Abstract: An Overview of the Systems Engineering and Vehicle Design Process The Conceptual Design and Tradeoffs Process Taking a Closer Look at the STS Design Sequence Aerothermodynamics Discipline Thermal Heating and Design Structures and Materials Propulsion Systems Flight Mechanics and Trajectories Avionics and Flight Controls Multidisciplinary Design Optimization Life Support and Human Factors/Ergonomics Payloads and Integration Launch and Mission Operations Related Topics and Programmatics Appendices

Abstract: This paper describes the avionics developed for a miniature acrobatic helicopter and the applications for such a system. The avionics system is designed to safely achieve a robust, high-bandwidth feedback control system while meeting physical specifications. The system that is currently implemented has provided an efficient platform for testing new closed-loop controllers and has yielded critical flight data used for developing simple models of small-scale helicopter dynamics. The helicopter has already demonstrated successful flight under a body-axis velocity/heading rate-tracking controller.

Abstract: The new technologies in flight control avionics systems selected for the Boeing 777 airplane program consists of the following: Fly-By-Wire (FBW), ARINC 629 Bus, Deferred Maintenance. The FBW must meet extremely high levels of functional integrity and availability. The heart of the FBW concept is the use of triple redundancy for all hardware resources: computing system, airplane electrical power, hydraulic power and communication path. The architecture of the 777 flight controls system follows the earliest Boeing 7J7 design. The Boeing designed global DATAC bus, also known as ARINC 629 data bus, is used to communicate among all computing systems. Each DATAC bus is isolated, both physically and electrically from the other two. The three DATAC buses are not synchronized. The control system performance under the autonomous and asynchronous DATAC bus operation has been studied. The primary flight computers (PFCs) form a triple-triple redundant system; three PFC channels and three computing lanes in each channel. Each channel is also isolated, both physically and electrically from the other two. The microprocessor hardware for three computing lanes in each channel are dissimilar to facilitate detection of generic design errors of the most complicated hardware devices; microprocessors. The Byzantine general problem has been considered in the design of the PFC redundancy management to cope with functional asymmetry and communication asymmetry. The deferred maintenance is to provide hot spare modules within an LRU such that the airplane dispatchability can be enhanced. This concept is applied to the three major avionics systems, PFC, Air Data Inertial Reference System (ADIRU) and Airplane Information Management System (AIMS).

Abstract: An aircraft display and control system generally includes a processor, a cursor control and selection device, a multifunction keyboard, an aeronautical information database, a geographic database, and a plurality of display devices. Users, such as an aircraft pilot and copilot, can perform flight plan entry and modification by manipulating graphical and textual information on the display devices using the cursor control device and the multifunction keyboard. In one embodiment, the present invention provides an interface to flight deck information systems that is intuitive and easy to use, and which enables flight crew members to easily and effectively enter and modify data displayed by the aircraft flight deck, substantially centralizes avionics controls within one controller, and decreases flight crew “heads-down” time.

Abstract: We present an embedded autopilot design for the Stanford DragonFly Unmanned Aerial Vehicle (UAV) of which the digital computer in the avionics is only capable of processing sampled data and executing discrete-time control policies. We demonstrate that linear control design is not sufficient to satisfy performance requirements for specified high performance maneuvers at slow sample rates. We design a new nonlinear digital controller using an approximate feedback linearization. The sampled nonlinear dynamics for the feedback linearization is obtained using the Adams-Bashforth method, and the resulting control law is augmented with the discrete disturbance accommodation control to improve the performance and stability of the controlled system. The control law is implemented on a Hardware-in-the-Loop Simulation, which is a testbed platform that provides a faithful laboratory representation of the DragonFly UAV in flight: sensor and actuator packet delay and communication constraints in the control, are included in this testbed. We evaluate the control law using different sample rates and present our results. Keyword: UAV flight control, discrete-time control policy, approximate feedback linearization, disturbance accommodation, embedded systems.

