Class providing an "Attitude and Heading Reference System" (AHRS) interface to a navX-sensor. More...

#include <AHRS.h>

Inheritance diagram for AHRS:

Classes
struct	BoardYawAxis
	Structure describing the current board orientation w/respect to the IMU axes of measurement. More...

Public Types
enum	BoardAxis { kBoardAxisX = 0 , kBoardAxisY = 1 , kBoardAxisZ = 2 }
	Enumeration of all board axes. More...

enum	SerialDataType { kProcessedData = 0 , kRawData = 1 }
	navX-Sensor support Serial Data types More...

Public Member Functions
	AHRS (frc::SPI::Port spi_port_id)
	Constructs the AHRS class using SPI communication and the default update rate. More...

	AHRS (frc::I2C::Port i2c_port_id)
	Constructs the AHRS class using I2C communication and the default update rate. More...

	AHRS (frc::SerialPort::Port serial_port_id)
	Constructs the AHRS class using serial communication and the default update rate, and returning processed (rather than raw) data. More...

	AHRS (frc::SPI::Port spi_port_id, uint8_t update_rate_hz)
	The AHRS class provides an interface to AHRS capabilities of the KauaiLabs navX Robotics Navigation Sensor via SPI, I2C and Serial (TTL UART and USB) communications interfaces on the RoboRIO. More...

	AHRS (frc::SPI::Port spi_port_id, uint32_t spi_bitrate, uint8_t update_rate_hz)
	The AHRS class provides an interface to AHRS capabilities of the KauaiLabs navX Robotics Navigation Sensor via SPI, I2C and Serial (TTL UART and USB) communications interfaces on the RoboRIO. More...

	AHRS (frc::I2C::Port i2c_port_id, uint8_t update_rate_hz)
	Constructs the AHRS class using I2C communication, overriding the default update rate with a custom rate which may be from 4 to 200, representing the number of updates per second sent by the sensor. More...

	AHRS (frc::SerialPort::Port serial_port_id, AHRS::SerialDataType data_type, uint8_t update_rate_hz)
	Constructs the AHRS class using serial communication, overriding the default update rate with a custom rate which may be from 4 to 200, representing the number of updates per second sent by the sensor. More...

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

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

void	SetAngleAdjustment (double angle)
	Sets an amount of angle to be automatically added before returning a angle from the getAngle() method. More...

double	GetAngleAdjustment ()
	Returns the currently configured adjustment angle. More...

void	Reset () override
	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...

AHRS::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 (ITimestampedDataSubscriber callback, void callback_context)
	Registers a callback interface. More...

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

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

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

void	EnableLogging (bool enable)
	Enables or disables logging (via Console I/O) of AHRS library internal behaviors, including events such as transient communication errors. More...

void	EnableBoardlevelYawReset (bool enable)
	Enables or disables board-level yaw zero (reset) requests. More...

bool	IsBoardlevelYawResetEnabled ()
	Returns true if Board-level yaw resets are enabled. More...

int16_t	GetGyroFullScaleRangeDPS ()
	Returns the sensor full scale range (in degrees per second) of the X, Y and X-axis gyroscopes. More...

int16_t	GetAccelFullScaleRangeG ()
	Returns the sensor full scale range (in G) of the X, Y and X-axis accelerometers. More...

void	Calibrate () override
	Gyro interface implementation.

Detailed Description

Class providing an "Attitude and Heading Reference System" (AHRS) interface to a navX-sensor.

Member Enumeration Documentation

◆ BoardAxis

enum AHRS::BoardAxis

Enumeration of all board axes.

Enumerator
kBoardAxisX	Board X (left/right) Axis.
kBoardAxisY	Board Y (forward/reverse) Axis.
kBoardAxisZ	Board Z (up/down) Axis.

◆ SerialDataType

enum AHRS::SerialDataType

navX-Sensor support Serial Data types

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

Constructor & Destructor Documentation

◆ AHRS() [1/7]

AHRS::AHRS ( frc::SPI::Port spi_port_id )

Constructs the AHRS class using SPI communication and the default update rate.

This constructor should be used if communicating via SPI.

Parameters

spi_port_id SPI port to use.

◆ AHRS() [2/7]

AHRS::AHRS ( frc::I2C::Port i2c_port_id )

Constructs the AHRS class using I2C communication and the default update rate.

This constructor should be used if communicating via I2C.

