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

Class KnownFrameAccelerometerLinearLeastSquaresCalibrator

java.lang.Object
com.irurueta.navigation.inertial.calibration.accelerometer.KnownFrameAccelerometerLinearLeastSquaresCalibrator
All Implemented Interfaces:
AccelerometerCalibrator, KnownFrameAccelerometerCalibrator<FrameBodyKinematics,KnownFrameAccelerometerLinearLeastSquaresCalibratorListener>, UnknownBiasAccelerometerCalibrator, UnorderedFrameBodyKinematicsAccelerometerCalibrator, AccelerometerCalibrationSource
public class KnownFrameAccelerometerLinearLeastSquaresCalibrator extends Object implements KnownFrameAccelerometerCalibrator<FrameBodyKinematics,KnownFrameAccelerometerLinearLeastSquaresCalibratorListener>, AccelerometerCalibrationSource, UnorderedFrameBodyKinematicsAccelerometerCalibrator
Estimates accelerometer biases, cross couplings and scaling factors.

This calibrator uses a linear approach to find a minimum least squared error solution.

To use this calibrator at least 4 measurements at different known frames must be provided. In other words, accelerometer samples must be obtained at 4 different positions, orientations and velocities (although typically velocities are always zero).

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. This is a 3x1 vector. - w is measurement noise. This is a 3x1 vector.

  • Field Details

    • DEFAULT_USE_COMMON_Z_AXIS

      public static final boolean DEFAULT_USE_COMMON_Z_AXIS
      Indicates whether by default a common z-axis is assumed for both the accelerometer and gyroscope.
      See Also:

    • MINIMUM_MEASUREMENTS

      public static final int MINIMUM_MEASUREMENTS
      Required minimum number of measurements.
      See Also:

    • EQUATIONS_PER_MEASUREMENT

      private static final int EQUATIONS_PER_MEASUREMENT
      Number of equations generated for each measurement.
      See Also:

    • COMMON_Z_AXIS_UNKNOWNS

      private static final int COMMON_Z_AXIS_UNKNOWNS
      Number of unknowns when common z-axis is assumed for both the accelerometer and gyroscope.
      See Also:

    • GENERAL_UNKNOWNS

      private static final int GENERAL_UNKNOWNS
      Number of unknowns for the general case.
      See Also:

    • measurements

      private Collection<FrameBodyKinematics> measurements
      Contains a collection of body kinematics measurements taken at different frames (positions, orientations and velocities). If a single device IMU needs to be calibrated, typically all measurements are taken at the same position, with zero velocity and multiple orientations. However, if we just want to calibrate a given IMU model (e.g. obtain an average and less precise calibration for the IMU of a given phone model), we could take measurements collected throughout the planet at multiple positions while the phone remains static (e.g. while charging), hence each measurement position will change, velocity will remain zero and orientation will be typically constant at horizontal orientation while the phone remains on a flat surface.

    • commonAxisUsed

      private boolean commonAxisUsed
      This flag indicates whether z-axis is assumed to be common for accelerometer and gyroscope. When enabled, this eliminates 3 variables from Ma matrix.

    • listener

      private KnownFrameAccelerometerLinearLeastSquaresCalibratorListener listener
      Listener to handle events raised by this calibrator.

    • estimatedBiases

      private double[] estimatedBiases
      Estimated accelerometer biases for each IMU axis expressed in meter per squared second (m/s^2).

    • estimatedMa

      private com.irurueta.algebra.Matrix estimatedMa
      Estimated accelerometer scale factors and cross coupling errors. This is the product of matrix Ta containing cross coupling errors and Ka containing scaling factors. So tat: 
           Ma = [sx    mxy  mxz] = Ta*Ka
          [myx   sy   myz]
          [mzx   mzy  sz ]
      Where: 
           Ka = [sx 0   0 ]
          [0  sy  0 ]
          [0  0   sz]
      and 
           Ta = [1          -alphaXy    alphaXz ]
          [alphaYx    1           -alphaYz]
          [-alphaZx   alphaZy     1       ]
      Hence: 
           Ma = [sx    mxy  mxz] = Ta*Ka =  [sx             -sy * alphaXy   sz * alphaXz ]
          [myx   sy   myz]            [sx * alphaYx   sy              -sz * alphaYz]
          [mzx   mzy  sz ]            [-sx * alphaZx  sy * alphaZy    sz           ]
      This instance allows any 3x3 matrix however, typically alphaYx, alphaZx and alphaZy are considered to be zero if the accelerometer z-axis is assumed to be the same as the body z-axis. When this is assumed, myx = mzx = mzy = 0 and the Ma matrix becomes upper diagonal: 
           Ma = [sx    mxy  mxz]
          [0     sy   myz]
          [0     0    sz ]
      Values of this matrix are unit-less.