Abstract: This paper describes the avionics developed for a miniature acrobatic helicopter and the applications for such a system. The avionics system is designed to safely achieve a robust, high-bandwidth feedback control system while meeting physical specifications. The system that is currently implemented has provided an efficient platform for testing new closed-loop controllers and has yielded critical flight data used for developing simple models of small-scale helicopter dynamics. The helicopter has already demonstrated successful flight under a body-axis velocity/heading rate-tracking controller.

Abstract: The DragonFly experimental test bed is a platform that supports new research and innovations in navigation, fault tolerant control and multiple vehicle coordination. It consists of two UAVs with modular onboard avionics packages, which communicate through a wired and wireless network to the ground and lab development systems running QNX real-time OS. Its modularity and networked architecture is key in supporting such a wide range of concurrent research. This paper gives an overview of the DragonFly experimental test bed and the specific research goals that it currently supports.

Abstract: Over the past 30 years, safety-critical avionics systems such as fly-by-wire (FBW) flight controls, full-authority digital engine controls, and other systems have been introduced on many commercial and military airplanes and spacecraft. Early FBW systems, such as on the F-16 and Airbus A320, were considered revolutionary and were introduced with extreme caution. These early systems and their successors all make use of redundant and fault-tolerant avionics to provide the required dependability and safety, but have used significantly different architectures. This paper examines the different levels of criticality and fault tolerance required by different types of avionics systems, establishes architectural categories of fault-tolerant architectures, and identifies the discriminating features of the different approaches. Examples of discriminators include the level of redundancy, methods of engaging backup systems, protection from software errors, and the use of dissimilar hardware and software. The strengths and weaknesses of the different approaches are identified. The paper concludes with some speculation on trends for future systems based on this evaluation of previous systems.

Abstract: Methods and apparatus are provided for airspace navigation. Airspace navigation information for an aircraft is displayed in a first mode, such as, in a horizontal mode. One or more navigation events may then be detected, such as, proximity to a terrain feature, weather, traffic etc. The airspace navigation information for the aircraft is then displayed using dual modes, e.g., a horizontal mode and a vertical mode. Display parameters, such as colors, resolution, distance, scale, etc. may be set automatically or by a user. The display may also include information, such as avionics systems information, and communications information.

Abstract: An avionics maintenance training device to train cognitive and psychomotor skills is disclosed. The training device is a physical mock-up of an actual aircraft's cabin assembly. The avionics maintenance training device includes actual avionics components and non-functional and functional physically replicated avionics components of the actual aircraft. The avionics maintenance training device further includes an instructor workstation, a simulator/stimulator, and an interactive electronic training manual. The training device runs the actual operational flight program of the aircraft. The replicated components are three-dimensional components with physical characteristics similar to the avionics components they replicate to teach component removal and replacement skills. The actual and replicated avionics components are located in the training device in positions similar to positions of the avionics components in the aircraft to replicate accessibility. The training device also includes replicated cables that connect to the functional physically replicated components and the simulator/stimulator. The training device further includes placards to replace avionics components that are not pertinent to training.

Abstract: The Space Shuttle navigation architecture was originally designed in the 1970s A variety of on-board and ground based navigation sensors and computers are used during the ascent, orbit coast, rendezvous, (including proximity operations and docking) and entry flight phases With the advent of GPS navigation and tightly coupled GPS/INS Units employing strapdown sensors, opportunities to improve and streamline the Shuttle navigation process are being pursued These improvements can potentially result in increased safety, reliability, and cost savings in maintenance through the replacement of older technologies and elimination of ground support systems (such as Tactical Air Control and Navigation (TACAN), Microwave Landing System (MLS) and ground radar) Selection and missionization of "off the shelf" GPS and GPS/INS units pose a unique challenge since the units in question were not originally designed for the Space Shuttle application Various options for integrating GPS and GPS/INS units with the existing orbiter avionics system were considered in light of budget constraints, software quality concerns, and schedule limitations An overview of Shuttle navigation methodology from 1981 to the present is given, along with how GPS and GPS/INS technology will change, or not change, the way Space Shuttle navigation is performed in the 21 5 century

