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This paper studies the problem of aircraft midair conflict resolution, which is a key technology to enable the coordinated and decentralized air traffic control envisioned in the Next Generation Air Transportation System (NextGen). The method proposed in this paper is based on stochastic optimal control, which is able to incorporate uncertainties in both aircraft and wind dynamics. The proposed numerical algorithm uses a Markov chain (MC) to approximate the continuous-time aircraft and wind dynamics, then the optimal control law is derived based on the MC. The proposed algorithm is able to resolve the conflicts between aircraft and moving convective weather regions. For conflict resolution between pairs of aircraft, a decomposition technique is proposed to reduce the computational complexity of the numerical algorithm. Simulations show that the proposed algorithm provides robustness against uncertainties in the system and is suitable for real applications. [ABSTRACT FROM PUBLISHER]

In this article, we consider the problem of autonomous navigation with a microaerial vehicle (MAV) in threedimensional (3-D) confined indoor environments with multiple floors. We present experimental results with ground truth comparisons and performance analysis. We also highlight field experiments in multiple environments. [ABSTRACT FROM PUBLISHER]

Quadrotor microaerial vehicles (MAVs) are simple robotic platforms with regard to their construction. In their basic form, they are no more than two counterrotating propeller pairs attached symmetrically to a rigid crosslike frame, along with the means to control the speed of each individual propeller. This symmetric design has enabled the quadrotor to become a simple but powerful vertical takeoff and landing aerial platform popular among the robotics community. [ABSTRACT FROM PUBLISHER]

An unmanned fying vehicle (UFV) is generally used to search for and track an adversary and even designed to go down with the adversary's vehicle under the extreme conditions of modern wars [1]. The precision of a UFV's electromagnetic sensors generally infuences the accuracy of its guidance. To improve the accuracy of the UFV's guidance system, advanced guidance technologies based on bionic vision have been studied in recent years. Some developments based on bioinspired intelligence [2], [3] have also been investigated for aerial systems. Bionic vision, such as that inspired by the vision of Limulus species (i.e., horseshoe crabs), fruit fies, birds, and humans [4], has become a hot research feld, and some of these new technologies have been applied to missile homing guidance. [ABSTRACT FROM PUBLISHER]

As the population size increases and more people travel by air, it is important that safety of the national air transportation system is maintained at current levels. A number of initiatives have been enacted in order to address safety and performance of the national air transportation system under an increased throughput. The most notable U.S. initiative is NextGen, which involves many aspects of air travel including but not limited to: reconsideration of aircraft travel routes, incorporation of new navigation and surveillance technologies, and new methods for detecting and resolving potential conficts before they occur [1]. [ABSTRACT FROM PUBLISHER]

This article presented extended simulations in order to characterize the interference between multiple airborne and terrestrial mobile terminals. The interference analysis is performed considering three cellular networks: (i) GSM-1800 MHz, (ii) UMTS-2100 MHz, and (iii) UMTS-1800 MHz. In the radio interference study, the impact of the onboard base station emissions on the terrestrial mobile terminals was examined and evaluated. The compound interference (in decibels) with the terrestrial terminal was found to follow the Gaussian distribution. The results showed that there is visibility of the onboard networks in terms of noise floor increase, especially for GSM-1800 MHz networks, and the output of the base station should be adjusted around 0 dBm, if we want to avoid using an extra RF shielding in the aircraft cabin. The results for UMTS-2100 or UMTS-1800 networks showed that there is no need for extra attenuation unless the aircraft base station transmits more than 10 dBm. Finally, a general statistical analysis of SIR on a ground mobile station, taking into account the airborne and terrestrial shadowing parameters, was also presented. [ABSTRACT FROM PUBLISHER]

The joint RTCA SC-217/EUROCAE WG-44 committee completed the latest revisions of the AMDB user requirements and interchange specifications DO-272C and DO-291B in 2011. One of the major novelties is the introduction of the ASRN. The ASRN supports manual editing of taxi routes, data link transmissions of taxi routes, and highly detailed display of taxi routes in the cockpit. [ABSTRACT FROM PUBLISHER]

