The Composition and Technical Indicators of the VSAT Satellite System

Ⅰ. What is the vsat satellite system?

VSAT is the abbreviation of VERY SMALL APERTURE TERMINAL, also known as satellite small data station (small station) or personal earth station (PES). It is 1.2-2.4M.

Using this system for communication has the characteristics of strong flexibility, high reliability, convenient use, and the small station can be directly installed on the user end. The VSAT user data terminal can be directly connected to the computer to complete communication such as data transfer, file exchange, and image transmission. mission, thereby getting rid of the problem of long-distance communication ground interruption stations. It is a good choice to use VSAT as a dedicated long-distance communication system.

Ⅱ. The composition of the vsat satellite system

The VSAT satellite communication system consists of two parts: space and ground.

The space part of the VSAT satellite communication system is the satellite, which generally uses a geostationary orbit communication satellite, and the satellite can work in different frequency bands, such as C, ku and Ka frequency bands. The transmitting power of the transponder on the star should be as large as possible, so that the antenna size of the VSAT ground terminal should be as small as possible.

The ground part of the vsat satellite system consists of a central station, a remote station and a network control unit. The role of the central station is to collect data from the satellite and then distribute the data to each remote station. The remote station is the main body of the satellite communication network. VSAT The satellite communication network is composed of many remote stations, the more these stations, the lower the cost shared by each station.

Generally, the remote station is directly installed at the user and connected to the user's terminal equipment.

Ⅲ. Technical indicators of vsat satellite system

1. System parameters

Outgoing carrier frequency: information rate 512KBPS, 12FEC, BPSK modulation, time division multiplexing (TDM).

Inward carrier frequency: information rate 128KBPS, 12FEC, BPSK modulation method, frequency division multiple access, time division multiple access hybrid method (FDMA TDMA).

Bit error rate: less than 1×10-7 when EB No>6.5dB.

2. Data communication

Rate: asynchronous: 75-19.2kbps;

Synchronization: (using interface protocol) 1.2-56kbps;

Sync: 1.2-65kbps;

Procedures: SDLC, X.25, BITT;

Electrical interface: master station: RS-232C, RS-449, V35 (DTE, DCE are available);

Small station: RS-232C (DCE);

Circuit connection mode: point-to-point connection, point-to-multipoint connection.

3. Voice communication

Using RELP (Residual Excited Linear Prediction) coding.

Interface: master station: private branch exchange (PABX) - four-wire E8M

Small station: telephone DTME, line loop signal, RJ11 connector private branch exchange (PABX) - four-wire E8M

4. Fax

In-band analog (G3), baseband (G3 or G4).

5. Small station configuration

Standard configuration: One data port (RS-232C).

Extended configuration: three data ports or one data port and one voice port.

6. Small station working environment

Temperature: indoor unit 10-40°C;

Outdoor unit -30-50℃;

Power supply: 220±10%, 50HZ;

Power consumption is about: 400W.