基于DO-178C的机载软件质量保证与管理

DO-178C 作为机载软件适航可接受的符合性标准,明确要求机载软件综合过程中必须包含软件质量保证（SQA）过程。以机载软件的软件生命周期定义、过程和数据为基础,从目标、活动和符合性评审三个方面分析基于DO-178C 的软件质量保证过程的实施;结合软件项目质量管理技术和工具,从规划软件质量管理、管理软件质量和控制软件质量三个过程研究基于DO-178C 的软件质量管理方法并给出工程实践建议。结果表明：本文将软件质量保证与质量管理紧密结合,形成了适航要求的相关证据,提供了符合需求的民用机载软件,有效保证了机载软件的质量和持续改进措施。     

Advances in DoD's ATS Framework

The Automatic Test System (ATS) Executive Directorate (ED) is charged with developing objectives for the Department of Defense (DoD) ATS modernization. The DoD ATS Framework Working Group (FWG) was established by the ATS ED to create a Framework addressing these objectives. The FWG consists of two sub-groups: Management, that includes members from all of the DoD Services, and Technical. The Framework is made up of key elements and associated specifications and standards that form the open system architecture approach for DoD ATSs. In addition to creating and updating key element definitions, the FWG focuses on identifying commercial ATS related specifications that might satisfy the elements in the Framework. The standards specified in the DoD ATS Framework are documented in the DoD's Information Technology Standards Repository (DISR) and thereby become a mandatory requirement for all DoD ATS acquisitions. The Framework is also being specifically called out in DoD ATS requirements documents so that its standards are incorporated in future DoD ATS acquisitions, such as the Navy's eCASS.     

一种提高通用处理模块数据完整性的设计方法

航空电子产品中为了满足高安全等级应用的驻留需求，通用处理模块的数据完整性指标需要达到 Level A（10-9）级。基于当前元器件的可靠性和产品设计的复杂度，产品的数据完整性一般在10-3 到10-5 的水平， 无法满足产品的设计需求。本文提出了一种基于数据锁步的设计方法，该方法可用当前的软硬件资源在工程项 目中设计出满足高完整性要求的产品。     

靶场GNSS增强、监测与评估系统建设构想

针对靶场GNSS（全球导航卫星系统）增强、监测与评估的测量精度和可靠性保障、异常分析和电磁环境监测等复杂技术需求,明确了靶场GNSS增强、监测与评估的概念,分析了各类方法的特点,确定了以大范围基准站网为主干,采用广域差分增强和地面完好性通道监测满足提高测量精度和可靠性主要需求,采用车载信号监测和干扰监测一体化系统满足不同区域间发的异常分析和电磁环境监测需求的技术路线.设计了系统体系架构,重点分析了系统实时工作模式和数据处理流程,为系统建设提供了有益的参考.     

System Considerations for the New DME/P International Standard

The International Civil Aviation Organization (ICAO) has completed technical standards for the precision distance measuring equipment (DME/P). The DME/P is an integral element of the microwave landing system (MLS) and will provide the precision ranging function to complement the already standardized azimuth and elevation guidance functions of the system. In 1978 an ICAO meeting concluded that the DME/P should be integrated into the existing standards for the conventional DME (DME/N) as a compatible service. The motivation for this was economic. It was reasoned that a single L-band airborne unit could satisfy the need for both existing enroute and the new precision approach and landing services, thereby avoiding unnecessary duplication of on-board ranging equipment. Furthermore, this approach would permit existing conventional airborne equipment to obtain service from the new DME/P ground facilities at least during the initial stages of MLS implementation. These compatibility requirements were later incorporated into the DME/P statement of operational requirements which was accepted at an ICAO meeting in April 1981. Further, they have been a primary focus in the DME/P standardization effort which has been actively pursued since late 1980. The conceptual design of the DME/P that evolved from the ICAO process is discussed here. The comptability issues are highlighted, and it is shown how they are accommodated in the system synthesis which also treats the obvious need for a guidance function of high integrity and robust performance in the severe multipath environment encountered in approach and landing operations.     