Abstract: As civil controlled airspace moves toward requiring new communication capabilities, the military will need to equip their aircraft if worldwide, unrestricted airspace access is to be maintained. The USAF has built a Reconfigurable Cockpit and Avionics Testbed (RCAT) with VHF, HF and SATCOM data links and ground stations to demonstrate the utility of these data links. This facility has been used to evaluate techniques available to encrypt ACARS data link messages. This paper discusses the results of these demonstrations and documents the strengths and limitations of the "commercial-off-the-shelf" (COTS) equipment and infrastructure for security of military AOC messages. It also hopes to stimulate discussion among military users about requirements for their use of ACARS.

Abstract: An Xcell-60 5 foot rotor diameter hobby helicopter was instrumented to perform autonomous aggressive maneuvers. The avionics system, state estimator design, and vibration isolation are presented. An analysis of helicopter dynamics based on manual flight data is given.

Abstract: This paper is a proposal for a future method of avionics data communication. The need for this proposal results from the shortcomings in the current avionics architecture, video distribution network, and in the MIL-STD-1553 data communication system. The separately wired video and data communication systems can be combined to save weight, which is especially critical for rotorcraft. Aircraft, once fielded, have limited capacity for modification and improvement due to fixed computer throughput and processing performance, network bandwidth, and space available in the avionics equipment bays. The changes proposed by this paper are to be made in conjunction with the replacement of the redundant computer boxes with open system avionics functions on industry standard circuit cards. This open architecture approach was developed over the last ten years and is now being implemented in many aircraft applications including the F-22 and the RAH-66 programs. The V-22 rotorcraft, which although just entering production, is being modified for joint service customers where modern computer performance and expanded data network bandwidth is needed. The changes of this proposal will fill this need, reduce the weight of upcoming production models, and provide growth or spare capability so that additional video and data components can be added with minimal effect on existing components. This paper examines the current V-22 avionics video and data communication hardware and wiring and propose a new implementation of open system architecture standards with integrated digital video and data communication based on ANSI standard copper fibre channel.

Abstract: Safe, reliable, and low cost space-based navigation is being provided with embedded INS/GPS systems such as the space integrated GPS/INS (SIGI). The SIGI is being used for various space vehicle applications such as launch vehicles, orbital vehicles, and re-entry vehicles. This paper describes current space vehicle navigation capabilities. The SIGI is being enhanced to provide additions to these existing capabilities with such items as higher processing and a commercial-off-the-shelf operating system. This will allow hosting of various software applications such as advanced navigation functions, flight control, guidance and vehicle management algorithms. The SIGI can host redundancy management functions by incorporating a cross channel data link card (CCDL) using a high speed firewire bus. The SIGI can then be used as a redundancy management platform which has application to current space vehicle avionics topologies incorporating distributed processing architectures.

Abstract: Speech recognition features desired by air traffic controllers, such as the ability to use complex messages and address hundreds of individual aircraft could not be implemented a decade ago, but these tasks became possible with improved speech recognition engines and an increase in processing power and memory. Speech recognition was a key element in the air traffic controller (ATC) workstation used to support a Controller-Pilot Data Link Communications (CPDLC) system. Our work, under the direction of the Avionics Engineering Center at Ohio University, was in support of the Federal Aviation Administration's (FAA) Runway Incursion Reduction Program (RIRP) and the National Aeronautics and Space Administration's (NASA) Runway Incursion Prevention System (RIPS) conducted at the Dallas-Fort Worth International Airport (DFW). This paper examines the challenges and opportunities of developing voice recognition software solutions in ATC workstations using multiple dialects and accents, complex and varied grammars and terminology, accuracy, hardware restrictions, and user-training procedures.

