An Inertial Measurement Unit (IMU) typically combines which sensors?

• A. Magnetometer and Proximity Sensor
• B. GPS and Gyroscope
• C. Accelerometer and Magnetometer
• D. Gyroscope and Accelerometer

Answer: (D)

An IMU is built to sense motion and rotation in real time using a pair of core sensors: an accelerometer and a gyroscope. The accelerometer measures linear acceleration along three axes, which includes the constant pull of gravity when the device is oriented relative to the ground. This helps determine tilt and detect changes in velocity. The gyroscope, on the other hand, measures angular velocity around three axes, capturing how fast the device is rotating. When you combine these two sensors, you get a reliable picture of both how the device is moving through space and how it is rotating, across a wide range of speeds. The gyroscope provides fast rotational data, but its readings can drift over time if used alone; the accelerometer provides a gravity-referenced reference that helps correct that drift through sensor fusion. In many systems, a magnetometer might be added to help with heading, and GPS provides position from outside the inertial frame, but those aren’t the core sensors that define a basic IMU.