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Digital Avionics Systems Conference, 2009. DASC '09. IEEE/AIAA 28th

Date 23-29 Oct. 2009

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  • [Copyright notice]

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  • Conference general chair

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  • [Table of contents]

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  • Comparing two industry game changers: Integrated modular avionics and the iPhone

    Page(s): 1.A.1-1 - 1.A.1-13
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (354 KB) |  | HTML iconHTML  

    Many aircraft owners and operators have asked, ¿Why can't avionics systems on my aircraft subscribe to the innovative design principles of my cell phone?¿ This common revelation is driven by the fact that cell phones are typically characterized as cheap, yet powerful electronic devices that drive the leading edge of technology. In contrast Avionics are typically characterized as the polar opposite: expensive electronic devices that are based on old, previous-generation technology. This paper explores the cell phone product model and compares it to the avionics product model. The objective is to highlight concepts that can drive avionics innovation as well as to highlight the fundamental differences between avionics and consumer electronics products. The most notable product in the cell phone market today is the Apple iPhone1. The iPhone is a successful, transformational cell phone product that has changed the cell phone market. It provides a good case study since there is a lot of data available for this product. The question is to identify how that technological success can be applied to an avionics product. To this end, the iPhone is compared to Integrated Modular Avionics (IMA), which has also been a game changer. Both products provide a general processing platform that has redefined their respective industries. This comparison aims to highlight lessons learned from the iPhone success that can drive IMA product success. In addition, the comparison aims to highlight the differences between the products to explain why an avionics system is more expensive and larger in size than a consumer electronics product such as a cell phone. View full abstract»

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  • An integrated modular avionics development environment

    Page(s): 1.A.2-1 - 1.A.2-9
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    The ARINC 653 standard has taken a leading role within the aeronautical industry in the development of safety-critical systems based on the Integrated Modular Avionics (IMA) concept. One of the main promises of IMA is cost saving in reduced development, integration and verification and validation effort. To exploit the full potential of cost savings, it is necessary to establish an effective way to prototype, develop, test and analyse on-board applications without having access to the final IMA target platform for all engineers. Target platforms are usually extremely expensive considering hardware and software prices as well as training costs. This paper describes the architecture of the Integrated Modular Avionics Development Environment (IMADE) that is based on Linux and the ARINC 653 simulator Simulated IMA (SIMA) that was developed by Skysoft Portugal, 2007-2009. View full abstract»

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  • Implementing logical synchrony in integrated modular avionics

    Page(s): 1.A.3-1 - 1.A.3-12
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    Many avionics systems must be implemented as redundant, distributed systems in order to provide the necessary level of fault tolerance. To correctly perform their function, the individual nodes of these systems must agree on some part of the global system state. Developing protocols to achieve this agreement is greatly simplified if the nodes execute synchronously relative to each other, but many Integrated Modular Avionics architectures assume nodes will execute asynchronously. This paper presents a simple design pattern, Physically Asynchronous/Logically Synchronous (PALS), that allows developers to design and verify a distributed, redundant system as though all nodes execute synchronously. This synchronous design can then be distributed over a physically asynchronous architecture in such a way that the logical correctness of the design is preserved. Use of this complexity reducing design pattern greatly simplifies the development and verification of fault tolerant distributed applications, ensures optimal system performance, and provides a standard argument for system certification. View full abstract»

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  • Re-configuration of task in flight critical system — Error detection and control

    Page(s): 1.A.4-1 - 1.A.4-10
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    The paper presents the error detection and control for control metrics of the re-configuration algorithm in an embedded avionics application with extensive checks and validation. This is being carried out in real-time for decision-making. The success of the re-configurable algorithm is based on the integrity of the data from multiple sources. Hence, the integrity checks of these sources need to be controlled and maintained. Integrity checks as part of error detection and control mechanism is implemented using the Hamming code with error detection and error handling capabilities. The paper presents the experimental simulation studies in both Xilinx platform and VxWorks with target. The control parameters used in the re-configuration algorithm is treated with phase conditions of flight, data sampling and averaging before it is being applied for decision-making process. The integrity and error control/detection is quite critical particularly for the validation of control parameters used for re-configuration in the algorithm and hence the error detection and control scheme is designed and simulated using the Xilinx FPGA platform. The paper presents the algorithm in brief, data sampling techniques based on multiple threshold, identification of phases in flight, error detection/control mechanisms for data integrity and validity. The experimental and simulation studies related to the above areas are detailed with results. View full abstract»

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  • Challenges in updating military safety-critical hardware

