Showing papers on "Required navigation performance published in 2006"

A measurement domain receiver autonomous integrity monitoring algorithm

Abstract: One of the key approaches to monitor the integrity of Global Satellite Navigation Systems (GNSS) is receiver autonomous integrity monitoring (RAIM). Existing RAIM algorithms utilise two tests in the position domain (for RAIM availability) and measurement domain (for failure detection). This paper proposes an alternative RAIM algorithm, which is based entirely in the measurement domain. This algorithm can be used for sensitivity analyses to support performance specification and system design. It can also be used during actual flight operations where the trigger is the phase of flight and its required navigation performance (RNP) parameters. This is made possible by computationally efficient calculation of the chi-squared parameters. The algorithm reverts to the current approach if the phase of flight is unknown. Simulation results for non-precision approach (NPA) have been used to demonstrate the effectiveness of the proposed algorithm.

Performance of Honeywell's Inertial/GPS Hybrid (HIGH) for RNP Operations

Abstract: Honeywell has developed an algorithm that tightly integrates GPS and IRS into a hybrid navigation solution adequate to achieve 100% worldwide availability of RNP 0.1 without the use of differential corrections. This algorithm, referred to as Honeywell Inertial GPS Hybrid (HIGH), improves all four of the navigation characteristics critical for RNP operations - accuracy, integrity, continuity and availability. With its increased level of availability, HIGH can support RNP operations that are lower than can be achieved with stand-alone GPS. RNP operations require the navigation system provide an integrity bound called Horizontal Integrity Limit (HIL). An RNP operation can proceed as long as the HIL remains below the threshold required for that operational level. On average, stand-alone HILs are at least 50% worse than HIGH HILs under good satellite geometries, and become significantly degraded or unavailable when in RAIM holes or during GPS outages. HIGH enhances system continuity by coasting on the inertial when no satellite measurements are available. Honeywell has applied the HIGH technology on both military and commercial aircraft platforms. Operational benefits of HIGH are examined and contrasted with stand-alone GPS based solutions. HIGH is based on Honeywell's solution separation method to provide the integrity level and the Fault Detection and Exclusion (FDE) capability. With this method, a bank of Kalman filters is used to provide multiple hybrid solutions, each excluding different combinations of zero, one or two satellites. The algorithm detects and isolates a satellite failure by comparing the various solutions. Since one of the solutions will not contain the effects of the satellite error, an uncorrupted solution is always available. Appendix R of RTCA/DO-229C provides the requirements and test procedures for tightly integrated GPS/Inertial systems. Honeywell's HIGH implementations have demonstrated compliance to Appendix R. Compliance to Appendix R is critical to ensure a consistent basis for certification for these types of systems. The paper provides results from flight tests and simulations implementing the HIGH technology. These results support the claimed enhanced performance for integrity, continuity and availability and are contrasted with stand-alone GPS systems. The results clearly show that HIGH can support lower RNP operations such as RNP 0.1 as well as future lower RNP levels. Plans for enhancing the performance in future applications are also examined. I. INTRODUCTION The required navigation performance (RNP) concept allows aircraft to operate in a defined airspace based on the

Required Navigation Performance and 3D Paths in High-Traffic ATM Operations

Abstract: This paper describes an operational concept that enables increased airport and airspace capacity through the integration of Flight Management System (FMS) Required Navigation Performance (RNP) capabilities and ground based air traffic management (ATM) automation tools. The concept applies to en route and terminal area operations and uses voice or data link for air/ground communications. This concept is technically feasible for implementation in the 2008-2012 timeframe, assuming that advanced automation tools currently under development are deployed by Air Traffic Service Providers. This near-term step is key to successful transition to the Next Generation Air Transportation System (NGATS), as it will make a concrete step away from tactical controller vectoring to trajectory-based operations. The paper will provide estimates of potential NAS-wide operational benefits of this concept due to increased airport and airspace capacity and increased flight profile efficiency. Airport and airspace capacity is represented in the Boeing National Flow Model (NFM), which is used to assess the potential delay benefits in current and future schedules that can be expected as system capacity is increased. The NFM is used to model the potential increase in airspace capacity that will be enabled by RNP routes and reduced controller workload due to enhanced automation capabilities.

