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

Class KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibrator

java.lang.Object
com.irurueta.navigation.inertial.calibration.accelerometer.KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibrator
All Implemented Interfaces:
AccelerometerCalibrator, KnownBiasAccelerometerCalibrator, KnownBiasAndFrameAccelerometerCalibrator<FrameBodyKinematics,KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibratorListener>, UnorderedFrameBodyKinematicsAccelerometerCalibrator
public class KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibrator extends Object implements KnownBiasAndFrameAccelerometerCalibrator<FrameBodyKinematics,KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibratorListener>, UnorderedFrameBodyKinematicsAccelerometerCalibrator
Estimates accelerometer cross couplings and scaling factors. This estimator assumes that biases are known.

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

To use this estimator 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. This is a known 3x1 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_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 KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibratorListener listener
      Listener to handle events raised by this estimator.

    • biasX

      private double biasX
      Known x coordinate of accelerometer bias expressed in meters per squared second (m/s^2).

    • biasY

      private double biasY
      Known y coordinate of accelerometer bias expressed in meters per squared second (m/s^2).

    • biasZ

      private double biasZ
      Known z coordinate of accelerometer bias expressed in meters 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 estimator is running.

  • Constructor Details

    • KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibrator

      public KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibrator()
      Constructor.

    • KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibrator

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

    • KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibrator

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

    • KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibrator

      public KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibrator(Collection<FrameBodyKinematics> measurements, KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibratorListener 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.

    • KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibrator

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

    • KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibrator

      public KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibrator(boolean commonAxisUsed, KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibratorListener 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.

    • KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibrator

      public KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibrator(Collection<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.

    • KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibrator

      public KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibrator(Collection<FrameBodyKinematics> measurements, boolean commonAxisUsed, KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibratorListener 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.

    • KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibrator

      public KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibrator(double biasX, double biasY, double biasZ)
      Constructor.
      Parameters:
      biasX - known x coordinate of accelerometer bias expressed in meters per squared second (m/s^2).
      biasY - known y coordinate of accelerometer bias expressed in meters per squared second (m/s^2).
      biasZ - known z coordinate of accelerometer bias expressed in meters per squared second (m/s^2).

    • KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibrator

      public KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibrator(double biasX, double biasY, double biasZ, KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibratorListener listener)
      Constructor.
      Parameters:
      biasX - known x coordinate of accelerometer bias expressed in meters per squared second (m/s^2).
      biasY - known y coordinate of accelerometer bias expressed in meters per squared second (m/s^2).
      biasZ - known z coordinate of accelerometer bias expressed in meters per squared second (m/s^2).
      listener - listener to handle events raised by this calibrator.

    • KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibrator

      public KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibrator(Collection<FrameBodyKinematics> measurements, double biasX, double biasY, double biasZ)
      Constructor.
      Parameters:
      measurements - collection of body kinematics measurements taken at different frames (positions, orientations and velocities).
      biasX - known x coordinate of accelerometer bias expressed in meters per squared second (m/s^2).
      biasY - known y coordinate of accelerometer bias expressed in meters per squared second (m/s^2).
      biasZ - known z coordinate of accelerometer bias expressed in meters per squared second (m/s^2).

    • KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibrator

      public KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibrator(Collection<FrameBodyKinematics> measurements, double biasX, double biasY, double biasZ, KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibratorListener listener)
      Constructor.
      Parameters:
      measurements - collection of body kinematics measurements taken at different frames (positions, orientations and velocities).
      biasX - known x coordinate of accelerometer bias expressed in meters per squared second (m/s^2).
      biasY - known y coordinate of accelerometer bias expressed in meters per squared second (m/s^2).
      biasZ - known z coordinate of accelerometer bias expressed in meters per squared second (m/s^2).
      listener - listener to handle events raised by this calibrator.

    • KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibrator

      public KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibrator(double biasX, double biasY, double biasZ, boolean commonAxisUsed)
      Constructor.
      Parameters:
      biasX - known x coordinate of accelerometer bias expressed in meters per squared second (m/s^2).
      biasY - known y coordinate of accelerometer bias expressed in meters per squared second (m/s^2).
      biasZ - known z coordinate of accelerometer bias expressed in meters per squared second (m/s^2).
      commonAxisUsed - indicates whether z-axis is assumed to be common for accelerometer and gyroscope.

    • KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibrator

      public KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibrator(double biasX, double biasY, double biasZ, boolean commonAxisUsed, KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibratorListener listener)
      Constructor.
      Parameters:
      biasX - known x coordinate of accelerometer bias expressed in meters per squared second (m/s^2).
      biasY - known y coordinate of accelerometer bias expressed in meters per squared second (m/s^2).
      biasZ - known z coordinate of accelerometer bias expressed in meters per squared second (m/s^2).
      commonAxisUsed - indicates whether z-axis is assumed to be common for accelerometer and gyroscope.
      listener - listener to handle events raised by this calibrator.

    • KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibrator

      public KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibrator(Collection<FrameBodyKinematics> measurements, double biasX, double biasY, double biasZ, boolean commonAxisUsed)
      Constructor.
      Parameters:
      measurements - collection of body kinematics measurements taken at different frames (positions, orientations and velocities).
      biasX - known x coordinate of accelerometer bias expressed in meters per squared second (m/s^2).
      biasY - known y coordinate of accelerometer bias expressed in meters per squared second (m/s^2).
      biasZ - known z coordinate of accelerometer bias expressed in meters per squared second (m/s^2).
      commonAxisUsed - indicates whether z-axis is assumed to be common for accelerometer and gyroscope.

    • KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibrator

      public KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibrator(Collection<FrameBodyKinematics> measurements, double biasX, double biasY, double biasZ, boolean commonAxisUsed, KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibratorListener listener)
      Constructor.
      Parameters:
      measurements - collection of body kinematics measurements taken at different frames (positions, orientations and velocities).
      biasX - known x coordinate of accelerometer bias expressed in meters per squared second (m/s^2).
      biasY - known y coordinate of accelerometer bias expressed in meters per squared second (m/s^2).
      biasZ - known z coordinate of accelerometer bias expressed in meters per squared second (m/s^2).
      commonAxisUsed - indicates whether z-axis is assumed to be common for accelerometer and gyroscope.
      listener - listener to handle events raised by this calibrator.

    • KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibrator

      public KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibrator(com.irurueta.units.Acceleration biasX, com.irurueta.units.Acceleration biasY, com.irurueta.units.Acceleration biasZ)
      Constructor.
      Parameters:
      biasX - known x coordinate of accelerometer bias.
      biasY - known y coordinate of accelerometer bias.
      biasZ - known z coordinate of accelerometer bias.

    • KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibrator

      public KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibrator(com.irurueta.units.Acceleration biasX, com.irurueta.units.Acceleration biasY, com.irurueta.units.Acceleration biasZ, KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibratorListener listener)
      Constructor.
      Parameters:
      biasX - known x coordinate of accelerometer bias.
      biasY - known y coordinate of accelerometer bias.
      biasZ - known z coordinate of accelerometer bias.
      listener - listener to handle events raised by this calibrator.

    • KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibrator

      public KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibrator(Collection<FrameBodyKinematics> measurements, com.irurueta.units.Acceleration biasX, com.irurueta.units.Acceleration biasY, com.irurueta.units.Acceleration biasZ)
      Constructor.
      Parameters:
      measurements - collection of body kinematics measurements taken at different frames (positions, orientations and velocities).
      biasX - known x coordinate of accelerometer bias.
      biasY - known y coordinate of accelerometer bias.
      biasZ - known z coordinate of accelerometer bias.

    • KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibrator

      public KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibrator(Collection<FrameBodyKinematics> measurements, com.irurueta.units.Acceleration biasX, com.irurueta.units.Acceleration biasY, com.irurueta.units.Acceleration biasZ, KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibratorListener listener)
      Constructor.
      Parameters:
      measurements - collection of body kinematics measurements taken at different frames (positions, orientations and velocities).
      biasX - known x coordinate of accelerometer bias.
      biasY - known y coordinate of accelerometer bias.
      biasZ - known z coordinate of accelerometer bias.
      listener - listener to handle events raised by this calibrator.

    • KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibrator

      public KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibrator(com.irurueta.units.Acceleration biasX, com.irurueta.units.Acceleration biasY, com.irurueta.units.Acceleration biasZ, boolean commonAxisUsed)
      Constructor.
      Parameters:
      biasX - known x coordinate of accelerometer bias.
      biasY - known y coordinate of accelerometer bias.
      biasZ - known z coordinate of accelerometer bias.
      commonAxisUsed - indicates whether z-axis is assumed to be common for accelerometer and gyroscope.

    • KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibrator

      public KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibrator(com.irurueta.units.Acceleration biasX, com.irurueta.units.Acceleration biasY, com.irurueta.units.Acceleration biasZ, boolean commonAxisUsed, KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibratorListener listener)
      Constructor.
      Parameters:
      biasX - known x coordinate of accelerometer bias.
      biasY - known y coordinate of accelerometer bias.
      biasZ - known z coordinate of accelerometer bias.
      commonAxisUsed - indicates whether z-axis is assumed to be common for accelerometer and gyroscope.
      listener - listener to handle events raised by this calibrator.

    • KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibrator

      public KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibrator(Collection<FrameBodyKinematics> measurements, com.irurueta.units.Acceleration biasX, com.irurueta.units.Acceleration biasY, com.irurueta.units.Acceleration biasZ, boolean commonAxisUsed)
      Constructor.
      Parameters:
      measurements - collection of body kinematics measurements taken at different frames (positions, orientations and velocities).
      biasX - known x coordinate of accelerometer bias.
      biasY - known y coordinate of accelerometer bias.
      biasZ - known z coordinate of accelerometer bias.
      commonAxisUsed - indicates whether z-axis is assumed to be common for accelerometer and gyroscope.

    • KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibrator

      public KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibrator(Collection<FrameBodyKinematics> measurements, com.irurueta.units.Acceleration biasX, com.irurueta.units.Acceleration biasY, com.irurueta.units.Acceleration biasZ, boolean commonAxisUsed, KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibratorListener listener)
      Constructor.
      Parameters:
      measurements - collection of body kinematics measurements taken at different frames (positions, orientations and velocities).
      biasX - known x coordinate of accelerometer bias.
      biasY - known y coordinate of accelerometer bias.
      biasZ - known z coordinate of accelerometer bias.
      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 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:
      getMeasurements in interface KnownBiasAndFrameAccelerometerCalibrator<FrameBodyKinematics,KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibratorListener>
      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 KnownBiasAndFrameAccelerometerCalibrator<FrameBodyKinematics,KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibratorListener>
      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 estimator 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 estimator is currently running.

    • getListener

      public KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibratorListener getListener()
      Gets listener to handle events raised by this estimator.
      Specified by:
      getListener in interface KnownBiasAndFrameAccelerometerCalibrator<FrameBodyKinematics,KnownBiasAndFrameAccelerometerLinearLeastSquaresCalibratorListener>
      Returns:
      listener to handle events raised by this estimator.

    • setListener

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

    • getBiasX

      public double getBiasX()
      Gets known x coordinate of accelerometer bias expressed in meters per squared second (m/s^2).
      Specified by:
      getBiasX in interface KnownBiasAccelerometerCalibrator
      Returns:
      x coordinate of accelerometer bias.

    • setBiasX

      public void setBiasX(double biasX) throws com.irurueta.navigation.LockedException
      Sets known x coordinate of accelerometer bias expressed in meters per squared second (m/s^2).
      Specified by:
      setBiasX in interface KnownBiasAccelerometerCalibrator
      Parameters:
      biasX - x coordinate of accelerometer bias.
      Throws:
      com.irurueta.navigation.LockedException - if estimator is currently running.

    • getBiasY

      public double getBiasY()
      Gets known y coordinate of accelerometer bias expressed in meters per squared second (m/s^2).
      Specified by:
      getBiasY in interface KnownBiasAccelerometerCalibrator
      Returns:
      y coordinate of accelerometer bias.

    • setBiasY

      public void setBiasY(double biasY) throws com.irurueta.navigation.LockedException
      Sets known y coordinate of accelerometer bias expressed in meters per squared second (m/s^2).
      Specified by:
      setBiasY in interface KnownBiasAccelerometerCalibrator
      Parameters:
      biasY - y coordinate of accelerometer bias.
      Throws:
      com.irurueta.navigation.LockedException - if estimator is currently running.

    • getBiasZ

      public double getBiasZ()
      Gets known z coordinate of accelerometer bias expressed in meters per squared second (m/s^2).
      Specified by:
      getBiasZ in interface KnownBiasAccelerometerCalibrator
      Returns:
      z coordinate of accelerometer bias.