    • running

      private boolean running
      Indicates whether calibrator is running.

  • Constructor Details

    • KnownFrameAccelerometerLinearLeastSquaresCalibrator

      public KnownFrameAccelerometerLinearLeastSquaresCalibrator()
      Constructor.

    • KnownFrameAccelerometerLinearLeastSquaresCalibrator

      public KnownFrameAccelerometerLinearLeastSquaresCalibrator(KnownFrameAccelerometerLinearLeastSquaresCalibratorListener listener)
      Constructor.
      Parameters:
      listener - listener to handle events raised by this calibrator.

    • KnownFrameAccelerometerLinearLeastSquaresCalibrator

      public KnownFrameAccelerometerLinearLeastSquaresCalibrator(Collection<? extends FrameBodyKinematics> measurements)
      Constructor.
      Parameters:
      measurements - collection of body kinematics measurements taken at different frames (positions, orientations and velocities).

    • KnownFrameAccelerometerLinearLeastSquaresCalibrator

      public KnownFrameAccelerometerLinearLeastSquaresCalibrator(Collection<? extends FrameBodyKinematics> measurements, KnownFrameAccelerometerLinearLeastSquaresCalibratorListener listener)
      Constructor.
      Parameters:
      measurements - collection of body kinematics measurements taken at different frames (positions, orientations and velocities).
      listener - listener to handle events raised by this calibrator.

    • KnownFrameAccelerometerLinearLeastSquaresCalibrator

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

    • KnownFrameAccelerometerLinearLeastSquaresCalibrator

      public KnownFrameAccelerometerLinearLeastSquaresCalibrator(boolean commonAxisUsed, KnownFrameAccelerometerLinearLeastSquaresCalibratorListener listener)
      Constructor.
      Parameters:
      commonAxisUsed - indicates whether z-axis is assumed to be common for accelerometer and gyroscope.
      listener - listener to handle events raised by this calibrator.

    • KnownFrameAccelerometerLinearLeastSquaresCalibrator

      public KnownFrameAccelerometerLinearLeastSquaresCalibrator(Collection<? extends FrameBodyKinematics> measurements, boolean commonAxisUsed)
      Constructor.
      Parameters:
      measurements - collection of body kinematics measurements taken at different frames (positions, orientations and velocities).
      commonAxisUsed - indicates whether z-axis is assumed to be common for accelerometer and gyroscope.

    • KnownFrameAccelerometerLinearLeastSquaresCalibrator

      public KnownFrameAccelerometerLinearLeastSquaresCalibrator(Collection<? extends FrameBodyKinematics> measurements, boolean commonAxisUsed, KnownFrameAccelerometerLinearLeastSquaresCalibratorListener listener)
      Constructor.
      Parameters:
      measurements - collection of body kinematics measurements taken at different frames (positions, orientations and velocities).
      commonAxisUsed - indicates whether z-axis is assumed to be common for accelerometer and gyroscope.
      listener - listener to handle events raised by this calibrator.

  • Method Details

    • getMeasurements

      public Collection<FrameBodyKinematics> getMeasurements()
      Gets a collection of body kinematics measurements taken at different frames (positions, orientations and velocities). If a single device IMU needs to be calibrated, typically all measurements are taken at the same position, with zero velocity and multiple orientations. However, if we just want to calibrate a given IMU model (e.g. obtain an average and less precise calibration for the IMU of a given phone model), we could take measurements collected throughout the planet at multiple positions while the phone remains static (e.g. while charging), hence each measurement position will change, velocity will remain zero and orientation will be typically constant at horizontal orientation while the phone remains on a flat surface.
      Specified by:
      getMeasurements in interface KnownFrameAccelerometerCalibrator<FrameBodyKinematics,KnownFrameAccelerometerLinearLeastSquaresCalibratorListener>
      Specified by:
      getMeasurements in interface UnorderedFrameBodyKinematicsAccelerometerCalibrator
      Returns:
      a collection of body kinematics measurements taken at different frames (positions, orientations and velocities).

