The AHRS class provides accesst to the VMX-pi IMU and Attitude/Heading Reference System functionality. More...

#include <AHRS.h>

Public Types
enum	SerialDataType { kProcessedData = 0, kRawData = 1 }

Public Member Functions
float	GetPitch ()
	Returns the current pitch value (in degrees, from -180 to 180) reported by the sensor. More...

float	GetRoll ()
	Returns the current roll value (in degrees, from -180 to 180) reported by the sensor. More...

float	GetYaw ()
	Returns the current yaw value (in degrees, from -180 to 180) reported by the sensor. More...

float	GetCompassHeading ()
	Returns the current tilt-compensated compass heading value (in degrees, from 0 to 360) reported by the sensor. More...

void	ZeroYaw ()
	Sets the user-specified yaw offset to the current yaw value reported by the sensor. More...

bool	IsCalibrating ()
	Returns true if the sensor is currently performing automatic gyro/accelerometer calibration. More...

bool	IsConnected ()
	Indicates whether the sensor is currently connected to the host computer. More...

double	GetByteCount ()
	Returns the count in bytes of data received from the sensor. More...

double	GetUpdateCount ()
	Returns the count of valid updates which have been received from the sensor. More...

long	GetLastSensorTimestamp ()
	Returns the sensor timestamp corresponding to the last sample retrieved from the sensor. More...

float	GetWorldLinearAccelX ()
	Returns the current linear acceleration in the X-axis (in G). More...

float	GetWorldLinearAccelY ()
	Returns the current linear acceleration in the Y-axis (in G). More...

float	GetWorldLinearAccelZ ()
	Returns the current linear acceleration in the Z-axis (in G). More...

bool	IsMoving ()
	Indicates if the sensor is currently detecting motion, based upon the X and Y-axis world linear acceleration values. More...

bool	IsRotating ()
	Indicates if the sensor is currently detecting yaw rotation, based upon whether the change in yaw over the last second exceeds the "Rotation Threshold.". More...

float	GetBarometricPressure ()
	Returns the current barometric pressure, based upon calibrated readings from the onboard pressure sensor. More...

float	GetAltitude ()
	Returns the current altitude, based upon calibrated readings from a barometric pressure sensor, and the currently-configured sea-level barometric pressure [navX Aero only]. More...

bool	IsAltitudeValid ()
	Indicates whether the current altitude (and barometric pressure) data is valid. More...

float	GetFusedHeading ()
	Returns the "fused" (9-axis) heading. More...

bool	IsMagneticDisturbance ()
	Indicates whether the current magnetic field strength diverges from the calibrated value for the earth's magnetic field by more than the currently- configured Magnetic Disturbance Ratio. More...

bool	IsMagnetometerCalibrated ()
	Indicates whether the magnetometer has been calibrated. More...

float	GetQuaternionW ()
	Returns the imaginary portion (W) of the Orientation Quaternion which fully describes the current sensor orientation with respect to the reference angle defined as the angle at which the yaw was last "zeroed". More...

float	GetQuaternionX ()
	Returns the real portion (X axis) of the Orientation Quaternion which fully describes the current sensor orientation with respect to the reference angle defined as the angle at which the yaw was last "zeroed". More...

float	GetQuaternionY ()
	Returns the real portion (X axis) of the Orientation Quaternion which fully describes the current sensor orientation with respect to the reference angle defined as the angle at which the yaw was last "zeroed". More...

float	GetQuaternionZ ()
	Returns the real portion (X axis) of the Orientation Quaternion which fully describes the current sensor orientation with respect to the reference angle defined as the angle at which the yaw was last "zeroed". More...

void	ResetDisplacement ()
	Zeros the displacement integration variables. More...

void	UpdateDisplacement (float accel_x_g, float accel_y_g, int update_rate_hz, bool is_moving)
	Each time new linear acceleration samples are received, this function should be invoked. More...

float	GetVelocityX ()
	Returns the velocity (in meters/sec) of the X axis [Experimental]. More...

float	GetVelocityY ()
	Returns the velocity (in meters/sec) of the Y axis [Experimental]. More...