    • setBiasZ

      public void setBiasZ(double biasZ) throws com.irurueta.navigation.LockedException
      Sets known z coordinate of accelerometer bias expressed in meters per squared second (m/s^2).
      Specified by:
      setBiasZ in interface KnownBiasAccelerometerCalibrator
      Parameters:
      biasZ - z coordinate of accelerometer bias.
      Throws:
      com.irurueta.navigation.LockedException - if estimator is currently running.

    • getBiasXAsAcceleration

      public com.irurueta.units.Acceleration getBiasXAsAcceleration()
      Gets known x coordinate of accelerometer bias.
      Specified by:
      getBiasXAsAcceleration in interface KnownBiasAccelerometerCalibrator
      Returns:
      x coordinate of accelerometer bias.

    • getBiasXAsAcceleration

      public void getBiasXAsAcceleration(com.irurueta.units.Acceleration result)
      Gets known x coordinate of accelerometer bias.
      Specified by:
      getBiasXAsAcceleration in interface KnownBiasAccelerometerCalibrator
      Parameters:
      result - instance where result data will be stored.

    • setBiasX

      public void setBiasX(com.irurueta.units.Acceleration biasX) throws com.irurueta.navigation.LockedException
      Sets known x coordinate of accelerometer bias.
      Specified by:
      setBiasX in interface KnownBiasAccelerometerCalibrator
      Parameters:
      biasX - x coordinate of accelerometer bias.
      Throws:
      com.irurueta.navigation.LockedException - if estimator is currently running.

    • getBiasYAsAcceleration

      public com.irurueta.units.Acceleration getBiasYAsAcceleration()
      Gets known y coordinate of accelerometer bias.
      Specified by:
      getBiasYAsAcceleration in interface KnownBiasAccelerometerCalibrator
      Returns:
      y coordinate of accelerometer bias.

    • getBiasYAsAcceleration

      public void getBiasYAsAcceleration(com.irurueta.units.Acceleration result)
      Gets known y coordinate of accelerometer bias.
      Specified by:
      getBiasYAsAcceleration in interface KnownBiasAccelerometerCalibrator
      Parameters:
      result - instance where result data will be stored.

    • setBiasY

      public void setBiasY(com.irurueta.units.Acceleration biasY) throws com.irurueta.navigation.LockedException
      Sets known y coordinate of accelerometer bias.
      Specified by:
      setBiasY in interface KnownBiasAccelerometerCalibrator
      Parameters:
      biasY - y coordinate of accelerometer bias.
      Throws:
      com.irurueta.navigation.LockedException - if estimator is currently running.

    • getBiasZAsAcceleration

      public com.irurueta.units.Acceleration getBiasZAsAcceleration()
      Gets known z coordinate of accelerometer bias.
      Specified by:
      getBiasZAsAcceleration in interface KnownBiasAccelerometerCalibrator
      Returns:
      z coordinate of accelerometer bias.

    • getBiasZAsAcceleration

      public void getBiasZAsAcceleration(com.irurueta.units.Acceleration result)
      Gets known z coordinate of accelerometer bias.
      Specified by:
      getBiasZAsAcceleration in interface KnownBiasAccelerometerCalibrator
      Parameters:
      result - instance where result data will be stored.

    • setBiasZ

      public void setBiasZ(com.irurueta.units.Acceleration biasZ) throws com.irurueta.navigation.LockedException
      Sets known z coordinate of accelerometer bias.
      Specified by:
      setBiasZ in interface KnownBiasAccelerometerCalibrator
      Parameters:
      biasZ - z coordinate of accelerometer bias.
      Throws:
      com.irurueta.navigation.LockedException - if estimator is currently running.

    • setBiasCoordinates

      public void setBiasCoordinates(double biasX, double biasY, double biasZ) throws com.irurueta.navigation.LockedException
      Sets known accelerometer bias coordinates expressed in meters per squared second (m/s^2).
      Specified by:
      setBiasCoordinates in interface KnownBiasAccelerometerCalibrator
      Parameters:
      biasX - x coordinate of accelerometer bias.
      biasY - y coordinate of accelerometer bias.
      biasZ - z coordinate of accelerometer bias.
      Throws:
      com.irurueta.navigation.LockedException - if estimator is currently running.

