GPS M码综述

M码信号是GPS系统采取的主要抗干扰措施,M码信号设计是未来军用GPS基础设施的核心问题,美国GPS联合计划办公室已于2001年8月批准了M码信号结构,计划在2004年发射第一颗M码卫星。本文介绍GPSM码信号的设计要求,M码信号调制方式设计以及信号捕获设计。     

商用飞机的经济性设计

介绍商用飞机经济性设计的定义,阐述商用飞机经济性设计的主要研究内容,提出商用飞机设计使用的指标框架体系。在此基础上,给出商用飞机经济性设计的主要方法和分析模型。最后提出民机经济性设计的研究方向。     

数据采集系统在固体火箭发动机试验中的应用

重点介绍 HP VXI总线数据采集系统在固体火箭发动机试验中的应用 ,其中包括数据采集和处理程序 ,及 VXI设备的基本性能调试。并对软件设计思路和相关问题进行了讨论。通过与原有数据采集系统进行试验比较 ,表明该测试系统合乎程序动态试验的技术要求 ,性能优异。     

A review of advanced turboprop transport aircraft

The application of advanced technologies shows the potential for significant improvement in the fuel efficiency and operating costs of future transport aircraft envisioned for operation in the 1990s time period. One of the more promising advanced technologies is embodied in an advanced turboprop concept originated by Hamilton Standard and NASA and known as the propfan. The propfan concept features a highly loaded multibladed, variable pitch propeller geared to a high pressure ratio gas turbine engine. The blades have high sweepback and advanced airfoil sections to achieve 80 percent propulsive efficiency at M=0.80 cruise speed. Aircraft system studies have shown improvements in fuel efficiency of 15–20 percent for propfan advanced transport aircraft as compared to equivalent turbofan transports. Beginning with the Lockheed C-130 and Electra turboprop aircraft, this paper presents an overview of the evolution of propfan aircraft design concepts and system studies. These system studies include possible civil and military transport applications and data on the performance, community and far-field noise characteristics and operating costs of propfan aircraft design concepts. NASA Aircraft Energy Efficiency (ACEE) program propfan projects with industry are reviewed with respect to system studies of propfan aircraft and recommended flight development programs.     

Recent developments of electric vehicles and their propulsionsystems

Major recent electric vehicle (EV) programs in North America, Europe, and Japan are reviewed. The developments discussed include electric vehicles for fleet operation and electric passenger cars for urban transit. All major auto makers have had their own concept electric vehicle programs, targeted at commercial production in the late 1990s. It Is noted that, with different objectives for various electric vehicles, considerations such as cost, reliability, efficiency, maintenance, durability, weight, size, and noise level should be compromised for the propulsion system design. Consequently, DC motor drives, induction motor drives, and permanent magnet brushless DC motor drives will continually be used for EV propulsion systems in the future, with DC drives being gradually replaced by AC drives. The rapid advances in power semiconductor devices and microprocessors have made it possible to build reliable and cost-effective AC drive systems     

An IPC-based Prolog design pattern for integrating backward chaining inference into applications or embedded systems

Prolog is one of the most important candidates to build expert systems and AI-related programs and has potential applications in embedded systems. However, Prolog is not suitable to develop many kinds of components, such as data acquisition and task scheduling, which are also crucial. To make the best use of the advantages and bypass the disadvantages, it is attractive to integrate Prolog with programs developed by other languages. In this paper, an IPC-based method is used to integrate backward chaining inference implemented by Prolog into applications or embedded systems. A Prolog design pattern is derived from the method for reuse, whose principle and definition are provided in detail. Additionally, the design pattern is applied to a target system, which is free software, to verify its feasibility. The detailed implementation of the application is given to clarify the design pattern. The design pattern can be further applied to wide range applications and embedded systems and the method described in this paper can also be adopted for other logic programming languages.     

计算机软硬件系统应用于工业控制

电子计算机自问世以来，发展非常迅速，与之相应软件系统的应用也步入了一个新的阶段。软硬件相结合使计算机在工业控制中成为一个强有力的工具。本文针对研华工业控制计算机及其配置的数据采集与控制卡等硬件．利用标准Turbo C语言编制数据采集代码。准确实时地实现工业生产、试验等现场控制。     

毫米波鳍线平衡混频器研究

 本文研究了一种八毫米波段平衡混频器的工程设计方法,并给出了实验测试结果。在针对实际电路结构建立起等效电路模型后,采用最优化方法对电路结构参量作了优化。对实际制做的混频器性能作了初步测试,最佳双边带噪声系数约为6dB(其中包括1.4dB中放噪声贡献在内)。     

Challenges of future aircraft propulsion: A review of distributed propulsion technology and its potential application for the all electric commercial aircraft

This paper highlights the role of distributed propulsion technology for future commercial aircraft. After an initial historical perspective on the conceptual aspects of distributed propulsion technology and a glimpse at numerous aircraft that have taken distributed propulsion technology to flight, the focal point of the review is shifted towards a potential role this technology may entail for future commercial aircraft. Technological limitations and challenges of this specific technology are also considered in combination with an all electric aircraft concept, as means of predicting the challenges associated with the design process of a next generation commercial aircraft.     

