Plain English Meaning

The parts inside an INS that let the aircraft figure out where it is on its own, without help from ground stations or satellites. Sensors feel every movement, a computer adds it all up, and a screen shows the crew the result.

Full Definition

The physical and electronic parts that together make up an Inertial Navigation System (INS): an accelerometer assembly that senses motion in each axis, gyroscopes that maintain a stable reference frame, a navigation computer that integrates the sensed accelerations into position and velocity, a control display unit (CDU) for crew input and readout, and a power supply with battery backup. Together these components the aircraft's position purely from internal sensing, with no external signals.