Analysis of Shipborne Satcom System

Satcom VSAT ship earth stations can complete two-way transmission tasks of voice, tactical data, command telegram, and image, or receive broadcast information. According to the requirements of information transmission and the different missions of ship communication, there are differences in configuration scale and complexity. According to the different frequency bands used, they can be divided into UHF shipborne stations, SMF shipborne stations, EHF shipborne stations, and L-band shipborne stations.

Compared with other communication systems, the advantages of shipborne satellite earth stations are: long communication distance, able to communicate with anywhere within the effective coverage of satellite beams; can achieve global communication by relaying between satcoms; high reliability and can be used as all-weather communication means.

The biggest difference between shipborne satellite earth stations and other fixed ground satellite earth stations is that the antenna of shipborne stations must constantly track the satellite. Because the antenna base is fixed on the ship structure, and the antenna will move with the ship's pitching, rolling, and yawing, the antenna of shipborne earth stations must have the ability to track the satellite quickly.

In addition, due to the limited carrying capacity and space of ships, the volume of shipborne satellite earth station antennas is generally smaller.

Product introduction and application of shipborne satcom system

The shipborne satcom system adopts completely independent intellectual property rights of software radio technology, which can support networking methods such as SCPC/FDMA, TDMA and CDMA. It has the characteristics of low working threshold, fast synchronization, high transmission efficiency, and high-speed burst.

In addition to conventional shipborne satcom, it is particularly suitable for concealed communication such as submarines. The communication terminal is highly integrated and has multiple secure machine interfaces.

The main features of shipborne satcom system

• Completely independent intellectual property rights: safe and reliable. All design and engineering are self-developed, using software radio technology, and mastering all technical details, which can be adaptively modified for applications.

• Low working threshold: about 2dB lower than domestic competitors. The volume and weight of the airborne satcom system have strict requirements for the antenna. The low threshold can reduce the power amplifier power or reduce the antenna aperture. Under the same conditions, the lower the demodulation threshold, the more residual links and the higher the reliability. That is, in remote areas with poor satellite coverage, the system has stronger availability; or higher data transmission rate and larger channel capacity.

• High spectrum utilization: the filter roll-off coefficient is 0.15, while other domestic products are 0.4 or 0.5, saving resources of shipborne satcom systems.

• Low power spectral density: low threshold means low transmission power and low power spectral density. It can also further reduce the power spectral density through spread spectrum to prevent adjacent satellite interference and increase system availability.