Application of Required Navigation Performance in High-Traffic Conditions for Houston Airspace

Abstract: Boeing has developed a near-term operational concept for implementation in the 20082012 timeframe. The concept is fundamentally based on 3D paths enabling the execution of flight trajectories with FMS navigational capabilities and navigational performance bounds. Houston airspace is the first target airspace for implementation of this concept. Based on an in-depth analysis of current operational constraints in Houston a set of conceptual designs has been derived that applies concept elements in Houston airspace. The paper presents programmatic background of the Houston activity, describes the conceptual designs and presents associated capacity and efficiency benefits of the proposed designs.

A Trajectory Modeling Environment for the Study of Arrival Traffic Delivery Accuracy

Abstract: This pap er presents the development and preliminary results of a trajectory analysis and modeling environment developed in MATLAB and applied to the study of the effects of navigation performance on arrival timing accuracy . This work supports ongoing efforts at The Boeing Company to develop new air traffic management (ATM) concepts and procedures based on accurate navigation standards such as Required Navigation Performance (RNP) and Required Time of Arrival (RTA) . The arrival management concept studied involves th e use of advanced ground automation that perform s sequencing and spacing based on FMS paths rather than relying on controller tactical vectoring . These paths can be defined in three dimensions from prior to top of descent (TOD) to the meter fix and then to the runway , potentially including speed and altitude constraints when needed and would be communicated to the air crew via voice communication and executed to standards (e.g. RNP, RTA) by t he air navigation function embedded in the Flight Management Syste m (FMS). This concept is viewed as a transition step towards the US next generation air traffic system currently being studied by the Joint Planning and Development Office (JPDO).

Airport Capacity and NAS -Wide Delay Benefits Assessment of Near -Term Operational Concepts

Abstract: Boeing Commercial Airplanes (BCA) has evaluated the airport capacity and NAS -wide delay benefits of an operational concept for Air Traffic Management (ATM) for implementation in the 2008 – 2012 timeframe. The concept enables increased airport and airspace capacity through the integration of Flight Management System (FMS) Required Navigation Performance (RNP) capabilities, ground -based Air Traffic Management (ATM) automation tools, 3D path -based operations, Local Area Augmentation System (LAAS), and advanced runway concepts for closely -spaced parallel, converging, and crossing runways. Benefit applications for these near -term capabilities are proposed and the increase in airport capacity for the 35 U. S. National Airspace System (NAS) benchmark airports is evaluated using the Boeing Airport Capacity Constraints Model. The increased airport capacities are then used by the National Flow Model (NFM) to evaluate the NAS -wide delay benefits. Results for annualized average arrival delay show that a 20 – 25% increase in airport capac ity associated with the implementation of the near -term operational concept produces a nearly 50% reduction in delay by 2020 . The capacity increases enabled by the implementation of this near -term operational concept in 2012 are adequate to serve the antic ipated traffic growth. However, by 2015, additional system improvements will be needed to maintain delay performance at or below today’s levels .

Perceived Pilot Workload and Perceived Safety of RNAV (GNSS) Approaches

Abstract: Area navigation global navigation satellite system (RNAV (GNSS)) approaches have been used in Australia since 1998 and have now become a common non-precision approach Since their inception, however, there has been minimal research of pilot performance during normal operations outside of the high capacity airline environment Three thousand five hundred Australian pilots with an RNAV (GNSS) endorsement were mailed a questionnaire asking them to rate their perceived workload, situational awareness, chart interpretability, and safety on a number of different approach types Further questions asked pilots to outline the specific aspects of the RNAV (GNSS) approach that affected these assessments Responses were received from 748 pilots, and answers were analysed based on the aircraft performance category For pilots operating Category A and Category B aircraft (predominantly single and twin-engine propeller aircraft), the RNAV (GNSS) approach resulted in the highest perceived pilot workload (mental and perceptual workload, physical workload, and time pressure), more common losses of situational awareness, and the lowest perceived safety compared with all other approaches evaluated, apart from the NDB approach For pilots operating Category C aircraft (predominantly high capacity jet airliners), the RNAV (GNSS) approach only presented higher perceived pilot workload and less perceived safety than the precision ILS approach and visual day approach but lower workload and higher safety than the other approaches evaluated The different aircraft category responses were likely to have been due the high capacity aircraft having advanced automation capabilities and operating mostly in controlled airspace The concern most respondents had regarding the design of RNAV (GNSS) approaches was that they did not use references for distance to the missed approach point on the approach chart and cockpit displays Other problems raised were short and irregular segment distances and multiple minimum segment altitude steps, that the RNAV (GNSS) approach chart was the most difficult chart to interpret, and that five letter long waypoint names differing only by the last letter can easily be misread

