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SpecialIntroduction of GSN (Ground Station Network) working groupOrganizationGSN is the woking group organized by University Space Engineering Consortium (UNISEC) which is a non-profitable orbanization to support practical space development activities in universities and collages. GSN has been active to construct a network-based ground station system for satellites operation.
Figure: participating universities and collages (as of April 2008)
BackgroundRecently, university or collage students in some countries are developing a handmade satellite called "cubesat". In this kind of project, sending commands and receiving telemetry to satellites are executed by using their own ground stations installed in universities or collages. The ground station consists of usual amateur radio equipment, antenna rotors for pointing to a satellite, and packet communication devices.
Figure (left): CubeSat XI-IV, developed by The University of Tokyo, launched in June 2003, still operational Figure (right): Sugadaira GSN station, installed in Sugadaira Space Radio Observatory organized by The University of Electro-Communications ObjectiveThe objective of GSN-WG is to construct a network-based ground station system for satellites operation. Adding the function of remote control via the Internet to the similar ground stations in all the world, satellites can be operated under the cooperation of world ground stations. Expected meritsIncreasing the communication timeIn case of a low-earth-orbit satellite, the altitude is about 800 km, and the orbital period is only 100 minutes. So, the time, which a single ground station can communicate with a satellite, is only 10 minutes per single pass, and it is only 40 minutes per day. Using the plural ground stations installed in the world, more communication time can be obtained and the possibility of missions will be extended. Using the substitution station quicklyBy equipment trouble and bad weather conditions, the situation to unexpectedly bump into poor satellite communication happens frequently. Especially in a big city, illegal radio communications often interrupts satellite communications. In this kind of bad situation, an other ground station can quickly substitute. Constructing the collaborative relationshipThe merits will be also generated when the non-remote or manual control of ground station. When a satellite is firstly tracked just after the launch, members in each station manually control their ground station to find the satellite, and the information is reported to the host organization when the telemetry including initial conditions can be received. Also, when an operating satellite have some unknown troubles, more information for the trouble shooting can be collected. It is the great merit to construct the collaborative relationship among people engaging in satellite operations. History of activities
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