Purpose – The purpose of this paper is to design a new standard instrument arrival called the point merge system (PMS) for converging runways. The PMS enables controllers to handle traffic with no heading instruction, as well as aiming to reduce a controller's frequency occupancy time. Design/methodology/approach – The point merge model was designed for converging runways. Istanbul International Ataturk Airport, which has converging runways, was chosen as an application area for this model. The same 50 traffic arrivals per hour were used both for point merge and vectoring. Implementation was compared using a real time simulation. Findings – The simulation results show that the total average number of instructions is about 33 per cent less and the frequency occupancy is about 37 per cent less for point merge than for vectoring. In addition, in terms of trajectory dispersion, in point merge, traffic is within a narrower triangular area, while in vectoring large traffic dispersion occurs. Practical implications – The point merge model for converging runways proposed in this paper can be applied by airspace designers and air navigation service providers to perform efficient standard instrument arrival routes. Originality/value – The PMS has been developed for single and parallel runways; however, in this study, the point merge model is designed for converging runways at Istanbul International Ataturk Airport. [ABSTRACT FROM AUTHOR]

Urban search and rescue missions raise special requirements on robotic systems. Small aerial systems provide essential support to human task forces in situation assessment and surveillance. As external infrastructure for navigation and communication is usually not available, robotic systems must be able to operate autonomously. A limited payload of small aerial systems poses a great challenge to the system design. The optimal tradeoff between flight performance, sensors, and computing resources has to be found. Communication to external computers cannot be guaranteed; therefore, all processing and decision making has to be done on board. In this article, we present an unmanned aircraft system design fulfilling these requirements. The components of our system are structured into groups to encapsulate their functionality and interfaces. We use both laser and stereo vision odometry to enable seamless indoor and outdoor navigation. The odometry is fused with an inertial measurement unit in an extended Kalman filter. Navigation is supported by a module that recognizes known objects in the environment. A distributed computation approach is adopted to address the computational requirements of the used algorithms. The capabilities of the system are validated in flight experiments, using a quadrotor. [ABSTRACT FROM AUTHOR]

Virtual target-based path-following techniques are extended to execute the task of vehicle following in the case of unmanned surface vehicles (USVs). Indeed, vehicle following is reduced to the problem of tracking a virtual target moving at a desired range from a master vessel, while separating the spatial and temporal constraints, giving priority to the former one. The proposed approach is validated experimentally in a harbor area with the help of the prototype USVs ALANIS and Charlie, developed by Consiglio Nazionale delle Ricerche-Istituto di Studi sui Sistemi Intelligenti per lAutomazione (CNR-ISSIA). [ABSTRACT FROM AUTHOR]

Purpose |!|#8211; The purpose of this paper is to present an adaptive controller of nonlinear path following for a fix-wing micro-aerial-vehicle (MAV) in flight. The adaptive controller discussed in this work was able to successfully complete the flight tasks in complicated terrain, with improved trajectory tracking precision and flight quality. Design/methodology/approach |!|#8211; The nonlinear desired trajectory was fitted by the method of fifth-order B-splines with a sequence of waypoints which are created and sent by the ground station. According to the relationship between the nonlinear desired trajectory and aircraft|!|#39;s flight path, the authors have built the relevant error equations of position and course under wind disturbances, based on the Serret-Frenet frame. The Lyapunov function can be constructed in virtue of the error equations and desired course function applying the vector field theory. On the basis of Lyapunov stability arguments, the authors have also constituted the course adaptive control law, which is converged asymptotically and stably. Findings |!|#8211; According to the nonlinear desired trajectory fitted by the proposed adaptive control methods, the authors have carried out the flight tests experiments with various positions, courses and airspeeds of aircraft. The experimental results show a good path following, as well as under wind disturbances. Practical implications |!|#8211; A new methodology for the nonlinear path following has been proposed, which is also proven to be promising for other special applications such as the path following in straight-line segment and orbit, etc. Originality/value |!|#8211; The paper provides a novel realization method for accurate path following for MAVs. This method can also be carried out in many applications by a simple hardware. [ABSTRACT FROM AUTHOR]

We present an algorithm for the distributed navigation and conflict avoidance of nonholonomic aircraft-like agents in 3-D space. The proposed feedback control scheme offers improved applicability to aircraft navigation and compatibility with Air Traffic Management practice with respect to previous work. Our approach aims to maintain a desired horizontal velocity for each aircraft, while limiting the climb or descent angle within bounds according to aircraft performance characteristics. Moreover, the algorithm is designed to favor straight and level flight, resulting in more sensible manoeuvres that require reduced steering effort. The proposed control scheme is based on the Navigation Functions methodology and offers formally guaranteed conflict avoidance and convergence properties. The performance characteristics of our method are demonstrated through simulation results. [ABSTRACT FROM AUTHOR]