float	GetVelocityZ ()
	Returns the velocity (in meters/sec) of the Z axis [Experimental]. More...

float	GetDisplacementX ()
	Returns the displacement (in meters) of the X axis since resetDisplacement() was last invoked [Experimental]. More...

float	GetDisplacementY ()
	Returns the displacement (in meters) of the Y axis since resetDisplacement() was last invoked [Experimental]. More...

float	GetDisplacementZ ()
	Returns the displacement (in meters) of the Z axis since resetDisplacement() was last invoked [Experimental]. More...

double	GetAngle ()
	Returns the total accumulated yaw angle (Z Axis, in degrees) reported by the sensor. More...

double	GetRate ()
	Return the rate of rotation of the yaw (Z-axis) gyro, in degrees per second. More...

void	Reset ()
	Reset the Yaw gyro. More...

float	GetRawGyroX ()
	Returns the current raw (unprocessed) X-axis gyro rotation rate (in degrees/sec). More...

float	GetRawGyroY ()
	Returns the current raw (unprocessed) Y-axis gyro rotation rate (in degrees/sec). More...

float	GetRawGyroZ ()
	Returns the current raw (unprocessed) Z-axis gyro rotation rate (in degrees/sec). More...

float	GetRawAccelX ()
	Returns the current raw (unprocessed) X-axis acceleration rate (in G). More...

float	GetRawAccelY ()
	Returns the current raw (unprocessed) Y-axis acceleration rate (in G). More...

float	GetRawAccelZ ()
	Returns the current raw (unprocessed) Z-axis acceleration rate (in G). More...

float	GetRawMagX ()
	Returns the current raw (unprocessed) X-axis magnetometer reading (in uTesla). More...

float	GetRawMagY ()
	Returns the current raw (unprocessed) Y-axis magnetometer reading (in uTesla). More...

float	GetRawMagZ ()
	Returns the current raw (unprocessed) Z-axis magnetometer reading (in uTesla). More...

float	GetPressure ()
	Returns the current barometric pressure (in millibar) [navX Aero only]. More...

float	GetTempC ()
	Returns the current temperature (in degrees centigrade) reported by the sensor's gyro/accelerometer circuit. More...

BoardYawAxis	GetBoardYawAxis ()
	Returns information regarding which sensor board axis (X,Y or Z) and direction (up/down) is currently configured to report Yaw (Z) angle values. More...

std::string	GetFirmwareVersion ()
	Returns the version number of the firmware currently executing on the sensor. More...

bool	RegisterCallback (IVMXTimestampedAHRSDataSubscriber callback, void callback_context)
	Registers a callback interface. More...

bool	DeregisterCallback (IVMXTimestampedAHRSDataSubscriber *callback)
	Deregisters a previously registered callback interface. More...

bool	BlockOnNewCurrentRegisterData (uint32_t timeout_ms, uint8_t first_reg_addr_out, uint8_t p_data_out, uint8_t requested_len, uint8_t *p_len_out)

bool	ReadConfigurationData (uint8_t first_reg_addr, uint8_t *p_data_out, uint8_t requested_len)

int	GetActualUpdateRate ()
	Returns the navX-Model device's currently configured update rate. More...

int	GetRequestedUpdateRate ()
	Returns the currently requested update rate. More...

void	Stop ()

Friends
class	::VMXPi

class	::VMXZero

Detailed Description

The AHRS class provides accesst to the VMX-pi IMU and Attitude/Heading Reference System functionality.

Member Enumeration Documentation

◆ SerialDataType

enum vmx::AHRS::SerialDataType

Enumerator
kProcessedData	(default): 6 and 9-axis processed data
kRawData	unprocessed data from each individual sensor

Member Function Documentation

◆ DeregisterCallback()

bool vmx::AHRS::DeregisterCallback ( IVMXTimestampedAHRSDataSubscriber * callback )

Deregisters a previously registered callback interface.

Be sure to deregister any callback which have been previously registered, to ensure that the object implementing the callback interface does not continue to be accessed when no longer necessary.

