Purpose

This document sets forth the basic features for a 10 MCU Inertial Reference System (IRS) consisting of the necessary inertial measuring devices and associated electronics specifically designed for installation in commercial transport-type aircraft. This system provides the basic outputs for aircraft angular rate and acceleration, and computed outputs of attitude, true heading, magnetic heading, velocity and present position. The inertial sensor outputs can be utilized as the primary reference for cockpit instruments and automatic flight control systems.

The inertial reference system outputs can also be used with a display unit to provide data for standalone navigation, or, alternately, be utilized by a navigation computer in association with other inputs to generate horizontal and vertical steering signals. The inertial reference unit may also be interfaced to an ARINC 743A Global Positioning System (GNSS) system to enhance the accuracy of the inertially derived navigation data.

The GNSS system comprises an antenna subsystem and a GNSS sensor unit (GNSSU). Computational capabilities to assimilate the GNSS-derived information are contained within the IRU.