The SINS with IMU rotated is the high performances position measurement system based on the fiber optic gyroscopes. We have presented a theoretical and experimental study of the IMU rotation. Several experiments have proven that the combination of the SINS with IMU rotation achieves very high performance. SINS size and weight make it particularly suitable as the position measurement system of the small vehicles for which precise position with meter or sub-meter level is a critical issue. The experimental results showed that, the position errors which are calculated by SINS with IMU rotation, are much less than IMU static. Where, the position error which is caused by IMU double-axis rotation is 1.47 nm, which is much less than IMU single-axis rotation 6.06 nm. Therefore, the proposed position determination method is highly beneficial in providing accurate position of vehicle for several navigation applications, such as Missile boat and helicopter take off and landing platform on the aircraft carrier, etc. [ABSTRACT FROM PUBLISHER]

The feasibility of using the physical structure of a passive aerodynamic attitude-stabilization system on a nano-satellite as a multi-frequency antenna is shown. Four metallic strips that deploy from the rear of the satellite provide drag torques that stabilize pitch and yaw. These metallic strips are simultaneously used as an antenna for radio communication. The antenna uses physical band-stop filters on the metallic strips to allow the antenna to resonate at different frequencies. An impedance-matching network provides a 50 ohm match to a single coaxial connector. Full-wave electromagnetic analyses of the complete antenna structure on a three-unit CubeSat are presented, together with measured results. [ABSTRACT FROM AUTHOR]

Herein we have outlined a framework for investigation into the feasibility of using an airship equipped with a GMTI radar payload to provide persistent wide area surveillance sufficient to monitor vehicle and personnel movement on the ground. A study and analysis needs to be performed in order to determine the system requirements and the feasibility of modifying a currently existing radar system to adequately perform the required functions. This has described a methodology for determining if and how, existing airborne or ground-based MTI radar systems could be modified to perform these functions. [ABSTRACT FROM PUBLISHER]

Satellite navigation has been used for aircraft navigation for more than 50 years. In the last ten years, the capabilities of satellite navigation have been expanded to more demanding phases of flight, in particular vertical guidance down to 200 ft, thanks to the implementation of augmentation systems. In this paper, we attempt to predict the state of satellite navigation in the next 15 years. We will start by reviewing the challenges that must be addressed by satellite navigation for aircraft guidance. Then, we will describe the current techniques that enable satellite navigation for aviation and the level of performance they achieve today. This will be followed by a description of the upcoming changes to satellite navigation, which include the launch of new constellations and the introduction of new civil signals. Despite these developments, satellite navigation is inherently vulnerable to radio-frequency interference so that backup navigation systems are still necessary. Nonetheless, these improvements will have a great impact on the availability and level of service achieved by satellite navigation, in particular enabling worldwide coverage of vertical guidance. [ABSTRACT FROM PUBLISHER]

To commemorate the centennial of the Proceedings of the IEEE, several authors from diverse areas of expertise examine space exploration from its beginnings in the middle of the last century and look onward to half a century in the future. Beginning by examining the reasons why the two 20th century superpowers believed that space exploration was an important investment, the chronological review of early developments includes discussions on science, commerce, and national security; the evolution of space-related technologies; progress and advancements in launch vehicles, spacecraft, and spacecraft payloads; and improvements in space communications and tracking. With the subjects of robotic solar system exploration and crewed missions to space discussed in some detail, the great advances of the last 60 years establish a foundation for addressing the challenges of future human flight beyond Earth's vicinity—challenges that are technical, political, social, and economic in nature. The authors take a pragmatic view in making forecasts for the future of spaceflight: they limit their conjecture, for the most part, to the next 50 years. While it is very difficult to make realistic predictions for longer periods, the authors are confident that space exploration continues to grasp the public's imagination and desire to know more about the universe, and that it continues to build on many of the same questions that inspired the space program in the mid-20th century. [ABSTRACT FROM PUBLISHER]

The continuous growth of air traffic demand, skyrocketing fuel price, and increasing concerns on safety and environmental impact of air transportation necessitate the modernization of the air traffic management (ATM) system in the United States. The design of such a large-scale networked system that involves complex interactions among automation and human operators poses new challenges for many engineering fields. This paper investigates several important facets of the future ATM system from a systems-level point of view. In particular, we develop a hierarchical decentralized decision architecture that can design 4-D (space+time) path plans for a large number of flights while satisfying weather and capacity constraints of the overall system. The proposed planning framework respects preferences of individual flights and encourages information sharing among different decision makers in the system, and thus has a great potential to reduce traffic delays and weather risks while maintaining safety standards. The framework is validated through a large-scale simulation based on real traffic data over the entire airspace of the contiguous United States. We envision that the hierarchical decentralization approach developed in this paper would also provide useful insights into the design of decision and information hierarchies for other large-scale infrastructure systems. [ABSTRACT FROM PUBLISHER]

