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

Class LMedSRobustKnownGravityNormAccelerometerCalibrator

java.lang.Object
com.irurueta.navigation.inertial.calibration.accelerometer.RobustKnownGravityNormAccelerometerCalibrator
com.irurueta.navigation.inertial.calibration.accelerometer.LMedSRobustKnownGravityNormAccelerometerCalibrator
All Implemented Interfaces:
AccelerometerCalibrator, AccelerometerNonLinearCalibrator, OrderedStandardDeviationBodyKinematicsAccelerometerCalibrator, QualityScoredAccelerometerCalibrator, UnknownBiasAccelerometerCalibrator, UnknownBiasNonLinearAccelerometerCalibrator, AccelerometerBiasUncertaintySource, AccelerometerCalibrationSource
public class LMedSRobustKnownGravityNormAccelerometerCalibrator extends RobustKnownGravityNormAccelerometerCalibrator
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 position where gravity norm is known 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 LMedS, and yet the algorithm could still produce even smaller thresholds in estimated results.

  • Constructor Details

    • LMedSRobustKnownGravityNormAccelerometerCalibrator

      public LMedSRobustKnownGravityNormAccelerometerCalibrator()
      Constructor.

    • LMedSRobustKnownGravityNormAccelerometerCalibrator

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

    • LMedSRobustKnownGravityNormAccelerometerCalibrator

      public LMedSRobustKnownGravityNormAccelerometerCalibrator(List<StandardDeviationBodyKinematics> measurements)
      Constructor.
      Parameters:
      measurements - collection of body kinematics measurements with standard deviations taken at the same position with zero velocity and unknown different orientations.

    • LMedSRobustKnownGravityNormAccelerometerCalibrator

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

    • LMedSRobustKnownGravityNormAccelerometerCalibrator

      public LMedSRobustKnownGravityNormAccelerometerCalibrator(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.

    • LMedSRobustKnownGravityNormAccelerometerCalibrator

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

    • LMedSRobustKnownGravityNormAccelerometerCalibrator

      public LMedSRobustKnownGravityNormAccelerometerCalibrator(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.

    • LMedSRobustKnownGravityNormAccelerometerCalibrator

      public LMedSRobustKnownGravityNormAccelerometerCalibrator(Double groundTruthGravityNorm)
      Constructor.
      Parameters:
      groundTruthGravityNorm - ground truth gravity norm expressed in meters per squared second (m/s^2).
      Throws:
      IllegalArgumentException - if provided gravity norm value is negative.

    • LMedSRobustKnownGravityNormAccelerometerCalibrator

      public LMedSRobustKnownGravityNormAccelerometerCalibrator(Double groundTruthGravityNorm, List<StandardDeviationBodyKinematics> measurements)
      Constructor.
      Parameters:
      groundTruthGravityNorm - ground truth gravity norm expressed in meters per squared second (m/s^2).
      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.
      Throws:
      IllegalArgumentException - if provided gravity norm value is negative.

    • LMedSRobustKnownGravityNormAccelerometerCalibrator

      public LMedSRobustKnownGravityNormAccelerometerCalibrator(Double groundTruthGravityNorm, List<StandardDeviationBodyKinematics> measurements, RobustKnownGravityNormAccelerometerCalibratorListener listener)
      Constructor.
      Parameters:
      groundTruthGravityNorm - ground truth gravity norm expressed in meters per squared second (m/s^2).
      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.
      Throws:
      IllegalArgumentException - if provided gravity norm value is negative.

    • LMedSRobustKnownGravityNormAccelerometerCalibrator

      public LMedSRobustKnownGravityNormAccelerometerCalibrator(Double groundTruthGravityNorm, List<StandardDeviationBodyKinematics> measurements, boolean commonAxisUsed)
      Constructor.
      Parameters:
      groundTruthGravityNorm - ground truth gravity norm expressed in meters per squared second (m/s^2).
      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.
      Throws:
      IllegalArgumentException - if provided gravity norm value is negative.

