IMA aircraft improvements

Integrated modular avionics (IMA) is being suggested as the means by which new capabilities can be deployed on aircraft at an affordable cost. RTCA SC-200 is presently considering the guidance document for IMA. All of the functionality that IMA offers can be achieved through a conventional federated architecture; however, the cost, size, and weight penalties of the federated solution make it economically infeasible. IMA is seen as the way forward. It is assuming greater importance as the aircraft industry transitions to commercial-off-the-shelf (COTS) technology with its attendant obsolescence and reliability concerns. IMA may be one of the most cost-effective ways by which rapid obsolescence can be managed. Ironically, this move to COTS is also the greatest threat to IMA systems. IMA achieves reductions in size, cost, and weight by providing a set of flexible hardware and software resources that can be statically or dynamically mapped to a set of required avionics functional capabilities. This introduces a number of new complexities such as mixed criticalities and reconfiguration. We do not address these issues herein. Rather we discuss the mechanisms by which electronics degrades and how a classical safety assessment of a reconfigurable IMA system can be ified by this degradation. We argue that, with the advent of COTS, it is no longer justifiable to consider that electronics has an effectively constant failure rate. Physical considerations suggest that electronics failure occurs when environmental and operating stress causes the accumulation of damage to the underlying structures to exceed the threshold strength of the constituent materials and interfaces. Finally, we suggest how finite-life electronics effects may be mitigated.     

Digital avionics-an international perspective

It is maintained that the dynamism of electronics technology, especially in displays, microprocessors and software, makes for exciting promises and problems in avionics. International barriers are disappearing, and the trends towards downsizing, new alliances, and consolidation should ultimately lead to a stronger avionics industry worldwide     

1553 emulation over ATM (asynchronous transfer mode)-a hybridavionics communications architecture

The issue of meeting the higher communications requirements of future aircraft avionics systems in an incremental manner is addressed. A communications architecture is proposed which is based upon a switched network technology from the telecommunications area asynchronous transfer mode (ATM). However, the major step of migrating all existing avionics equipment into an ATM compliant form is avoided by the process of “emulating” a current avionics data bus such as MIL-STD-1553B over an ATM network. This allows current 1553 subsystems to co-exist with ATM compliant equipment on a single physical ATM network     

Year 2000 impact on automated testing

Both US military and industry rely on automatic testing to verify the quality of manufacture and repair. Many testers still rely on computers designed and manufactured in the early 1980's. This includes systems using embedded controllers. Year 2000 problems can surface in computer operating systems, compilers, test programs, and in embedded systems. Until the impact of the Y2K “bug” is addressed, the risk of test program failure is unknown in most legacy automatic test systems. Problems may include embedded controllers in proprietary designs, old operating systems, and unique test program code. This paper will address the potential problem areas in automatic testing, and suggest an approach for determining the best course of action. In order to evaluate the impact, a complete systems inventory must be done to identify all potential sources of problems. Little attention has been paid to the legacy automated test systems and the potential impact of the Y2K problem on such systems. Although newer systems are less likely to be affected, no one can be sure until a complete inventory and test has been accomplished     

Aging avionics and net-centric operations

The transformation to net-centric operations necessitates evaluation of existing avionics capabilities, identification of deficiencies of these avionics for net-centric operations, and evaluation of alternative avionics that can provide the needed capabilities. The Global Information Grid (GIG) enables net-centric operations. The purpose of the GIG is to provide end users real-time or near-real-time access to multiple information sources ranging from airborne/satellite/ground sensors (video imagery and processed visual information/data) to databases. The end users in an aircraft view and interact with this information through the human system interface (HSI) or "smart" displays. The information is transmitted across a Gigabit Ethernet on-board the aircraft that interfaces with multiple channels of a software programmable radio that acts as a hub in the GIG network, or on-board sensors and processors. This paper presents the mandated capabilities, and the processes involved in determination of upgrades needed to achieve net-centric operations.     