◆ GetActualUpdateRate()

int vmx::AHRS::GetActualUpdateRate ( )

Returns the navX-Model device's currently configured update rate.

Note that the update rate that can actually be realized is a value evenly divisible by the navX-Model device's internal motion processor sample clock (200Hz). Therefore, the rate that is returned may be lower than the requested sample rate.

The actual sample rate is rounded down to the nearest integer that is divisible by the number of Digital Motion Processor clock ticks. For instance, a request for 58 Hertz will result in an actual rate of 66Hz (200 / (200 / 58), using integer math.

Returns: Returns the current actual update rate in Hz (cycles per second).

◆ GetAltitude()

float vmx::AHRS::GetAltitude ( )

Returns the current altitude, based upon calibrated readings from a barometric pressure sensor, and the currently-configured sea-level barometric pressure [navX Aero only].

This value is in units of meters.

NOTE: This value is only valid sensors including a pressure sensor. To determine whether this value is valid, see isAltitudeValid().

Returns: Returns current altitude in meters (as long as the sensor includes an installed on-board pressure sensor).

◆ GetAngle()

double vmx::AHRS::GetAngle ( )

Returns the total accumulated yaw angle (Z Axis, in degrees) reported by the sensor.

NOTE: The angle is continuous, meaning it's range is beyond 360 degrees. This ensures that algorithms that wouldn't want to see a discontinuity in the gyro output as it sweeps past 0 on the second time around.

Note that the returned yaw value will be offset by a user-specified offset value; this user-specified offset value is set by invoking the zeroYaw() method.

Returns: The current total accumulated yaw angle (Z axis) of the robot in degrees. This heading is based on integration of the returned rate from the Z-axis (yaw) gyro.

◆ GetBarometricPressure()

float vmx::AHRS::GetBarometricPressure ( )

Returns the current barometric pressure, based upon calibrated readings from the onboard pressure sensor.

This value is in units of millibar.

NOTE: This value is only valid for a navX Aero. To determine whether this value is valid, see isAltitudeValid().

Returns: Returns current barometric pressure (navX Aero only).

◆ GetBoardYawAxis()

BoardYawAxis vmx::AHRS::GetBoardYawAxis ( )

Returns information regarding which sensor board axis (X,Y or Z) and direction (up/down) is currently configured to report Yaw (Z) angle values.

NOTE: If the board firmware supports Omnimount, the board yaw axis/direction are configurable.

For more information on Omnimount, please see:

http://navx-mxp.kauailabs.com/navx-mxp/installation/omnimount/

Returns: The currently-configured board yaw axis/direction.

◆ GetByteCount()

double vmx::AHRS::GetByteCount ( )

Returns the count in bytes of data received from the sensor.

This could can be useful for diagnosing connectivity issues.

If the byte count is increasing, but the update count (see getUpdateCount()) is not, this indicates a software misconfiguration.

Returns: The number of bytes received from the sensor.

◆ GetCompassHeading()

float vmx::AHRS::GetCompassHeading ( )

Returns the current tilt-compensated compass heading value (in degrees, from 0 to 360) reported by the sensor.

Note that this value is sensed by a magnetometer, which can be affected by nearby magnetic fields (e.g., the magnetic fields generated by nearby motors).

Before using this value, ensure that (a) the magnetometer has been calibrated and (b) that a magnetic disturbance is not taking place at the instant when the compass heading was generated.

Returns: The current tilt-compensated compass heading, in degrees (0-360).

◆ GetDisplacementX()

float vmx::AHRS::GetDisplacementX ( )

Returns the displacement (in meters) of the X axis since resetDisplacement() was last invoked [Experimental].

NOTE: This feature is experimental. Displacement measures rely on double-integration of acceleration values from MEMS accelerometers which yield "noisy" values. The resulting displacement are not known to be very accurate, and the amount of error increases quickly as time progresses.

Returns: Displacement since last reset (in meters).

◆ GetDisplacementY()

float vmx::AHRS::GetDisplacementY ( )

Returns the displacement (in meters) of the Y axis since resetDisplacement() was last invoked [Experimental].