    • LMedSRobustKnownGravityNormAccelerometerCalibrator

      public LMedSRobustKnownGravityNormAccelerometerCalibrator(Double groundTruthGravityNorm, List<StandardDeviationBodyKinematics> measurements, boolean commonAxisUsed, RobustKnownGravityNormAccelerometerCalibratorListener listener)
      Constructor.
      Parameters:
      groundTruthGravityNorm - ground truth gravity norm expressed in meters per squared second (m/s^2).
      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.
      Throws:
      IllegalArgumentException - if provided gravity norm value is negative.

    • LMedSRobustKnownGravityNormAccelerometerCalibrator

      public LMedSRobustKnownGravityNormAccelerometerCalibrator(Double groundTruthGravityNorm, List<StandardDeviationBodyKinematics> measurements, double[] initialBias)
      Constructor.
      Parameters:
      groundTruthGravityNorm - ground truth gravity norm expressed in meters per squared second (m/s^2).
      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 or if provided gravity norm value is negative.

    • LMedSRobustKnownGravityNormAccelerometerCalibrator

      public LMedSRobustKnownGravityNormAccelerometerCalibrator(Double groundTruthGravityNorm, List<StandardDeviationBodyKinematics> measurements, double[] initialBias, RobustKnownGravityNormAccelerometerCalibratorListener listener)
      Constructor.
      Parameters:
      groundTruthGravityNorm - ground truth gravity norm expressed in meters per squared second (m/s^2).
      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 or if provided gravity norm value is negative.

    • LMedSRobustKnownGravityNormAccelerometerCalibrator

      public LMedSRobustKnownGravityNormAccelerometerCalibrator(Double groundTruthGravityNorm, List<StandardDeviationBodyKinematics> measurements, boolean commonAxisUsed, double[] initialBias)
      Constructor.
      Parameters:
      groundTruthGravityNorm - ground truth gravity norm expressed in meters per squared second (m/s^2).
      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 or if provided gravity norm value is negative.

    • LMedSRobustKnownGravityNormAccelerometerCalibrator

      public LMedSRobustKnownGravityNormAccelerometerCalibrator(Double groundTruthGravityNorm, List<StandardDeviationBodyKinematics> measurements, boolean commonAxisUsed, double[] initialBias, RobustKnownGravityNormAccelerometerCalibratorListener listener)
      Constructor.
      Parameters:
      groundTruthGravityNorm - ground truth gravity norm expressed in meters per squared second (m/s^2).
      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 or if provided gravity norm value is negative.

    • LMedSRobustKnownGravityNormAccelerometerCalibrator

      public LMedSRobustKnownGravityNormAccelerometerCalibrator(Double groundTruthGravityNorm, List<StandardDeviationBodyKinematics> measurements, com.irurueta.algebra.Matrix initialBias)
      Constructor.
      Parameters:
      groundTruthGravityNorm - ground truth gravity norm expressed in meters per squared second (m/s^2).
      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 or if provided gravity norm value is negative.

    • LMedSRobustKnownGravityNormAccelerometerCalibrator

      public LMedSRobustKnownGravityNormAccelerometerCalibrator(Double groundTruthGravityNorm, List<StandardDeviationBodyKinematics> measurements, com.irurueta.algebra.Matrix initialBias, RobustKnownGravityNormAccelerometerCalibratorListener listener)
      Constructor.
      Parameters:
      groundTruthGravityNorm - ground truth gravity norm expressed in meters per squared second (m/s^2).
      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.
      Throws:
      IllegalArgumentException - if provided bias matrix is not 3x1 or if provided gravity norm value is negative.

    • LMedSRobustKnownGravityNormAccelerometerCalibrator

      public LMedSRobustKnownGravityNormAccelerometerCalibrator(Double groundTruthGravityNorm, List<StandardDeviationBodyKinematics> measurements, boolean commonAxisUsed, com.irurueta.algebra.Matrix initialBias)
      Constructor.
      Parameters:
      groundTruthGravityNorm - ground truth gravity norm expressed in meters per squared second (m/s^2).
      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 or if provided gravity norm value is negative.

