Package com.irurueta.navigation.inertial.calibration.accelerometer

Class LMedSRobustKnownPositionAccelerometerCalibrator

java.lang.Object
com.irurueta.navigation.inertial.calibration.accelerometer.RobustKnownPositionAccelerometerCalibrator
com.irurueta.navigation.inertial.calibration.accelerometer.LMedSRobustKnownPositionAccelerometerCalibrator
All Implemented Interfaces:
AccelerometerCalibrator, AccelerometerNonLinearCalibrator, OrderedStandardDeviationBodyKinematicsAccelerometerCalibrator, QualityScoredAccelerometerCalibrator, UnknownBiasAccelerometerCalibrator, UnknownBiasNonLinearAccelerometerCalibrator, AccelerometerBiasUncertaintySource, AccelerometerCalibrationSource
public class LMedSRobustKnownPositionAccelerometerCalibrator extends RobustKnownPositionAccelerometerCalibrator
Robustly estimates accelerometer biases, cross couplings and scaling factors using a LMedS algorithm to discard outliers.

To use this calibrator at least 10 measurements taken at a single known position must be taken at 10 different unknown orientations and zero velocity when common z-axis is assumed, otherwise at least 13 measurements are required.

Measured specific force is assumed to follow the model shown below: 

     fmeas = ba + (I + Ma) * ftrue + w
Where: - fmeas is the measured specific force. This is a 3x1 vector. - ba is accelerometer bias. Ideally, on a perfect accelerometer, this should be a 3x1 zero vector. - I is the 3x3 identity matrix. - Ma is the 3x3 matrix containing cross-couplings and scaling factors. Ideally, on a perfect accelerometer, this should be a 3x3 zero matrix. - ftrue is ground-truth specific force. - w is measurement noise.

  • 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

    • LMedSRobustKnownPositionAccelerometerCalibrator

      public LMedSRobustKnownPositionAccelerometerCalibrator()
      Constructor.

    • LMedSRobustKnownPositionAccelerometerCalibrator

      public LMedSRobustKnownPositionAccelerometerCalibrator(RobustKnownPositionAccelerometerCalibratorListener listener)
      Constructor.
      Parameters:
      listener - listener to be notified of events such as when estimation starts, ends or its progress significantly changes.

    • LMedSRobustKnownPositionAccelerometerCalibrator

      public LMedSRobustKnownPositionAccelerometerCalibrator(List<StandardDeviationBodyKinematics> measurements)
      Constructor.
      Parameters:
      measurements - list of body kinematics measurements taken at a given position with different unknown orientations and containing the standard deviations of accelerometer and gyroscope measurements.

    • LMedSRobustKnownPositionAccelerometerCalibrator

      public LMedSRobustKnownPositionAccelerometerCalibrator(boolean commonAxisUsed)
      Constructor.
      Parameters:
      commonAxisUsed - indicates whether z-axis is assumed to be common for accelerometer and gyroscope.

    • LMedSRobustKnownPositionAccelerometerCalibrator

      public LMedSRobustKnownPositionAccelerometerCalibrator(double[] initialBias)
      Constructor.
      Parameters:
      initialBias - initial accelerometer bias to be used to find a solution. This must have length 3 and is expressed in meters per squared second (m/s^2).
      Throws:
      IllegalArgumentException - if provided bias array does not have length 3.

    • LMedSRobustKnownPositionAccelerometerCalibrator

      public LMedSRobustKnownPositionAccelerometerCalibrator(com.irurueta.algebra.Matrix initialBias)
      Constructor.
      Parameters:
      initialBias - initial bias to find a solution.
      Throws:
      IllegalArgumentException - if provided bias matrix is not 3x1.

    • LMedSRobustKnownPositionAccelerometerCalibrator

      public LMedSRobustKnownPositionAccelerometerCalibrator(com.irurueta.algebra.Matrix initialBias, com.irurueta.algebra.Matrix initialMa)
      Constructor.
      Parameters:
      initialBias - initial bias to find a solution.
      initialMa - initial scale factors and cross coupling errors matrix.
      Throws:
      IllegalArgumentException - if either provided bias matrix is not 3x1 or scaling and coupling error matrix is not 3x3.

