In an inertial navigation system, what makes it a self-contained system?

An inertial navigation system is classified as a self-contained system because it operates independently of outside information. This means that it does not rely on external signals, such as GPS or other satellite data, to determine the position and orientation of the vehicle. Instead, the system continuously measures the acceleration and rotation of the object through onboard sensors, such as accelerometers and gyroscopes, allowing it to calculate its current position based solely on its initial conditions and the internal measurements. This self-sufficiency is a key characteristic of inertial navigation systems, making them particularly useful in environments where external signals may be unreliable or unavailable, such as underwater or in space.

While the system may use previous positions and calculations as part of its internal processes, the defining feature of a self-contained inertial navigation system is its ability to function without needing any external information.