Guidance System, Stellar-Inertial, XN-2

The XN-2 was one of the first operational stellar-inertial systems that successfully assisted in navigating an aircraft. It combined the inertial systems of the Autonetics XN-1 (see 1963-0369, NASM 1382), with a device that acquired one or more stars during flight. The combination gave a system that could continue to operate during low-altitude or other phases of a flight, when the stars were obscured by clouds or the sun, but with much greater accuracy than all-inertial systems, since the stellar fix could correct for the inevitable drift that occurred in the inertial system's gyros. The XN-2 was built by an operation of North American Aircraft (established as the Autonetics Division in 1955), and installed on a YC-97 airplane. On April 10, 1952 it successfully assisted with the navigation of a flight.