Human Factors Considerations for Area Navigation Departure and Arrival Procedures

Abstract: Area navigation (RNAV) procedures are being implemented in the United States and around the world as part of a transition to a performance-based navigation system. These procedures are providing significant benefits and have also caused some human factors issues to emerge. Under sponsorship from the Federal Aviation Administration (FAA), the National Aeronautics and Space Administration (NASA) has undertaken a project to document RNAV-related human factors issues and propose areas for further consideration. The component focusing on RNAV Departure and Arrival Procedures involved discussions with expert users, a literature review, and a focused review of the NASA Aviation Safety Reporting System (ASRS) database. Issues were found to include aspects of air traffic control and airline procedures, aircraft systems, and procedure design. Major findings suggest the need for specific instrument procedure design guidelines that consider the effects of human performance. Ongoing industry and government activities to address air-ground communication terminology, design improvements, and chart-database commonality are strongly encouraged. A review of factors contributing to RNAV in-service errors would likely lead to improved system design and operational performance.

RNP RNAV Arrival Route Coordination

Abstract: Current terminal operations are changing as more terminal Area Navigation (RNAV) routes are defined that aircraft are expected to fly Previously, arriving aircraft filing a Standard Terminal Arrival Route (STAR) were given vectors to guide them to the runway when the aircraft transitioned from the STAR and entered the terminal area There are, however, efforts underway to extend these STARs as routes in the terminal area that overlay the current traffic patterns resulting from the vectors that controllers give to the aircraft Since these RNAV STAR extensions are overlays, they typically have merge points prior to the merge on final The challenge for terminal controllers managing merges are wind and speed differentials due to the altitude change along the arrival paths The geometry of a merge (the number of turns and the length of each route prior to the merge) makes it more challenging to identify a potential merge problem early enough to prevent vectoring an aircraft off the RNAV procedure To achieve the additional expected benefits and efficiencies from these terminal routes, the controllers will need automation support to assist them in managing the traffic where the routes merge Currently there is an automation aid in the US terminal automation systems (Automated Radar Tracking Systems (ARTS) and Standard Terminal Automation Replacement System (STARS)) that helps controllers synchronize two streams of traffic, namely the Converging Runway Display Aid (CRDA)

Optimizing Flight Paths for RNP Aircraft in Busy Terminal Areas - First Step Towards 4-D Navigation

Abstract: The next generation air transportation system (NGATS) concepts, defined by the Joint Planning and Development Office (JPDO), consider 4D navigation as one of the core elements. During intervals of heavy traffic, establishing and achieving 4D operations for arrivals in busy terminal areas will be a major challenge. This paper presents the development and demonstration of a decision support tool called logical expansion of arrivals and departures to enhance RNP (required navigation performance) (LEADER). This human-in-the-loop simulation tool (with controller, pilot and traffic management coordinator (TMC) workstations) permits each aircraft, based on its capabilities, to fly desired 3D flight paths (shortest flight paths with continuous descent) under varying wind conditions. A flexible terminal area route structure is developed that eliminates all traffic merge points prior to the traffic converging on to the final approaches. The design of the tool is based on minimizing the variations between the aircraft flight planning and actual operations by defining routes all the way to touchdown and establishing landing schedules using accurate flight time estimates and pair-wise wake vortex separations. Traffic under high density conditions at a major airport during instrument meteorological conditions (IMC) was simulated. The results show significant savings in distance traveled and flight times, as well as a reduction in air/ground communications that would provide reduced operating costs for the users and lower workload for the operators. On an average, the flights saved 10.94 nmi in distance flown, 2 minutes and 16 seconds in flying time and reduced air/ground communications by 30 percent. Since the terminal areas involve most complex traffic patterns due to continuously climbing and descending flights, the tool offers a foundation and a first step towards realizing the future goal of using 4D navigation from end to end in the entire National Airspace System (NAS)

