G

G/T

Antenna gain-to-noise-temperature (G/T) is a figure of merit in the characterization of antenna performance, where G is the antenna gain in decibels at the receive frequency, and T is the equivalent noise temperature of the receiving system in kelvins. T is the summation of the antenna noise temperature and the RF chain noise temperature from the antenna terminals to the receiver output. Satellite antenna aperture is closely related to quality factor（G/T value）of earth station. G/T value and satellite power demand, i.e. equivalent rent bandwidth, show logarithmic linear relationship. In other words, the value of equivalent rent bandwidth increases with the narrowing of antenna aperture. Therefore, when selecting earth station aperture, it is not the smaller, the better.

View Source: https://en.wikipedia.org/wiki/Antenna_gain-to-noise-temperature

Gain-to-noise-temperature

Antenna gain-to-noise-temperature (G/T) is a figure of merit in the characterization of antenna performance, where G is the antenna gain in decibels at the receive frequency, and T is the equivalent noise temperature of the receiving system in kelvins. T is the summation of the antenna noise temperature and the RF chain noise temperature from the antenna terminals to the receiver output. Satellite antenna aperture is closely related to quality factor（G/T value）of earth station. G/T value and satellite power demand, i.e. equivalent rent bandwidth, show logarithmic linear relationship. In other words, the value of equivalent rent bandwidth increases with the narrowing of antenna aperture. Therefore, when selecting earth station aperture, it is not the smaller, the better.

View Source: https://en.wikipedia.org/wiki/Antenna_gain-to-noise-temperature

Galileo

Galileo is the global navigation satellite system (GNSS) that is currently being created by the European Union (EU) and the European Space Agency (ESA). The €5 billion project is named after the Italian astronomer Galileo Galilei. One of the aims of Galileo is to provide an indigenous alternative high-precision positioning system upon which European nations can rely, independently from the Russian GLONASS and US GPS systems, in case they were disabled by their operators. The use of basic (low-precision) Galileo services will be free and open to everyone. The high-precision capabilities will be available for paying commercial users. Galileo is intended to provide horizontal and vertical position measurements within 1-metre precision, and better positioning services at high latitudes than other positioning systems.

View Source: http://en.wikipedia.org/wiki/Galileo_%28satellite_navigation%29

Geostationary Orbit

A special geosynchronous orbit which is circular and lying over the equator such that the satellite seems to remain stationary in the sky as seem from a location on the surface of Earth.

View Source: http://en.wikipedia.org/wiki/Geostationary_orbit

GIS

A geographic information system (GIS) is a system designed to capture, store, manipulate, analyze, manage, and present all types of spatial or geographical data.

View Source: http://education.nationalgeographic.com/education/encyclopedia/geographic-information-system-gis/?ar_a=1

GLONASS

A space-based satellite navigation system operated by the Russian Aerospace Defence Forces. It provides an alternative to Global Positioning System (GPS) and is the second alternative navigational system in operation with global coverage and of comparable precision.

View Source: http://en.wikipedia.org/wiki/GLONASS

GNSS

GNSS stands for Global Navigation Satellite System, and is the standard generic term for satellite navigation systems that provide autonomous geo-spatial positioning with global coverage. This term includes e.g. the GPS, GLONASS, Galileo, Beidou and other regional systems.

View Source: http://en.wikipedia.org/wiki/Satellite_navigation

GPRS

General packet radio service (GPRS) is a packet oriented mobile data service on the 2G and 3G cellular communication system's global system for mobile communications (GSM). GPRS was originally standardized by European Telecommunications Standards Institute (ETSI) in response to the earlier CDPD and i-mode packet-switched cellular technologies. It is now maintained by the 3rd Generation Partnership Project (3GPP). GPRS usage is typically charged based on volume of data transferred, contrasting with circuit switched data, which is usually billed per minute of connection time. Usage above the bundle cap is either charged per megabyte or disallowed.

View Source: https://en.wikipedia.org/wiki/General_Packet_Radio_Service

GPS

The Global Positioning System (GPS) is a space-based satellite navigation system that provides location and time information in all weather conditions, anywhere on or near the earth where there is an unobstructed line of sight to four or more GPS satellites. The system provides critical capabilities to military, civil, and commercial users around the world. The United States government created the system, maintains it, and makes it freely accessible to anyone with a GPS receiver.

View Source: http://en.wikipedia.org/wiki/Global_Positioning_System

Ground Station

A ground station, earth station, or earth terminal is a terrestrial radio station designed for extraplanetary telecommunication with spacecraft, or reception of radio waves from an astronomical radio source. Ground stations are located either on the surface of the Earth or in its atmosphere. Earth stations communicate with spacecraft by transmitting and receiving radio waves in the super high frequency or extremely high frequency bands (e.g., microwaves). When a ground station successfully transmits radio waves to a spacecraft (or vice versa), it establishes a telecommunications link. A principal telecommunications device of the ground station is the parabolic antenna.

View Source: http://en.wikipedia.org/wiki/Ground_station

GSM

GSM (Global System for Mobile Communications, originally Groupe Spécial Mobile), is a standard developed by the European Telecommunications Standards Institute (ETSI) to describe protocols for second-generation (2G) digital cellular networks used by mobile phones, first deployed in Finland in July 1992. As of 2014 it has become the default global standard for mobile communications - with over 90% market share, operating in over 219 countries and territories.

View Source: http://en.wikipedia.org/wiki/GSM