Parameters

i2c_port_id I2C port to use

◆ AHRS() [3/7]

AHRS::AHRS ( frc::SerialPort::Port serial_port_id )

Constructs the AHRS class using serial communication and the default update rate, and returning processed (rather than raw) data.

This constructor should be used if communicating via either TTL UART or USB Serial interface.

Parameters

serial_port_id SerialPort to use

◆ AHRS() [4/7]

AHRS::AHRS	(	frc::SPI::Port	spi_port_id,
		uint8_t	update_rate_hz
	)

The AHRS class provides an interface to AHRS capabilities of the KauaiLabs navX Robotics Navigation Sensor via SPI, I2C and Serial (TTL UART and USB) communications interfaces on the RoboRIO.

The AHRS class enables access to basic connectivity and state information, as well as key 6-axis and 9-axis orientation information (yaw, pitch, roll, compass heading, fused (9-axis) heading and magnetic disturbance detection.

Additionally, the ARHS class also provides access to extended information including linear acceleration, motion detection, rotation detection and sensor temperature.

If used with the navX Aero, the AHRS class also provides access to altitude, barometric pressure and pressure sensor temperature data

Author: Scott

◆ AHRS() [5/7]

AHRS::AHRS	(	frc::SPI::Port	spi_port_id,
		uint32_t	spi_bitrate,
		uint8_t	update_rate_hz
	)

The AHRS class provides an interface to AHRS capabilities of the KauaiLabs navX Robotics Navigation Sensor via SPI, I2C and Serial (TTL UART and USB) communications interfaces on the RoboRIO.

The AHRS class enables access to basic connectivity and state information, as well as key 6-axis and 9-axis orientation information (yaw, pitch, roll, compass heading, fused (9-axis) heading and magnetic disturbance detection.

Additionally, the ARHS class also provides access to extended information including linear acceleration, motion detection, rotation detection and sensor temperature.

If used with the navX Aero, the AHRS class also provides access to altitude, barometric pressure and pressure sensor temperature data

This constructor allows the specification of a custom SPI bitrate, in bits/second.

Author: Scott

◆ AHRS() [6/7]

AHRS::AHRS	(	frc::I2C::Port	i2c_port_id,
		uint8_t	update_rate_hz
	)

Constructs the AHRS class using I2C communication, overriding the default update rate with a custom rate which may be from 4 to 200, representing the number of updates per second sent by the sensor.

This constructor should be used if communicating via I2C.

Note that increasing the update rate may increase the CPU utilization.

Parameters

i2c_port_id	I2C Port to use
update_rate_hz	Custom Update Rate (Hz)

◆ AHRS() [7/7]

AHRS::AHRS	(	frc::SerialPort::Port	serial_port_id,
		AHRS::SerialDataType	data_type,
		uint8_t	update_rate_hz
	)

Constructs the AHRS class using serial communication, overriding the default update rate with a custom rate which may be from 4 to 200, representing the number of updates per second sent by the sensor.

This constructor should be used if communicating via either TTL UART or USB Serial interface.

Note that the serial interfaces can communicate either processed data, or raw data, but not both simultaneously. If simultaneous processed and raw data are needed, use one of the register-based interfaces (SPI or I2C).

Note that increasing the update rate may increase the CPU utilization.

Parameters

serial_port_id	SerialPort to use
data_type	either kProcessedData or kRawData
update_rate_hz	Custom Update Rate (Hz)

Member Function Documentation

◆ DeregisterCallback()

bool AHRS::DeregisterCallback ( ITimestampedDataSubscriber * 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.

◆ EnableBoardlevelYawReset()

void AHRS::EnableBoardlevelYawReset ( bool enable )

Enables or disables board-level yaw zero (reset) requests.

Board-level yaw resets are processed by the sensor board and the resulting yaw angle may not be available to the client software until at least 2 update cycles have occurred. Board-level yaw resets however do maintain synchronization between the yaw angle and the sensor-generated Quaternion and Fused Heading values.

Conversely, Software-based yaw resets occur instantaneously; however, Software- based yaw resets do not update the yaw angle component of the sensor-generated Quaternion values or the Fused Heading values.

Parameters

enable

◆ EnableLogging()

void AHRS::EnableLogging ( bool enable )

Enables or disables logging (via Console I/O) of AHRS library internal behaviors, including events such as transient communication errors.

