随着卫星导航系统的快速发展,基于低地球轨道(low earth orbit,LEO)卫星的高精度可信导航已成为当前研究的热点.然而,LEO卫星导航的安全可信问题一直阻碍其大规模应用,基于扩频码和导航电文(spreading code and navigation data based a...随着卫星导航系统的快速发展,基于低地球轨道(low earth orbit,LEO)卫星的高精度可信导航已成为当前研究的热点.然而,LEO卫星导航的安全可信问题一直阻碍其大规模应用,基于扩频码和导航电文(spreading code and navigation data based authentication proposal,SNAP)认证方案在解决上述问题中展现了良好势头.本文的重点是解决SNAP信号的间歇跟踪算法及性能分析,并得到跟踪误差的解析表达式.研究结果表明:由于间歇跟踪导致的误差累积服从高斯分布,其均值与多普勒频移变化率成正比,均方差可等价于载噪比(carrie noise ratio,CNR)的损失,相较载波环,码环受多普勒的影响较小.本文的研究结果为间歇跟踪结构下接收机系统参数设计提供重要理论参考.展开更多
To improve the robustness of the Low Earth Orbit(LEO) satellites networks and realise load balancing, a Cross-layer design and Ant-colony optimization based Load-balancing routing algorithm for LEO Satellite Networks(...To improve the robustness of the Low Earth Orbit(LEO) satellites networks and realise load balancing, a Cross-layer design and Ant-colony optimization based Load-balancing routing algorithm for LEO Satellite Networks(CAL-LSN) is proposed in this paper. In CALLSN, mobile agents are used to gather routing information actively. CAL-LSN can utilise the information of the physical layer to make routing decision during the route construction phase. In order to achieve load balancing, CALLSN makes use of a multi-objective optimization model. Meanwhile, how to take the value of some key parameters is discussed while designing the algorithm so as to improve the reliability. The performance is measured by the packet delivery rate, the end-to-end delay, the link utilization and delay jitter. Simulation results show that CAL-LSN performs well in balancing traffic load and increasing the packet delivery rate. Meanwhile, the end-to-end delay and delay jitter performance can meet the requirement of video transmission.展开更多
文摘随着卫星导航系统的快速发展,基于低地球轨道(low earth orbit,LEO)卫星的高精度可信导航已成为当前研究的热点.然而,LEO卫星导航的安全可信问题一直阻碍其大规模应用,基于扩频码和导航电文(spreading code and navigation data based authentication proposal,SNAP)认证方案在解决上述问题中展现了良好势头.本文的重点是解决SNAP信号的间歇跟踪算法及性能分析,并得到跟踪误差的解析表达式.研究结果表明:由于间歇跟踪导致的误差累积服从高斯分布,其均值与多普勒频移变化率成正比,均方差可等价于载噪比(carrie noise ratio,CNR)的损失,相较载波环,码环受多普勒的影响较小.本文的研究结果为间歇跟踪结构下接收机系统参数设计提供重要理论参考.
基金supported by the National Natural Science Foundation of China under Grant No.61271281the National High Technology Research and Development Program of China (863 Program) under Grant No.SS2013AA010503
文摘To improve the robustness of the Low Earth Orbit(LEO) satellites networks and realise load balancing, a Cross-layer design and Ant-colony optimization based Load-balancing routing algorithm for LEO Satellite Networks(CAL-LSN) is proposed in this paper. In CALLSN, mobile agents are used to gather routing information actively. CAL-LSN can utilise the information of the physical layer to make routing decision during the route construction phase. In order to achieve load balancing, CALLSN makes use of a multi-objective optimization model. Meanwhile, how to take the value of some key parameters is discussed while designing the algorithm so as to improve the reliability. The performance is measured by the packet delivery rate, the end-to-end delay, the link utilization and delay jitter. Simulation results show that CAL-LSN performs well in balancing traffic load and increasing the packet delivery rate. Meanwhile, the end-to-end delay and delay jitter performance can meet the requirement of video transmission.