Abstract: The X-33 is an unmanned advanced technology demonstrator with a mission to validate new technologies for the next generation of Reusable Launch Vehicles. Various system redundancies are designed in the X-33 to enhance the probability of successfully completing its mission in the event of faults and failures during flight. One such redundant system is the Vehicle and Mission Computer that controls the X-33 ea, and manages the avionics subsystems. Historically, redundancy management and applications such as flight control and vehicle management tended to be highly coupled. One of the technologies that the X-33 will demonstrate is the Redundancy Management System (RMS) that uncouples the applications from the redundancy management details, in the same way that real-time operating systems have uncoupled applications from task scheduling, communication and synchronization details.

Abstract: An electronic radio system multifunction slice (100) for a electronic radio system (400). The slice (100) includes an antenna interface (102), several multi-band transceivers (106-112), a processor (104), and an avionics interface (114). The antenna interface (102) couples to the antenna preconditioners of the aircraft. The processor (104) is coupled to the multi-band transceivers (106-112) and antenna interface (102), and controls the transceivers (106-112) and antenna interface (102) to provide signal and data processing for at least two independent radio function threads. The processor (104) is also coupled to the avionics interface (114), which connects to the avionics network of the aircraft. Each multifunction slice 100 provides a programmable multifunction radio.

Abstract: A common flight deck module for use with a plurality of aircraft platforms. The common flight deck module includes a discrete structure that is independent of the structure of the aircraft fuselage and may includes an avionics system and other hardware, controls and equipment. The common flight deck module is configured to “plug into” the fuselage from each of the aircraft platforms. The “plug in” modularity of the common flight deck module permits the standardization of various components and procedures to thereby make possible efficiency-based cost reductions for both aircraft manufacturers and aircraft consumers.

Abstract: While today's aircraft have integrated alerting systems for conditions inside the aircraft (ECAM, EICAS), there is no comparable fully integrated alerting system for conditions outside of the aircraft. Current and near-future, separate alerting systems warn of conditions such as time-critical terrain, traffic, wind shear, clear air turbulence, wake vortices, each using different alerting and display philosophies to present information to the flight crew. Separate systems contribute to alert proliferation and the potential for multiple conflicting alerts during emergency situations. An integrated alerting system should deconflict alerts, and present information in an integrated fashion. In response to these issues, we have developed the Alerting and Notification of Conditions Outside the Aircraft (ANCOA) concept. Key aspects of the concept include: (1) deconflicting currently separate alerts such as TCAS and EGPWS; (2), categorization (weather, traffic, ground) and prioritization (time-critical, tactical and strategic) of alerts to reduce pilot information processing requirements; (3) directional, multidimensional aural cueing to allow quick "pre-processing" of the condition (this aids in time-critical responses and prioritizing the alerted condition relative to the ongoing task); and (4) integrated graphic presentation of conditions external to the aircraft to support better situation awareness. This paper discusses the theory and implementation of the ANCOA concept, and presents a usability study to evaluate the display configuration, ease-of-use, functionality, and navigation of information within an initial simulator prototype. Nine pilots participated in six scenarios under various conditions in the Honeywell Laboratories Medium-Fidelity Flight Simulator. Additionally, pilots conducted an information categorization task, filled out pre- and post-questionnaires, and were interviewed for qualitative assessments. The data were used to assess if the ANCOA integrated system could effectively prioritize and de-conflict information, support improved detection and identification of threats, increase overall situation awareness, and support better planning decisions. A revised prototype is presented, based on the results of the evaluation.

Abstract: A system and method for debugging a partitioned avionics computer which uses a debugging dump memory and a debugging dump memory controller which take control of the main system bus of the computer for a predetermined amount of time.

