Inerttijärjestelmät

Inerttijärjestelmät, or Inertial Navigation Systems (INS) in English, are self-contained navigation devices that continuously calculate a craft's position, orientation, and velocity without needing external references. They achieve this by using a combination of accelerometers and gyroscopes. Accelerometers measure acceleration along each axis, and when integrated over time, they provide velocity and position changes. Gyroscopes measure angular velocity, allowing the system to track changes in orientation.

The core of an INS is a platform that is kept stable in a specific orientation, often by gimbals or a similar mechanism. Modern INS often use "strapdown" systems where the sensors are rigidly attached to the vehicle and their outputs are mathematically compensated for the vehicle's motion. The accuracy of an INS depends heavily on the quality of its sensors and the precision of its initial alignment.

INS are particularly valuable in environments where external navigation signals, such as GPS, may be unavailable or unreliable, such as underwater, in tunnels, or during electronic warfare. They are crucial for the navigation of aircraft, submarines, spacecraft, and missiles. While INS can drift over time due to sensor inaccuracies, they are often combined with other navigation systems, like GPS, to provide a more robust and accurate navigation solution through a process called sensor fusion.