Inertial Measurement Unit
A device that measures acceleration and rotation using accelerometers and gyroscopes, tracking an object's motion and orientation without external signals.
A self-contained sensor system that measures linear acceleration and angular velocity using accelerometers and gyroscopes. It calculates position, velocity, and orientation by integrating these measurements over time, requiring no external signals. Widely used in aircraft, spacecraft, submarines, and smartphones for navigation and motion tracking.
What this means in real life
When your smartphone rotates to landscape mode or a fitness tracker counts your steps, an inertial measurement unit inside detects the acceleration and tilt of your device without needing GPS or external reference points.
What it isn’t
It is not a GPS receiver or compass. While those rely on external signals (satellites or Earth's magnetic field), this device works entirely standalone by measuring motion and acceleration from within the object itself.
Commonly misused online
People often conflate it with GPS or assume it provides absolute position. In reality, it only measures changes in motion; position errors accumulate over time without external corrections.