Geographical Reference Eighth field of the Item Q containing co-ordinates and radius. Geographical association of a NOTAM to the co-ordinates of the location it refers to and the radius with the precision of 1 nautical Mile. Geometric Altitude Height above the local earth surface. Geometric Dilution of Precision The ratio of position error of a multi-lateration system. More precisely, it is the ratio of the standard deviation of the position error to the standard deviation of the measurement errors, assuming all measurements errors are statistically independent and have a zero mean and the same standard distribution. GDOP is the measure of the "goodness" of the geometry of the multi-lateration sources as seen by the observer; a low GDOP is desirable, a high GDOP undesirable. Geostationary See Geostationary Satellite Orbit. Geostationary Integrity Channel A system that broadcasts GNSS integrity information via an geostationary satellite. Geostationary Satellite Orbit An equatorial satellite orbit that results in a constant fixed position of the satellite over a particular earth surface reference point. (GPS satellites are not geostationary). Some proposed integrity schemes use geostationary satellites. Gestalt A perceptual pattern or structure possessing qualities as a whole that cannot be described merely as a sum of its parts. Ghost Track Last and unassociated part of a track that was an associated track before. Glideslope The vertical guidance part of an instrument landing system which establishes a safe glide path (usually three degrees) to a runway. Global NAVCOM Annual event co-ordinated by IATA. Held in consultation with ICAO, GNC addresses key issues and technological advances related to ICAO's Future Air Navigation System. Delegates representing airlines, manufacturers, regulatory authorities and academic institutions from around the world attend this event in order to keep in touch with the latest developments concerning FANS/CNS/ATM. Global Navigation Satellite System A worldwide position, velocity, and time determination system, that include one or more satellite constellations, receivers, and system integrity monitoring, augmented as necessary to support the required navigation performance for the actual phase of operation. Global Navigation Satellite System Integrity Broad A ground based transmission which provides users with an up to date report on the functional quality and integrity of GNSS satellites and their associated signals at any given time. Global Navigation Satellite System Panel The Air Navigation Commission agreed in principle to the establishment of a GNSS Panel to address the technical and operation aspects of GNSS. The first meeting to be held by the end of 1994.

 
Global Network Addressing
An internet work addressing plan covering world-wide aeronautical operations which enables all
participating sub networks to function in a single integrated global network.
Global Network Addressing Domain
An addressing domain consisting of all the NSAP addresses in the OSI environment.