Performance trials of an Integrated loran/GPS/IMU navigation system, part i

Abstract: "The 2001 Volpe National Transportation Systems Center report on GPS vulnerabilities identified Loran-C as one possible backup system for GPS. The Federal Aviation Administration (FAA) observed in its recently completed Navigation and Landing Transition Study that Loran-C, as an independent radio navigation system, is theoretically the best backup for GPS; however, this study also observed that Loran-COs potential benefits hinge upon the level of position accuracy actually realized (as measured by the 2 drms error radius). For aviation applications this is the ability to support non-precision approach (NPA) at a Required Navigation Performance (RNP) of 0.3 which equates to a 2 drms error of 309 meters and for marine applications this is the ability to support Harbor Entrance and Approach (HEA) with 8-20 m of accuracy. The recently released report of the DOT Radionavigation Task Force recommended to Ocomplete the evaluation of enhanced Loran to validate the expectation that it will provide the performance to support aviation NPA and maritime HEA operations.O To meet this need, the FAA is currently leading a team consisting of members from industry, government, and academia to provide guidance to the policy makers in their evaluation of the future of enhanced Loran (eLoran) in the United States. Through FAA sponsoring, the U.S. Coast Guard Academy (USCGA) is responsible for conducting some of the tests and evaluations to help determine whether eLoran can provide the accuracy, availability, integrity, and continuity to meet these requirements. The key to meeting HEA accuracy requirements is an accurate ASF spatial grid. This can be met by a very dense grid of ASF values; however, this increases the problems with grid distribution and storage on the receiver. Previous work (ION AM June 2004) suggested that a sparse grid can be used and accuracy targets still reached by interpolating the points in between the grid values. The difficulty is in creating a grid with accurate grid point data. Several options for uniform grids were tested (ION NTM Jan 2005) and did not yield sufficient accuracy. In this work we have created a more accurate grid using non-uniform spacing and better matching of data to grid points. An integrated Loran/GPS/IMU receiver has been developed that incorporated this new ASF grid. This receiver integrates IMU information (velocity and acceleration) and ASF data from a stored grid into the Loran position solution to improve the accuracy and consistency of the resulting position. Initial results of this receiver were reported in (ION NTM Jan 2005). Since then, extensive work has been done to characterize the IMU errors and biases in order to better incorporate the IMU data into the integrated receiver. A Kalman filter is used to integrate the information and to predict forward the position to remove the time lag caused by the Loran filtering. The GPS information (position, time) is used to measure the ASF values in real-time to track deviations from the stored ASF grid. These grid differences are used to correct the grid values in the absence of a local ASF monitor station. Performance of the receiver is presented using an ASF grid alone, an ASF grid corrected using temporal ASF variations from a local ASF monitor site, and an ASF grid corrected using the real-time calculated grid differences. Finally, how all of these efforts lead towards meeting the accuracy requirements is shown."