基于COTS的航空电子软件开发

介绍了商用货架产品(COTS)在航空电子软件开发中应用的优点和缺点,和基于COTS的航电软件构架;并给出了一个开发过程和部分开发工具。最后通过一个实例说明基于COTS的航电软件开发是实际可行的。     

Sustainment of legacy automatic test systems: lessons learned on TPS transportability

Sustainment of legacy automatic test systems (ATS) saves cost through the re-use of software and hardware. The ATS consists of the automatic test equipment (ATE), the test program sets (TPSs), and associated software. The associated software includes the architecture the TPSs run on, known as the control software or test station test executive. In some cases, to sustain the legacy ATS, it is more practical to develop a replacement ATE with the latest instrumentation, often in the form of commercial off-the-shelf (COTS) hardware and software. The existing TPSs, including their hardware and test programs, then need to be transported, or translated, to the new test station. In order to understand how to sustain a legacy ATS by translating TPSs, one must realize the full architecture of the legacy ATS to be replaced. It must be understood that TPS transportability does not only include translating the original TPS from an existing language (such as ATLAS) to a new language (such as "C") to run on a new test station, but includes transporting the run-time environment created by the legacy ATS. This paper examines the similarities and differences of legacy ATE and modern COTS ATE architectures, how the ATS testing philosophy impacts the ease of TPS transportability from legacy ATE to modern-day platforms, and what SEI has done to address the issues that arise out of TPS transportability.     

Aviation electronics/avionics

International regulations prohibit aircraft from entering high-density airspace and heavily trafficked over-ocean airways without suitable avionics. The widespread use of GPS navigation and increasing complexity of passenger entertainment systems have become the latest electronics trends on large commercial aircraft. The cost of avionics plus software is approaching 50% of the total. New aircraft have multiple computers and millions of lines of software. The following sections present the most important avionics subsystems and highlight some differences between military and commercial aircraft     

基于机载多核弱序存储模型的共享内存驱动软件设计方法研究

随着航空电子系统承载的应用日趋复杂,飞机对机载计算机的计算力和功耗比要求不断提升,这也推动了嵌入式多核处理器的加速应用和普及。多核处理器在航空电子设备的深入应用,随之而来的是运行其上的软件复杂度急剧上升,面向应用的航电系统设计面临挑战。多核处理器平台由于需要面对并行、指令乱序、资源共享冲突等问题,而目前国内大多数机载嵌入式软件和驱动仍然是基于单核处理器设计和实现的,影响最大的是在机载嵌入式实时操作系统环境下的驱动软件,因此需要充分考虑多核带来的各方面影响,尤其是需要兼顾共享内存等资源的使用冲突和实时高效要求。本文结合机载航电多核处理平台的特点,提出了一种基于机载多核弱序存储模型的共享内存驱动软件设计方法,并基于该方法设计了FC 总线驱动和MBI 总线驱动,项目应用结果表明,设计的驱动程序在多核处理器平台上数据传输正确,验证了方法的正确性和有效性。     

Embedded information system re-engineering

Currently fielded embedded information systems face readiness challenges imposed by evolving missions and extended service lifespans. The ability to overcome these challenges is constrained by such factors as shrinking budgets, limited computational capacity and diminished manufacturing sources effects that impact both hardware and software options. Wholesale redevelopment is often cost prohibitive, particularly since large portions of embedded applications continue to fulfil mission requirements. Solutions must preserve prior investments while providing efficient pathways for continued technology refresh. A technology solution for affordable modernization of legacy system software is being development. The Embedded Information System Re-engineering (EISR) project is developing an automation-assisted JOVIAL-to-C re-engineering capability that permits simultaneous modernization of both the structure and source language of legacy embedded applications. Engineers will be able to apply the proven labor-saving visualization and analysis features of modern CASE tools to legacy JOVIAL applications. EISR will thus allow the DoD to recapture previous investments in proven legacy algorithms and mission capabilities while permitting the full exploitation of COTS economies of scale. This paper describes in brief the goals and objectives of the EISR project, and provides the current status of the EISR capability.     

