Articles by St. D. Ilcev

The first generation of satellite standard of DVB-S known as Digital Video Broadcasting-Return Channel via Satellite (DVB-RCS) about ten years ago quickly became around the globe one of the key solutions in almost every new satellite communication project for broadcast, broadband and multimedia interactive applications including high-speed Internet. The second generation of DVB-S2 CCM (Constant Coding Modulation) standard was presented a few years ago as a new more cost effective, efficient, reliable, secure and functional solution. The DVB-S2 CCM can be upgraded and cost less than the third generation of DVB-S2 ACM (Adaptive Coded Modulation) platform, forward and reverse compatible. In this article will be introduced the latest DVB-S2 Space and Ground segments, respectively, for interactive transmission of Voice, Data and Video (VDV) over IP (VDVoIP). The Ground Segment will be represented by HUB as GES (Ground Earth Station) and VSAT equipment known Satellite Interactive Terminal (SIT) or Remotes, compliant to all DVB-RCS standards for civilian and military solutions.

The communication Mobile Satellite Antenna (MSA) for transport applications are relatively large and heavy, especially the airborne High Gain Antenna (HGA) system for Inmarsat-H and High Speed Data (HSD) Aircraft Earth Stations (AES). Thus, over the past decade the steering airborne antenna system, which comprises the mechanical assembly, the control electronic system, the microwave electronic package and the antenna assembly (arrays and steering elements), has been reduced considerably in both physical size and weight. These reductions brought about by greater Effective Isotropic Radiated Power (EIRP) from satellite transponders coupled with GaAs-FET technology at the front end the receiver leading to higher G/N RF amplifiers, have made initially the fitting of shipborne antennas on tracks, locomotives and airplanes a reality. A little later airborne and vehicle borne MSA were developed on the basis of these shipborne antennas. The MSA systems are always required to be pointed towards the satellite in spite of mobile motions. Namely, the mount system is one of the main requirements in designing the MSA systems from the technical and rational viewpoints. The several types of mount system are used: such as mechanical, electrical and other, especially those concerned with shipborne MSA. Whereas, in the case of airborne and vehicleborne MSA, electrical pointing systems are preferable.

A Mobile Satellite Communications (MSC) system is radio-relay station temporarily located at determined position in space (approximately between 20 and 36,000 km) to receive RF signals from different Mobile Earth Stations (MES), amplify the signals and transmit them back to Land Earth Stations (LES), which are connected to the ground telecommunication infrastructure. To provide those all functions in order satellite has to be equipped with adequate subsystems integrated by payload and bus. The payload is usually located inside of satellite body, which contains the transponder or transceiver system (satellite receivers and transmitters). The transponder is also connected to the receiving and transmitting antenna system, which are mounted outside on the satellite body. Therefore, each satellite must be stabilized in its orbital slot, which has to counteract the forces acting on the satellite motion and to keep the antennas of a satellite constantly pointing to a specific footprint of the Earth.