交通流特性参数的识别与测量

提出一种用于交通流管理控制系统中交通流特性参数自动检测的新办法 ,介绍该方法的基本原理、识别模型及据此方法研制成功的在线实时智能检测系统的实验结果。这个系统较好地应用了模式识别技术 ,故不仅能自动区分机动车与非机动车 ,判别车型 ,准确地检测出机动车流特性参数 ,而且能自动准确地检测出非机动车 (自行车 )群体流量。此系统样机现场连续运行 3年多 ,已获满意结果     

关于开发适合我国国情的TDRSS的设想

简介国际“跟踪与数据中继卫星系统”（ＴＤＲＳＳ）的概况，强调中国的特殊性，提出尽快建立军民两用、综合应用、中等性能的ＴＤＲＳＳ，以尽早获得最基本的近全球的跟踪、通信与自主导航的能力，从而填补天基支撑的空白。主张综合功能一步到位，超过日本；性能上接近日本，逐步提高。在技术思路上，建议采用ＰＣＭ－ＯＱＰＳＫ 及ＰＣＭ－ＣＤＭＡ－ＢＰＳＫ数据传输体制；星本体测控与用户的跟踪导航统一采用单通道单脉冲测角、伪码测距的单站定轨体制，并利用星本体测控数据提高用户的跟踪导航精度；主张在ＴＤＲＳＳ的设计中全面贯彻ＣＣＳＤＳ协议标准，尽早参与区域以至全球的高速信息网。最后，对下世纪初实现具有中国特色的ＴＤＲＳＳ的技术关键与可能性，提出了看法。指出，中国的ＴＤＲＳＳ将超越航天测控网的范畴，而成为全球战略技术信息的天基传递网，并终将成为全球高速信息网的重要组成部分     

Survey of mission evolution and flexibility in the Space Shuttle program

Given the diversity of missions it has accomplished and the myriad of adaptations it has undergone, the US Space Shuttle is widely regarded as a highly flexible space vehicle. With the Shuttle’s upcoming 2011 retirement, it is instructive to survey the history of this vehicle’s flexibility for the insights it can provide to the design and characterization of flexibility in future space systems. Data are presented on the evolution of mission requirements over time for 120 missions performed by the Space Shuttle over a period of some 27 years. Distinct trends in the time domain – as well as their causes – are identified and discussed, and early manifest plans from 1982 serve as a confirmation that these trends were not originally anticipated. Eight examples are then presented of engineering modifications that allowed the Shuttle to adapt and accommodate these requirement changes. Several additional instances of Shuttle flexibility are explored, such as post-Columbia disaster modification, upgrade programs and derived vehicles, and one case in which flexibility was inhibited by an early design decision.     

多惯性仪表冗余系统测量数据的预处理

介绍了多惯性仪表冗余惯性测量系统数据融合前的测量异常值去除、系统误差修正和一致性检验的基本方法。针对测量数据一致性检验,讨论了置信距离测度和信任度函数两种处理方法。仿真结果表明后者能更好地确定一致性的惯性仪表测量数据。     

卫星导航进近技术进展

全球卫星定位系统（GNSS）增强系统能提供全天候无间断的卫星导航信号，可以辅助飞机进行进近。本文介绍了全球卫星导航系统进近着陆系统的基本组成、工作原理和功能特点，并对国内外研究进展进行了阐述。针对GNSS进近研究中的热点问题，重点论述了地基增强系统（GBAS）、星基增强系统（SBAS）、用户自主完好性监测（RAIM）等技术的发展现状，指出了GNSS进近技术实际工程应用仍然存在的问题，探讨了GNSS进近技术未来的发展方向。     