    Page(s): 1.A.5-1 - 1.A.5-8
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (181 KB) |  | HTML iconHTML  

    In this paper, we describe challenges and suggest solutions when upgrading military safety-critical hardware where RTCA/DO-254 never was applied but is required now and not only for application specific integrated circuits (ASICs), programmable logic devices (PLDs), and complex commercial-off-the-shelf (COTS) but for all hardware. Several challenges relate to modification to previously developed hardware resulting from hardware or technology enhancements, or procurement difficulties. View full abstract»

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  • Enabling FlexRay for avionic data buses

    Page(s): 1.B.1-1 - 1.B.1-14
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    The aeronautic industry and its suppliers show increasing interest in utilizing the automotive FlexRay protocol for their applications, more than ever since an opening of the standard for all industries and field of applications becomes apparent. With its combination of deterministic and flexible c o m m u n ication and data rates up to 10 Mbit/s on a single twisted wire pair, FlexRay is a promising candidate for future system developments and the modernization of CAN based systems. Currently, the performance of the protocol is rather unknown i n a n aeronautic environment, in particular with respect to its physical layer. This paper analyzes the signal decoding process of FlexRay and derives dedicated signal integrity criteria for the protocol. An efficient method based on the transmission and evaluation of worst-case bit patterns is developed for the assessment of signal integrity on demanding topologies with significant attenuation and resulting inter-symbol interferences. RS485 is discussed as a possible alternative physical layer for the FlexRay protocol to improve the communication performance. Finally, a use-case topology with a harness length of 90 m is presented to evaluate the achievable performance when utilizing the FlexRay protocol. Signal integrity is demonstrated and validated on the topology at a data rate of 10 Mbit/s to prove the suitability of FlexRay for aeronautic applications. View full abstract»

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  • VOIP in ATC communications — Where are we today

    Page(s): 1.B.2-1 - 1.B.2-9
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    Under the auspices of Eurocae WG-67 industry and global Air Traffic Navigation Service Providers have collectively developed a set of standards, which look promising for global implementation in ATC. This paper provides a compact description of the main notions of the recommendations developed in Eurocae WG-67. Results of interoperability testing and field trials within operational environments conducted in the first half of 2009 are discussed demonstrating the applicability of SIP and RTP protocols to ATC communications. Industry (radio and voice communication systems) and major air traffic navigation service providers (ANSPs) agreed on field trial testing of IP based equipment with the aim to allow for a seamless airspace that is managed flexibly within dynamic airspace blocks. The paper describes selected radio practices and outlines associated requirements for absolute and relative delay as well as minimal end-to-end data rates of ground-to-air transmission compared to results from those field-trials. View full abstract»

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  • Feasibility study of IEEE 802.15.4 for aerospace wireless sensor networks

    Page(s): 1.B.3-1 - 1.B.3-10
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    Wireless communications has been a reliable data link means in many aerospace applications, including critical ones. The major concern for using wireless links for aerospace sensors is the feasibility of their in the aerospace setting; i.e., whether wireless links will negatively affect the overall reliability and safety of the aircrafts. In a previous paper, we studied the feasibility issue and concluded that with appropriate choice of wireless communication schemes and parameters, the wireless links can have reasonable immunity to interferences, low interference to other on-board wireless systems, and good security performance. In this paper, we consider the feasibility of adapting an existing technology, IEEE 802.15.4, to implement the wireless links for aerospace sensors, with focuses on immunity to interferences and data security. We conclude that a wireless network based on IEEE 802.15.4-compatible devices is appropriate for non-critical aerospace applications, at least from building a demo system's point of view. View full abstract»

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  • AFDX software network stack implementation — Practical lessons learned

    Page(s): 1.B.5-1 - 1.B.5-10
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    AFDX is gaining traction all over the avionics market, and even in some surprising areas outside of avionics, because it offers adopters the advantages of Ethernet network connectivity and bandwidth that they have been waiting to make use of for many years. This paper will begin by outlining some basic principles of AFDX versus standard Ethernet and explaining why it is such an important standard with respect to providing the inherent safety and security mechanisms that the avionics community requires. It will then discuss AFDX end system implementation options by contrasting many of the most common arguments for and against the implementation of an end system AFDX stack in software versus hardware. This paper will go on to provide some practical insight by examining a real software AFDX end system implementation and will provide feedback on the experience gained during the development of that implementation, including practical limitations, measured performance, processing platform considerations and lessons learned. In conclusion the paper will consider some possible future AFDX enhancements, look at industry trends and provide a look at other market segments that appear to be seriously considering the adoption of AFDX, and will attempt to provide some reasons why. View full abstract»

