Low-orbit satellite communication system Globalstar

System Globalstar established to provide global mobile and fixed communication, we have many years of trouble-free operations and use the latest advances in telecommunications technology. System for mobile satellite communication Globalstar was commissioned in 1999 and has more than 275 thousand subscribers in more than 120 countries. The owner of the Globalstar satellite communications system is the same Globalstar L.P. company - international consortium created by the Corporation LoralSpace & Communications (New-York) and Qualcomm (San Diego), which was established in 1991.

The space segment

The space segment is a constellation of 48 low-earth-orbit satellites that provide coverage to almost the entire surface of the Earth between 74° North and South latitude.

The original specifications satellite fleet Globalstar presented in the table:

The satellite consists of antenna, trapezoidal enclosure, two solar panels and magnetometer.The launch of the satellites grouping Globalstar was carried out boosters "Delta II" (USA) and “Soyuz-Ikar" (Russia). The runs were carried out from Kennedy Center in Florida and from the Baikonur cosmodrome in Kazakhstan.

The principle of operation the mobile satellite communication system Globalstar is presented in figure.

 Like the repeater, Globalstar fleet with 48 low-earth-orbit (LEO) satellites, raises aboard signals with 80 % of the Earth's surface, except for the extreme polar regions and some mid-ocean areas. Several satellites accept the call and transmit it to the nearest ground gateway. This diversity path signal transmission ensures the fact that the request is not lost, even if the phone is in the range from one satellite to another. After that, on earth gateway the signal is processed with all these satellites and choose the best. If a building or landscape block your phone signal on one of satellites, the ground station selects another best signal from another satellite. This "soft-handoff" prevents interruption of the call and thus, the second satellite now supports the transmission of the initial signal-to-earth "gateways".

Ground segment

Ground segment system Globalstar consists of the centers of the spacecraft control, link control, network of regional land nodal stations mates and data network.

Ground Station Pair (SP) are used for radio access system users Globalstar to the centers of the switching system for establishing communication between the subscribers and to subscribers of satellite and ground-based fixed and mobile networks, the operator of which is interconnectivity.

Ground control centers (GCE) are responsible for the planning and management of satellites with terminal stations mates and for coordination with Control Centers satellites (NMC). NCU plan to graphics communications for stations mate (SS), as well as control the allocation of satellite resources of each SS.

The control center satellite segment (CCSS) monitors the satellite system. Together with the tools backup Center, he produces the control of the orbits, the processing of the telemetry data and issue commands on a satellite constellation. The satellites of the Globalstar system continuously transmit telemetry data, monitoring the reliability of the system, as well as information about the General condition of the satellites. The center also tracks the satellites and their deployment in space. NMC, NCU keep in constant contact via the data network Globalstar.

Data network Globalstar - connective network, which provides an internal connection between the SP, GCE and CCSS.

The user segment

Globalstar has combined the latest advances in the field of communication technologies to create a user equipment of new generation, which fully meet the modern requirements. The combination of low-orbit satellite communication systems and vast experience of companies of Qualcomm, Telit, Ericsson - equipment manufacturers - have been formed, compact, easy to use research and providing good quality satellite telephones. Created by partners Globalstar perfect equipment meets the most demanding users.

The Globalstar system was formed as a system intended to provide mobile communications in areas where there is no or underdeveloped cellular communication, as the addition and expansion of capacity and coverage of cellular networks, as well as for stationary communication in remote areas with low population density, where inefficient infrastructure of a public network.

Globalstar subscribers are business and individuals working in areas that are not covered by cellular networks, or the specifics of the work, which involves frequent business trips. This is a very broad audience: media, geologists, employees of oil and gas engineers builders and all those who work in the field. Power structures of different countries can also use satellite communications Globalstar its activities.

Special kits for installation on vehicles can be effective when used on commercial vehicles, both domestically and abroad, on fishing and other marine and river vessels, railway transport, cargo protection and control routes and all kinds of transportation.

In Kazakhstan, with the current low population density, the development of mobile satellite communications for voice and data transmission at any point, is extremely important. In economically developing regions of the world recognized the fact that modern telecommunications are crucial fundamental state, industrial and social development, in the sense that it is not the welfare provides an increase in the density of the telephone network and the telephone network density create wealth. There is no doubt that the development of a global satellite communications system Globalstar in Kazakhstan will allow to accelerate the development of other industries in the country.

The system uses the user terminals of several types:

• portable satellite phones, same cell phones and compatible with GSM, CDMA;

• fixed user terminals connecting hubs and payphones for remote sites where there are no terrestrial communications;

• Satellite modems for conventional and high-speed data transmission;

• mobile kits installed on a mobile or stationary device for the implementation of monitoring systems and telematics.