Multi-computer VXIbus system set up and use

VXI has matured into a flexible bus architecture with which to develop various types of instrumentation systems. This paper details the multi-computer approach used in the VXI-based system that CACI developed for the Air Force. The system, the Engine Test/Trim Automated System II (ETTAS II) is designed to test: all Air Force jet engines. The paper discusses how to integrate multiple computers in a VXI-based system, including discussions on: setting up the computers; selecting register-based versus message-based computers; setting up and using shared-memory; defining and separating tasks for each computer. The shared memory discussion talks about different ways to structure the shared memory, including setting up a system-level “Current-Value Table” (CVT) for all instruments, as well as how other devices, including another computer can access the shared memory space. The paper shows how Commercial-Off-the-Shelf (COTS) software products NI-VXI, LabVIEW, and NI-VISA (National Instruments) can be used to satisfy all these requirements. The paper shows how the multi-computer approach can be cost-effective in many cases     

Next generation space avionics: layered system implementation

Advances in electronics over the past decade have produced major improvements in the power and flexibility of computer systems. Unfortunately current avionics systems for space applications typically have not leveraged these COTS advantages. A decade ago, the state-of-the-art for avionics systems made a step change to the Integrated Modular Avionics (IMA) used in the Boeing 777. This next generation avionics architecture is not based upon traditional Byzantine redundancy structures, but on a truth-based scheme where each element knows when an internal failure occurs and removes itself from the system. IMA utilizes a lock-step microprocessor design that communicates to a COTS Backplane for input/output, and to a Virtual Backplane/spl trade/ (a reliable high-speed serial bus) for intra-system communication. The system functions are implemented using a time and space partitioned operating system. The entire system provides the simplicity of a simplex system, implements the highest level of reliability providing complete flexibility to reconfigure both software applications and hardware interfaces, allows for rapid prototyping using low-cost COTS hardware, and is easily expandable beyond the initial point implementation. As the only 5/sup th/ generation avionics architecture, the concepts incorporated into Honeywell's IMA are ideally suited to be the backbone of the next generation Space Exploration Program avionics architectures.     

Avionics cost of ownership

The cost of ownership of avionics includes not only the development and acquisition cost, but also the yearly operating and support (O and S) (maintenance) cost of hardware, software, and support equipment. This paper presents an avionics cost of ownership methodology developed for USAF, its data sources, and business metrics computed for USAF decision makers as we move toward operating avionics as a business. The business model is used to determine which existing avionics are candidates for replacement with new technology and to prioritize the replacements. These avionics are often used on multiple aircraft types which necessitates analysis of the causes of the high cost of ownership on each type. Databases are used to document the processing functions, data flow, and constraints of the item being analyzed. These constraints include physical, environmental, electrical, and data interfaces. Databases containing alternatives are evaluated against standard mission scenarios for aircraft utilizing these high cost avionics to determine their impact on performance, O and S costs, and mission effectiveness. The results of the foregoing analyses steps are then used in life cycle cost analyses which consider different retrofit scenarios for each alternative for each aircraft type against the avionics being analyzed for replacement. The alternatives are prioritized and a risk analysis performed considering technical, schedule, and cost growth risks. The avionics cost of ownership methodology described in this paper processes data from USAF maintenance organizations. This has revealed the very large expenditures being made to support highly unreliable avionics. These methods can be applied to all military and commercial aircraft systems to determine not only the cost of ownership of existing systems, but also the cost of ownership of new systems when they are retrofit     

