基于FPGA的CCSDS图像数据压缩系统的设计

针对CCSDS图像数据压缩(IDC)标准,提出了一种基于FPGA的CCSDS IDC并行实现方案.该方案包括离散小波变换(DWT)、直流系数量化编码、位平面编码(BPE)、码字拼接等4个模块.位平面编码模块采用了并行扫描、并行编码的快速算法,以提高编码速度.仿真结果表明了本方案的可行性和有效性,处理时间比现有的CCSDS IDC串行编码改进方法减少了13.6%,适用于空间通信的图像数据压缩编码.     

长三角制造业高级化测度及其影响因素分析

基于传统产业升级理论提出"制造业高级化"概念,并从制造业结构优度和价值链高度两个维度构建制造业高级化指数。对长三角制造业高级化的测度结果显示,上海、江苏、浙江制造业高级化程度正在逐渐提高。以制造业高级化指数为因变量,以对外贸易依存度、市场化程度、人力资源素质和经济发展阶段为自变量,建立多元线性回归模型,分析各因素对制造业高级化的影响。研究结果表明,依靠外向型、依靠投资驱动尤其是政府投资驱动的经济发展方式,对制造业高级化的作用有限;人力资源素质的提高是制造业高级化的关键驱动因素。在此基础上从研发投入、人才培养、品牌战略等方面分析了推进制造业高级化的相关政策。     

Observer-based sliding mode control for a class of discrete systems via delta operator approach

In this paper, an observer-based sliding mode control (SMC) problem is investigated for a class of uncertain delta operator systems with nonlinear exogenous disturbance. A novel robust stability condition is obtained for a sliding mode dynamics by using Lyapunov theory in delta domain. Based on a designed sliding mode observer, a sliding mode controller is synthesized by employing SMC theory combined with reaching law technique. The robust asymptotical stability problem is also discussed for the closed-loop system composed of the observer dynamics and the state estimation error dynamics. Furthermore, the reachability of sliding surfaces is also investigated in state-estimate space and estimation error space, respectively. Finally, a numerical example is given to illustrate the feasibility and effectiveness of the developed method.     

深空探测VLBI测量技术

深空探测活动离不开深空测控网的支持,但是,现有航天测控系统不能满足深空探测工程的需求。VLBI测量技术测量精度高,定轨时间短,是一种很好的深空测量方法。文章讨论了VLBI的概念和差分VLBI的基本原理,VLBI的定位体制及角度测量的变换,详细分析了差分VLBI的测量精度,并展望了ΔVLBI在我国未来深空探测中的应用前景。