    • setMeasurements

      public void setMeasurements(Collection<? extends FrameBodyKinematics> measurements) throws com.irurueta.navigation.LockedException
      Sets a collection of body kinematics measurements taken at different frames (positions, orientations and velocities). If a single device IMU needs to be calibrated, typically all measurements are taken at the same position, with zero velocity and multiple orientations. However, if we just want to calibrate the a given IMU model (e.g. obtain an average and less precise calibration for the IMU of a given phone model), we could take measurements collected throughout the planet at multiple positions while the phone remains static (e.g. while charging), hence each measurement position will change, velocity will remain zero and orientation will be typically constant at horizontal orientation while the phone remains on a flat surface.
      Specified by:
      setMeasurements in interface KnownFrameAccelerometerCalibrator<FrameBodyKinematics,KnownFrameAccelerometerLinearLeastSquaresCalibratorListener>
      Specified by:
      setMeasurements in interface UnorderedFrameBodyKinematicsAccelerometerCalibrator
      Parameters:
      measurements - collection of body kinematics measurements taken at different frames (positions, orientations and velocities).
      Throws:
      com.irurueta.navigation.LockedException - if calibrator is currently running.

    • getMeasurementType

      public AccelerometerCalibratorMeasurementType getMeasurementType()
      Indicates the type of measurement used by this calibrator.
      Specified by:
      getMeasurementType in interface AccelerometerCalibrator
      Returns:
      type of measurement used by this calibrator.

    • isOrderedMeasurementsRequired

      public boolean isOrderedMeasurementsRequired()
      Indicates whether this calibrator requires ordered measurements in a list or not.
      Specified by:
      isOrderedMeasurementsRequired in interface AccelerometerCalibrator
      Returns:
      true if measurements must be ordered, false otherwise.

    • isQualityScoresRequired

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

    • isCommonAxisUsed

      public boolean isCommonAxisUsed()
      Indicates whether z-axis is assumed to be common for accelerometer and gyroscope. When enabled, this eliminates 3 variables from Ma matrix.
      Specified by:
      isCommonAxisUsed in interface AccelerometerCalibrator
      Returns:
      true if z-axis is assumed to be common for accelerometer and gyroscope, false otherwise.

    • setCommonAxisUsed

      public void setCommonAxisUsed(boolean commonAxisUsed) throws com.irurueta.navigation.LockedException
      Specifies whether z-axis is assumed to be common for accelerometer and gyroscope. When enabled, this eliminates 3 variables from Ma matrix.
      Specified by:
      setCommonAxisUsed in interface AccelerometerCalibrator
      Parameters:
      commonAxisUsed - true if z-axis is assumed to be common for accelerometer and gyroscope, false otherwise.
      Throws:
      com.irurueta.navigation.LockedException - if calibrator is currently running.

    • getListener

      public KnownFrameAccelerometerLinearLeastSquaresCalibratorListener getListener()
      Gets listener to handle events raised by this calibrator.
      Specified by:
      getListener in interface KnownFrameAccelerometerCalibrator<FrameBodyKinematics,KnownFrameAccelerometerLinearLeastSquaresCalibratorListener>
      Returns:
      listener to handle events raised by this calibrator.

    • setListener

      public void setListener(KnownFrameAccelerometerLinearLeastSquaresCalibratorListener listener) throws com.irurueta.navigation.LockedException
      Sets listener to handle events raised by this calibrator.
      Specified by:
      setListener in interface KnownFrameAccelerometerCalibrator<FrameBodyKinematics,KnownFrameAccelerometerLinearLeastSquaresCalibratorListener>
      Parameters:
      listener - listener to handle events raised by this calibrator.
      Throws:
      com.irurueta.navigation.LockedException - if calibrator is currently running.

