Which of the following best describes inertial navigation systems?

Inertial navigation systems are designed to operate independently without needing external references. They utilize internal sensors, such as accelerometers and gyroscopes, to measure motion and orientation. This self-contained nature allows them to track the position and velocity of a moving object based solely on its own movement data, making them highly effective in various applications, from aviation to spacecraft navigation.

This independence from external inputs means that they can function in environments where GPS signals might be unreliable or unavailable, such as underwater or in space. The ability to calculate navigation details using only internal data enhances their reliability in many critical situations, which is a significant advantage over systems that solely depend on external sources.