Shevchenko I.V., Mitikov U.A., Timoshenko Zh. I.
Oles Honchar Dnipropetrovsk National University
SPACE SYSTEM OF COMMUNICATION
At present the growth of information is the characteristic in all spheres of a man activity. Besides the development of traditional facilities of information (telephonies, telegraphies, broadcasts) transfer there was a requirement in creating its new kinds – television, exchange by data in automatic control system and computer, transmissions of matrices for printing of newspapers etc.
Global character of economic problems and scientific researches, wide intergovernmental integration and co-operation, in production, trade, research activity, expansion over of exchange in the area of culture were brought to the considerable increase of international and intercontinental connections, including an exchange of telecasts. Building the distant surface and submarine cable lines requires the enormous expenses of all types of resources. Considerably by a greater carrying capacity, distance of action, for the different types of connection a radio contact the disposes possibility of alteration. However radio link possess certain defects, hampering their application in many cases. The new ways of overcoming peculiar to the distant radio contact defects opened starts SV on the orbits of artificial companions of Earth and creation on their basis of the space system of connection.
A space communication network is intended for providing all types of telecommunication (intertown, international, intercontinental), broadcasting and teletranslations, information transfer in the network of Internet etc.
Practice confirmed that the use of SV for connection in particular distant international and intercontinental, television and telecontrol, at the transmission of large volumes of information allows to remove many difficulties peculiar to the traditional radio contact. The use of the passive or active retransmitting is thus possible.
In spite of obvious simplicity, cheapness and certain technical dignities of such а space communication (possibility of simultaneous work of a large number of correspondents, dependence of quality of connection only on a reflectivity SV), it has serious defects. In particular, 12 for maintenance of steady connection large power of transmitter and high sensitiveness of surface takers-offs are required. But even at implementation of these terms radio links work steadily not enough, with large hindrances. In addition, the term of active existence of such SV because of change of their form and worsening reflecting properties appeared small. Therefore principle of passive reflection did not find further development in space communication networks.
Became firmly established and got wide distribution principle of the use SV connections with the active retransmitting. Devices treatments (by filters), purging an useful signal from hindrances.
Principle of space-communication with the active retransmitting inggests setting on SV corresponding aerials, receiving and transmitting devices, and also sources of feed. It allows substantially to decrease power of transmitter and sensitiveness of surface takers-offs. One of key is a question about the parameters of orbits SV.
The use of а space communication allowed to accomplish a quality jump in organization of connection. So, mobile communication which recently seem so exotic firmly entered the life and became accessible to million people during only one decade. The development of а space communication will be directed to the further providing global steady and continuous connection of subscribers of different level, the increase of carrying capacity of communication and organization of multilevel telecommunication spaces networks.