NOTE: This feature is experimental. Displacement measures rely on double-integration of acceleration values from MEMS accelerometers which yield "noisy" values. The resulting displacement are not known to be very accurate, and the amount of error increases quickly as time progresses.

Returns: Displacement since last reset (in meters).

◆ GetDisplacementZ()

float vmx::AHRS::GetDisplacementZ ( )

Returns the displacement (in meters) of the Z axis since resetDisplacement() was last invoked [Experimental].

NOTE: This feature is experimental. Displacement measures rely on double-integration of acceleration values from MEMS accelerometers which yield "noisy" values. The resulting displacement are not known to be very accurate, and the amount of error increases quickly as time progresses.

Returns: Displacement since last reset (in meters).

◆ GetFirmwareVersion()

std::string vmx::AHRS::GetFirmwareVersion ( )

Returns the version number of the firmware currently executing on the sensor.

To update the firmware to the latest version, please see:

http://navx-mxp.kauailabs.com/navx-mxp/support/updating-firmware/

Returns: The firmware version in the format [MajorVersion].[MinorVersion]

◆ GetFusedHeading()

float vmx::AHRS::GetFusedHeading ( )

Returns the "fused" (9-axis) heading.

The 9-axis heading is the fusion of the yaw angle, the tilt-corrected compass heading, and magnetic disturbance detection. Note that the magnetometer calibration procedure is required in order to achieve valid 9-axis headings.

The 9-axis Heading represents the sensor's best estimate of current heading, based upon the last known valid Compass Angle, and updated by the change in the Yaw Angle since the last known valid Compass Angle. The last known valid Compass Angle is updated whenever a Calibrated Compass Angle is read and the sensor has recently rotated less than the Compass Noise Bandwidth (~2 degrees).

Returns: Fused Heading in Degrees (range 0-360)

◆ GetLastSensorTimestamp()

long vmx::AHRS::GetLastSensorTimestamp ( )

Returns the sensor timestamp corresponding to the last sample retrieved from the sensor.

Note that this sensor timestamp is only provided when the Register-based IO methods (SPI, I2C) are used; sensor timestamps are not provided when Serial-based IO methods (TTL UART, USB) are used.

Returns: The sensor timestamp corresponding to the current AHRS sensor data.

◆ GetPitch()

float vmx::AHRS::GetPitch ( )

Returns the current pitch value (in degrees, from -180 to 180) reported by the sensor.

Pitch is a measure of rotation around the X Axis.

Returns: The current pitch value in degrees (-180 to 180).

◆ GetPressure()

float vmx::AHRS::GetPressure ( )

Returns the current barometric pressure (in millibar) [navX Aero only].

This value is valid only if a barometric pressure sensor is onboard.

Returns: Returns the current barometric pressure (in millibar).

◆ GetQuaternionW()

float vmx::AHRS::GetQuaternionW ( )

Returns the imaginary portion (W) of the Orientation Quaternion which fully describes the current sensor orientation with respect to the reference angle defined as the angle at which the yaw was last "zeroed".

Each quaternion value (W,X,Y,Z) is expressed as a value ranging from -2 to 2. This total range (4) can be associated with a unit circle, since each circle is comprised of 4 PI Radians.

For more information on Quaternions and their use, please see this definition.

Returns: Returns the imaginary portion (W) of the quaternion.

◆ GetQuaternionX()

float vmx::AHRS::GetQuaternionX ( )

Returns the real portion (X axis) of the Orientation Quaternion which fully describes the current sensor orientation with respect to the reference angle defined as the angle at which the yaw was last "zeroed".

Each quaternion value (W,X,Y,Z) is expressed as a value ranging from -2 to 2. This total range (4) can be associated with a unit circle, since each circle is comprised of 4 PI Radians.

For more information on Quaternions and their use, please see this description.

Returns: Returns the real portion (X) of the quaternion.

◆ GetQuaternionY()

float vmx::AHRS::GetQuaternionY ( )

Returns the real portion (X axis) of the Orientation Quaternion which fully describes the current sensor orientation with respect to the reference angle defined as the angle at which the yaw was last "zeroed".