    • LMedSRobustKnownGravityNormAccelerometerCalibrator

      public LMedSRobustKnownGravityNormAccelerometerCalibrator(Double groundTruthGravityNorm, List<StandardDeviationBodyKinematics> measurements, boolean commonAxisUsed, com.irurueta.algebra.Matrix initialBias, RobustKnownGravityNormAccelerometerCalibratorListener listener)
      Constructor.
      Parameters:
      groundTruthGravityNorm - ground truth gravity norm expressed in meters per squared second (m/s^2).
      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 or if provided gravity norm value is negative.

    • LMedSRobustKnownGravityNormAccelerometerCalibrator

      public LMedSRobustKnownGravityNormAccelerometerCalibrator(Double groundTruthGravityNorm, List<StandardDeviationBodyKinematics> measurements, com.irurueta.algebra.Matrix initialBias, com.irurueta.algebra.Matrix initialMa)
      Constructor.
      Parameters:
      groundTruthGravityNorm - ground truth gravity norm expressed in meters per squared second (m/s^2).
      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 or if provided gravity norm value is negative.

    • LMedSRobustKnownGravityNormAccelerometerCalibrator

      public LMedSRobustKnownGravityNormAccelerometerCalibrator(Double groundTruthGravityNorm, List<StandardDeviationBodyKinematics> measurements, com.irurueta.algebra.Matrix initialBias, com.irurueta.algebra.Matrix initialMa, RobustKnownGravityNormAccelerometerCalibratorListener listener)
      Constructor.
      Parameters:
      groundTruthGravityNorm - ground truth gravity norm expressed in meters per squared second (m/s^2).
      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 or if provided gravity norm value is negative.

    • LMedSRobustKnownGravityNormAccelerometerCalibrator

      public LMedSRobustKnownGravityNormAccelerometerCalibrator(Double groundTruthGravityNorm, List<StandardDeviationBodyKinematics> measurements, boolean commonAxisUsed, com.irurueta.algebra.Matrix initialBias, com.irurueta.algebra.Matrix initialMa)
      Constructor.
      Parameters:
      groundTruthGravityNorm - ground truth gravity norm expressed in meters per squared second (m/s^2).
      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 or if provided gravity norm value is negative.

    • LMedSRobustKnownGravityNormAccelerometerCalibrator

      public LMedSRobustKnownGravityNormAccelerometerCalibrator(Double groundTruthGravityNorm, List<StandardDeviationBodyKinematics> measurements, boolean commonAxisUsed, com.irurueta.algebra.Matrix initialBias, com.irurueta.algebra.Matrix initialMa, RobustKnownGravityNormAccelerometerCalibratorListener listener)
      Constructor.
      Parameters:
      groundTruthGravityNorm - ground truth gravity norm expressed in meters per squared second (m/s^2).
      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 or if provided gravity norm value is negative.

    • LMedSRobustKnownGravityNormAccelerometerCalibrator

      public LMedSRobustKnownGravityNormAccelerometerCalibrator(com.irurueta.units.Acceleration groundTruthGravityNorm)
      Constructor.
      Parameters:
      groundTruthGravityNorm - ground truth gravity norm.
      Throws:
      IllegalArgumentException - if provided gravity norm value is negative.

    • LMedSRobustKnownGravityNormAccelerometerCalibrator

      public LMedSRobustKnownGravityNormAccelerometerCalibrator(com.irurueta.units.Acceleration groundTruthGravityNorm, List<StandardDeviationBodyKinematics> measurements)
      Constructor.
      Parameters:
      groundTruthGravityNorm - ground truth gravity norm.
      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.
      Throws:
      IllegalArgumentException - if provided gravity norm value is negative.

