Guidance
Gyro/Accelerometer Calibration
determine the yaw offset value it is currently using.
NOTE: If navX-sensor is moving during startup, this Yaw Offset Calibration may take longer than 2
seconds, and may not be calculated at all if the sensor continues moving long enough. Therefore it is
important to keep a navX-sensor still until initial calibration and Initial Yaw Offset calibration completes.
On-the-fly Gyro Calibration
In addition to Startup Calibration, during normal operation navX-sensor will automatically re-calibrate
the gyroscope (e.g., to account for ongoing temperature changes) during operation, whenever it detects
several seconds of no motion. This process is completely transparent to the user. Therefore each time
navX-sensor for several seconds, the gyroscopes are re-calibrated “on-the-fly”. The purpose of On-the-fly
Gyro re-calibration is to help maintain yaw accuracy when shifts in ambient temperature occur during
operation.
This On-the-fly Gyro Calibration can help deal with cases where the sensor was moving during Startup
Calibration, but note that the yaw is not zeroed at the completion of On-the-fly Calibration. So once
again, it’s important to keep the sensor still during Startup Calibration.
Runtime Yaw Zeroing
Your robot software can optionally provide the robot operator a way to reset the yaw angle to Zero at any
time. Please see the documentation for the
The importance of stillness
This is the most important takeaway from this discussion: It is very important that navX-sensor be held
still during the above calibration periods. In support of this, navX-sensors indicate when they are
calibrating; we recommend you incorporate this information into your software. Please see the discussion
of the
for more details on this indication.
Magnetometer Calibration
navX-sensors require calibration in order to yield optimal results. We highly recommend taking the time
to understand this calibration process – successful calibration is vital to ensure optimal performance.
Careful and accurate Magnetometer Calibration is crucial in order to yield valid compass heading,
9-axis heading and magnetic disturbance detection.
Magnetometer Calibration is not typically required for use in many FIRST FRC robot applications,
including Field-oriented drive. Magnetometer Calibration is a manual process and is recommended for
advanced users who need to calculate absolute heading.
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