    • LMedSRobustKnownPositionAccelerometerCalibrator

      public LMedSRobustKnownPositionAccelerometerCalibrator(com.irurueta.navigation.frames.ECEFPosition position)
      Constructor.
      Parameters:
      position - position where body kinematics measures have been taken.

    • LMedSRobustKnownPositionAccelerometerCalibrator

      public LMedSRobustKnownPositionAccelerometerCalibrator(com.irurueta.navigation.frames.ECEFPosition position, List<StandardDeviationBodyKinematics> measurements)
      Constructor.
      Parameters:
      position - position where body kinematics measures have been taken.
      measurements - list of body kinematics measurements taken at a given position with different unknown orientations and containing the standard deviations of accelerometer and gyroscope measurements.

    • LMedSRobustKnownPositionAccelerometerCalibrator

      public LMedSRobustKnownPositionAccelerometerCalibrator(com.irurueta.navigation.frames.ECEFPosition position, List<StandardDeviationBodyKinematics> measurements, RobustKnownPositionAccelerometerCalibratorListener listener)
      Constructor.
      Parameters:
      position - position where body kinematics measures have been taken.
      measurements - list of body kinematics measurements taken at a given position with different unknown orientations and containing the standard deviations of accelerometer and gyroscope measurements.
      listener - listener to be notified of events such as when estimation starts, ends or its progress significantly changes.

    • LMedSRobustKnownPositionAccelerometerCalibrator

      public LMedSRobustKnownPositionAccelerometerCalibrator(com.irurueta.navigation.frames.ECEFPosition position, List<StandardDeviationBodyKinematics> measurements, boolean commonAxisUsed)
      Constructor.
      Parameters:
      position - position where body kinematics measures have been taken.
      measurements - list of body kinematics measurements taken at a given position with different unknown orientations and containing the standard deviations of accelerometer and gyroscope measurements.
      commonAxisUsed - indicates whether z-axis is assumed to be common for accelerometer and gyroscope.

    • LMedSRobustKnownPositionAccelerometerCalibrator

      public LMedSRobustKnownPositionAccelerometerCalibrator(com.irurueta.navigation.frames.ECEFPosition position, List<StandardDeviationBodyKinematics> measurements, boolean commonAxisUsed, RobustKnownPositionAccelerometerCalibratorListener listener)
      Constructor.
      Parameters:
      position - position where body kinematics measures have been taken.
      measurements - list of body kinematics measurements taken at a given position with different unknown orientations and containing the standard deviations of accelerometer and gyroscope measurements.
      commonAxisUsed - indicates whether z-axis is assumed to be common for accelerometer and gyroscope.
      listener - listener to be notified of events such as when estimation starts, ends or its progress significantly changes.

    • LMedSRobustKnownPositionAccelerometerCalibrator

      public LMedSRobustKnownPositionAccelerometerCalibrator(com.irurueta.navigation.frames.ECEFPosition position, List<StandardDeviationBodyKinematics> measurements, double[] initialBias)
      Constructor.
      Parameters:
      position - position where body kinematics measures have been taken.
      measurements - collection of body kinematics measurements with standard deviations taken at the same position with zero velocity and unknown different orientations.
      initialBias - initial accelerometer bias to be used to find a solution. This must have length 3 and is expressed in meters per squared second (m/s^2).
      Throws:
      IllegalArgumentException - if provided bias array does not have length 3.

    • LMedSRobustKnownPositionAccelerometerCalibrator

      public LMedSRobustKnownPositionAccelerometerCalibrator(com.irurueta.navigation.frames.ECEFPosition position, List<StandardDeviationBodyKinematics> measurements, double[] initialBias, RobustKnownPositionAccelerometerCalibratorListener listener)
      Constructor.
      Parameters:
      position - position where body kinematics measures have been taken.
      measurements - collection of body kinematics measurements with standard deviations taken at the same position with zero velocity and unknown different orientations.
      initialBias - initial accelerometer bias to be used to find a solution. This must have length 3 and is expressed in meters per squared second (m/s^2).
      listener - listener to handle events raised by this calibrator.
      Throws:
      IllegalArgumentException - if provided bias array does not have length 3.