    • setBiasCoordinates

      public void setBiasCoordinates(com.irurueta.units.Acceleration biasX, com.irurueta.units.Acceleration biasY, com.irurueta.units.Acceleration biasZ) throws com.irurueta.navigation.LockedException
      Sets known accelerometer bias coordinates.
      Specified by:
      setBiasCoordinates in interface KnownBiasAccelerometerCalibrator
      Parameters:
      biasX - z coordinate of accelerometer bias.
      biasY - y coordinate of accelerometer bias.
      biasZ - z coordinate of accelerometer bias.
      Throws:
      com.irurueta.navigation.LockedException - if estimator is currently running.

    • getBiasAsTriad

      public AccelerationTriad getBiasAsTriad()
      Gets known accelerometer bias.
      Specified by:
      getBiasAsTriad in interface KnownBiasAccelerometerCalibrator
      Returns:
      known accelerometer bias.

    • getBiasAsTriad

      public void getBiasAsTriad(AccelerationTriad result)
      Gets known accelerometer bias.
      Specified by:
      getBiasAsTriad in interface KnownBiasAccelerometerCalibrator
      Parameters:
      result - instance where result will be stored.

    • setBias

      public void setBias(AccelerationTriad bias) throws com.irurueta.navigation.LockedException
      Sets known accelerometer bias.
      Specified by:
      setBias in interface KnownBiasAccelerometerCalibrator
      Parameters:
      bias - accelerometer bias to be set.
      Throws:
      com.irurueta.navigation.LockedException - if calibrator is currently running.

    • getBias

      public double[] getBias()
      Gets known accelerometer bias as an array. Array values are expressed in meters per squared second (m/s^2).
      Specified by:
      getBias in interface KnownBiasAccelerometerCalibrator
      Returns:
      array containing coordinates of known bias.

    • getBias

      public void getBias(double[] result)
      Gets known accelerometer bias as an array. Array values are expressed in meters per squared second (m/s^2).
      Specified by:
      getBias in interface KnownBiasAccelerometerCalibrator
      Parameters:
      result - instance where result data will be copied to.
      Throws:
      IllegalArgumentException - if provided array does not have length 3.

    • setBias

      public void setBias(double[] bias) throws com.irurueta.navigation.LockedException
      Sets known accelerometer bias as an array. Array values are expressed in meters per squared second (m/s^2).
      Specified by:
      setBias in interface KnownBiasAccelerometerCalibrator
      Parameters:
      bias - known accelerometer bias.
      Throws:
      com.irurueta.navigation.LockedException - if calibrator is currently running.
      IllegalArgumentException - if provided array does not have length 3.

    • getBiasAsMatrix

      public com.irurueta.algebra.Matrix getBiasAsMatrix()
      Gets known accelerometer bias as a column matrix.
      Specified by:
      getBiasAsMatrix in interface KnownBiasAccelerometerCalibrator
      Returns:
      known accelerometer bias as a column matrix.

    • getBiasAsMatrix

      public void getBiasAsMatrix(com.irurueta.algebra.Matrix result)
      Gets known accelerometer bias as a column matrix.
      Specified by:
      getBiasAsMatrix in interface KnownBiasAccelerometerCalibrator
      Parameters:
      result - instance where result data will be copied to.
      Throws:
      IllegalArgumentException - if provided matrix is not 3x1.

    • setBias

      public void setBias(com.irurueta.algebra.Matrix bias) throws com.irurueta.navigation.LockedException
      Sets known accelerometer bias as a column matrix.
      Specified by:
      setBias in interface KnownBiasAccelerometerCalibrator
      Parameters:
      bias - accelerometer bias to be set.
      Throws:
      com.irurueta.navigation.LockedException - if calibrator is currently running
      IllegalArgumentException - if provided matrix is not 3x1.

    • 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 estimator is ready to start the estimator.
      Specified by:
      isReady in interface AccelerometerCalibrator
      Returns:
      true if estimator is ready, false otherwise.

    • isRunning

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

    • calibrate

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

    • getEstimatedMa

      public com.irurueta.algebra.Matrix getEstimatedMa()
      Gets estimated accelerometer scale factors and ross 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 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.

    • 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.

    • convertAcceleration

      private static double convertAcceleration(double value, com.irurueta.units.AccelerationUnit unit)
      Converts acceleration value and unit to meters per squared second.
      Parameters:
      value - acceleration value.
      unit - unit of acceleration value.
      Returns:
      converted value.

    • convertAcceleration

      private static double convertAcceleration(com.irurueta.units.Acceleration acceleration)
      Converts acceleration instance to meters per squared second.
      Parameters:
      acceleration - acceleration instance to be converted.
      Returns:
      converted value.