SAE ARP4102/12A

This document specifies requirements for both an Airborne Landing Guidance System (AGLS) electronic device. This equipment shall device relative aircraft position and situation information for flight along precision three-dimensional paths within the appropriate coverage area. The precision three-dimensional path may be an ILS straight-in look-alike path or a complex, curved path. The requirements are applicable to electronic devices capable of receiving signals or other information from one or more sources, including but not limited to ISL, MLS, GNSS< or IRU inputs.