    • getMinimumRequiredMeasurements

      public int getMinimumRequiredMeasurements()
      Gets minimum number of required measurements.
      Specified by:
      getMinimumRequiredMeasurements in interface AccelerometerCalibrator
      Returns:
      minimum number of required measurements.

    • isReady

      public boolean isReady()
      Indicates whether calibrator is ready to start the calibration.
      Specified by:
      isReady in interface AccelerometerCalibrator
      Returns:
      true if calibrator is ready, false otherwise.

    • isRunning

      public boolean isRunning()
      Indicates whether calibrator is currently running or not.
      Specified by:
      isRunning in interface AccelerometerCalibrator
      Returns:
      true if calibrator is running, false otherwise.

    • 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.
      Specified by:
      calibrate in interface AccelerometerCalibrator
      Throws:
      com.irurueta.navigation.LockedException - if calibrator is currently running.
      com.irurueta.navigation.NotReadyException - if calibrator is not ready.
      CalibrationException - if calibration fails for numerical reasons.

    • getEstimatedBiases

      public double[] getEstimatedBiases()
      Gets array containing x,y,z components of estimated accelerometer biases expressed in meters per squared second (m/s^2).
      Specified by:
      getEstimatedBiases in interface AccelerometerCalibrationSource
      Specified by:
      getEstimatedBiases in interface UnknownBiasAccelerometerCalibrator
      Returns:
      array containing x,y,z components of estimated accelerometer biases.

    • getEstimatedBiases

      public boolean getEstimatedBiases(double[] result)
      Gets array containing x,y,z components of estimated accelerometer biases expressed in meters per squared second (m/s^2).
      Specified by:
      getEstimatedBiases in interface UnknownBiasAccelerometerCalibrator
      Parameters:
      result - instance where estimated accelerometer biases will be stored.
      Returns:
      true if result instance was updated, false otherwise (when estimation is not yet available).

    • getEstimatedBiasesAsMatrix

      public com.irurueta.algebra.Matrix getEstimatedBiasesAsMatrix()
      Gets column matrix containing x,y,z components of estimated accelerometer biases expressed in meters per squared second (m/s^2).
      Specified by:
      getEstimatedBiasesAsMatrix in interface UnknownBiasAccelerometerCalibrator
      Returns:
      column matrix containing x,y,z components of estimated accelerometer biases.

    • getEstimatedBiasesAsMatrix

      public boolean getEstimatedBiasesAsMatrix(com.irurueta.algebra.Matrix result) throws com.irurueta.algebra.WrongSizeException
      Gets column matrix containing x,y,z components of estimated accelerometer biases expressed in meters per squared second (m/s^2).
      Specified by:
      getEstimatedBiasesAsMatrix in interface UnknownBiasAccelerometerCalibrator
      Parameters:
      result - instance where result data will be stored.
      Returns:
      true if result was updated, false otherwise.
      Throws:
      com.irurueta.algebra.WrongSizeException - if provided result instance has invalid size.

    • getEstimatedBiasFx

      public Double getEstimatedBiasFx()
      Gets x coordinate of estimated accelerometer bias expressed in meters per squared second (m/s^2).
      Specified by:
      getEstimatedBiasFx in interface UnknownBiasAccelerometerCalibrator
      Returns:
      x coordinate of estimated accelerometer bias or null if not available.

    • getEstimatedBiasFy

      public Double getEstimatedBiasFy()
      Gets y coordinate of estimated accelerometer bias expressed in meters per squared second (m/s^2).
      Specified by:
      getEstimatedBiasFy in interface UnknownBiasAccelerometerCalibrator
      Returns:
      y coordinate of estimated accelerometer bias or null if not available.

    • getEstimatedBiasFz

      public Double getEstimatedBiasFz()
      Gets z coordinate of estimated accelerometer bias expressed in meters per squared second (m/s^2).
      Specified by:
      getEstimatedBiasFz in interface UnknownBiasAccelerometerCalibrator
      Returns:
      z coordinate of estimated accelerometer bias or null if not available.

    • getEstimatedBiasFxAsAcceleration

      public com.irurueta.units.Acceleration getEstimatedBiasFxAsAcceleration()
      Gets x coordinate of estimated accelerometer bias.
      Specified by:
      getEstimatedBiasFxAsAcceleration in interface UnknownBiasAccelerometerCalibrator
      Returns:
      x coordinate of estimated accelerometer bias or null if not available.

