Methodology for cost-effective software fault tolerance formission-critical systems

A computing capabilities continue to advance, there will be a concurrent rise in the number of both hardware and software faults. These will be caused by the greater volume of more complex software, by the increased number of untested software states, and by more incidents of hardware/software interaction faults as a result of increased hardware speed and density. The traditional software implemented fault tolerance: approaches have been successfully utilized in life-critical systems, such as digital flight controls, where their additional costs can be easily justified. Examples include N-Version Programming and Recovery Block approaches. However, there is still a need for dependable computing for mission-critical applications as well. Often, these traditional techniques are avoided for mission-critical systems due to the difficulty in justifying their extra up-front development cost. We provide an alternative for the high “sunk cost” of traditional software fault tolerance techniques. The methodology, called data fusion integrity processes (DFIPs), is a simple, yet effective technique for mission-critical systems. In addition, the approach establishes a framework from which other costlier, more extensive traditional techniques can be added. We present details of the DFIP methodology and a DFIP framework for Ada programs. We also briefly discuss development of a DFIP code generation system which exploits Java that will enable users to quickly build a DFIP framework in Ada, and select reusable DFIP component methods     

一种新型高效容错体系结构的研究与实现

由于辐射而在电路的时序逻辑部分和组合逻辑部分产生的逻辑软错误已经逐渐成为阻碍系统可靠性和稳定性的主要威胁。提出了一种结合了基于主／g．1atch设计和改进的时间冗余策略两种技术的容错体系结构,通过ISCAS’89测试基准电路进行验证并对实验结果的分析发现,该容错体系结构获得了很高的容错性能。     

Implementing reusable, instrument independent test programs in thefactory

Development of computer programs that control test sequences on Automatic Test Equipment (ATE) is costly and time consuming. Test Programs are usually written by specifying the instruments to be used in the ATE and the sequence of the setup and measurement parameters for these instruments. Reuse of test program software on other ATE is usually not possible without rewriting, revalidating and re-releasing the programs. This paper describes an implementation of a test program software development system and a standard of software runtime architecture used in our factories. The object-oriented development environment and its associated class libraries allow test programs to be written without knowledge of the ATE on which they will be run. Two main principles guided the design: the software architecture was based on recognized formal and industry standards; and our implementation used commercial off-the-shelf software products when possible. Emerging standards such as the IEEE-1226 (ABBET) as well as defacto industry standards including VXI Plug and Play have made our implementation possible. The current draft of the ABBET and P&P standards do not promote this instrument independence, but it is hoped that this will be added as the standards mature. Three immediate benefits are: cost savings that result from reusing validated test programs; cycle time reductions that result from concurrently developing test program software and ATE; and software defect reductions that result from using proven software     

基于ARM的CAN通信系统的设计与实现

CAN总线是一种多主方式的串行总线.本文设计实现了基于高级RISC处理器(ARM)的CAN协议通信系统,具有高抗干扰性和良好的实时性,应用简单、可靠性高、开发成本低.本文详细介绍了该系统的硬件设计,软件设计,以及通信测试结果.     

浅析Blob在S3C44B0上的移植

嵌入式Linux系统通常由三部份组成:Bootloader、Kernel和File System,其中Bootloader的任务是为调用Kernel准备必要的软硬件环境。Blob是一款功能强大的Bootloader,本文介绍了Blob的运行过程和整体结构,同时给出将Blob移植到基于S3C44B0目标板的过程,并对移植过程中的关键代码进行了分析,为项目的后续开发打下基础。     

捷联惯性导航计算机小型化设计

为满足捷联惯性导航计算机的小型化和实时性要求,本文设计了一种使用基于SoC技术设计的A2F500芯片为硬件平台的实现方案。新型的导航计算机与传统的以DSP+FPGA为架构的导航计算机相比,有效地减小了体积,降低了功耗和成本,提高了系统的可靠性,达到了预期的目标,对导航计算机的进一步小型化具有重要意义。     

