利用iHCO通信卫星实现导航通信的关键技术研究

A Geostationary Earth Orbit (GEO) communication satellite is considered as being in end-of-life when it remains about one-year fuel. The satellite company will launch a new satellite to replace the end-of-life one for service. According to the international practice, the satellite in end-of-life will be pushed into the graveyard orbit which is more than 300 kilometers above GEO. In that orbit, the fuel of the satellite is emptied, the payload and power are closed. The satellite becomes the space junk. Here this kind of communication satellite is pushed into the inclined Highly Circular Orbit (iHCO) with about 200 kilometers, the satellite will slowly drift west relative to the Earth, around a circle with about 100 days. If we uplink the signal to the satellite, the user can navigation and communication can be achieved in coverage area, combined with GEO satellite constellation. The aboard fuel can be completely exhausted, and full-life utilization of communication satellite can be realized. Key technology of navigation and communication using iHCO communication satellites, including three aspects of the content of iHCO satellite constellation optimization, the network optimization of global control and monitor, and iHCO communication satellite application. Based on regional navigation system with GEO communication satellite, a navigation and communication constellation with iHCO satellites can play a significant role in the development of communication satellite navigation.

通常情况下，地球同步轨道(GEO)通信卫星剩余一年左右的燃料时即进入寿命末期，卫星公司会发射新卫星接替原卫星业务。按照国际惯例，这种寿命末期卫星被推至比GEO轨道高300公里以上的坟墓轨道，排空燃料，关闭有效载荷及电源，成为空间垃圾。如果把这类通信卫星推至比地球同步轨道高约200千米的倾斜高圆轨道(iHCO)，卫星相对地球缓慢向西漂移，大约100天绕地球一圈，在此期间对iHCO卫星上行信号，结合已部署的GEO通信卫星星座，用户可以在覆盖区域内实现导航通信。iHCO卫星可以工作到燃料彻底用尽，实现通信卫星的全寿命周期利用。本项目重点研究利用iHCO通信卫星实现导航通信的关键技术，包括iHCO卫星优化导航通信星座、全球测控组网优化、iHCO卫星导航通信应用等三方面内容。在利用GEO通信卫星实现区域导航系统的基础上，利用iHCO通信卫星组建导航通信星座，对通信卫星导航发展有重要意义。

把地球同步轨道通信卫星推高约300千米得到iHCO卫星，利用该类卫星可以实现全球导航通信。利用iHCO卫星可以解决卫星导航通信频率拥挤的局面，开创通信全频段导航全球应用的新局面。同时，卫星可以工作到燃料彻底用尽，实现通信卫星的全寿命周期利用。结合iHCO卫星的运动规律和波束覆盖，本项目重点研究利用iHCO卫星实现导航通信的关键技术，构建基于iHCO卫星的全球导航通信系统。主要研究内容包括（1）iHCO轨道优化研究、（2）iHCO卫星导航通信星座优化研究、（3）iHCO卫星全球测控组网研究、（4）iHCO卫星导航通信的优化利用等四个方面。通过本项目的研究，得到优化的iHCO轨道、优化的iHCO导航通信星座、全球测控组网方案。在项目执行期内，共发表科研论文20篇，申报发明专利8项，申报软件著作权6项，撰写内部技术报告8项。