    • LMedSRobustKnownGravityNormAccelerometerCalibrator

      public LMedSRobustKnownGravityNormAccelerometerCalibrator(com.irurueta.units.Acceleration groundTruthGravityNorm, List<StandardDeviationBodyKinematics> measurements, RobustKnownGravityNormAccelerometerCalibratorListener listener)
      Constructor.
      Parameters:
      groundTruthGravityNorm - ground truth gravity norm.
      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.
      Throws:
      IllegalArgumentException - if provided gravity norm value is negative.

    • LMedSRobustKnownGravityNormAccelerometerCalibrator

      public LMedSRobustKnownGravityNormAccelerometerCalibrator(com.irurueta.units.Acceleration groundTruthGravityNorm, List<StandardDeviationBodyKinematics> measurements, boolean commonAxisUsed)
      Constructor.
      Parameters:
      groundTruthGravityNorm - ground truth gravity norm.
      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.
      Throws:
      IllegalArgumentException - if provided gravity norm value is negative.

    • LMedSRobustKnownGravityNormAccelerometerCalibrator

      public LMedSRobustKnownGravityNormAccelerometerCalibrator(com.irurueta.units.Acceleration groundTruthGravityNorm, List<StandardDeviationBodyKinematics> measurements, boolean commonAxisUsed, RobustKnownGravityNormAccelerometerCalibratorListener listener)
      Constructor.
      Parameters:
      groundTruthGravityNorm - ground truth gravity norm.
      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.
      Throws:
      IllegalArgumentException - if provided gravity norm value is negative.

    • LMedSRobustKnownGravityNormAccelerometerCalibrator

      public LMedSRobustKnownGravityNormAccelerometerCalibrator(com.irurueta.units.Acceleration groundTruthGravityNorm, List<StandardDeviationBodyKinematics> measurements, double[] initialBias)
      Constructor.
      Parameters:
      groundTruthGravityNorm - ground truth gravity norm.
      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 or if provided gravity norm value is negative.

    • LMedSRobustKnownGravityNormAccelerometerCalibrator

      public LMedSRobustKnownGravityNormAccelerometerCalibrator(com.irurueta.units.Acceleration groundTruthGravityNorm, List<StandardDeviationBodyKinematics> measurements, double[] initialBias, RobustKnownGravityNormAccelerometerCalibratorListener listener)
      Constructor.
      Parameters:
      groundTruthGravityNorm - ground truth gravity norm.
      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 or if provided gravity norm value is negative.

    • LMedSRobustKnownGravityNormAccelerometerCalibrator

      public LMedSRobustKnownGravityNormAccelerometerCalibrator(com.irurueta.units.Acceleration groundTruthGravityNorm, List<StandardDeviationBodyKinematics> measurements, boolean commonAxisUsed, double[] initialBias)
      Constructor.
      Parameters:
      groundTruthGravityNorm - ground truth gravity norm.
      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 or if provided gravity norm value is negative.

    • LMedSRobustKnownGravityNormAccelerometerCalibrator

      public LMedSRobustKnownGravityNormAccelerometerCalibrator(com.irurueta.units.Acceleration groundTruthGravityNorm, List<StandardDeviationBodyKinematics> measurements, boolean commonAxisUsed, double[] initialBias, RobustKnownGravityNormAccelerometerCalibratorListener listener)
      Constructor.
      Parameters:
      groundTruthGravityNorm - ground truth gravity norm.
      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 or if provided gravity norm value is negative.

    • LMedSRobustKnownGravityNormAccelerometerCalibrator

      public LMedSRobustKnownGravityNormAccelerometerCalibrator(com.irurueta.units.Acceleration groundTruthGravityNorm, List<StandardDeviationBodyKinematics> measurements, com.irurueta.algebra.Matrix initialBias)
      Constructor.
      Parameters:
      groundTruthGravityNorm - ground truth gravity norm.
      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 or if provided gravity norm value is negative.