Each quaternion value (W,X,Y,Z) is expressed as a value ranging from -2 to 2. This total range (4) can be associated with a unit circle, since each circle is comprised of 4 PI Radians.

For more information on Quaternions and their use, please see:

https://en.wikipedia.org/wiki/Quaternions_and_spatial_rotation

Returns: Returns the real portion (X) of the quaternion.

◆ GetQuaternionZ()

float vmx::AHRS::GetQuaternionZ ( )

Returns the real portion (X axis) of the Orientation Quaternion which fully describes the current sensor orientation with respect to the reference angle defined as the angle at which the yaw was last "zeroed".

Each quaternion value (W,X,Y,Z) is expressed as a value ranging from -2 to 2. This total range (4) can be associated with a unit circle, since each circle is comprised of 4 PI Radians.

For more information on Quaternions and their use, please see:

https://en.wikipedia.org/wiki/Quaternions_and_spatial_rotation

Returns: Returns the real portion (X) of the quaternion.

◆ GetRate()

double vmx::AHRS::GetRate ( )

Return the rate of rotation of the yaw (Z-axis) gyro, in degrees per second.

The rate is based on the most recent reading of the yaw gyro angle.

Returns: The current rate of change in yaw angle (in degrees per second)

◆ GetRawAccelX()

float vmx::AHRS::GetRawAccelX ( )

Returns the current raw (unprocessed) X-axis acceleration rate (in G).

NOTE: this value is unprocessed, and should only be accessed by advanced users. This raw value has not had acceleration due to gravity removed from it, and has not been rotated to the world reference frame. Gravity-corrected, world reference frame-corrected X axis acceleration data is accessible via the GetWorldLinearAccelX() method.

Returns: Returns the current acceleration rate (in G).

◆ GetRawAccelY()

float vmx::AHRS::GetRawAccelY ( )

Returns the current raw (unprocessed) Y-axis acceleration rate (in G).

NOTE: this value is unprocessed, and should only be accessed by advanced users. This raw value has not had acceleration due to gravity removed from it, and has not been rotated to the world reference frame. Gravity-corrected, world reference frame-corrected Y axis acceleration data is accessible via the GetWorldLinearAccelY() method.

Returns: Returns the current acceleration rate (in G).

◆ GetRawAccelZ()

float vmx::AHRS::GetRawAccelZ ( )

Returns the current raw (unprocessed) Z-axis acceleration rate (in G).

NOTE: this value is unprocessed, and should only be accessed by advanced users. This raw value has not had acceleration due to gravity removed from it, and has not been rotated to the world reference frame. Gravity-corrected, world reference frame-corrected Z axis acceleration data is accessible via the GetWorldLinearAccelZ() method.

Returns: Returns the current acceleration rate (in G).

◆ GetRawGyroX()

float vmx::AHRS::GetRawGyroX ( )

Returns the current raw (unprocessed) X-axis gyro rotation rate (in degrees/sec).

NOTE: this value is un-processed, and should only be accessed by advanced users. Typically, rotation about the X Axis is referred to as "Pitch". Calibrated and Integrated Pitch data is accessible via the GetPitch() method.

Returns: Returns the current rotation rate (in degrees/sec).

◆ GetRawGyroY()

float vmx::AHRS::GetRawGyroY ( )

Returns the current raw (unprocessed) Y-axis gyro rotation rate (in degrees/sec).

NOTE: this value is un-processed, and should only be accessed by advanced users. Typically, rotation about the T Axis is referred to as "Roll". Calibrated and Integrated Pitch data is accessible via the GetRoll() method.

Returns: Returns the current rotation rate (in degrees/sec).

◆ GetRawGyroZ()

float vmx::AHRS::GetRawGyroZ ( )

Returns the current raw (unprocessed) Z-axis gyro rotation rate (in degrees/sec).

NOTE: this value is un-processed, and should only be accessed by advanced users. Typically, rotation about the T Axis is referred to as "Yaw". Calibrated and Integrated Pitch data is accessible via the GetYaw() method.