Integrating system engineering software tools

System engineering projects typically involve the use of a variety of design, analysis, simulation, and management software tools that are home-grown or commercial-off-the-shelf (COTS). Very often, these applications are hosted on dissimilar computing platforms in a network environment. An application deployed on one platform may not be easily ported to another platform, and it usually cannot be readily accessed by software on the other platform. Enhancing the inter-operation among software applications or tools will greatly increase the effectiveness of the system engineering process. The middleware technology currently being developed by the computer industry promises to provide the needed software interface for integrating tools across a heterogeneous computer network. This paper discusses the experience of applying the middleware technology to software tools used in system engineering     

机载嵌入式软件的系统测试

针对航空电子系统的功能特点,分析了某航电分系统控制管理计算机软件的特征和要求,结合机载嵌入式软件的系统测试需求,提出利用航电分系统设计开发试验平台,通过总线上的故障注入和数据采集方法,实现机载嵌入式软件的系统测试。     

航空电子系统中应用多核处理器的挑战分析

作为嵌入式计算的一种,航空电子系统中的处理器具有强实时性、高确定性、高安全性的特征。因此,同其他嵌入式系统相比,在航空电子系统中应用多核处理器面临更多的挑战。针对多核处理器基本的软硬件架构,对挑战产生的原因进行了简要的分析,指出了在航空电子系统中应用多核处理器需要解决的问题。     

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     

Development of a TPS reuse library using COTS tools

In the past, functional test requirements (FTR) or test requirement documents (TRD) and test program sets (TPS) were standalone items developed by individual engineers. In some cases, one engineer would write the FTR/TRD and another would develop the TPS. Commercial ATLAS FTRs are prepared in ARINC 616 and 626 ATLAS. Military TRDs are written in IEEE ATLAS 716 versions. Previous test reuse attempts have not been successful because additional software, like browsers, is required to support these efforts. It was difficult to justify writing new software; for example, browsers to manage the application software. Today, commercial-off-the-shelf (COTS) tools are in place to browse and view information from circuit diagrams to documents to source code. These tools can develop hierarchies to organize the information. These COTS tools are available throughout Boeing on many types of workstations and personal computers on every engineer's desk. This paper discusses how a reusable test library (RTL) is being developed using commercial-off-the-shelf (COTS) tools, such as Mosaic, to address commercial and military test applications. It describes each of the tools and the process to develop TPSs using the reuse library. It defines the metrics and benefits achieved     

Use of service history for certification credit for COTS [avionic software]

Much has been written in the last ten years about how the use of commercial-off-the-shelf (COTS) components would revolutionize the aerospace industry avionics, communication, navigation, surveillance/air traffic management (CNS/ATM) as well as global air traffic management (GATM). Civil aviation authorities around the world have been faced with numerous requests to certify aircraft containing increasing percentages of COTS components, much of it never designed or intended for use in the safety critical environment of an aircraft. Product service history is one method for demonstrating that such software is acceptable for use. In theory, product service history would seem to be a fairly simple concept, both to understand and to apply. However, in practice, such use has proven extremely problematic, as questions of how to measure the historic performance and the relevance of the provided data have surfaced. This paper elaborates a research effort funded by the United States Federal Aviation Administration to collect, analyze, and synthesize what is known and understood about applying product service history. The effort is limited to the topic of software product service history as applied in the certification of airborne systems and equipment.     

面向适航符合性的智能航电系统认证研究进展

民用飞机航电系统引入人工智能/机器学习技术会带来可信性、不确定性和可解释性等问题,有必要通过有效的符合性方法向公众与利益攸关方证实智能航电系统的适航安全性。首先,分析了智能航电系统的等级分类和应用现状,阐述了现有指南和标准的适用性;然后,基于对当前研究成果的梳理,总结了包含可信度分析、安全性评估、安全风险缓解和认证/批准活动的智能航电系统认证框架实施流程及其技术细节;最后,给出智能航电系统在全生命周期各个阶段的符合性验证要求及实现方法建议,评估了符合性验证对现有适航体系的影响,为民用飞机智能航电系统的设计与认证提供了参考依据。