    • LMedSRobustKnownGravityNormAccelerometerCalibrator

      public LMedSRobustKnownGravityNormAccelerometerCalibrator(com.irurueta.units.Acceleration groundTruthGravityNorm, List<StandardDeviationBodyKinematics> measurements, com.irurueta.algebra.Matrix initialBias, RobustKnownGravityNormAccelerometerCalibratorListener listener)
      Constructor.
      Parameters:
      groundTruthGravityNorm - ground truth gravity norm.
      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.
      Throws:
      IllegalArgumentException - if provided bias matrix is not 3x1 or if provided gravity norm value is negative.

    • LMedSRobustKnownGravityNormAccelerometerCalibrator

      public LMedSRobustKnownGravityNormAccelerometerCalibrator(com.irurueta.units.Acceleration groundTruthGravityNorm, List<StandardDeviationBodyKinematics> measurements, boolean commonAxisUsed, com.irurueta.algebra.Matrix initialBias)
      Constructor.
      Parameters:
      groundTruthGravityNorm - ground truth gravity norm.
      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 or if provided gravity norm value is negative.

    • LMedSRobustKnownGravityNormAccelerometerCalibrator

      public LMedSRobustKnownGravityNormAccelerometerCalibrator(com.irurueta.units.Acceleration groundTruthGravityNorm, List<StandardDeviationBodyKinematics> measurements, boolean commonAxisUsed, com.irurueta.algebra.Matrix initialBias, RobustKnownGravityNormAccelerometerCalibratorListener listener)
      Constructor.
      Parameters:
      groundTruthGravityNorm - ground truth gravity norm.
      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 or if provided gravity norm value is negative.

    • LMedSRobustKnownGravityNormAccelerometerCalibrator

      public LMedSRobustKnownGravityNormAccelerometerCalibrator(com.irurueta.units.Acceleration groundTruthGravityNorm, List<StandardDeviationBodyKinematics> measurements, com.irurueta.algebra.Matrix initialBias, com.irurueta.algebra.Matrix initialMa)
      Constructor.
      Parameters:
      groundTruthGravityNorm - ground truth gravity norm.
      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 or if provided gravity norm value is negative.

    • LMedSRobustKnownGravityNormAccelerometerCalibrator

      public LMedSRobustKnownGravityNormAccelerometerCalibrator(com.irurueta.units.Acceleration groundTruthGravityNorm, List<StandardDeviationBodyKinematics> measurements, com.irurueta.algebra.Matrix initialBias, com.irurueta.algebra.Matrix initialMa, RobustKnownGravityNormAccelerometerCalibratorListener listener)
      Constructor.
      Parameters:
      groundTruthGravityNorm - ground truth gravity norm.
      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 or if provided gravity norm value is negative.

    • LMedSRobustKnownGravityNormAccelerometerCalibrator

      public LMedSRobustKnownGravityNormAccelerometerCalibrator(com.irurueta.units.Acceleration groundTruthGravityNorm, List<StandardDeviationBodyKinematics> measurements, boolean commonAxisUsed, com.irurueta.algebra.Matrix initialBias, com.irurueta.algebra.Matrix initialMa)
      Constructor.
      Parameters:
      groundTruthGravityNorm - ground truth gravity norm.
      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 or if provided gravity norm value is negative.

    • LMedSRobustKnownGravityNormAccelerometerCalibrator

      public LMedSRobustKnownGravityNormAccelerometerCalibrator(com.irurueta.units.Acceleration groundTruthGravityNorm, List<StandardDeviationBodyKinematics> measurements, boolean commonAxisUsed, com.irurueta.algebra.Matrix initialBias, com.irurueta.algebra.Matrix initialMa, RobustKnownGravityNormAccelerometerCalibratorListener listener)
      Constructor.
      Parameters:
      groundTruthGravityNorm - ground truth gravity norm.
      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 or if provided gravity norm value is negative.

  • 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 RobustKnownGravityNormAccelerometerCalibrator
      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.