Very small aperture terminal is used for receiving and transmitting information such as narrowband data, Radio Frequency Identification (RFID) data, and Supervisory Control and Data Acquisition (SCADA). It is named after a relatively small dish-shaped antenna with a diameter not exceeding 10 feet (3 meters). VSATs are commonly used for commercial purposes such as transmitting credit card data and providing companies with stable communication infrastructure.
Data is usually transmitted from a network hub to a satellite following a typical orbit. When the satellites are near the ground stations, they transfer the data to the earth. Transmitted data usually varies between 56 Kbits/s and 4 Mbits/s. VSATs then use the transceiver to receive the data, which is interpreted for the end-user.
Small aperture terminals are used as miniature communication antennas capable of interacting with other Very Small Aperture Terminals (VSAT). They also act as bidirectional satellite ground stations and relay information back to orbiting satellites. This allows real-time communication between end-users and hubs.
Remote areas such as offshore oil rigs or places where telephone lines cannot reach frequently use small aperture terminals to access external communication. Maritime communication, such as very small aperture terminals installed on ships, is often more complex. Since ships are not stationary, terminals need to constantly adjust their configuration to align with satellites.
The average very small aperture terminal size ranges from 34 inches (75 centimeters) to 3.93 feet (1.2 meters), making it highly portable. Setting up a small aperture terminal is straightforward and takes only a few minutes from assembly to operation. The cost of a single terminal is much cheaper than traditional satellite antennas. This makes it ideal for locations where installing large satellite antennas is difficult.
Very small aperture terminal uses a dedicated second-layer network to transfer data, making security one of its advantages. Broadband data can be transmitted using protocol accelerators on the antenna. However, signal strength and dish size still affect transmission quality.
The topology layout of a small aperture terminal configuration system is usually divided into three types. The star topology uses satellites to send data to terminals. The mesh topology uses strategically separated systems for terminals to pass data from hubs to end-users. On the other hand, a combination topology effectively increases network coverage by using stars and mesh layouts by having satellites transmit data to VSAT grids.