Inspection aircraft equipped with cameras and other sensors are routinely used for asset location, inspection, monitoring, and hazard identification of oil-gas pipelines, roads, bridges, and power transmission grids. This paper is concerned with automated flight of fixed-wing inspection aircraft to track approximately linear infrastructure. We propose a guidance law approach that seeks to maintain aircraft trajectories with desirable position and orientation properties relative to the infrastructure under inspection. Furthermore, this paper also proposes the use of an adaptive maneuver selection approach, in which maneuver primitives are adaptively selected to improve the aircraft's attitude behavior. We employ an integrated design methodology particularly suited for an automated inspection aircraft. Simulation studies using full nonlinear semicoupled six degree-of-freedom equations of motion are used to illustrate the effectiveness of the proposed guidance and adaptive maneuver selection approaches in realistic flight conditions. Experimental flight test results are given to demonstrate the performance of the design. [ABSTRACT FROM AUTHOR]

The characterization of complex air traffic situations is an important issue in air traffic management (ATM). Within the current ground-based ATM system, complexity metrics have been introduced with the goal of evaluating the difficulty experienced by air traffic controllers in guaranteeing the appropriate aircraft separation in a sector. The rapid increase in air travel demand calls for new generation ATM systems that can safely and efficiently handle higher levels of traffic. To this purpose, part of the responsibility for separation maintenance will be delegated to the aircraft, and trajectory management functions will be further automated and distributed. The evolution toward an autonomous aircraft framework envisages new tasks where assessing complexity may be valuable and requires a whole new perspective in the definition of suitable complexity metrics. This paper presents a critical analysis of the existing approaches for modeling and predicting air traffic complexity, examining their portability to autonomous ATM systems. Possible applications and related requirements will be discussed. [ABSTRACT FROM PUBLISHER]

The increasing congestion of commercial airspaces necessitated more efficient air traffic control (ATC) methods. The Automatic Dependent Surveillance-Broadcast (ADS-B) protocol is at the heart of the next-generation of ATC systems and is currently being rolled out in most countries. With ADS-B, an aircraft determines its own position by using global navigation satellite systems and broadcasts it periodically over the 1090-MHz radio frequency to ground stations or other aircraft in proximity. This approach increases the accuracy of aircraft localization and enables lower separation requirements and improved situational awareness for pilots and controllers. At the same time, it is supposed to significantly reduce the costs of air traffic surveillance compared with former independent surveillance radar systems. [ABSTRACT FROM PUBLISHER]

Abstract: Ionospheric disturbances are known to have adverse effects on the satellite-based communication and navigation. One particular type of ionospheric effects, observed during major geomagnetic storms and threatening the integrity performance of both ground-based and space-based GNSS augmentation systems, is the sharp increase/decrease in the ionospheric delay that propagates in horizontal direction, thus called for convenience ‘moving ionospheric wall’. This paper presents preliminary results from researching such anomalous ionospheric delay gradients at European middle latitudes during the storm events of 29 October 2003 and 20 November 2003. For the purpose, 30-s GPS data from the Belgian permanent network was used for calculating and analysing the slant ionospheric delay and total electron content values. It has been found that, during these two particular storm events, substantial gradients did occur in Europe although they were not so pronounced as in the American sector. [Copyright &y& Elsevier]

When using airborne LIDAR to produce digital elevation models, the Global Positioning System (GPS) positioning of the LIDAR instrument is often the limiting factor, with accuracies typically quoted as being 10-30 cm. However, a comprehensive analysis of the accuracy and precision of GPS positioning of aircraft over large temporal and spatial scales is lacking from the literature. Here, an assessment is made of the likely GPS contribution to the airborne LIDAR measurement error budget by analyzing more than 500 days of continuous GPS data over a range of baseline lengths (3-960 km) and elevation differences (400-2000 m). Height errors corresponding to the 95th percentile are < 0.15 m when using algorithms commonly applied in commercial software over 3-km baselines. These errors increase to 0.25. m at 45 km and > 0.5 m at 250 km. At aircraft altitudes, relative heights are shown to be potentially biased by additional errors approaching 0.2 m, partly due to unmodeled tropospheric zenith total delay (ZTD). The application of advanced algorithms, including parameterization of the residual ZTD, gives error budgets that are largely constant despite baseline length and elevation differences. In this case, height errors corresponding to the 95th percentile are < 0.22 m out to 960 km, and similar levels are shown for one randomly chosen day over a 2300-km baseline. [ABSTRACT FROM AUTHOR]

