我国深空测控设备的发展途径探索

深空测控通信是目前航天测控通信领域中难度最大、技术最尖端的部分,而深空探测将是下世纪继续升温的世界性的航天热点。本文讨论了我国深空探测的必要性,重点从深空测控设备的角度出发,讨论了月球探测中针对ＵＳＢ设备的改造方案以及从长远和发展的眼光出发、针对火星探测的深空测控设备方案和发展方向。     

基于CBR和RBR的航天测控设备故障诊断专家系统

采用CBR和RBR混合推理设计了航天测控设备故障诊断专家系统，建立了系统的层次诊断结构模型。介绍了产生式和基于案例的知识表示方法，并详述了系统所采用的基于规则和基于案例的诊断推理机制。最后，基于CLIPS和Visual C 混合编程的方法进行了系统实现，详细介绍了两种语言的嵌入设计。     

基于地面测量的卫星导航系统时间同步技术研究

根据卫星导航系统地面观测数据的特点,建立了站间和星地时间同步的状态空间方程和量测方程,设计了序列Kalman滤波算法,综合利用时间同步观测数据及伪距观测数据,求解出监测站及导航卫星钟差。通过仿真计算表明,本文所建立的模型及设计的序列Kalman滤波算法,提高了卫星导航系统站间和星地时间同步的精度,具有一定的应用价值。     

Time delay compensation in lateral-directional flight control systems at high angles of attack

The previous studies of time delay compensation in flight control systems are all based on the conventional aerodynamic derivative model and conducted in longitudinal motions at low angles of attack. In this investigation, the effects of time delay on the lateral-directional stability augmentation system in high-α regime are discussed based on the $\dot{\beta }$ model, which is proposed in our previous work and proved as a more accurate aerodynamic model to reveal the lateral-directional unsteady aerodynamic characteristics at high angles of attack. Both the $\dot{\beta }$ model and the quasi-steady model are used for simulating the effects of time delay on the flying qualities in high-α maneuvers. The comparison between the simulation results shows that the flying qualities are much more sensitive to the mismatch of feedback gains than the state errors caused by time delay. Then a typical adaptive controller based on the conventional dynamic derivative model and a gain-prediction compensator based on $\dot{\beta }$ model are designed to address the time delay in different maneuvers. The simulation results show that the gain-prediction compensator is much simpler and more efficient at high angles of attack. Finally, the gain-prediction compensator is combined with a linearized $\dot{\beta }$ model reference adaptive controller to compensate the adverse effects of very large time delay, which exhibits excellent performance when addressing the extreme conditions at high angles of attack.     

RS码的时域编码频域译码技术

通过对于RS码的时域编码／频域译码的算法进行分析,找到了它们的不同之处及转换方法,得出了时域编码／频域译码的混合编译码方法,提高了运算速度和纠错能力。