What sensors does an Inertial Navigation System (INS) use?

• A. Gyroscopes and accelerometers
• B. Magnetic compass and GPS
• C. Radar and lidar
• D. Pitot tubes and static ports

Answer: (A)

The key idea is that an INS determines motion from internal motion sensors, without relying on external references. The sensors that make this possible are gyroscopes and accelerometers. Gyroscopes measure angular velocity around each axis, telling you how fast the device is rotating. Accelerometers measure linear acceleration along each axis, indicating how quickly velocity is changing. By integrating the angular velocity, the system updates its orientation; by integrating the accelerations (properly accounting for rotation), it updates velocity and then position. Together, these three‑axis measurements let the INS track how you’re moving and oriented over time, producing a navigation solution that’s self-contained—though in practice it’s often aided by external data to correct drift. Magnetic compass and GPS, Radar and lidar, or Pitot tubes and static ports don’t provide the fundamental inertial measurements needed for dead‑reckoning navigation, which is why the combination of gyroscopes and accelerometers is the correct choice.