialTransmittedPowerdBm - initial transmitted power to start the estimation of radio source transmitted power (expressed in dBm's)
      listener - listener in charge of attending events raised by this instance.
    • LMedSRobustRssiRadioSourceEstimator2D

      public LMedSRobustRssiRadioSourceEstimator2D(List<? extends RssiReadingLocated<S,com.irurueta.geometry.Point2D>> readings, Double initialTransmittedPowerdBm, RobustRssiRadioSourceEstimatorListener<S,com.irurueta.geometry.Point2D> listener)
      Constructor. Sets signal readings belonging to the same radio source.
      Parameters:
      readings - signal readings belonging to the same radio source.
      initialTransmittedPowerdBm - initial transmitted power to start the estimation of radio source transmitted power (expressed in dBm's)
      listener - listener in charge of attending events raised by this instance.
      Throws:
      IllegalArgumentException - if readings are not valid.
    • LMedSRobustRssiRadioSourceEstimator2D

      public LMedSRobustRssiRadioSourceEstimator2D(List<? extends RssiReadingLocated<S,com.irurueta.geometry.Point2D>> readings, com.irurueta.geometry.Point2D initialPosition, Double initialTransmittedPowerdBm)
      Constructor. Sets signal readings belonging to the same radio source.
      Parameters:
      readings - signal readings belonging to the same radio source.
      initialPosition - initial position to start the estimation of radio source position.
      initialTransmittedPowerdBm - initial transmitted power to start the estimation of radio source transmitted power (expressed in dBm's).
      Throws:
      IllegalArgumentException - if readings are not valid.
    • LMedSRobustRssiRadioSourceEstimator2D

      public LMedSRobustRssiRadioSourceEstimator2D(com.irurueta.geometry.Point2D initialPosition, Double initialTransmittedPowerdBm)
      Constructor.
      Parameters:
      initialPosition - initial position to start the estimation of radio source position.
      initialTransmittedPowerdBm - initial transmitted power to start the estimation of radio source transmitted power (expressed in dBm's).
    • LMedSRobustRssiRadioSourceEstimator2D

      public LMedSRobustRssiRadioSourceEstimator2D(com.irurueta.geometry.Point2D initialPosition, Double initialTransmittedPowerdBm, RobustRssiRadioSourceEstimatorListener<S,com.irurueta.geometry.Point2D> listener)
      Constructor.
      Parameters:
      initialPosition - initial position to start the estimation of radio source position.
      initialTransmittedPowerdBm - initial transmitted power to start the estimation of radio source transmitted power (expressed in dBm's).
      listener - in charge of attending events raised by this instance.
    • LMedSRobustRssiRadioSourceEstimator2D

      public LMedSRobustRssiRadioSourceEstimator2D(List<? extends RssiReadingLocated<S,com.irurueta.geometry.Point2D>> readings, com.irurueta.geometry.Point2D initialPosition, Double initialTransmittedPowerdBm, RobustRssiRadioSourceEstimatorListener<S,com.irurueta.geometry.Point2D> listener)
      Constructor. Sets signal readings belonging to the same radio source.
      Parameters:
      readings - signal readings belonging to the same radio source.
      initialPosition - initial position to start the estimation of radio source position.
      initialTransmittedPowerdBm - initial transmitted power to start the estimation of radio source transmitted power (expressed in dBm's).
      listener - listener in charge of attending events raised by this instance.
      Throws:
      IllegalArgumentException - if readings are not valid.
    • LMedSRobustRssiRadioSourceEstimator2D

      public LMedSRobustRssiRadioSourceEstimator2D(List<? extends RssiReadingLocated<S,com.irurueta.geometry.Point2D>> readings, com.irurueta.geometry.Point2D initialPosition, Double initialTransmittedPowerdBm, double initialPathLossExponent)
      Constructor. Sets signal readings belonging to the same radio source.
      Parameters:
      readings - signal readings belonging to the same radio source.
      initialPosition - initial position to start the estimation of radio source position.
      initialTransmittedPowerdBm - initial transmitted power to start the estimation of radio source transmitted power (expressed in dBm's).
      initialPathLossExponent - initial path loss exponent. A typical value is 2.0.
      Throws:
      IllegalArgumentException - if readings are not valid.
    • LMedSRobustRssiRadioSourceEstimator2D

      public LMedSRobustRssiRadioSourceEstimator2D(com.irurueta.geometry.Point2D initialPosition, Double initialTransmittedPowerdBm, double initialPathLossExponent)
      Constructor.
      Parameters:
      initialPosition - initial position to start the estimation of radio source position.
      initialTransmittedPowerdBm - initial transmitted power to start the estimation of radio source transmitted power (expressed in dBm's).
      initialPathLossExponent - initial path loss exponent. A typical value is 2.0.
    • LMedSRobustRssiRadioSourceEstimator2D