基于TPS的航空火控装备板卡测试系统设计

针对航空火控装备三级修理难度大的情况,提出了基于测试程序集(TPS)技术的航空火控装备板卡测试系统设计方法。根据被测装备LRU和PCB的特点和种类,确立了以板卡测试为主,辅以其他方法的测试方案,并给出了测试系统硬件设计和软件设计思路。系统对降低维修费用、提高装备的完好率具有十分重要的意义。     

基于虚拟机QEMU的嵌入式全系统仿真测试环境的研究与实现

为了能节省测试设备的成本和提高嵌入式软件系统测试的效率,本论文设计了一个基于QEMU虚拟机技术的通用嵌入式全系统仿真测试环境,来实现嵌入式软件的系统测试。本文将着重介绍本测试系统中被测设备硬件仿真部分的设计与实现,以及针对该部分进行测试的测试结果。     

Mechanical engineering's role in multi-disciplinary radar design

Successful execution of a program and full satisfaction of the customer's requirements is a challenge for any contractor. Raytheon Company responds to this challenge by following a proven program execution methodology. The methodology includes all program aspects from financial planning to engineering to validation and test. This discusses the engineering team and the role of the mechanical engineer. A radar system is ultimately an assembly of advanced electronics and software. However, the design, fabrication, assembly, integration, and test Of this complex system requires a coherent multi-disciplinary approach. Raytheon, like many contractors, chooses to assemble an integrated product team (IPT) including all engineering disciplines. Mechanical engineering is integral to satisfying performance requirements, performing preliminary and detailed design, transition of the design to manufacturing, and implementation of the hardware in the field. During definition, mechanical engineering assists fundamental architecture development, conceptual design, and requirements development which precludes issues that are sometimes ignored to the detriment of many programs. These design issues include environmental protection, structural stiffness to meet deflection requirements, cooling system capacity to properly remove dissipated heat, manufacturabilit3' to control cost, maintainability to enable repair in the field, and transportability. Recognizing and trading off these issues early greatly increases the Probability Of satisfying customer objectives. This discusses the approach Raytheon is taking to ensure an overall multi-disciplinary solution to our design challenges from the perspective of the mechanical engineer.     

Malfunction Detection System for Advanced Spacecraft

A design approach for a Malfunction Detection System (MDS) to beused on board a manned spacecraft is considered. This design is directed toward orbiting laboratory type vehicles, in which man will be subjected to hostile environments for extended periods of time. The prime purpose of the MDS will be to monitor and evaluate critical signals and display out-of-tolerance conditions. This paper initially discusses a mathematical model approach to a monitoring-system design. Another topic covered is the feasibility of using some value less than the specified tolerance as a signal ?test? limit. Finally, various design decisions and trade-offs involved in choosing a monitoring subsystem configuration are discussed, and the conclusion is that the approach is feasible and could be expanded to include other capabilities.     

VXI based breadboard module use

Plug-in VXI based breadboard modules are an excellent solution to achieve a lower costing, time and hardware saving test bench. These breadboard modules are equipped with built-in VXI bus interface circuitry and a breadboard area for creating a design to suit your test needs. A prime example for the use of this capability was demonstrated on a recent radar system test bench created to test many unique Units Under Test (UUTs) previously tested on separate test benches. A single breadboard module design replaced the dedicated interface and control hardware within the many test benches and test fixtures previously used to test the individual UUTs. This paper presents some design considerations and techniques implemented as part of this VXI breadboard module that can be useful when creating a VXI breadboard design. It also addresses the inherent built-in test capabilities provided by the module in conjunction with the techniques presented in the paper     

基于CPCI架构航天器测试设备的故障诊断设计与实现

基于CPCI总线架构的航天器测试设备可以实现模块化、集成化和通用化设计,有利于测试系统的再次开发、直接沿用以及后续维护.某型号的综合电子和控制分系统地面测试设备采用基于CPCI总线的架构,使用VxWorks操作系统作为核心调度,采取模块化FPGA开发接口和特定功能.提出以监听任务、功能模块、板卡运行时间为检测手段,实现了对系统测试设备故障的诊断,尤其是反作用轮转速模块,软件能自主进行故障处理.在分系统及整星测试的使用过程中,此方法有效提高了设备的可靠度,提高了对星上产品的安全保护,保证整星大型试验的连续可靠运行.此方法对于其他地面测试设备的故障诊断具有一定的借鉴作用.     