    • LMedSRobustKnownPositionAccelerometerCalibrator

      public LMedSRobustKnownPositionAccelerometerCalibrator(com.irurueta.navigation.frames.ECEFPosition position, List<StandardDeviationBodyKinematics> measurements, boolean commonAxisUsed, double[] initialBias)
      Constructor.
      Parameters:
      position - position where body kinematics measures have been taken.
      measurements - collection of body kinematics measurements with standard deviations taken at the same position with zero velocity and unknown different orientations.
      commonAxisUsed - indicates whether z-axis is assumed to be common for accelerometer and gyroscope.
      initialBias - initial accelerometer bias to be used to find a solution. This must have length 3 and is expressed in meters per squared second (m/s^2).
      Throws:
      IllegalArgumentException - if provided bias array does not have length 3.

    • LMedSRobustKnownPositionAccelerometerCalibrator

      public LMedSRobustKnownPositionAccelerometerCalibrator(com.irurueta.navigation.frames.ECEFPosition position, List<StandardDeviationBodyKinematics> measurements, boolean commonAxisUsed, double[] initialBias, RobustKnownPositionAccelerometerCalibratorListener listener)
      Constructor.
      Parameters:
      position - position where body kinematics measures have been taken.
      measurements - collection of body kinematics measurements with standard deviations taken at the same position with zero velocity and unknown different orientations.
      commonAxisUsed - indicates whether z-axis is assumed to be common for accelerometer and gyroscope.
      initialBias - initial accelerometer bias to be used to find a solution. This must have length 3 and is expressed in meters per squared second (m/s^2).
      listener - listener to handle events raised by this calibrator.
      Throws:
      IllegalArgumentException - if provided bias array does not have length 3.

    • LMedSRobustKnownPositionAccelerometerCalibrator

      public LMedSRobustKnownPositionAccelerometerCalibrator(com.irurueta.navigation.frames.ECEFPosition position, List<StandardDeviationBodyKinematics> measurements, com.irurueta.algebra.Matrix initialBias)
      Constructor.
      Parameters:
      position - position where body kinematics measures have been taken.
      measurements - collection of body kinematics measurements with standard deviations taken at the same position with zero velocity and unknown different orientations.
      initialBias - initial bias to find a solution.
      Throws:
      IllegalArgumentException - if provided bias matrix is not 3x1.

    • LMedSRobustKnownPositionAccelerometerCalibrator

      public LMedSRobustKnownPositionAccelerometerCalibrator(com.irurueta.navigation.frames.ECEFPosition position, List<StandardDeviationBodyKinematics> measurements, com.irurueta.algebra.Matrix initialBias, RobustKnownPositionAccelerometerCalibratorListener listener)
      Constructor.
      Parameters:
      position - position where body kinematics measures have been taken.
      measurements - collection of body kinematics measurements with standard deviations taken at the same position with zero velocity and unknown different orientations.
      initialBias - initial bias to find a solution.
      listener - listener to handle events raised by this calibrator.

    • LMedSRobustKnownPositionAccelerometerCalibrator

      public LMedSRobustKnownPositionAccelerometerCalibrator(com.irurueta.navigation.frames.ECEFPosition position, List<StandardDeviationBodyKinematics> measurements, boolean commonAxisUsed, com.irurueta.algebra.Matrix initialBias)
      Constructor.
      Parameters:
      position - position where body kinematics measures have been taken.
      measurements - collection of body kinematics measurements with standard deviations taken at the same position with zero velocity and unknown different orientations.
      commonAxisUsed - indicates whether z-axis is assumed to be common for accelerometer and gyroscope.
      initialBias - initial bias to find a solution.
      Throws:
      IllegalArgumentException - if provided bias matrix is not 3x1.

    • LMedSRobustKnownPositionAccelerometerCalibrator

      public LMedSRobustKnownPositionAccelerometerCalibrator(com.irurueta.navigation.frames.ECEFPosition position, List<StandardDeviationBodyKinematics> measurements, boolean commonAxisUsed, com.irurueta.algebra.Matrix initialBias, RobustKnownPositionAccelerometerCalibratorListener listener)
      Constructor.
      Parameters:
      position - position where body kinematics measures have been taken.
      measurements - collection of body kinematics measurements with standard deviations taken at the same position with zero velocity and unknown different orientations.
      commonAxisUsed - indicates whether z-axis is assumed to be common for accelerometer and gyroscope.
      initialBias - initial bias to find a solution.
      listener - listener to handle events raised by this calibrator.
      Throws:
      IllegalArgumentException - if provided bias matrix is not 3x1.