A methodology for evaluating, comparing, and selecting softwaresafety and reliability standards

The regulated industries, which in the FDA's (US Food and Drug Administration) case include the manufacturers of food, cosmetics, pharmaceuticals, and medical devices, are responsible for selecting and justifying the selection and use of appropriate national and/or international consensus standards. This paper documents the results of a scientific inquiry which was undertaken to develop a methodology to evaluate and select individual standards as well as compatible sets of standards. Initially the scope was limited to software safety and reliability standards. Since then it has been expanded to other areas. It was found that six categories of criteria are important when evaluating the potential use of software safety standards: General Factors, Product Characterization, Process Characterization, Personnel Characterization, Risk Management, and Overall Standards Framework. The criteria in each of the six categories must be addressed, How they are addressed is both a technical and a policy decision. The goal should not be to try to find the “ultimate” standard because there isn't any. Rather the goal should be to select a balanced “diet” of standards based on these six categories. The methodology provides a systematic framework from which to make an objective determination about the appropriateness of using a particular standard     

Certification of production-representative/productionsoftware-intensive systems for dedicated test and evaluation

Fundamental questions that arise in the certification of readiness for dedicated test and evaluation of software-intensive systems are addressed. They concern what comprises production-representative or production software, what are the software impacts on dedicated system operational test readiness, how software impacts should be considered in the certification process, and what are the retest/recertification requirements associated with software changes/modifications. A paradigm is proposed that answers these questions and outlines guidelines for implementing a solution to these issues. The paradigm is based on existing test and evaluation events and uses a combination of defense and commercial standards and definitions to propose criteria for software certification and retest or regression test     

综合化航空电子系统可信软件技术

航空电子系统要求航空任务的执行具有确定性、可预测和可控性。深入分析综合化航空电子系统软件安全性、可靠性、完整性和实时性需求,提出了综合化航空电子系统软件可信性的定义。首次将可信计算引入到综合化航空电子系统中,建立综合化航空电子系统可信软件体系结构,在此基础上,提出软件可信运行环境构建方法和可靠性增强技术。这些技术能够保障综合化航空电子系统的可预测性,对保证飞机任务的执行及其安全具有重要的作用,为研制适合于中国大飞机的综合化航空电子系统可信软件奠定基础。     

简单用户微编码器件适航要求研究

用户微编码器件的便捷性与高效性,使其在机载设备研制中被广泛应用。由于具有高度集成性和复杂性,难以通过传统方法对开发过程中产生的设计错误进行管理和评估,其使用会对飞机的安全性造成影响,因此通常采用研制保证方法表明用户微编码器件的适航符合性。但在实际项目中,用户微编码器件实现的功能可能较为简单,采用充分的确定性测试和分析相结合的方法足以表明其功能确定性,确保其在机载设备中的使用安全性。通过对现有适航咨询通告、工业标准及实践指南等资料的分析和研究,旨在梳理出简单用户微编码器件通过充分的确定性测试和分析相结合的方法表明适航符合性需满足的相关要求和关键要素,为机载设备制造商完成简单用户微编码器件的适航验证提供支持和帮助。     

基于CMMI的软件测试项目过程管理

针对独立的第三方软件测试项目特点,运用基于CMM I的软件项目管理方法,将需求管理、测试项目策划、项目监督与控制、质量保证和配置管理要求贯彻在软件测试过程中,给出了软件测试项目过程管理解决方案。该方案保证了软件测试项目的质量,提高了测试项目的技术水平和管理水平。     

一种VxWorks BSP 软件自动生成技术的设计与实现

VxWorks BSP 软件的可视化开发和代码自动生成技术是基于BSP 中最小系统配置单元组件化封装 以及常用外设驱动的标准化、通用化、组件化设计与封装实现的。该技术的实现可以使开发人员能够通过在可 视化工具中填写对应硬件信息，完成BSP 软件代码及对应文档的自动生成，实现了软件需求的直观化输入到 需求与设计的黑盒转化。能有效提高软件开发效率，增加软件成熟度，提高软件产品质量。     