End-to-end validation process for the INTA-Nanosat-1B Attitude Control System

This paper describes the end-to-end validation process for the Attitude Control Subsystem (ACS) of the satellite INTA-NanoSat-1B (NS-1B). This satellite was launched on July 2009 and it has been fully operative since then. The development of its ACS modules required an exhaustive integration and a system-level validation program. Some of the tests were centred on the validation of the drivers of sensors and actuators and were carried out over the flying model of the satellite. Others, more complex, constituted end-to-end tests where the concurrency of modules, the real-time control requirements and even the well-formedness of the telemetry data were verified. This work presents an incremental and highly automatised way for performing the ACS validation program based on two development suites and an end-to-end validation environment. The validation environment combines a Flat Satellite (FlatSat) configuration and a real-time emulator working in closed-loop. The FlatSat is built using the NS-1B Qualification Model (QM) hardware and it can run a complete version of the on-board software with the ACS modules fully integrated. The real-time emulator, running on an industrial PC, samples the actuation signals and emulates the sensors signals to close the control loop with the FlatSat. This validation environment constitutes a low-cost alternative to the classical three axes tilt table, with the advantage of being easily configured for working under specific orbit conditions, in accordance with any of the selected tests. The approach has been successfully applied to the NS-1B in order to verify different ACS modes under multiple orbit scenarios, providing an exhaustive coverage and reducing the risk of eventual errors during the satellite's lifetime. The strategy was applied also during the validation of the maintenance and reconfiguration procedures required once the satellite was launched. This paper describes in detail the complete ACS validation process that was performed and it shows the most relevant errors detected and fixed during testing. Finally it summarises some of the most significant conclusions.     

以主轴系统刚度与总功耗之比值为目标函数的液体静压轴承优化设计方法

本文介绍以主轴系统刚度与总功耗之比值最大比值最大为目标函数、主轴系统刚度的校验准则为主要约束条件的液体静压轴承优化设计方法，与普通设计方法相比，两种不同结构液体静压承经优化设计后，其单位总功耗的主轴系统刚度都成倍增加。     

Solar Nebula Magnetohydrodynamics

The dynamical state of the solar nebula depends critically upon whether or not the gas is magnetically coupled. The presence of a subthermal field will cause laminar flow to break down into turbulence. Magnetic coupling, in turn, depends upon the ionization fraction of the gas. The inner most region of the nebula (≲0.1 AU) is magnetically well-coupled, as is the outermost region (≳10 AU). The magnetic status of intermediate scales (∼1 AU) is less certain. It is plausible that there is a zone adjacent to the inner disk in which turbulent heating self-consistently maintains the requisite ionization levels. But the region adjacent to the active outer disk is likely to be magnetically ``dead.' Hall currents play a significant role in nebular magnetohydrodynamics. Though still occasionally argued in the literature, there is simply no evidence to support the once standard claim that differential rotation in a Keplerian disk is prone to break down into shear turbulence by nonlinear instabilities. There is abundant evidence—numerical, experimental, and analytic—in support of the stabilizing role of Coriolis forces. Hydrodynamical turbulence is almost certainly not a source of enhanced turbulence in the solar nebula, or in any other astrophysical accretion disk. This revised version was published online in June 2006 with corrections to the Cover Date.     

基于“笔”输入模式的产品结构草图快速设计系统研究

为了减少设计人员从想法到设计实现之间的障碍,本文提出一种新的设计途径——"直接手绘"的方式来支撑产品结构草图设计过程,使得进行产品开发的功能结构、材料工艺、设计开发过程、制造模式等都发生了深远的变化。首先给出快速设计系统的总体方案,然后重点剖析阐述快速设计系统的软件设计,最后以算例形式验证了基于"笔"输入的三维航天产品结构草图快速设计方法及系统。     

基于态势感知一致性的UAV集群分布式协同性能分析

针对现有无人机集群分布式协同方法没有细致考虑态势感知过程，忽略了对抗环境下态势信息的不确定性对集群协同的影响，对协同性能缺乏量化分析等问题，提出基于态势感知一致性的无人机集群分布式协同方法，并分析协同性能。从集群协同作战角度分析协同方法的实质，考虑态势信息不确定性，给出集群态势感知一致性分析，建立态势觉察一致性、态势理解一致性等概念，并设计协同方法；建立协同时间、协同信息量等指标，分析指标特性，量化分析协同性能；在给定的仿真场景下，对比分析各协同方法性能。结果表明，所提方法协同性能较好，更切合对抗环境，对集群协同作战研究有一定的积极意义。