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  • Collaboration of wake vortex models and sensors in modern avionic systems

    Page(s): 1.C.1-1 - 1.C.1-9
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (342 KB) |  | HTML iconHTML  

    Today's airport capacity is severely limited by separation of approaching and to a lesser extent departing aircraft to ensure that following aircraft do not encounter the wake vortex generated by the preceding one. The encounter of wake vortices, especially during take-off and landing, can cause critical or even catastrophic flight situations for the succeeding plane. Historically, the wake vortex separation standards are based on a `worst-case-scenario' assuming calm and still air conditions responsible for a relatively long wake vortex lifetime. They have proven sufficiently safe but are unnecessarily limiting capacity in favourable, even in average weather conditions. Thus a capacity increase brought about by any change in separation rules has at least to preserve (or, given the expected traffic growth, even improve) the current level of safety. Accordingly, wake vortex warning systems have been devised to increase airside capacity and are nearing experimental implementation. The current systems contain a forecasting component based on meteorological conditions and on propagating the vortex evolution. Secondly a sensing system is ensuring the required level of safety. Both the model predictions and the sensing systems each have their advantages but also individual drawbacks. This paper presents a novel approach on collaboration of the wake vortex prediction and the sensing part. A general overview on the wake vortex phenomenon is given and an approach of fusing the wake vortex prediction with wake vortex measurement is shown. By means of examples the major advantages of the collaboration approach are presented. A discussion on implementation constraints of the proposed system closes the paper. View full abstract»

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  • Analysis of advanced flight management systems (FMS), flight management computer (FMC) field observations, trials; lateral and vertical path integration

    Page(s): 1.C.2-1 - 1.C.2-16
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1824 KB) |  | HTML iconHTML  

    The differences in performance of various manufacturers' flight management systems (FMSs) and their associated flight management computers (FMCs) have the potential for significant impact on the air traffic control system and as such need to be examined and reexamined. While area navigation (RNAV) and required navigation performance (RNP) procedures and routes are designed according to criteria contained in Federal Aviation Administration (FAA) orders, FMC manufacturers build their systems in accordance with minimum aviation system performance standards (MASPS) and minimum operational performance standards (MOPS) for area navigation systems, technical service orders and advisory circulars. It is anticipated that the resulting performance of the aircraft FMC will meet the procedure design requirements identified in the FAA criteria. Airlines and air traffic controllers have as their goal flight procedures where aircraft operations meet expectations for repeatability and predictability to levels of performance sufficient to support performance based operations in the National Airspace System (NAS). Sometimes, due to the nearly independent development of procedure design criteria and aircraft performance standards, the paths of various aircraft on the same procedure do not overlap and do not match the expectancy of the procedure designer. These differences may result from any or all of the following: variations in FMC equipment installed on the aircraft; variations and errors in procedure coding in the FMC navigation database; variations in aircraft-to-FMC interface and associated aircraft performance capabilities; and variations in flight crew training and procedures. The hypothesis of this paper is that the basic FMCs built by avionics manufacturers and installed as the core of the FMC/FMS combinations in various airframe platforms perform differently and we will attempt to quantify those differences. This paper focuses on aspects of lateral and vertical flight FMC - performance when processing mandatory block altitudes, aircraft bank angle on turns above flight level nineteen thousand five hundred feet (FL195), determining the vertical transition point at fly-by waypoints, and execution of optimized profile descents (OPDs). Public instrument procedures flown using RNAV are used as the baseline for measuring performance variations. Controlled field observations trials were made using thirteen test benches and four simulators at seven major FMC manufacturers and three airlines. The intent of this report is to contribute technical data as a foundation for the acceptance of mandatory block altitude usage in RNAV and basic RNP procedures; allow standard instrument departure (SID) and standard arrival (STAR) procedure design criteria to utilize bank angles in excess of five degrees above FL195; satisfy an open FAA/Industry Aeronautical Charting Forum issue concerning the vertical transition point at fly-by waypoints; and assess FMC processing of an optimized profile descent. View full abstract»

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  • An analysis of low-cost simulated flight management systems for aviation research