Quality and security, they work together

The importance of considering computer security as part of the software quality assurance practice is discussed. Issues that point to the need for integration of quality assurance and computer security disciplines are raised. To address some of these issues, the NASA Automated Information Security (AIS) program is presented as a model that may be used for improving interactions between the quality assurance and computer security community of professionals. The information presented does not comprise an answer to documenting all computer security interactions with quality assurance, but it does present a currently working baseline model and can serve as a basis for future research and discussion     

编制摸拟器设计和性能数据要求的初步考虑

在研制飞行模拟器时，飞行模拟器的设计和性能数据是必需的。这些数据不仅是形成满足飞行模拟器各种规范和标准要求的基础，而且也是构成模拟器逼真度要求的基础。根据国际航空运输协会的要求，初步讨论了编制飞行模拟器设计和性能数据要求所考虑的因素。     

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SCADE的飞控软件的适航验证与确认

中国民用航空规章第25部对机载软件提出了适航要求,DO178B是对适航要求的符合性方法,但其中一些验证和确认目标并不适用于基于SCADE的软件验证。为此,分析了飞控软件的适航要求和符合性方法,并对基于SCADE的飞控软件的开发流程和传统的开发流程进行了分析对比,对基于SCADE的飞控软件的适航验证与确认工作提出了建议。     

System integration: performance doesn't measure-up

The issues that arise in system integration are examined. These relate to software, subsystem mismatch, interface standards, human resource allocation, requirements, and testability. Long-term goals are discussed     

民用飞机刹车控制系统软件构型管理研究

民用飞机刹车控制系统构型管理在系统设计开发过程和适航符合性验证过程中发挥着关键作用。为了提升民用飞机刹车控制系统软件构型管理能力,使该系统设计开发的软件满足适航要求,介绍刹车控制系统软件构型管理的概念和方法,描述如何运用系统思维和信息化流程手段将构型管理和软件设计相结合,开展软件全生命周期过程构型管理活动。结合DO-178C 的要求,提出建立以产品构型为核心的构型数据数字化管理机制,实现刹车控制系统软件研制的单一数据源。结果表明：通过和构型基线管理相结合建立一个统一的构型数据库,在构型库中严格按照阶段的状态进行准确记录,确保了状态信息的实时性、可追溯性、完整性及有效性,达到了最终构型控制目标,可以满足适航要求。     

面向高级在轨系统的动态服务质量保证方法研究

AOS(Advanced Orbiting System,高级在轨系统)已经逐渐被各国空间组织采用,随着空间任务的发展趋势更多样化和复杂化,对AOS的QoS(Quality of Service,服务质量)也提出了更高要求.针对AOS服务质量的提升需求,提出了一种虚拟信道优先级策略,使用大容量缓存结合数据压缩动态策略和遥测数据抽帧策略相结合的QoS保证方法,通过分析返向链路带宽与航天器遥测用户带宽的裕量,可以动态调整QoS保证,以适应不同应用环境下的航天器AOS的QoS保证需求.通过模拟不同的工况进行仿真试验,结果表明,该AOS服务质量保证方法适用于返向链路带宽裕量充足和不足的工况,比传统的全同步策略和同步异步结合策略拥有更广泛的适应范围.     

新形势下航天测控系统建设转型思考

针对航天测控系统建设目前所面临的角色定位转换、功能体制转型,以及任务要求不断提高、测控技术快速发展等新形势和新要求,分析了航天测控系统的建设管理和功能体制现状,提出了坚持一体规划、推动系统建设,坚持与时俱进、提升建设标准,坚持信息主导、突出建设重点的系统建设转型思路.并在此建设思路的基础上,提出了装备研制向型谱化、标准化转型,维修保障向全寿命、体制化转型,软件开发向产品化、装备化转型,以及推进一体化网络化、强化综合能力、重视安全性可靠性等建设举措.     

电子产品中铅焊接金脆问题浅析

针对航天电子产品广泛采用的Sn-Pb焊料在镀金表面焊接形成焊点的工艺,分析了工业及国内外航天相关标准文件中对焊接后焊点中含金量的要求以及焊点含金量、时效、器件不同封装形式对焊点可靠性的影响,并深入分析了合金焊点金相组织结构,最后介绍了一般去金工艺要求与去金不到位而导致器件失效案例。