    • LMedSRobustKnownPositionAccelerometerCalibrator

      public LMedSRobustKnownPositionAccelerometerCalibrator(com.irurueta.navigation.frames.ECEFPosition position, List<StandardDeviationBodyKinematics> measurements, com.irurueta.algebra.Matrix initialBias, com.irurueta.algebra.Matrix initialMa)
      Constructor.
      Parameters:
      position - position where body kinematics measures have been taken.
      measurements - collection of body kinematics measurements with standard deviations taken at the same position with zero velocity and unknown different orientations.
      initialBias - initial bias to find a solution.
      initialMa - initial scale factors and cross coupling errors matrix.
      Throws:
      IllegalArgumentException - if either provided bias matrix is not 3x1 or scaling and coupling error matrix is not 3x3.

    • LMedSRobustKnownPositionAccelerometerCalibrator

      public LMedSRobustKnownPositionAccelerometerCalibrator(com.irurueta.navigation.frames.ECEFPosition position, List<StandardDeviationBodyKinematics> measurements, com.irurueta.algebra.Matrix initialBias, com.irurueta.algebra.Matrix initialMa, RobustKnownPositionAccelerometerCalibratorListener listener)
      Constructor.
      Parameters:
      position - position where body kinematics measures have been taken.
      measurements - collection of body kinematics measurements with standard deviations taken at the same position with zero velocity and unknown different orientations.
      initialBias - initial bias to find a solution.
      initialMa - initial scale factors and cross coupling errors matrix.
      listener - listener to handle events raised by this calibrator.
      Throws:
      IllegalArgumentException - if either provided bias matrix is not 3x1 or scaling and coupling error matrix is not 3x3.

    • LMedSRobustKnownPositionAccelerometerCalibrator

      public LMedSRobustKnownPositionAccelerometerCalibrator(com.irurueta.navigation.frames.ECEFPosition position, List<StandardDeviationBodyKinematics> measurements, boolean commonAxisUsed, com.irurueta.algebra.Matrix initialBias, com.irurueta.algebra.Matrix initialMa)
      Constructor.
      Parameters:
      position - position where body kinematics measures have been taken.
      measurements - collection of body kinematics measurements with standard deviations taken at the same position with zero velocity and unknown different orientations.
      commonAxisUsed - indicates whether z-axis is assumed to be common for accelerometer and gyroscope.
      initialBias - initial bias to find a solution.
      initialMa - initial scale factors and cross coupling errors matrix.
      Throws:
      IllegalArgumentException - if either provided bias matrix is not 3x1 or scaling and coupling error matrix is not 3x3.

    • LMedSRobustKnownPositionAccelerometerCalibrator

      public LMedSRobustKnownPositionAccelerometerCalibrator(com.irurueta.navigation.frames.ECEFPosition position, List<StandardDeviationBodyKinematics> measurements, boolean commonAxisUsed, com.irurueta.algebra.Matrix initialBias, com.irurueta.algebra.Matrix initialMa, RobustKnownPositionAccelerometerCalibratorListener listener)
      Constructor.
      Parameters:
      position - position where body kinematics measures have been taken.
      measurements - collection of body kinematics measurements with standard deviations taken at the same position with zero velocity and unknown different orientations.
      commonAxisUsed - indicates whether z-axis is assumed to be common for accelerometer and gyroscope.
      initialBias - initial bias to find a solution.
      initialMa - initial scale factors and cross coupling errors matrix.
      listener - listener to handle events raised by this calibrator.
      Throws:
      IllegalArgumentException - if either provided bias matrix is not 3x1 or scaling and coupling error matrix is not 3x3.

    • LMedSRobustKnownPositionAccelerometerCalibrator

      public LMedSRobustKnownPositionAccelerometerCalibrator(com.irurueta.navigation.frames.NEDPosition position)
      Constructor.
      Parameters:
      position - position where body kinematics measures have been taken.