In the 2020 time frame, the Global Positioning System (6PS) will be fully modernized, and other satellite navigation systems will be operational. With an additional layer of fault detection, these systems will provide vertical guidance worldwide. This capability will be born of three important technologies. First and foremost, avionics will receive signals on two frequencies: LI/EI and L5/ESa. This frequency diversity will do much to obviate the impact of ionospheric storms that troubles aviation use of GPS today. Secondly, a multiplicity of data broadcasts will be available to convey integrity information from the ground to the airborne users. These will include the navigation satellites themselves, geostationary satellites, and possibly terrestrial transmitters. However, the most important change will be the most subtle. The fault monitoring burden will be split between the aircraft and the supporting ground systems in a new way relative to the fault-detection techniques used in 2008. This new integrity allocation and the associated architectures are the subject of this paper. [ABSTRACT FROM AUTHOR]

Abstract-We present a novel planning strategy which is applicable to high performance unmanned aerial vehicles. The proposed approach takes as input a 3-D sequence of way-points connected by straight flight trim conditions, and "smooths" it in an optimal way with the goal of making it compatible with the vehicle dynamics. The smoothing step is achieved by selecting appropriate sequences of alternating trims and maneuvers from within a precOmputed library of motion primitives. The resulting extremal trajectory is compatible with the vehicle and therefore trackable with small errors; furthermore, it is guaranteed to stay within the flight envelope boundary, alleviating the need for flight envelope protection systems. Yet it can be computed in real-time using closed-form expressions, all nonlinearities due to the vehicle model being confined to the stored library of motion primitives. The new method is demonstrated for the aggressive maneuvering of a helicopter. [ABSTRACT FROM AUTHOR]

The specialists at M.M. Gromov Flight Research Institute (FRI) have developed special techniques and facilities to evaluate the aircraft pilot - navigational equipment for conformance to specified requirements. On-board trajectory measurement complex equipment is used for data recording and determination of actual values of trajectory parameters. The parameter values are obtained using the differential mode of the satellite navigation system. The flight test process is monitored at the flight test control center. The use of a test-bench and simulation complex allows reducing the scope and costs of flight tests. Flight test data are transmitted to the specialists for processing via local computer network on the day of flight tests. This covers the description of facilities used for testing pilot - navigational equipment of new aircraft at the M.M. Gromov Flight Research Institute. [ABSTRACT FROM PUBLISHER]

A description of the design, operation, and test results of a Micro-Electro-Mechanical (MEMS)-based navigation system for the Micro Air Vehicle (MAV) is presented. The MAV is a small Unmanned Aerial Vehicle (UAV) built by Honeywell. It is one of the first applications to use Honeywell's new HG1930 MEMS inertial measurement unit (IMU). The raw IMU measurements are transmitted via a serial interface to a processor board where the inertial solution is blended in a Kalman filter with measurements from GPS, a barometric altimeter, and a magnetometer. The navigation is performed by Honeywell's ECTOS lie navigation software. The modular ECTOS architecture allows easy customization for use with various IMUs and aiding sources, creating a flexible navigation solution which can be customized to the user's requirements. The MAV has been extensively flight tested both on- and off-tether. Results are presented showing the performance of the MAV navigation system. [ABSTRACT FROM PUBLISHER]

Global Positioning System (GPS) receivers and GPS-based swath guidance systems are used on agricultural aircraft for remote sensing, airplane guidance, and to support variable-rate aerial application of crop inputs such as insecticides, cotton growth regulators, and defoliants. Agricultural aircraft travel at much greater speeds than ground equipment (65 m/s, typically), so longitudinal (along-track) error in GPS-derived position is likely to be pronounced. Due to rapid ground speeds, determination of exact GPS-derived aircraft location requires special methodologies. To meet the need for determining ground position accurately, a ground-based spotting system using two strategically placed mirrors was designed to reflect sunlight to the belly of the aircraft when the plane passed over a ground reference point. The light beam was detected by a photocell on the airplane, causing a solid state relay to close through appropriate circuitry. When the relay closed, a record was placed in the data file for the airplane's Satloc GPS receiver, accurate to 0.01 s allowing exact position to be logged. Two stand-alone GPS receivers were evaluated along with the Satloc system, and their readings were compared with readings from the Satloc. For one day of testing used as an example, the Satloc lagged the ground reference point by an average of -4.53 m (S.D. = 0.68) in the east-west directions and led the reference point in the north-south directions by an average of +7.88 m (S.D. = 0.52). Positioning data from one stand-alone GPS receiver showed a distinct ground speed dependency, making it unsuitable for use in aircraft. Output from the other receiver (designed for aircraft use) was insensitive to ground speed changes but exhibited a look-ahead equivalent to 2-s at the ground speeds evaluated. [ABSTRACT FROM PUBLISHER]

