Study of a limit in the Space Collaboration System

为了保证校际卫星网络（空间协同系统）运行的稳定性和可扩展性，给出了系统控制设备的规格限制，并提出了扩展规格。发射站切换时间的测量显示，与现有VSAT号的切换操作在6.5秒内完成。通信信号采用开槽aloha方式控制，定时安排不与突发信号发生碰撞，以控制载波。增加参与站会导致启动会话时出现问题。同时，会话信息从HUB站传输到VSAT站。增加台站需要大量的时间来发送数据，并且会导致人员配置时间的延迟。解决这一问题的方法之一是在现有系统中增加带内信号。雨水衰减特性是通过接收卫星信标信号来测量的，以检查由于雨水衰减对链路质量的影响。我们观察到0.25mm/m的功率衰减为2dB。但通过接收卫星遥测信号，预计降雨衰减不会造成前馈上余量大于10dB的残缺物。SOS扩展的主要要求是远程操作。这是因为学校每个校区只有一个VSAT站，由于空间不足，SOS设备通常安装在演讲室或会议室。这种情况造成了由SOS共享房间的预订冲突，因此即使应答器信道可用，SOS也不能经常使用。为了解决这个问题，需要在不同的房间使用SOS进行远程操作，这是通过音频和视频信号的传输以及通道控制系统的远程控制来完成的。我们讨论了三种远程链接控制方法：(1)触摸面板方法，(2)窗口共享方法，(3)WWW方法。由于其广泛性和灵活性，我们选择了WWW方法，并将其安装到SOS上。音视频的传播需要根据现有设备和所要求的质量合理选择媒介，如同轴电缆、光纤、无线系统、综合业务数字网等。我们在国际论坛上评估了SOS远程操作的可用性。少

To make stability and extension of operation on the inter-university satellite network (Space Collaboration System : SCS), we provide specification limit of the system control equipment and propose specification of the extension. The measurement of switching time of transmitting station shows the operation with the present VSAT number switching them Within 6.5 sec. The communication signal is controlled with slotted aloha method, and the timing is arranged not to collide the burst signals for controlling carriers. Increasing participant stations causes problems in starting the session. At the time, the session information is transferred from a HUB station to VSAT stations. Increasing the stations requires much time to send the data, and it causes delay of the staffing time. One of solution for this problem is to add in-band to the present system.Rain attenuation characteristic is measured by receiving a satellite beacon signal to check effect for link quality due to the rain attenuatio … More ns. We observed power attenuation of 2dB for 0.25mm/m. But it is expected that the rain attenuation does not cause disabled things with margin over 10dB on AGO by receiving a satellite telemetry signal.The primary requirement of the SOS extension is remote operation. This is based on the reason that Each campus has only one VSAT station in the university, and the SOS facilities have been installed usually in a lecture room or meeting room because of lack of space. This situation has caused collision of reservations for the room shared by the SCS, so the SOS could not be used very often even though the transponder channel was available. To solve this problem required a remote operation by using the SOS in a different room from where it was installed, This was accomplished by the transfer of audio and video signals and the remote control of the channel control system. We discuss three methods of the remote link control : (l)Touch Panel Method, (2) Window-Share Method, (3) WWW Method. We selected the WWW Method due to the extensity and flexibility, and installed it to the SOS.Distribution of audio and video need reasonable choice of media for the present equipment and required quality, such as coaxial cable, optical fiber, wireless system, and ISDN.We evaluated the usability of remote operation of the SOS in the international forum. Less