Returns: Returns the current rotation rate (in degrees/sec).

◆ GetRawMagX()

float vmx::AHRS::GetRawMagX ( )

Returns the current raw (unprocessed) X-axis magnetometer reading (in uTesla).

NOTE: this value is unprocessed, and should only be accessed by advanced users. This raw value has not been tilt-corrected, and has not been combined with the other magnetometer axis data to yield a compass heading. Tilt-corrected compass heading data is accessible via the GetCompassHeading() method.

Returns: Returns the mag field strength (in uTesla).

◆ GetRawMagY()

float vmx::AHRS::GetRawMagY ( )

Returns the current raw (unprocessed) Y-axis magnetometer reading (in uTesla).

NOTE: this value is unprocessed, and should only be accessed by advanced users. This raw value has not been tilt-corrected, and has not been combined with the other magnetometer axis data to yield a compass heading. Tilt-corrected compass heading data is accessible via the GetCompassHeading() method.

Returns: Returns the mag field strength (in uTesla).

◆ GetRawMagZ()

float vmx::AHRS::GetRawMagZ ( )

Returns the current raw (unprocessed) Z-axis magnetometer reading (in uTesla).

NOTE: this value is unprocessed, and should only be accessed by advanced users. This raw value has not been tilt-corrected, and has not been combined with the other magnetometer axis data to yield a compass heading. Tilt-corrected compass heading data is accessible via the GetCompassHeading() method.

Returns: Returns the mag field strength (in uTesla).

◆ GetRequestedUpdateRate()

int vmx::AHRS::GetRequestedUpdateRate ( )

Returns the currently requested update rate.

rate. Note that not every update rate can actually be realized, since the actual update rate must be a value evenly divisible by the navX-Model device's internal motion processor sample clock (200Hz).

To determine the actual update rate, use the getActualUpdateRate() method.

Returns: Returns the requested update rate in Hz (cycles per second).

◆ GetRoll()

float vmx::AHRS::GetRoll ( )

Returns the current roll value (in degrees, from -180 to 180) reported by the sensor.

Roll is a measure of rotation around the X Axis.

Returns: The current roll value in degrees (-180 to 180).

◆ GetTempC()

float vmx::AHRS::GetTempC ( )

Returns the current temperature (in degrees centigrade) reported by the sensor's gyro/accelerometer circuit.

This value may be useful in order to perform advanced temperature- correction of raw gyroscope and accelerometer values.

Returns: The current temperature (in degrees centigrade).

◆ GetUpdateCount()

double vmx::AHRS::GetUpdateCount ( )

Returns the count of valid updates which have been received from the sensor.

This count should increase at the same rate indicated by the configured update rate.

Returns: The number of valid updates received from the sensor.

◆ GetVelocityX()

float vmx::AHRS::GetVelocityX ( )

Returns the velocity (in meters/sec) of the X axis [Experimental].

NOTE: This feature is experimental. Velocity measures rely on integration of acceleration values from MEMS accelerometers which yield "noisy" values. The resulting velocities are not known to be very accurate.

Returns: Current Velocity (in meters/squared).

◆ GetVelocityY()

float vmx::AHRS::GetVelocityY ( )

Returns the velocity (in meters/sec) of the Y axis [Experimental].

NOTE: This feature is experimental. Velocity measures rely on integration of acceleration values from MEMS accelerometers which yield "noisy" values. The resulting velocities are not known to be very accurate.

Returns: Current Velocity (in meters/squared).

◆ GetVelocityZ()

float vmx::AHRS::GetVelocityZ ( )

Returns the velocity (in meters/sec) of the Z axis [Experimental].

NOTE: This feature is experimental. Velocity measures rely on integration of acceleration values from MEMS accelerometers which yield "noisy" values. The resulting velocities are not known to be very accurate.

Returns: Current Velocity (in meters/squared).

◆ GetWorldLinearAccelX()

float vmx::AHRS::GetWorldLinearAccelX ( )

Returns the current linear acceleration in the X-axis (in G).