Purpose – To study the application of three-dimensional differential geometric (DG) guidance commands to a realistic missile defense engagement, and the application of the Newton's iterative algorithm to DG guidance problems. Design/methodology/approach – The classical differential geometry theory is introduced firstly to transform all the variables in DG guidance commands from an arc length system to the time domain. Then, an algorithm for the angle-of-attack and the sideslip angle is developed by assuming the guidance curvature command and guidance torsion command equal to its corresponding value of current trajectory. Furthermore, Newton's iteration is utilized to develop iterative solution of the stated algorithm and the two-dimensional DG guidance system so as to facilitate easy computation of the angle-of-attack and the sideslip angle, which are formulated to satisfy the DG guidance law. Findings – DG guidance law is viable and effective in the realistic missile defense engagement, and it is shown to be a generalization of gain-varying proportional navigation (PN) guidance law and performs better than the classical PN guidance law in the case of intercepting a maneuvering target. Moreover, Newton's iterative algorithm has sufficient accuracy for DG guidance problem. Originality/value – Provides further study on DG guidance problem associated with its iterative solution. [ABSTRACT FROM AUTHOR]

The small aircraft transportation system (SATS) concept envisions doorstop to destination transportation in a safe and timely manner. Data communications are a key component in achieving the aviation-related operational performance improvements that are sought. However, data communication doesn't start when you get into the aircraft; it starts back at the location where the flight is planned. In fact, data communications support the pilot in all phases of the flight: flight planning, pre-flight, departure, en route, transition, approach, landing, and rollout as well as for a missed approach. The Internet is being used to perform flight planning activities, and the mobile communications available today support Internet access en route to the departure airfield. On-board the aircraft, data communications provide surveillance and air traffic control (ATC) support to the pilot. The location of other aircraft is available to the pilot and ATC system through automatic dependent surveillance-broadcast (ADS-B) and traffic information service-broadcast (TIS-B) applications that transmit the location of other aircraft in the vicinity. Other aircraft locations are used to forecast potential conflicts and, thus, enhance flight safety. As the aircraft nears a SATS-equipped airfield, the pilot uses data link messages to request a landing sequence. The airport management module (AMM) provides a landing sequence assignment to the aircraft. As the pilot maneuvers the aircraft for a landing, he/she is using data-linked surveillance data to determine the location of other aircraft and maintain a safe separation distance between aircraft even in a low visibility environment. [ABSTRACT FROM PUBLISHER]

A description of the design, operation, and test results of a miniature, low-cost, integrated GPS/inertial navigation system that uses commercial off-the-shelf micro-electro-mechanical system (MEMS) accelerometers and gyroscopes. The MEMS inertial measurement unit (EMU) is packaged in a small size and provides the raw EMU data through a serial interface to a processor board where the inertial navigation solution and integrated GPS/inertial Kalman filter is generated. The GPS/inertial software integration is performed using NAVSYS' modular InterNav software product. This allows integration with different low-cost GPS chip sets or receivers and also allows the integrated GPS/inertial navigation solution to be embedded as an application on a customer's host computer. This modular object-oriented architecture facilitates integration of the miniature MEMS GPS/INS navigation system for embedded navigation applications and is designed to handle the large errors characteristic of a low-grade MEMS IMU. Test results are presented showing the performance of the integrated MEMS GPS/inertial navigation system. Data is provided showing the position, velocity, and attitude accuracy when operating with GPS aiding and also for periods where GPS dropouts occur and alternative navigation update sources are used to bound the MEMS inertial navigation error growth. [ABSTRACT FROM PUBLISHER]

