Which set of sensors are typically included in an Inertial Measuring Unit (IMU)?

• A. Accelerometer, Gyroscope, and Magnetometer
• B. Accelerometer and Gyroscope
• C. Gyroscope and Magnetometer
• D. Accelerometer, Magnetometer, and Barometer

Answer: (A)

An IMU is designed to capture motion and orientation in 3D space by combining sensors that measure different aspects of movement. The accelerometer measures linear acceleration on each axis, the gyroscope tracks how fast the device is rotating around each axis, and the magnetometer provides a reference to Earth’s magnetic field to help determine heading. Together, these three sensors enable robust estimation of orientation and motion through sensor fusion, with the magnetometer helping to correct long-term drift in the gyroscope and providing an absolute reference for heading.

Including all three makes the common, full-featured IMU. If the magnetometer were missing, you’d still get motion and rotation data, but heading would drift over time. If the accelerometer were missing, you’d lose information about translational acceleration and gravity direction. A barometer is useful for altitude data but is not part of the core inertial sensing set.