World linear acceleration refers to raw acceleration data, which has had the gravity component removed, and which has been rotated to the same reference frame as the current yaw value. The resulting value represents the current acceleration in the x-axis of the body (e.g., the robot) on which the sensor is mounted.

Returns: Current world linear acceleration in the X-axis (in G).

◆ GetWorldLinearAccelY()

float vmx::AHRS::GetWorldLinearAccelY ( )

Returns the current linear acceleration in the Y-axis (in G).

World linear acceleration refers to raw acceleration data, which has had the gravity component removed, and which has been rotated to the same reference frame as the current yaw value. The resulting value represents the current acceleration in the Y-axis of the body (e.g., the robot) on which the sensor is mounted.

Returns: Current world linear acceleration in the Y-axis (in G).

◆ GetWorldLinearAccelZ()

float vmx::AHRS::GetWorldLinearAccelZ ( )

Returns the current linear acceleration in the Z-axis (in G).

World linear acceleration refers to raw acceleration data, which has had the gravity component removed, and which has been rotated to the same reference frame as the current yaw value. The resulting value represents the current acceleration in the Z-axis of the body (e.g., the robot) on which the sensor is mounted.

Returns: Current world linear acceleration in the Z-axis (in G).

◆ GetYaw()

float vmx::AHRS::GetYaw ( )

Returns the current yaw value (in degrees, from -180 to 180) reported by the sensor.

Yaw is a measure of rotation around the Z Axis (which is perpendicular to the earth).

Note that the returned yaw value will be offset by a user-specified offset value; this user-specified offset value is set by invoking the zeroYaw() method.

Returns: The current yaw value in degrees (-180 to 180).

◆ IsAltitudeValid()

bool vmx::AHRS::IsAltitudeValid ( )

Indicates whether the current altitude (and barometric pressure) data is valid.

This value will only be true for a sensor with an onboard pressure sensor installed.

If this value is false for a board with an installed pressure sensor, this indicates a malfunction of the onboard pressure sensor.

Returns: Returns true if a working pressure sensor is installed.

◆ IsCalibrating()

bool vmx::AHRS::IsCalibrating ( )

Returns true if the sensor is currently performing automatic gyro/accelerometer calibration.

Automatic calibration occurs when the sensor is initially powered on, during which time the sensor should be held still, with the Z-axis pointing up (perpendicular to the earth).

NOTE: During this automatic calibration, the yaw, pitch and roll values returned may not be accurate.

Once calibration is complete, the sensor will automatically remove an internal yaw offset value from all reported values.

Returns: Returns true if the sensor is currently automatically calibrating the gyro and accelerometer sensors.

◆ IsConnected()

bool vmx::AHRS::IsConnected ( )

Indicates whether the sensor is currently connected to the host computer.

A connection is considered established whenever communication with the sensor has occurred recently.

Returns: Returns true if a valid update has been recently received from the sensor.

◆ IsMagneticDisturbance()

bool vmx::AHRS::IsMagneticDisturbance ( )

Indicates whether the current magnetic field strength diverges from the calibrated value for the earth's magnetic field by more than the currently- configured Magnetic Disturbance Ratio.

This function will always return false if the sensor's magnetometer has not yet been calibrated; see isMagnetometerCalibrated().

Returns: true if a magnetic disturbance is detected (or the magnetometer is uncalibrated).

◆ IsMagnetometerCalibrated()

bool vmx::AHRS::IsMagnetometerCalibrated ( )

Indicates whether the magnetometer has been calibrated.

Magnetometer Calibration must be performed by the user.

Note that if this function does indicate the magnetometer is calibrated, this does not necessarily mean that the calibration quality is sufficient to yield valid compass headings.

Returns: Returns true if magnetometer calibration has been performed.

◆ IsMoving()

bool vmx::AHRS::IsMoving ( )

Indicates if the sensor is currently detecting motion, based upon the X and Y-axis world linear acceleration values.

If the sum of the absolute values of the X and Y axis exceed a "motion threshold", the motion state is indicated.

Returns: Returns true if the sensor is currently detecting motion.