Aerothermodynamics – A critical review at DLR

The paper presents the results of a study done for the German Aerospace Center, DLR.¹ The goal of the study is to identify the required design capabilities in external hypersonic aerothermodynamics for future space transportation vehicles. Lessons learned from the latest German program on Technologies for Reusable Future Space Transportation Systems, TETRA, as well as experiences collected from past European technology programs and flight vehicles are taken into account. The study does not go in to details since it pretends to be a reference for future research programs in aerothermodynamics. The potentials and shortcomings of the major prediction tools for aerothermodynamics, i.e., computational fluid dynamics and wind tunnels are shortly highlighted. Overviews of the most relevant external flow problems encountered during the design of space vehicles are presented. Research fields that require serious improvements are also identified.     

基于PKI的IPSec-VPN代理网关的设计与实现

针对IPSec-VPN网关开发的特点,提出了PIG代理网关的概念,并就一个基于PKI的 IPSec-VPN网关开发的实例作了比较详细的描述,给出了实现的框图和几个主要算法的设计。     

液压试验台监控系统设计

介绍了基于研华设备卡为核心的液压试验台监控系统,在Windows2000环境下,以Microsoft VisualC++6.0为开发工具,运用多线程技术、双缓冲技术、模块化设计思想以及硬件中断机制,实现了液压试验监控系统连续实时数据采集、精确定时和实时过程控制。     

若干复合材料计算机程序评介

由于复合材料结构件的各向异性和层合性,使得复合材料结构的设计、分析要比金属复杂得多,工作最也要大得多,有些工作甚至是手工计算所不能胜任的,必须依靠计算机。因此,近十几年来复合材料的计算机程序迅速地被开发出来。虽然列入《复合材料设计手册》的程序有36个,但在编写过程中涉及的程序有60多个。本文仅就其中的一些做一粗浅的评介。     

共享内存网--面向飞机仿真的实时网络

将多台计算机连接起来,共同完成单个的实时任务,如飞机仿真是一项非常具有挑战性的工程任务。本文论述了计算机分布式仿真的一些独特要求,对目前使用的两种主要方法进行了总结,将共享内存网的概念和传统的方法进行了对比介绍,共享内存网的设计方法、性能参数以及详细的设计过程也有论述。     

Thrust vectoring for eurofighter - the first steps

Thrust vectoring has the potential to provide significant improvements in combat aircraft performance and stability. As Eurofighter Typhoon moves into production, ITP and MTU are pursuing a research and technology acquisition project to investigate the design of a thrust vectoring nozzle system suitable for future application to the EJ200 engine. This paper describes the current status and progress of this project.     

基于PTR2000的无线数据传输系统设计与实现

针对传统的工业测控系统中,传输数据采用的是有线方式,成本高、维护不方便,且在某些特殊的场合,布线困难甚至无法布线的问题,介绍了一种基于无线数据传输模块PTR2000的数据采集系统的总体结构,并着重讨论了硬件电路设计和通信协议的制定及具体实现。该系统可方便地嵌入到无线测控系统中,抗干扰能力强,具有广阔的应用前景。     

The White Sands Range and Range-Rate System

This paper discusses the concept, design, and design verification of the White Sands Range and Range-Rate System. Development of the system has been completed only through the design phase. The system is designed to meet requirements for high-accuracy midcourse tracking under severe target dynamics at the White Sands Missile Range. It is a multistatic Doppler and range tracker which operates at X band and incorporates transmitter, transponder, receiver, and baseline subsystems. The transmitter includes specially designed digital circuitry to synthesize test signals for target simulation during checkout of the system. The transponder signal is processed by a receiver which has been established theoretically to be the optimum realizable processor of continuous tracking data. The receiver incorporates specially designed carrier acquisition circuitry and digital VCO, and directly provides digital Doppler and tone phase data to facilitate real-time processing. The system utilizes data from other tracking systems at the Range for spatial acquisition, for aiding carrier acquisition in the receiver, and for resolving range ambiguities.     

ISE: intelligent synthesis environment for future aerospace systems

The Intelligent Synthesis Environment (ISE) being developed by NASA, UVA, and JPL for significantly enhancing the rapid creation of innovative affordable products and missions is described. ISE uses a synergistic combination of leading-edge technologies, including high-performance computing, high-capacity communications and networking, virtual product development, knowledge-based engineering, computational intelligence, human-computer interaction, and product information management. The environment will link scientists, design teams, manufacturers, suppliers, and consultants who participate in the mission synthesis, as well as in the creation and operation of the aerospace system. It will radically advance the process by which complex science missions are synthesized, and high-tech engineering systems are designed, manufactured, and operated. The evolution of engineering design is described along with the shortcomings of current product development techniques. The need for ISE to create high-science payoff missions and aerospace systems at affordable costs is discussed. The five major components critical to ISE and some of their sub-elements are described: namely, human-ISE interaction; infrastructure for distributed collaboration; rapid synthesis and simulation tools; intelligent life-cycle system integration; and cultural change in the creative process. Related government and industry programs are outlined and future impact of ISE on complex missions and aerospace systems is discussed.     

固液动力探空火箭箭载数据采集系统设计

针对固液动力探空火箭在进行测试、飞行试验时,需要实时测量并记录推力、燃料供给速率以及吹除系统工况信息的问题,设计并工程实现了对箭载重要设备输出信号进行监控和采集记录的数据采集系统.以STM32F103RB微控制器为核心,完成了数据采集、存储、传输等电路的设计,并在Real View MDK集成开发环境下,运用C语言完成了控制、测试程序的编写.最后,通过Real View ULINKR仿真器实现了软硬件的联合测试,验证了系统的供电控制、采样频率、工况记录等功能都满足设计要求,完成了对箭载重要设备监控和采集记录的任务.只需修改微控制器内的操控程序,就可将此数据采集系统应用于不同型号的固液动力探空火箭.