    Page(s): 1.C.3-1 - 1.C.3-9
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    High fidelity Flight Management System (FMS) simulators are available as add-ons for Microsoft Flight Simulator. These FMS add-ons cost no more than $100 and are used by virtual pilots on personal computers to enhance the realism of their aviation experience. Are these low-cost simulators sufficiently capable to support NextGen aviation research? This paper assesses the fidelity of these low-cost desktop simulators by comparing simulated flight tracks, from several varieties of simulated FMS, to operational flight tracks from commercial airlines using real FMSs, and flight tracks produced by a GE Aviation FMS test bench. Some uncertainty exists in the results of ground speed analysis; however the lateral and vertical flight profiles produced by the FMS simulators correlate well with the test bench output and operational data. View full abstract»

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  • Flight management system prediction and execution of idle-thrust descents

    Page(s): 1.C.4-1 - 1.C.4-12
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    To enable arriving aircraft to fly optimized descents computed by the flight management system (FMS) in congested airspace, ground automation must accurately predict descent trajectories. To support development of the predictor and its uncertainty models, descents from cruise to the meter fix were executed in a B737-700 simulator with a commercial FMS using vertical navigation. The FMS computed the intended descent path for a specified speed profile assuming idle thrust after top of descent (TOD), and then it controlled the avionics without human intervention. The test matrix varied aircraft weight, descent speed, and wind conditions. The first analysis in this paper determined the effect of the test matrix parameters on the FMS computation of TOD. Increasing weight by 10,000 lb moved TOD about 4.5 nmi farther from the meter fix, increasing along-track wind by 25 kt moved it about 4.6 nmi farther away, and varying the descent speed from 250 KCAS to 320 KCAS moved the TOD about 25 nmi. The execution of the descents was analyzed by comparing simulator state data to the specified speed profile and to the FMS predictions. The FMS generally flew its predicted three-dimensional trajectory accurately, with altitude error less than 200 ft. It engaged the throttle if the speed dropped 15 KCAS below the target speed but allowed the speed to increase arbitrarily above the target unless it reached a performance limit. In the runs with descent speed too slow but correct wind conditions, the FMS meter fix arrival time prediction error was as large as 37 sec. Along-track wind error of 25 kt resulted in a meter fix arrival time error of roughly 30 sec if the target descent speed was met. The data from this analysis are used to estimate accuracy requirements for the ground automation system. View full abstract»

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  • Trajectory prediction for low-cost collision avoidance systems

    Page(s): 1.C.5-1 - 1.C.5-8
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    In this paper, a novel algorithm for estimation, filtering and prediction of glider and light aircraft trajectories based on GPS measurements is introduced. The algorithm uses Interacting Multiple Model (IMM) filters to detect specific maneuvers such as turning, circling or straight flight. An integrated wind model allows for quick estimation of local wind fields and helps achieving consistent prediction quality in windy conditions. The algorithm is shown to perform well compared to algorithms currently used in the FLARMreg collision avoidance system, particularly in windy conditions. View full abstract»

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  • Performance-based navigation fleet equipage evolution

    Page(s): 1.D.1-1 - 1.D.1-8
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (365 KB) |  | HTML iconHTML  

    As fleet avionics continue to evolve, the use of the solutions provided by performance-based navigation (PBN) will continue to grow and provide benefits to the aircraft operators. Due to these potential benefits, several air carriers in the United States have announced plans to retro-fit their fleets with PBN capabilities. However, it is important to understand the current snapshot of avionics, as well as the historic growth before analyzing the future forward-fit scenarios. Since 2004, the MITRE Corporation's Center for Advanced Aviation System Development (CAASD) has monitored the navigational avionics for Part 121 United States airlines. In this time span, the number of Part 121 airframes has dropped by more than 400 aircraft while the number of Part 121 aircraft with a flight management computer (FMC) has grown at approximately the same rate. This has resulted in a fleet wide growth in the percent of aircraft operating with an FMC from 79% to 90%. Also, the number of aircraft operating with a Global Positioning System (GPS) (also known as Global Navigation Satellite System (GNSS) navigational sensor) has grown with 1,100 additional aircraft operating with a GNSS sensor today. This has resulted in a growth from 47% of the aircraft in 2004 to 66% of the aircraft. There have been three primary reasons for the growth of PBN operational capability: equipped aircraft delivered to the system, current fleet retro-fits, and new knowledge of the airline operators. This paper will discuss the current equipage trends, capability, and identify the evolutionary change in Part 121 PBN avionics from 2004 through 2008. Additionally, this paper will discuss the next generation of aircraft and potential future scenarios for fleet avionics. View full abstract»

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  • New vehicle technologies and the next generation airspace system

