| dc.description.abstract | Because of the rapid growth of satellite services and congestion of lower frequencies bands, more and more commercial applications are being promoted for Ka-Band. In order to develop the emerging technology of space research and related applications, the first scientific satellite of Taiwan, ROCSAT-1, which has been launched on 1/27/1999. However for the direct broadcast experiment of digital TV signals, there are two important problems which we must understand at first. One is the characteristic of LEO satellite and the other is the characteristic of Ka-Band channel. For LEO satellites, systems at low elevation angle suffer not only large free space loss but also great tropospheric losses, such as rain attenuation, tropospheric scintillation, cloud attenuation, gas absorption, and so on, especially in Ka-Band channel. An evaluation of procedure that combines overall propagation impairments and the tracking of LEO ROCSAT-1 is built for our simulation system.
For having the better performance, a combined scheme of two-site diversity and robust coding system is used. The simulation results show that we can have longer available link time and less bit error probability by using this technique. By the analysis of LEO satellites, Ka-Band channel and improved methods of system performance, we will have more understanding on the characteristics of ROCSAT-1 ECP system. Finally, we present an effective plan for the future experiment. | en_US |