◆ IsRotating()

bool vmx::AHRS::IsRotating ( )

Indicates if the sensor is currently detecting yaw rotation, based upon whether the change in yaw over the last second exceeds the "Rotation Threshold.".

Yaw Rotation can occur either when the sensor is rotating, or when the sensor is not rotating AND the current gyro calibration is insufficiently calibrated to yield the standard yaw drift rate.

Returns: Returns true if the sensor is currently detecting motion.

◆ RegisterCallback()

bool vmx::AHRS::RegisterCallback	(	IVMXTimestampedAHRSDataSubscriber *	callback,
		void *	callback_context
	)

Registers a callback interface.

This interface will be called back when new data is available, based upon a change in the sensor timestamp.

Note that this callback will occur within the context of the device IO thread, which is not the same thread context the caller typically executes in.

◆ Reset()

void vmx::AHRS::Reset ( )

Reset the Yaw gyro.

Resets the Gyro Z (Yaw) axis to a heading of zero. This can be used if there is significant drift in the gyro and it needs to be recalibrated after it has been running.

◆ ResetDisplacement()

void vmx::AHRS::ResetDisplacement ( )

Zeros the displacement integration variables.

Invoke this at the moment when integration begins.

◆ UpdateDisplacement()

void vmx::AHRS::UpdateDisplacement	(	float	accel_x_g,
		float	accel_y_g,
		int	update_rate_hz,
		bool	is_moving
	)

Each time new linear acceleration samples are received, this function should be invoked.

This function transforms acceleration in G to meters/sec^2, then converts this value to Velocity in meters/sec (based upon velocity in the previous sample). Finally, this value is converted to displacement in meters, and integrated.

Returns: none.

◆ ZeroYaw()

void vmx::AHRS::ZeroYaw ( )

Sets the user-specified yaw offset to the current yaw value reported by the sensor.

This user-specified yaw offset is automatically subtracted from subsequent yaw values reported by the getYaw() method.

The documentation for this class was generated from the following files:

/home/pi/vmx/vmx-pi/hal/hal_cpp/include/AHRS.h
/home/pi/vmx/vmx-pi/hal/hal_cpp/src/AHRS.cpp

Public Types

Public Member Functions

Friends

Detailed Description

Member Enumeration Documentation

◆ SerialDataType

Member Function Documentation

◆ DeregisterCallback()

◆ GetActualUpdateRate()

◆ GetAltitude()

◆ GetAngle()

◆ GetBarometricPressure()

◆ GetBoardYawAxis()

◆ GetByteCount()

◆ GetCompassHeading()

◆ GetDisplacementX()

◆ GetDisplacementY()

◆ GetDisplacementZ()

◆ GetFirmwareVersion()

◆ GetFusedHeading()

◆ GetLastSensorTimestamp()

◆ GetPitch()

◆ GetPressure()

◆ GetQuaternionW()

◆ GetQuaternionX()

◆ GetQuaternionY()

◆ GetQuaternionZ()

◆ GetRate()

◆ GetRawAccelX()

◆ GetRawAccelY()

◆ GetRawAccelZ()

◆ GetRawGyroX()

◆ GetRawGyroY()

◆ GetRawGyroZ()

◆ GetRawMagX()

◆ GetRawMagY()

◆ GetRawMagZ()

◆ GetRequestedUpdateRate()

◆ GetRoll()

◆ GetTempC()

◆ GetUpdateCount()

◆ GetVelocityX()

◆ GetVelocityY()

◆ GetVelocityZ()

◆ GetWorldLinearAccelX()

◆ GetWorldLinearAccelY()

◆ GetWorldLinearAccelZ()

◆ GetYaw()

◆ IsAltitudeValid()

◆ IsCalibrating()

◆ IsConnected()

◆ IsMagneticDisturbance()

◆ IsMagnetometerCalibrated()

◆ IsMoving()

◆ IsRotating()

◆ RegisterCallback()

◆ Reset()

◆ ResetDisplacement()

◆ UpdateDisplacement()

◆ ZeroYaw()