inertial platform

The sensing devices used in inertial guidance and the platform on which they are mounted.

A self-contained system which can automatically determine the position, velocity, and attitude of a moving vehicle for the purpose of directing its future course. Based on prior knowledge of time, gravitational field, initial position, initial velocity, and initial orientation relative to a known reference frame, an inertial guidance system is capable of determining its present position, velocity, and orientation without the aid of external information. The generated navigational data are used to determine the future course for a vehicle to follow in order to bring it to its destination. Such systems have found application in the guidance and control of submarines, ships, aircraft, missiles, and spacecraft. See also Guidance systems.

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(DOD, NATO) A self-contained navigation system using inertial detectors, which automatically provides vehicle position, heading, and velocity. Also called INS.

The noun has one meaning:

Meaning #1: a system to control a plane or spacecraft; uses inertial forces
  Synonym: inertial navigation system