Flight-critical distributed systems: design considerations [avionics]

With the proliferation of so-called "smart" components and the availability of small, low-cost, and high-speed data networks, avionics that have traditionally been centralized are becoming distributed. A distributed approach offers many potential benefits, such as reduced development time and cost, simplified system installation, increased flexibility for system expansion or modifications, and greater reuse of proven components. The distributed approach can also reduce the risk associated with design errors by splitting complex hardware and software into more manageable components. However, distributed systems also introduce new challenges in meeting real-time deadlines and providing fault tolerance. This paper examines the many design considerations and identifies the strengths and weaknesses of each. Emerging automotive drive-by-wire alternatives are compared for application to aerospace systems. This paper is based on a Draper Laboratory-sponsored effort to look at flight-critical distributed systems and to evaluate emerging hardware and software for building them.     

A target cueing and tracking system (TCATS) for smart videoprocessing

A smart system that uses state-of-the-art image processing techniques to detect and track targets moving in video or infrared imagery is presented. It is a general-purpose system that was developed to be independent of the application and the user interface. TCATS has successfully demonstrated a high detection capability and the ability to ignore exterior environmental conditions, such as cloud shadows moving through the scene, snow, blowing dust, rain and moderate camera motion. TCATS can handle many targets and retain the identity of each object from one frame to the next. Special rugged hardware has been developed to reduce the size, cost, and power consumption and to increase the processing rate, reliability, and environmental operating capability of the system. TCATS can be incorporated into an existing video assessment system without a major cost outlay intruder. The TCATS algorithms, custom-developed hardware, and preliminary field test results are described     

Open systems architecture solutions for military avionics testing

Raytheon makes extensive use of open systems architecture methods in developing special test equipment (STE) for testing military avionics equipment. Such use has resulted in significant cost and schedule savings in the development of production test equipment for radar and infrared systems. With open systems architectures, a test system can be assembled using COTS products. This brings economies of scale to test equipment, which is normally built in very low quantities. Therefore, the potential cost savings due to COTS usage is proportionately greater in STE than in the higher volume avionics systems that are tested. A second major benefit of using COTS products is that test system development schedule cycle time is greatly reduced. This paper describes the application of Open Systems Architectures (OSA) to avionics testing. The following major architectures are surveyed: VME bus, VXI bus, IEEE GPIB, IEEE 1149.1 JTAG test bus, 1553 Military Bus, Fibre Channel, and COTS Test Applications Software. We describe how the benefits of OSA have been extended at Raytheon into achieving vertical test commonalities. The flexibility of OSA can be exploited to provide an overall optimum test solution, taking all levels of test into account. For example, test systems can be tailored with COTS products to provide integrated methods for avionics tests at the module, unit, and system levels. Test systems can be configured to maximize the reuse of COTS hardware over all test levels. Test software can also be programmed to optimize such reuse over levels of test. Additional test verticality synergies derived from such OSA usage are described, including: test false alarm avoidance; test cones of tolerance optimization; and efficient test of field returns     

