Inertial measurement unit

An inertial measurement unit (IMU) combines accelerometers and gyroscopes to measure an object's acceleration and rotation. Integrating these measurements estimates motion and orientation without relying on external references.

Accelerometer: A sensor that measures proper acceleration along one or more axes. Its readings provide the IMU's linear-acceleration measurements.
Inertial navigation system: A navigation system that derives position and velocity by integrating inertial sensor measurements. An IMU supplies the core measurements that an inertial navigation system integrates.
Inertial navigation: Navigation that estimates movement and position by integrating inertial measurements over time. It uses IMU measurements to maintain a trajectory without continuous external fixes.
Global Positioning System: A satellite-based navigation system that provides positioning and timing information to receivers. GPS can correct accumulated IMU position drift, but may fail indoors or under obstruction.
Gyroscope: A sensor that measures angular velocity around one or more axes. Its readings track rotation between orientation updates.
MEMS: Technology for fabricating miniature mechanical and electrical structures on a shared substrate. Many compact IMUs use MEMS accelerometers and gyroscopes.
Attitude and heading reference system: An electronic system that estimates an aircraft's orientation and heading from sensor measurements. Aircraft systems use IMUs as inputs for real-time attitude estimates.
Magnetometer: A sensor that measures magnetic fields and can estimate direction relative to Earth's field. A magnetometer can constrain heading, which accelerometers and gyroscopes alone cannot stabilize indefinitely.
Sensor fusion: The combination of measurements from multiple sensors to estimate a system's state. Fusion combines accelerometer and gyroscope data to reduce their separate weaknesses.
Sensor bias: A persistent offset between a sensor's expected output and its measured output. Small accelerometer or gyroscope biases grow into large motion-estimation errors.

Linked from 12 pages