    • getEstimatedBiasFxAsAcceleration

      public boolean getEstimatedBiasFxAsAcceleration(com.irurueta.units.Acceleration result)
      Gets x coordinate of estimated accelerometer bias.
      Specified by:
      getEstimatedBiasFxAsAcceleration in interface UnknownBiasAccelerometerCalibrator
      Parameters:
      result - instance where result will be stored.
      Returns:
      true if result was updated, false if estimation is not available.

    • getEstimatedBiasFyAsAcceleration

      public com.irurueta.units.Acceleration getEstimatedBiasFyAsAcceleration()
      Gets y coordinate of estimated accelerometer bias.
      Specified by:
      getEstimatedBiasFyAsAcceleration in interface UnknownBiasAccelerometerCalibrator
      Returns:
      y coordinate of estimated accelerometer bias or null if not available.

    • getEstimatedBiasFyAsAcceleration

      public boolean getEstimatedBiasFyAsAcceleration(com.irurueta.units.Acceleration result)
      Gets y coordinate of estimated accelerometer bias.
      Specified by:
      getEstimatedBiasFyAsAcceleration in interface UnknownBiasAccelerometerCalibrator
      Parameters:
      result - instance where result will be stored.
      Returns:
      true if result was updated, false if estimation is not available.

    • getEstimatedBiasFzAsAcceleration

      public com.irurueta.units.Acceleration getEstimatedBiasFzAsAcceleration()
      Gets z coordinate of estimated accelerometer bias.
      Specified by:
      getEstimatedBiasFzAsAcceleration in interface UnknownBiasAccelerometerCalibrator
      Returns:
      z coordinate of estimated accelerometer bias or null if not available.

    • getEstimatedBiasFzAsAcceleration

      public boolean getEstimatedBiasFzAsAcceleration(com.irurueta.units.Acceleration result)
      Gets z coordinate of estimated accelerometer bias.
      Specified by:
      getEstimatedBiasFzAsAcceleration in interface UnknownBiasAccelerometerCalibrator
      Parameters:
      result - instance where result will be stored.
      Returns:
      true if result was updated, false if estimation is not available.

    • getEstimatedBiasAsTriad

      public AccelerationTriad getEstimatedBiasAsTriad()
      Gets estimated accelerometer bias.
      Specified by:
      getEstimatedBiasAsTriad in interface UnknownBiasAccelerometerCalibrator
      Returns:
      estimated accelerometer bias or null if not available.

    • getEstimatedBiasAsTriad

      public boolean getEstimatedBiasAsTriad(AccelerationTriad result)
      Gets estimated accelerometer bias.
      Specified by:
      getEstimatedBiasAsTriad in interface UnknownBiasAccelerometerCalibrator
      Parameters:
      result - instance where result will be stored.
      Returns:
      true if estimated accelerometer bias is available and result was modified, false otherwise.

    • getEstimatedMa

      public com.irurueta.algebra.Matrix getEstimatedMa()
      Gets estimated accelerometer scale factors and cross coupling errors. This is the product of matrix Ta containing cross coupling errors and Ka containing scaling factors. So tat: 
           Ma = [sx    mxy  mxz] = Ta*Ka
          [myx   sy   myz]
          [mzx   mzy  sz ]
      Where: 
           Ka = [sx 0   0 ]
          [0  sy  0 ]
          [0  0   sz]
      and 
           Ta = [1          -alphaXy    alphaXz ]
          [alphaYx    1           -alphaYz]
          [-alphaZx   alphaZy     1       ]
      Hence: 
           Ma = [sx    mxy  mxz] = Ta*Ka =  [sx             -sy * alphaXy   sz * alphaXz ]
          [myx   sy   myz]            [sx * alphaYx   sy              -sz * alphaYz]
          [mzx   mzy  sz ]            [-sx * alphaZx  sy * alphaZy    sz           ]
      This instance allows any 3x3 matrix however, typically alphaYx, alphaZx and alphaZy are considered to be zero if the accelerometer z-axis is assumed to be the same as the body z-axis. When this is assumed, myx = mzx = mzy = 0 and the Ma matrix becomes upper diagonal: 
           Ma = [sx    mxy  mxz]
          [0     sy   myz]
          [0     0    sz ]
      Values of this matrix are unit-less.
      Specified by:
      getEstimatedMa in interface AccelerometerCalibrationSource
      Specified by:
      getEstimatedMa in interface AccelerometerCalibrator
      Returns:
      estimated accelerometer scale factors and cross coupling errors, or null if not available.