Using built-in-test to reduce TPS run times and improve TPSreliability

This paper addresses using information derived from Built-in-Test (BIT) to fault diagnose Units Under Test (UUTs), wherever possible. This philosophic approach to diagnostic testing is not new. It has been studied over the past 20 years under the visor of “Integrated Diagnostics”, but it has yet to be truly implemented in a “real life” military diagnostic test environment. The mindset of Test Program Set design engineering, along with customer and contractor management alike, remains “complete diagnostic testing based upon single catastrophic component failure modes”. If we are to generate cost efficient Test Program Sets (TPSs) under reduced military budget constraints, this will have to change! The test engineer must be encouraged to use methodologies to speed up development time and decrease TPS run times. Using present technology, this is possible now, and as the technology matures, will become a truly viable approach in the future. For the purpose of this paper, the author relies heavily on his extensive US Navy Automatic Test Equipment (ATE) and Test Program Set (TPS) experience, as well as on previous studies performed on using BIT to fault diagnose Unit Under Test failures on US Naval Air weapon systems     

AMETHYST: automatic alarm assessment becoming a reality

The aim of the AMETHYST (AutoMatic Event auTHentication SYSTems) project is to encourage the development of a high performance perimeter detection system which combines Video Motion Detection (VMD) technology with another type of Perimeter Intrusion Detection System (PIDS). AMETHYST will automatically assess the cause of PIDS alarms and pass to an operator those alarms likely to be caused by an intruder. It will filter out alarms not likely to have a human cause. A previous paper explaining and exploring the AMETHYST concept was presented at the 1995 Carnahan Conference. Since then PSDB has produced a single channel AMETHYST demonstrator and placed a contract for the development of an eight channel prototype AMETHYST system. This updated paper gives details of the hardware and software used with these two systems. Also described is PSDB's approach to the development of AMETHYST's automatic assessment algorithms. These will combine current expertise from Video Motion Detection (VMD) and Intelligent Scene Monitoring (ISM) systems with the unique AMETHYST approach. AMETHYST analyses picture sequences from before and after an alarm instead of continuously analysing live video. Sequences are provided by a Loop Framestore, either connected to or part of the AMETHYST system. The algorithms will be assessed and developed using PSDB's growing collection of over 150 alarm sequences     

Software architecture requirements for DoD automatic test systems

The DoD has achieved success with recent automatic test equipment (ATE) families, as evidenced by the navy's consolidated automated support system (CASS) and the army's integrated family of test equipment (IFTE) programs. However, as these systems age, the increased requirements for technology insertion due to instrument obsolescence and the demands of advanced electronics are becoming evident. Recent advances in test technology promise to yield reduced total ownership costs (TOC) for ATE which can incorporate the new technology. The DoD automatic test system (ATS) executive agent office (EAO) objective is to significantly reduce total ownership cost. Several objectives have been identified including use of synthetic instruments, support for legacy test product sets (TPSs), and more efficient ways of developing TPSs. The NxTest software architecture will meet the objectives by providing an open systems approach to the system software. This will allow for the incorporation of commercial applications in the TPS development and execution environments and support current advances in test technology     

VLSTA: virtual instrument standard test architecture

Diagrammatic programming environments provide a unique challenge for the developers of test software. These cost effective environments facilitate access to technologies such as VXI, provide speedy development of highly effective user interfaces, and eliminate many of the tasks often associated with hardware integration in complex test systems. Nonetheless, difficulties can arise when designing functional and diagnostic test software in this environment. This paper introduces VISTA, a promising new architecture which allows users to elude most of the difficulties of building detailed functional and diagnostic Test Program Sets (TPSs), while taking full advantage of the benefits of diagrammatic programming environments. Here we examine an implementation of the VISTA architecture, the integration of advanced diagnostics, and the use of diagrammatic programming as a test language cross compiler     

高精度固体推进剂爆热测试系统

为准确测量固体推进剂储存期间爆热值的变化,研究了高精度的爆热测试设备。针对影响爆热测试的主要因素,在测试系统硬件设计中采取了降低热量损失的多种措施,并采用了悬浮式光电隔离技术;在系统软件设计中则采用了数字滤波技术,建立了新的热量散失校正数学模型,并对影响测试精度的因素进行在线实时补偿。对标准物质的热值测试表明,系统测试相对误差小于０．１％,实现了推进剂爆热的高精度测试。