Parameters

enable

◆ GetAccelFullScaleRangeG()

int16_t AHRS::GetAccelFullScaleRangeG ( )

Returns the sensor full scale range (in G) of the X, Y and X-axis accelerometers.

Returns: accelerometer full scale range in G.

◆ GetActualUpdateRate()

int 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 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 AHRS::GetAngle ( ) const

override

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.

◆ GetAngleAdjustment()

double AHRS::GetAngleAdjustment ( )

Returns the currently configured adjustment angle.

See setAngleAdjustment() for more details.

If this method returns 0 degrees, no adjustment to the value returned via getAngle() will occur.

Returns: adjustment, in degrees (range: -360 to 360)

◆ GetBarometricPressure()

float 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()

AHRS::BoardYawAxis 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 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 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 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 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 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 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 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)

◆ GetGyroFullScaleRangeDPS()

int16_t AHRS::GetGyroFullScaleRangeDPS ( )

Returns the sensor full scale range (in degrees per second) of the X, Y and X-axis gyroscopes.

Returns: gyroscope full scale range in degrees/second.

◆ GetLastSensorTimestamp()

long 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 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 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 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 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 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 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 AHRS::GetRate ( ) const

override

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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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.

◆ IsBoardlevelYawResetEnabled()

bool AHRS::IsBoardlevelYawResetEnabled ( )

Returns true if Board-level yaw resets are enabled.

Conversely, returns false if Software-based yaw resets are active.

Returns: true if Board-level yaw resets are enabled.

◆ IsCalibrating()

bool 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 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 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 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 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 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 AHRS::RegisterCallback	(	ITimestampedDataSubscriber *	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 AHRS::Reset ( )

override

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 AHRS::ResetDisplacement ( )

Zeros the displacement integration variables.

Invoke this at the moment when integration begins.

◆ SetAngleAdjustment()

void AHRS::SetAngleAdjustment ( double adjustment )

Sets an amount of angle to be automatically added before returning a angle from the getAngle() method.

This allows users of the getAngle() method to logically rotate the sensor by a given amount of degrees.

NOTE 1: The adjustment angle is only applied to the value returned from getAngle() - it does not adjust the value returned from getYaw(), nor any of the quaternion values.

NOTE 2: The adjustment angle is notautomatically cleared whenever the sensor yaw angle is reset.

If not set, the default adjustment angle is 0 degrees (no adjustment).

Parameters

adjustment Adjustment in degrees (range: -360 to 360)

◆ UpdateDisplacement()

void 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 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.

NOTE: This method has no effect if the sensor is currently calibrating, since resetting the yaw will interfere with the calibration process.

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

C:/Users/scott/Documents/GitHub/navXG2/roborio/c++/navx_frc_cpp/include/AHRS.h
C:/Users/scott/Documents/GitHub/navXG2/roborio/c++/navx_frc_cpp/src/AHRS.cpp

Classes

Public Types

Public Member Functions

Detailed Description

Member Enumeration Documentation

◆ BoardAxis

◆ SerialDataType

Constructor & Destructor Documentation

◆ AHRS() [1/7]

◆ AHRS() [2/7]

◆ AHRS() [3/7]

◆ AHRS() [4/7]

◆ AHRS() [5/7]

◆ AHRS() [6/7]

◆ AHRS() [7/7]

Member Function Documentation

◆ DeregisterCallback()

◆ EnableBoardlevelYawReset()

◆ EnableLogging()

◆ GetAccelFullScaleRangeG()

◆ GetActualUpdateRate()

◆ GetAltitude()

◆ GetAngle()

◆ GetAngleAdjustment()

◆ GetBarometricPressure()

◆ GetBoardYawAxis()

◆ GetByteCount()

◆ GetCompassHeading()

◆ GetDisplacementX()

◆ GetDisplacementY()

◆ GetDisplacementZ()

◆ GetFirmwareVersion()

◆ GetFusedHeading()

◆ GetGyroFullScaleRangeDPS()

◆ 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()

◆ IsBoardlevelYawResetEnabled()

◆ IsCalibrating()

◆ IsConnected()

◆ IsMagneticDisturbance()

◆ IsMagnetometerCalibrated()

◆ IsMoving()

◆ IsRotating()

◆ RegisterCallback()

◆ Reset()

◆ ResetDisplacement()

◆ SetAngleAdjustment()

◆ UpdateDisplacement()

◆ ZeroYaw()