As part of the ICAO navigation systems panel ground-based regional augmentation system (GRAS) validation process, issues arose concerning the transition between VHF data broadcast (VDB) stations. The GRAS sub group was invited to demonstrate that hand-over occurs only after successful lock onto a new VDB after 60 seconds of tracking the new power level and that the use of the new data does not affect the availability, accuracy, and continuity of service. Airservices Australia was invited to provide a description/depiction of receiver power; position accuracy referenced to the truth system, and the horizontal protection error (HPE) and vertical protection error (VPE) on hand-over scenario. This paper shows results from 73 transitions and demonstrates that the change between VDB stations does not affect the availability, accuracy, or continuity of service. Additionally, an evaluation was made on the effects of spatial decorrelation on the GRAS broadcast message when broadcast from a site geographically displaced from a reference station. The results show that GRAS remains well within the horizontal and vertical alarm limits prescribed for approaches with vertical guidance (APV). [ABSTRACT FROM PUBLISHER]

Global positioning system (GPS) has clearly emerged as a fundamental utility with widespread private and commercial civilian applications. Many of these applications are directly related to safety-of-life uses such as all-weather aircraft precision approach and landing, ship navigation in restricted waters, and emergency response vehicle tracking and management. GPS has significantly improved efficiency in commercial applications such as truck, train, and even, individual container tracking and dispatch. There is a similar dependency within the military - not only in vehicle navigation ut also in areas such as precision weapon guidance and "blue force" tracking. This dependency on GPS has brought significant attention on the potential for an asymmetric vulnerability on this low signal power radio navigation system. Threat systems to GPS exist, are commercially available, and have been used in combat. The technology is not complex, and even simple, low-cost systems could cause significant GPS denial. Furthermore, as other global navigation satellite systems gain maturity and widespread use, one can easily imagine the threat expanding to cover those systems as well. Herein, we describe a project directed by Congress, starting in 1997, to develop the capability to detect and locate sources of unintentional interference and intentional jamming, and to assess the effectiveness and utility of such a system. Under this project, SPAWAR and FALON, Inc. have successfully developed and demonstrated a prototype system small enough to be compatible with unmanned aerial vehicles named location of GPS interferers (LOCO GPSI). The LOCO GPSI system employs short baseline antenna interferometry and a highly sensitive, rapidly scanning receiver to detect and precisely direction find (DF) the interference source. Interference source location is determined by triangulating successive DF lines of position. Ground and flight demonstration results suggest that performance objectives have b- een met. [ABSTRACT FROM PUBLISHER]

Two important elements in the avionics suite of modern aircraft are: the flight control system (FCS) and the flight management system (FMS). The FCS provides the capability to stabilize and control the aircraft, while the FMS is responsible for flight planning and navigation. A clear trend in the aerospace industry is to place greater reliance on software systems, and many FCS and FMS subsystems are implemented primarily in software. For example, within the FCS is the flight guidance system (FGS) that generates roll and pitch guidance commands. Similarly, within the FMS is the vertical navigation (VNAV) function that acts like a third crew member in the cockpit, ordering mode change requests and resetting target altitude values to enable the aircraft to track the vertical flight plan. We have developed formal, executable models of the requirements for the mode logic of a FGS and for portions of the VNAV functionality. We have also conducted a comprehensive software safety analysis on the FGS mode logic model, and are completing the analysis of the VNAV model. This analysis uses as its starting point several "traditional" safety analysis techniques such as a functional hazard assessment (FHA), a fault tree analysis (FTA), and a failure mode effects analysis (FMEA). However, we are also using formal methods techniques known as model checking and theorem proving to verify the presence of safety properties in the model. This paper summarizes the (now completed) safety analysis that was performed on the FGS model, and highlights the similarities and differences with the (still on-going) safety analysis of the FMS model. In particular, we summarize progress made to date in the use of formal methods to verify the presence of the required safety properties in the models themselves. [ABSTRACT FROM PUBLISHER]

The attitude heading reference system (AHRS) provides data for primary flight instruments, head-up displays, autopilots, and moving map navigation systems. Advances in solid-state MEMS rate sensors, coupled with Kalman filter algorithms designed to mitigate high drift rates, provide the basis for low-cost, high-performance AHRS for general aviation. This paper describes the performance of a low cost, miniaturized AHRS using automotive-grade MEMS sensors. The performance of the system is detailed. The implications for certification of this class of system and fault tolerance are discussed. [ABSTRACT FROM PUBLISHER]