    • LMedSRobustKnownPositionAccelerometerCalibrator

      public LMedSRobustKnownPositionAccelerometerCalibrator(com.irurueta.navigation.frames.NEDPosition position, List<StandardDeviationBodyKinematics> measurements)
      Constructor.
      Parameters:
      position - position where body kinematics measures have been taken.
      measurements - list of body kinematics measurements taken at a given position with different unknown orientations and containing the standard deviations of accelerometer and gyroscope measurements.

    • LMedSRobustKnownPositionAccelerometerCalibrator

      public LMedSRobustKnownPositionAccelerometerCalibrator(com.irurueta.navigation.frames.NEDPosition position, List<StandardDeviationBodyKinematics> measurements, RobustKnownPositionAccelerometerCalibratorListener listener)
      Constructor.
      Parameters:
      position - position where body kinematics measures have been taken.
      measurements - list of body kinematics measurements taken at a given position with different unknown orientations and containing the standard deviations of accelerometer and gyroscope measurements.
      listener - listener to be notified of events such as when estimation starts, ends or its progress significantly changes.

    • LMedSRobustKnownPositionAccelerometerCalibrator

      public LMedSRobustKnownPositionAccelerometerCalibrator(com.irurueta.navigation.frames.NEDPosition position, List<StandardDeviationBodyKinematics> measurements, boolean commonAxisUsed)
      Constructor.
      Parameters:
      position - position where body kinematics measures have been taken.
      measurements - list of body kinematics measurements taken at a given position with different unknown orientations and containing the standard deviations of accelerometer and gyroscope measurements.
      commonAxisUsed - indicates whether z-axis is assumed to be common for accelerometer and gyroscope.

    • LMedSRobustKnownPositionAccelerometerCalibrator

      public LMedSRobustKnownPositionAccelerometerCalibrator(com.irurueta.navigation.frames.NEDPosition position, List<StandardDeviationBodyKinematics> measurements, boolean commonAxisUsed, RobustKnownPositionAccelerometerCalibratorListener listener)
      Constructor.
      Parameters:
      position - position where body kinematics measures have been taken.
      measurements - list of body kinematics measurements taken at a given position with different unknown orientations and containing the standard deviations of accelerometer and gyroscope measurements.
      commonAxisUsed - indicates whether z-axis is assumed to be common for accelerometer and gyroscope.
      listener - listener to be notified of events such as when estimation starts, ends or its progress significantly changes.

    • LMedSRobustKnownPositionAccelerometerCalibrator

      public LMedSRobustKnownPositionAccelerometerCalibrator(com.irurueta.navigation.frames.NEDPosition position, List<StandardDeviationBodyKinematics> measurements, double[] initialBias)
      Constructor.
      Parameters:
      position - position where body kinematics measures have been taken.
      measurements - collection of body kinematics measurements with standard deviations taken at the same position with zero velocity and unknown different orientations.
      initialBias - initial accelerometer bias to be used to find a solution. This must have length 3 and is expressed in meters per squared second (m/s^2).
      Throws:
      IllegalArgumentException - if provided bias array does not have length 3.

    • LMedSRobustKnownPositionAccelerometerCalibrator

      public LMedSRobustKnownPositionAccelerometerCalibrator(com.irurueta.navigation.frames.NEDPosition position, List<StandardDeviationBodyKinematics> measurements, double[] initialBias, RobustKnownPositionAccelerometerCalibratorListener listener)
      Constructor.
      Parameters:
      position - position where body kinematics measures have been taken.
      measurements - collection of body kinematics measurements with standard deviations taken at the same position with zero velocity and unknown different orientations.
      initialBias - initial accelerometer bias to be used to find a solution. This must have length 3 and is expressed in meters per squared second (m/s^2).
      listener - listener to handle events raised by this calibrator.
      Throws:
      IllegalArgumentException - if provided bias array does not have length 3.

    • LMedSRobustKnownPositionAccelerometerCalibrator

      public LMedSRobustKnownPositionAccelerometerCalibrator(com.irurueta.navigation.frames.NEDPosition position, List<StandardDeviationBodyKinematics> measurements, boolean commonAxisUsed, double[] initialBias)
      Constructor.
      Parameters:
      position - position where body kinematics measures have been taken.
      measurements - collection of body kinematics measurements with standard deviations taken at the same position with zero velocity and unknown different orientations.
      commonAxisUsed - indicates whether z-axis is assumed to be common for accelerometer and gyroscope.
      initialBias - initial accelerometer bias to be used to find a solution. This must have length 3 and is expressed in meters per squared second (m/s^2).
      Throws:
      IllegalArgumentException - if provided bias array does not have length 3.

