Up In The Air

A very-small-aperture terminal (VSAT) is a two-way satellite ground station, a terminal station designed for extraplanetary communication with spacecraft, or reception of radio waves from an astronomical radio source, that has been placed into orbit by human endeavour. It could also be a stabilized maritime VSAT antenna, satellite communication through a VSAT on a ship at sea, with a dish antenna, a dish-shaped type of parabolic antenna designed to receive microwaves from communications satellites, which transmit data transmissions or broadcasts, such as satellite television, that is smaller than three meters. 

The majority of VSAT antennas range from 75 cm to 1.2 m. Data rates typically range from 56 kbit/s up to 4 Mbit/s. Its access satellite(s) in geosynchronous orbit (sometimes abbreviated GSO), an orbit around the Earth with an orbital period of one sidereal day (approximately 23 hours 56 minutes and four seconds), matching the Earth’s sidereal rotation period, to relay data from small remote earth station (terminals) to other terminals (in mesh topology, a type of networking where each node must not only capture and disseminate its own data, but also serves as a “relay” for other nodes, that is, it must collaborate to propagate the data in the network) or master earth station “hubs” (in star topology). 

VSATs are most commonly used to transmit narrowband data, which in radio, describes a channel in which the bandwidth of the message does not significantly exceed the channel’s coherence bandwidth. It could be the point of sale (POS)/point of purchase (POP), or checkout transactions, the location where a transaction occurs, such as: credit card; polling or Radio-Frequency Identification (RFID) data, the use of a wireless non-contact system that uses radio-frequency electromagnetic fields to transfer data from a tag attached to an object, for the purposes of automatic identification and tracking; or SCADA (supervisory control and data acquisition). SCADA generally refers to industrial control systems (ICS): computer systems that monitor and control industrial, infrastructure, or facility-based processes. The facility-based processes could be described as: industrial processes, which include those of manufacturing, production, power generation, fabrication, and refining, and may run in continuous, batch, repetitive, or discrete modes; infrastructure processes may be public or private, and include water treatment and distribution, wastewater collection and treatment, oil and gas pipelines, electrical power transmission and distribution, wind farms, civil defense siren systems, and large communication systems; and facility processes, occurring both in public facilities and private ones, including buildings airports, ships, and space stations. 

VSATs are also used to transmit broadband data, referring to a telecommunications signal or device of greater bandwidth, in some sense, than another standard or usual signal or device (and the broader the band, the greater the capacity for traffic. It is for the provision of satellite Internet access—Internet access provided through satellites—to remote locations, Voice over IP (VOIP; commonly referring to the communication protocols, technologies, methodologies, and transmission techniques involved in the delivery of voice communication and multimedia sessions over Internet Protocol (IP) networks, such as the Internet) or video. 

VSATs can also be for transportable, on-the-move (utilizing phased array antennas, which in antenna theory, is an array of antennas in which the relative phases of the respective signals feeding the antennas are varied in such a way that the effective radiation pattern of the array is reinforced in a desired direction and suppressed in undesired directions) or mobile maritime communication.

See: Strategic Defense Intiative’s Other Sensor Program Experiments