Purpose – To demonstrate that different approaches to commercialisation can determine the nature of intangible resources that managers can develop. Design/methodology/approach – A framework linking political strategy, financial capitalisation and business strategy is developed to analyse the management of intellectual capital in the commercialisation of air navigation services in New Zealand and Fiji. Case study evidence is organised as an intellectual capital portfolio and links are drawn to subsequent business outcomes for each organisation. Findings – Explains how key decisions about financial capitalisation and business strategy at the time of commercialisation influence the subsequent management and development of intangible resources in the organisation. Identifies how political assumptions about commercialisation can constrain or enhance subsequent management success in developing intellectual capital to pursue business growth. Research limitations/implications – The interpretations offered, although plausible in the context of the case studies, may not generalise to other situations. Practical implications – Key decision makers need to design commercialisation arrangements that will resource the desired intellectual capital portfolio of the commercialised organisation. Originality/value – The paper provides a framework for establishing a linkage between strategic management decisions and the development of an intellectual capital portfolio in the context of commercialisation. The paper develops the theoretical extent of intellectual capital concepts and provides practical analysis to decision makers contemplating commercialisation issues. [ABSTRACT FROM AUTHOR]

For the next 10 years new worldwide communication, navigation, and surveillance (CNS) requirements are being incrementally imposed upon commercial aircraft avionics, and upon the Air Traffic Control community, by the Aviation Administrations of most nations, including the FAA and the JAA. These requirements are the result of a decade of study by the United Nations' International Civil Aviation Organization (ICAO) to improve aviation safety and efficiency. In 2001, the USAF mandated compliance to the CNS requirements for its military aircraft, which is called Navigation Safety/Global Air Traffic Management (NS/GATM) by the USAF. By complying with these requirements, the C-17 will maintain its ability to fly internationally without CNS restrictions, such as requiring special handling. The Phase I study reported herein is the first phase of a three-phase study effort that will result in the C-17 achieving NS/GATM compliance for a specific set of NS/CNS requirements. [ABSTRACT FROM PUBLISHER]

Navigation and landing for the first half century of aviation fundamentally relied on radio-based electronic aids. The military began serious investigation of radio navigation during World War I. Up until WW II map reading, dead reckoning, and various means of radio direction finding were the primary methods of determining aircraft position. Since WWII a number of other navigation techniques, such as Doppler radar, radio inertial, pure inertial, aided inertial, and today's integrated GPS inertial, have been developed. Most of the inertial systems evolved from the military ICBM and subsequent space programs. [ABSTRACT FROM PUBLISHER]

The high speed anti-radiation missile (HARM) is an air-to-surface tactical missile designed to seek and destroy enemy radar-equipped air defense systems. Unfortunately, the HARM is "no respecter of persons," and it has been known, most notably during the Gulf War, to attack "friendly" targets. The international HARM upgrade project is a tri-national missile technology project sponsored by the United States, Italian, and German governments. The HARM precision navigation upgrade (PNU) program has as its goal, the development and installation of a PNU into the HARM that will improve the weapon's effectiveness, while nearly eliminating the likelihood of fratricide. The precision navigation system consists of a modern selective availability anti-spoofing module (SAASM) based Global Positioning System (GPS) receiver, and an inertial measurement unit (IMU), consisting of state-of-the-art fiber optic gyros and a modern micro-machined accelerometer triad. [ABSTRACT FROM PUBLISHER]

The synthetic vision implementation discussed in this paper comprises elements in the navigation display, the vertical profile display, and the primary flight display. The design rationale is provided based on an overview of the intended functions, options to implement these functions, and the justifications used in the selection of a specific option. [ABSTRACT FROM PUBLISHER]

A look into some future developments is presented. These are: the concept of an air vehicle that can stay aloft for days, weeks, even months; free flight; satellite navigation; intelligent transportation systems; automobile autopilot; personal airmobile; STAP; systems of systems; nanotechnology and MEMS [ABSTRACT FROM PUBLISHER]

This paper proposes an application of the Total Airspace and Airport Modeller (TAAM)2 tool for determining the impact of new Communications, Navigation, and Surveillance (CNS) ground-based and avionics technology on the efficiency of the National Airspace System (NAS). TAAM presents an opportunity to attack this problem by simulating aircraft movements using rules that mimic actual operations. The rules can be tailored to represent local procedures, restrictions, and conflict resolution strategies, producing a realistic picture of aircraft movement. This paper describes a novel method for manipulating TAAM output to produce a measure of the voice channel occupancy (VCO) in a sector. This method can be applied for current conditions, where all communications use the voice channel, and for the future case in which Controller-Pilot Data Link Communications (CPDLC) is used to issue controller/pilot instructions. TAAM could then be used to examine the benefits of CPDLC in terms of relieving restrictions or reducing vectoring and holding. Overall system benefits such as reduction in delays or distance traveled could be estimated from the TAAM results [ABSTRACT FROM PUBLISHER]