    • LMedSRobustKnownPositionAccelerometerCalibrator

      public LMedSRobustKnownPositionAccelerometerCalibrator(com.irurueta.navigation.frames.NEDPosition position, List<StandardDeviationBodyKinematics> measurements, boolean commonAxisUsed, double[] initialBias, RobustKnownPositionAccelerometerCalibratorListener listener)
      Constructor.
      Parameters:
      position - position where body kinematics measures have been taken.
      measurements - collection of body kinematics measurements with standard deviations taken at the same position with zero velocity and unknown different orientations.
      commonAxisUsed - indicates whether z-axis is assumed to be common for accelerometer and gyroscope.
      initialBias - initial accelerometer bias to be used to find a solution. This must have length 3 and is expressed in meters per squared second (m/s^2).
      listener - listener to handle events raised by this calibrator.
      Throws:
      IllegalArgumentException - if provided bias array does not have length 3.

    • LMedSRobustKnownPositionAccelerometerCalibrator

      public LMedSRobustKnownPositionAccelerometerCalibrator(com.irurueta.navigation.frames.NEDPosition position, List<StandardDeviationBodyKinematics> measurements, com.irurueta.algebra.Matrix initialBias)
      Constructor.
      Parameters:
      position - position where body kinematics measures have been taken.
      measurements - collection of body kinematics measurements with standard deviations taken at the same position with zero velocity and unknown different orientations.
      initialBias - initial bias to find a solution.
      Throws:
      IllegalArgumentException - if provided bias matrix is not 3x1.

    • LMedSRobustKnownPositionAccelerometerCalibrator

      public LMedSRobustKnownPositionAccelerometerCalibrator(com.irurueta.navigation.frames.NEDPosition position, List<StandardDeviationBodyKinematics> measurements, com.irurueta.algebra.Matrix initialBias, RobustKnownPositionAccelerometerCalibratorListener listener)
      Constructor.
      Parameters:
      position - position where body kinematics measures have been taken.
      measurements - collection of body kinematics measurements with standard deviations taken at the same position with zero velocity and unknown different orientations.
      initialBias - initial bias to find a solution.
      listener - listener to handle events raised by this calibrator.

    • LMedSRobustKnownPositionAccelerometerCalibrator

      public LMedSRobustKnownPositionAccelerometerCalibrator(com.irurueta.navigation.frames.NEDPosition position, List<StandardDeviationBodyKinematics> measurements, boolean commonAxisUsed, com.irurueta.algebra.Matrix initialBias)
      Constructor.
      Parameters:
      position - position where body kinematics measures have been taken.
      measurements - collection of body kinematics measurements with standard deviations taken at the same position with zero velocity and unknown different orientations.
      commonAxisUsed - indicates whether z-axis is assumed to be common for accelerometer and gyroscope.
      initialBias - initial bias to find a solution.
      Throws:
      IllegalArgumentException - if provided bias matrix is not 3x1.

    • LMedSRobustKnownPositionAccelerometerCalibrator

      public LMedSRobustKnownPositionAccelerometerCalibrator(com.irurueta.navigation.frames.NEDPosition position, List<StandardDeviationBodyKinematics> measurements, boolean commonAxisUsed, com.irurueta.algebra.Matrix initialBias, RobustKnownPositionAccelerometerCalibratorListener listener)
      Constructor.
      Parameters:
      position - position where body kinematics measures have been taken.
      measurements - collection of body kinematics measurements with standard deviations taken at the same position with zero velocity and unknown different orientations.
      commonAxisUsed - indicates whether z-axis is assumed to be common for accelerometer and gyroscope.
      initialBias - initial bias to find a solution.
      listener - listener to handle events raised by this calibrator.
      Throws:
      IllegalArgumentException - if provided bias matrix is not 3x1.

