navX MXP C++ Class Library for RoboRIO
navX MXP Robotics Navigation Sensor
Classes | Public Types | Public Member Functions | List of all members
AHRS Class Reference
Inheritance diagram for AHRS:

Classes

struct  BoardYawAxis
 

Public Types

enum  BoardAxis { kBoardAxisX = 0, kBoardAxisY = 1, kBoardAxisZ = 2 }
 
enum  SerialDataType { kProcessedData = 0, kRawData = 1 }
 

Public Member Functions

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

Member Enumeration Documentation

Enumerator
kProcessedData 

(default): 6 and 9-axis processed data

kRawData 

unprocessed data from each individual sensor

Constructor & Destructor Documentation

AHRS::AHRS ( 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_idSPI port to use.
AHRS::AHRS ( 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_idI2C port to use
AHRS::AHRS ( 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_idSerialPort to use
AHRS::AHRS ( 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::AHRS ( 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::AHRS ( 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_idI2C Port to use
update_rate_hzCustom Update Rate (Hz)
AHRS::AHRS ( 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_idSerialPort to use
data_typeeither kProcessedData or kRawData
update_rate_hzCustom Update Rate (Hz)

Member Function Documentation

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.

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
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).
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).
double 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.
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.

Parameters
adjustment,indegrees (range: -360 to 360)
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).
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.
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.
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).
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).
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).
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).
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]
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)
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.
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).
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).
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.
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.
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.
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.
double 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)
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).
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).
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).
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).
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).
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).
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).
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).
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).
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).
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).
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).
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.
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).
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).
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).
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).
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).
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).
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).
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.
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.
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.
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).
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.
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.
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.
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.

void 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.

void AHRS::ResetDisplacement ( )

Zeros the displacement integration variables.

Invoke this at the moment when integration begins.

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,indegrees (range: -360 to 360)
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.
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.


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