Abstract: Avionics Specialties in partnership with Honeywell has developed an integrated air data pressure sensor known as the integrated multi-function probe (IMFP). This continuously flow-aligned pressure-sensing device was developed using a multidisciplinary design approach encompassing computational fluid dynamic. (CFD), flow analysis, and experimentation. The computational investigation was performed using the finite element code, CFDesign, by Blue Ridge Numerics and consisted of pressure distribution studies for varying flows around conical sections. The application and integration of this technology to previously developed flow alignment and pressure transducing products lead to design similarity analysis saving considerable development time. Initial experimentation used to develop and refine the design and analysis consisted of laboratory bench testing, low and high-speed wind tunnel investigations, and subsonic flight-testing. Final performance verification was accomplished through data reduction and analysis of an extensive flight test program using a Lockheed Martin F-16 Fighting Falcon

Abstract: : The intent of this report is to provide findings about the state of the industry relative to the design objectives identified in guidance document DO-254 with focus on the implications for the use of commercial off-the shelf (COTS) electronic hardware components in safety critical airborne systems. The use of complex electronic hardware components in airborne systems poses a challenge to the meeting of safety requirements because, for complex components, complete verification is, at best, very difficult and, at worst, not achievable. In order to address the potential lack of complete verification, it is recommended that the hardware design life cycle processes should include design assurances to mitigate the possibility that design errors may be introduced into the hardware component and cause anomalous behavior. New technologies, being developed in the commercial sector, could provide enhanced safety in airborne systems if the technologies could be incorporated at an affordable cost. However, the use of COTS components in airborne systems raises a number of issues with respect to meeting airborne system safety requirements and DO-254 objectives. Commercial market trends are rapidly diverging from the needs of safety critical airborne systems. Issues with respect to COTS usage may become barriers in certain cases, if necessary assurances cannot be achieved in a cost effective manner. The assurances required for high criticality applications such as levels A and B will probably not be attainable for COTS components without mitigation by other means.

Abstract: A low cost MEMS inertial measurement unit (IMU) has been developed to be submitted for FAA approval. The system is a part of the Crossbow Technology, Inc AHRS500GA family of inertial sensor products. The system is an unaided, high performance, solid-state attitude and heading reference system intended for General Aviation applications. The strap-down inertial system provides attitude and heading measurement with static and dynamic accuracy comparable to traditional spinning mass and directional gyros. The system has been designed to comply with the Federal Aviation Authority's (FAA) high standards of safety and reliability, including extensive built in test (BIT) capability. Crossbow will demonstrate to the certification authority all of the concepts and methodologies employed to produce reliable software per guidelines in DO-178B "Software Considerations in Airborne Systems and Equipment Certification." Consideration will be given to all aspects of software production: planning, design, verification,management and quality control. Further, the system will provide an accurate inertial reference in avionic dynamic environments including altitude, temperature, shock, and vibration according to the guidelines in DO 160D "Environmental Conditions and Test Procedures for Airborne Equipment." The unit will be certified and manufactured according to the minimum performance standards described in: • TSO-C4c - Bank and Pitch Instruments • TSO-C3d - Turn and Slip Instrument • TSO-C6d - Direction Instrument, Magnetic (Gyroscopically Stabilized) In addition, a supplementary type certification (STC) will also be submitted for the unit as a primary flight instrument for Class I-III aircraft. The process of certification can be daunting, particularly the software certification effort.

Abstract: A method to detect application spoofing in a mixed use avionics display by indicating when a mixed use avionics display is displaying information from a non-certified source. The method comprises providing an avionics display having a display area that is capable of displaying information from a non-certified source. A data connection is established between the non-certified source and the avionics display. Information is provided from the non-certified source to the avionics display through the data connection. The information from the non-certified source is then displayed on the display area so that less than then entire display area is used in displaying the information. The displaying of information from the non-certified source on less than then the entire display area gives a visual indication that the information being displayed on the avionics display is from a non-certified source and susceptible to interference by a remote party and possible application spoofing.