    • LMedSRobustKnownPositionAccelerometerCalibrator

      public LMedSRobustKnownPositionAccelerometerCalibrator(com.irurueta.navigation.frames.NEDPosition position, List<StandardDeviationBodyKinematics> measurements, com.irurueta.algebra.Matrix initialBias, com.irurueta.algebra.Matrix initialMa)
      Constructor.
      Parameters:
      position - position where body kinematics measures have been taken.
      measurements - collection of body kinematics measurements with standard deviations taken at the same position with zero velocity and unknown different orientations.
      initialBias - initial bias to find a solution.
      initialMa - initial scale factors and cross coupling errors matrix.
      Throws:
      IllegalArgumentException - if either provided bias matrix is not 3x1 or scaling and coupling error matrix is not 3x3.

    • LMedSRobustKnownPositionAccelerometerCalibrator

      public LMedSRobustKnownPositionAccelerometerCalibrator(com.irurueta.navigation.frames.NEDPosition position, List<StandardDeviationBodyKinematics> measurements, com.irurueta.algebra.Matrix initialBias, com.irurueta.algebra.Matrix initialMa, RobustKnownPositionAccelerometerCalibratorListener listener)
      Constructor.
      Parameters:
      position - position where body kinematics measures have been taken.
      measurements - collection of body kinematics measurements with standard deviations taken at the same position with zero velocity and unknown different orientations.
      initialBias - initial bias to find a solution.
      initialMa - initial scale factors and cross coupling errors matrix.
      listener - listener to handle events raised by this calibrator.
      Throws:
      IllegalArgumentException - if either provided bias matrix is not 3x1 or scaling and coupling error matrix is not 3x3.

    • LMedSRobustKnownPositionAccelerometerCalibrator

      public LMedSRobustKnownPositionAccelerometerCalibrator(com.irurueta.navigation.frames.NEDPosition position, List<StandardDeviationBodyKinematics> measurements, boolean commonAxisUsed, com.irurueta.algebra.Matrix initialBias, com.irurueta.algebra.Matrix initialMa)
      Constructor.
      Parameters:
      position - position where body kinematics measures have been taken.
      measurements - collection of body kinematics measurements with standard deviations taken at the same position with zero velocity and unknown different orientations.
      commonAxisUsed - indicates whether z-axis is assumed to be common for accelerometer and gyroscope.
      initialBias - initial bias to find a solution.
      initialMa - initial scale factors and cross coupling errors matrix.
      Throws:
      IllegalArgumentException - if either provided bias matrix is not 3x1 or scaling and coupling error matrix is not 3x3.

    • LMedSRobustKnownPositionAccelerometerCalibrator

      public LMedSRobustKnownPositionAccelerometerCalibrator(com.irurueta.navigation.frames.NEDPosition position, List<StandardDeviationBodyKinematics> measurements, boolean commonAxisUsed, com.irurueta.algebra.Matrix initialBias, com.irurueta.algebra.Matrix initialMa, RobustKnownPositionAccelerometerCalibratorListener listener)
      Constructor.
      Parameters:
      position - position where body kinematics measures have been taken.
      measurements - collection of body kinematics measurements with standard deviations taken at the same position with zero velocity and unknown different orientations.
      commonAxisUsed - indicates whether z-axis is assumed to be common for accelerometer and gyroscope.
      initialBias - initial bias to find a solution.
      initialMa - initial scale factors and cross coupling errors matrix.
      listener - listener to handle events raised by this calibrator.
      Throws:
      IllegalArgumentException - if either provided bias matrix is not 3x1 or scaling and coupling error matrix is not 3x3.

  • 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 calibrator is currently running.

    • calibrate

      public void calibrate() throws com.irurueta.navigation.LockedException, com.irurueta.navigation.NotReadyException, CalibrationException
      Estimates accelerometer calibration parameters containing bias, scale factors and cross-coupling errors.
      Throws:
      com.irurueta.navigation.LockedException - if calibrator is currently running.
      com.irurueta.navigation.NotReadyException - if calibrator is not ready.
      CalibrationException - if estimation fails for numerical reasons.

    • getMethod

      public com.irurueta.numerical.robust.RobustEstimatorMethod getMethod()
      Returns method being used for robust estimation.
      Specified by:
      getMethod in class RobustKnownPositionAccelerometerCalibrator
      Returns:
      method being used for robust estimation.

    • isQualityScoresRequired

      public boolean isQualityScoresRequired()
      Indicates whether this calibrator requires quality scores for each measurement or not.
      Returns:
      true if quality scores are required, false otherwise.