    Page(s): 1.D.2-1 - 1.D.2-11
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    This paper discusses the impact of new vehicle technologies on the Next Generation Air Transportation System (NextGen). Five specific new vehicles are analyzed. The five vehicles, the analysis method, and sample results for three vehicles are presented. The main goal this paper is to analyze if new vehicles can help bridge the gap between anticipated air traffic demand twenty to thirty years from now and the air traffic demand that can be accommodated by implementing NextGen airspace system improvements. View full abstract»

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  • Electronics modernization as a competency

    Page(s): 1.D.3-1 - 1.D.3-9
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    The US industrial base has a large set of capabilities that is sometimes difficult to track as an acquisition official. Where the Department of Commerce helps track the most important technological inputs into Army Modernization and individual companies track technological inputs into their own modernization, some of the actual capabilities to `modernize' and upgrade existing electronics are hard to find or evolve rapidly. This paper describes capabilities that have proven to be valuable competencies when modernizing embedded electronics, and what tools and personnel are needed to provide an effective and efficient modernization capability. This will help the acquisition officer or procurement manager know what questions to ask and skills to demand from modernization suppliers. View full abstract»

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  • Algorithmic and architectural methods for performance enhancement of avionics systems

    Page(s): 1.D.4-1 - 1.D.4-6
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    Many studies on managing obsolescence and refreshing technology concentrate on replacing hardware to improve the performance of legacy systems. In contrast, the author's research has concentrated on the development of methods that can significantly enhance the performance of legacy systems while requiring few or no hardware modifications. If hardware replacement is allowed, these methods can be leveraged to further improve the upgraded systems. The methods can be characterized either as algorithmic or architectural methods. Algorithmic methods include techniques such as new data compression routines. A previous paper by the author and a fellow researcher has presented data compression routines that are suitable for implementation on legacy MIL-STD-1553 data buses. As expected, these routines where shown to increase the communication throughput. What may be less obvious is that they also increased the time available to perform computation. Architectural techniques include repartitioning of software functions and/or communications to free system resources. This paper presents these and other methods for increasing the performance of legacy avionics systems. The same techniques can also be applied to improve the design of new systems. View full abstract»

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  • Accomplishing equipage for NextGen

    Page(s): 1.D.5-1 - 1.D.5-10
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    The benefits of Next Generation Air Transportation System (NextGen) depend heavily on avionics, but building business cases for operators to expend funds for avionics retro-fit equipage is often very challenging; operators tend to require short times for return on investment and low risk. When the benefits of equipping involve Air Traffic Management (ATM), they are dependent on successful transition of one or many of automation, infrastructure, routes and procedure design, and the equipage of other aircraft - each the responsibility of stakeholders other than the equipping operator. To be successful, ongoing and future transitions involving avionics must be planned based on the way operator Value depends on breadth of aircraft Equipage. This must consider existing equipage and benefits independent of ATM changes, the nature of mixed equipage operations and benefits, and the allocation of benefits during transition. The economic relationships between Value and the Equipage are a strong determinant for what strategies for motivating equipage will be effective. For NextGen ATM-related avionics, risk avoidance, collaborative risk reduction, and performance-based operational incentives (operationally justified procedures implementing Best-Equipped Best-Served) will be essential to these transitions. View full abstract»

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  • Avionics architecture interface considerations between constellation vehicles

    Page(s): 1.E.2-1 - 1.E.2-10
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    In January 2004, the National Aeronautics and Space Administration (NASA) received new strategic guidance for Space Exploration. With this new guidance, the manned spaceflight community was given an exciting opportunity to develop new human qualified space vehicles based on the latest technology and methodology. The scope of NASA's Constellation program encompasses all elements that must work together to successfully complete the mission of returning humans to the moon. These elements include a launch system, crewed vehicle, and landing module, to name a few. Each element within the Constellation Program is considered a separate development project and this has led to the selection of different avionics architectural approaches on different vehicles. Additionally, legacy systems such as the International Space Station must also interface with the Constellation system. Interfaces between these elements (new and legacy), and especially between their avionics systems, must be carefully integrated to ensure mission success. This paper discusses considerations for the interoperability of varying avionics architectures within a complex system of systems such as Constellation. Currently, two of the major elements within the Constellation system are advancing into the design phase: the Orion Crew Exploration Vehicle (CEV) and the Ares I Launch Vehicle. These vehicles have chosen different avionics architecture approaches. The Orion vehicle is implementing an Integrated Modular Avionics (IMA) architecture with high integrity self-checking pair processors for fault management, while the Ares I element is implementing a Federated Avionics architecture with some integrated characteristics and a voting scheme for fault management. This paper discusses implications on the design of each vehicle due to the interface requirement between these two different avionics approaches. View full abstract»

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