Abstract: The automatic flight control computer was a revolutionary development in the early days of flight, even in its primitive electromechanical form. It evolved into an electronic computing device, starting as an analog computer and maturing into software run on a digital, general-purpose microprocessor. The current accepted industry standard is to use a dedicated microprocessor in its own enclosure for this function that is essentially firewalled from the rest of the systems on the aircraft. This paper will explore the opportunity to integrate the flight control function into an integrated processing platform, which is a robustly partitioned platform that supports multiple functions of dissimilar design assurance levels. This approach provides all of the benefits of an integrated system, while still maintaining the separation provided by a stand-alone unit. The paper will consider both the advantages and disadvantages of this approach. The discussion will describe each of the alternatives in general and then focus specifically on autopilot and flight control functions that have potential for integration. The end goal of the paper is to impress on the reader an understanding of the different alternatives available for autopilot, flight control, and avionics modernization in general. This includes the development of a selection matrix that will assist the reader in making decisions on how best to implement these functions according to criticality and the volatility of their future requirements.

Abstract: High performance communications, navigation, and identification (CNI) functions on modern military aircraft are increasingly required for mission readiness. The operation of simultaneous waveforms through an integrated avionics rack of shared resources becomes a test in moving data rapidly from one signal processing stage to the next. The IEEE 1394, or Firewire, is a commercial high bandwidth bus whose 64-bit addressing and maximum 400 Mbits/second throughput satisfies this demanding military avionics interconnect need. The challenge in applying this commercial product to integrated avionics is the requirement to seamlessly add message priority encoding. By having message priorities, the slower strategic communications links will not impair the performance of higher data rate tactical communications, thereby avoiding potentially life-threatening bottlenecks. The flight environment imposes additional challenges to ruggedize the cabling between integrated avionics racks and to utilize the full capabilities of the Firewire bus. A discussion of the physical, data link, network, and transport layers, as used in avionics applications will be done. Additionally, the versatility of 1394 in military avionics with its variable channel sizes, bandwidth on demand, hierarchical addressing, and upgrade to 800 and 1600 Mbps with a 64-bit wide data path, is emphasized. Finally, system maintenance advantages of 1394's hot pluggable features are discussed, with an eye toward cost reduction on the flight line and total operational time of the aircraft avionics systems.

Abstract: This paper describes an to develop an avionics architecture that enables replacement of deficient satellite hardware on-orbit as well as upgrade/adapt on-orbit systems. It is anticipated that routine, safe, and reliable spacecraft servicing will have significant payoff for many future types of science and military missions. The technologies that enable modern satellite servicing will therefore be critical for implementing new space architectures. Satellites that are placed on-orbit and are functionally lost due to simple failures beg for the development of an on-orbit replacement capability. Human intervention in space, however, carries risk and cost associated with it that would not be necessary if an autonomous satellite repair capability was developed. The associated capability to perform preplanned upgrades and adaptations to on-orbit space assets also has the potential for architecting high performance future spacecraft. Such a capability would allow system designers to accommodate differing rates of technology advancement and would minimize the need fore pre-launch risk reduction measures. The first step in developing a serviceable satellite is to evolve the tightly integrated satellite architectures of today toward an architecture that supports functional and/or physical replacement of anomalous or failed hardware. Draper Laboratory has performed a trade study to develop a single-point architecture that provides a growth path from the functionally efficient satellite designs of today to a functionally reliable modular architecture that will support the autonomous on-orbit upgrade and functional enhancement of tomorrow's satellites. This paper presents an overview of an architecture that can enable autonomous satellite servicing.

Abstract: This paper discusses the feasibility of employing reconfigurable hardware in the avionics systems of future generations of launch vehicles for space. Such technology has the potential of being orders of magnitude faster than conventional embedded computer technology for many applications. It can be argued that avionics architectures that use such reconfigurable elements may vastly improve the flexibility, efficiency, performance and reusability of the avionics system. It can also be argued that such a flexible environment will facilitate the implementation of advanced and mission-specific real-time fault tolerance, avoidance, and corrective techniques and would greatly facilitate sensor/data fusion operations. However, before this technology can be applied to such safety critical applications there are several issues that must be resolved. Such issues center around the suitability and robustness of reconfigurable hardware for in-flight operation. In this paper we investigate many of these issues, focussing upon the use of reconfigurable hardware to form a generic multi-functional launch controller element that can be replicated as needed and distributed throughout the launch vehicle.