    • getEstimatedSx

      public Double getEstimatedSx()
      Gets estimated x-axis scale factor.
      Specified by:
      getEstimatedSx in interface AccelerometerCalibrator
      Returns:
      estimated x-axis scale factor or null if not available.

    • getEstimatedSy

      public Double getEstimatedSy()
      Gets estimated y-axis scale factor.
      Specified by:
      getEstimatedSy in interface AccelerometerCalibrator
      Returns:
      estimated y-axis scale factor or null if not available.

    • getEstimatedSz

      public Double getEstimatedSz()
      Gets estimated z-axis scale factor.
      Specified by:
      getEstimatedSz in interface AccelerometerCalibrator
      Returns:
      estimated z-axis scale factor or null if not available.

    • getEstimatedMxy

      public Double getEstimatedMxy()
      Gets estimated x-y cross-coupling error.
      Specified by:
      getEstimatedMxy in interface AccelerometerCalibrator
      Returns:
      estimated x-y cross-coupling error or null if not available.

    • getEstimatedMxz

      public Double getEstimatedMxz()
      Gets estimated x-z cross-coupling error.
      Specified by:
      getEstimatedMxz in interface AccelerometerCalibrator
      Returns:
      estimated x-z cross-coupling error or null if not available.

    • getEstimatedMyx

      public Double getEstimatedMyx()
      Gets estimated y-x cross-coupling error.
      Specified by:
      getEstimatedMyx in interface AccelerometerCalibrator
      Returns:
      estimated y-x cross-coupling error or null if not available.

    • getEstimatedMyz

      public Double getEstimatedMyz()
      Gets estimated y-z cross-coupling error.
      Specified by:
      getEstimatedMyz in interface AccelerometerCalibrator
      Returns:
      estimated y-z cross-coupling error or null if not available.

    • getEstimatedMzx

      public Double getEstimatedMzx()
      Gets estimated z-x cross-coupling error.
      Specified by:
      getEstimatedMzx in interface AccelerometerCalibrator
      Returns:
      estimated z-x cross-coupling error or null if not available.

    • getEstimatedMzy

      public Double getEstimatedMzy()
      Gets estimated z-y cross-coupling error.
      Specified by:
      getEstimatedMzy in interface AccelerometerCalibrator
      Returns:
      estimated z-y cross-coupling error or null if not available.

    • calibrateCommonAxis

      private void calibrateCommonAxis() throws com.irurueta.algebra.AlgebraException
      Internal method to perform calibration when common z-axis is assumed for both the accelerometer and gyroscope.
      Throws:
      com.irurueta.algebra.AlgebraException - if there are numerical errors.

    • calibrateGeneral

      private void calibrateGeneral() throws com.irurueta.algebra.AlgebraException
      Internal method to perform general calibration.
      Throws:
      com.irurueta.algebra.AlgebraException - if there are numerical errors.

    • fillBiases

      private void fillBiases(double bx, double by, double bz)
      Fills estimated biases array with estimated values.
      Parameters:
      bx - x coordinate of bias.
      by - y coordinate of bias.
      bz - z coordinate of bias.

    • fillMa

      private void fillMa(double sx, double sy, double sz, double mxy, double mxz, double myx, double myz, double mzx, double mzy) throws com.irurueta.algebra.WrongSizeException
      Fills scale factor and cross coupling error matrix with estimated values.
      Parameters:
      sx - x scale factor
      sy - y scale factor
      sz - z scale factor
      mxy - x-y cross coupling
      mxz - x-z cross coupling
      myx - y-x cross coupling
      myz - y-z cross coupling
      mzx - z-x cross coupling
      mzy - z-y cross coupling
      Throws:
      com.irurueta.algebra.WrongSizeException - never happens.