      public LMedSRobustRssiRadioSourceEstimator2D(com.irurueta.geometry.Point2D initialPosition, Double initialTransmittedPowerdBm, double initialPathLossExponent, RobustRssiRadioSourceEstimatorListener<S,com.irurueta.geometry.Point2D> listener)
      Constructor.
      Parameters:
      initialPosition - initial position to start the estimation of radio source position.
      initialTransmittedPowerdBm - initial transmitted power to start the estimation of radio source transmitted power (expressed in dBm's).
      initialPathLossExponent - initial path loss exponent. A typical value is 2.0.
      listener - listener in charge of attending events raised by this instance.
    • LMedSRobustRssiRadioSourceEstimator2D

      public LMedSRobustRssiRadioSourceEstimator2D(List<? extends RssiReadingLocated<S,com.irurueta.geometry.Point2D>> readings, com.irurueta.geometry.Point2D initialPosition, Double initialTransmittedPowerdBm, double initialPathLossExponent, RobustRssiRadioSourceEstimatorListener<S,com.irurueta.geometry.Point2D> listener)
      Constructor. Sets signal readings belonging to the same radio source.
      Parameters:
      readings - signal readings belonging to the same radio source.
      initialPosition - initial position to start the estimation of radio source position.
      initialTransmittedPowerdBm - initial transmitted power to start the estimation of radio source transmitted power (expressed in dBm's).
      initialPathLossExponent - initial path loss exponent. A typical value is 2.0.
      listener - listener in charge of attending events raised by this instance.
      Throws:
      IllegalArgumentException - if readings are not valid.
  • Method Details

    • getStopThreshold

      public double getStopThreshold()
      Returns threshold to be used to keep the algorithm iterating in case that best estimated threshold using median of residuals is not small enough. Once a solution is found that generates a threshold below this value, the algorithm will stop. The stop threshold can be used to prevent the LMedS algorithm to iterate too many times in cases where samples have a very similar accuracy. For instance, in cases where proportion of outliers is very small (close to 0%), and samples are very accurate (i.e. 1e-6), the algorithm would iterate for a long time trying to find the best solution when indeed there is no need to do that if a reasonable threshold has already been reached. Because of this behaviour the stop threshold can be set to a value much lower than the one typically used in RANSAC, and yet the algorithm could still produce even smaller thresholds in estimated results.
      Returns:
      stop threshold to stop the algorithm prematurely when a certain accuracy has been reached.
    • setStopThreshold

      public void setStopThreshold(double stopThreshold) throws com.irurueta.navigation.LockedException
      Sets threshold to be used to keep the algorithm iterating in case that best estimated threshold using median of residuals is not small enough. Once a solution is found that generates a threshold below this value, the algorithm will stop. The stop threshold can be used to prevent the LMedS algorithm to iterate too many times in cases where samples have a very similar accuracy. For instance, in cases where proportion of outliers is very small (close to 0%), and samples are very accurate (i.e. 1e-6), the algorithm would iterate for a long time trying to find the best solution when indeed there is no need to do that if a reasonable threshold has already been reached. Because of this behaviour the stop threshold can be set to a value much lower than the one typically used in RANSAC, and yet the algorithm could still produce even smaller thresholds in estimated results.
      Parameters:
      stopThreshold - stop threshold to stop the algorithm prematurely when a certain accuracy has been reached.
      Throws:
      IllegalArgumentException - if provided value is zero or negative.
      com.irurueta.navigation.LockedException - if this solver is locked.
    • estimate

      public void estimate() throws com.irurueta.navigation.LockedException, com.irurueta.navigation.NotReadyException, com.irurueta.numerical.robust.RobustEstimatorException
      Robustly estimates position, transmitted power and path-loss exponent for a radio source.
      Specified by:
      estimate in class RobustRadioSourceEstimator<com.irurueta.geometry.Point2D,RssiReadingLocated<S extends RadioSource,com.irurueta.geometry.Point2D>,RobustRssiRadioSourceEstimatorListener<S extends RadioSource,com.irurueta.geometry.Point2D>>
      Throws:
      com.irurueta.navigation.LockedException - if instance is busy during estimation.
      com.irurueta.navigation.NotReadyException - if estimator is not ready.
      com.irurueta.numerical.robust.RobustEstimatorException - if estimation fails for any reason (i.e. numerical instability, no solution available, etc).
    • getMethod

      public com.irurueta.numerical.robust.RobustEstimatorMethod getMethod()
      Returns method being used for robust estimation.
      Specified by:
      getMethod in class RobustRssiRadioSourceEstimator<S extends RadioSource,com.irurueta.geometry.Point2D>
      Returns:
      method being used for robust estimation.