Airport ASF Mapping Methodology Update

Abstract: In 2001, the Volpe National Transportation Systems Center completed an evaluation of global positioning system (GPS) vulnerabilities and the potential impacts to transportation systems in the United States. One of the recommendations of this study was for the operation of backup system(s) to GPS; Loran-C was identified as one possible backup system. A significant factor limiting the accuracy of a Loran system is the spatial and temporal variation in the times of arrival (TOAs) observed by the receiver. A significant portion of these variations is due to the signals propagating over paths of varying conductivity; these TOA corrections which compensate for propagating over non-seawater paths are called additional secondary factors (ASFs). Hence, a key component in evaluating the utility of Loran as a GPS backup is a better understanding of ASFs and a key goal is deciding how to mitigate the effects of ASFs to achieve more accurate Loran-C positions while ensuring that the possibility of providing hazardous and misleading information (HMI) will be no greater than 1x10-7. The future of Loran for aviation is based on multi-station, multi-chain, all-in-view, digital signal processing (DSP)-based receivers observing TOA measurements with H-field antenna technology. For an aviation receiver, the approach to mitigate propagation issues under study is to use a single set of ASF values (one for each Loran tower) for a given airport. This value may have seasonal adjustments applied to it. The Loran receiver will use this set of static ASF values to improve position accuracy when conducting a non-precision approach (NPA). A Working Group is currently developing the procedures to be used to “map” the ASF values for an airport. The output of the Working Group will be a set of tested and documented procedures for conducting an airport survey; these procedures can then be followed to survey airports nationwide. The draft procedure has been tested during data collection at airports in Maine and Ohio. This paper discusses the results of this data collection: how well the spatial variation seen on the ground matches the BALOR model prediction and the implications of this on the proposed procedure, an analysis of how many ASFs should be required to meet Required Navigation Performance (RNP) 0.3 for each airport based on geometry and ASF variation in the area, and results of the position accuracy obtained by the aircraft flying approaches when using the airport ASF values.

Tunnels in the Sky

Abstract: This article describes implementation of Required Navigation Performance (RNP), an approach tool for aircraft that can improve safety, minimize fuel burn and save money for airlines. To use RNP as an approach tool, an aircraft flies down a tightly contained “tunnel” in the sky using onboard equipment to maintain separation from other “tunnels.” The tool, in the making for 15 years, is in the process of being implemented at remote airports where there is less air traffic. It is more complicated to implement where air traffic is more dense and there is greater fleet mix. In addition, as it moves to areas around the world, there has been a proliferation of standards, and some airlines are uncertain whether their pilots are approved to be operating certain procedures. The article also describes its relationship to Area Navigation (RNAV).

Map matching algorithms for intelligent transport systems applications

Abstract: Map matching algorithms play a key role in providing the navigation solution for many Intelligent Transport Systems (ITS) and Location Based Services (LBS). It is essential that the map matching algorithm used in the navigation module meets the specified requirements set for a particular service. Although the performance of a map matching algorithm depends on the characteristics of data inputs, the technique used in the algorithm can enhance the overall performance. This paper sets out to report on map matching algorithms developed by the authors in earlier work, and whether these can satisfy the required navigation performance (RNP) of various ITS services and LBS applications. This is achieved by testing the algorithms using real-world field data. The results suggest that these algorithms are capable of supporting the navigation function of many services including route guidance, bus priority at junctions, fleet management, etc. For the covering abstract see ITRD E134653.

Modeling Efficiency Gains from Diverging Departures at Atlanta Hartsfield-Jackson

Abstract: Atlanta Hartsfield-Jackson International Airport (ATL) implemented Area Navigation (RNAV) standard terminal arrival routes (STARs) and standard instrument departures (SIDs) in early 2005. Revisions to the RNAV SIDs implemented in April 2006 include diverging departure courses when ATL is in east flow operational configuration. The diverging departure courses can be expected to allow Air Traffic Control (ATC) to separate departing aircraft more efficiently, reduce delays, and provide significant benefits to operators. The MITRE Corporation's Center for Advanced Aviation System Development (CAASD) has been tasked by the Federal Aviation Administration (FAA) to measure the benefits associated with RNAV implementation at several high complexity/high traffic sites across the NAS, and has developed Monte-Carlo simulation modeling tools to assist in RNAV benefits analysis. This paper presents model estimates of the benefits for both the current implementation of ATL RNAV procedures as well as a planned future implementation at ATL.

Augumentation of GPS and GALILEO with GBAS: High Level Impact Study of Category-II/III Approaches and ASMGCS on Avionics Receiver Architecture

Abstract: This paper gives an overview of the future navigation needs of Civil Aviation in light of the rapid increase in air travel. Key issues are identified and the objectives pursued by ANASTASIA, a sixth framework European Commission project, presented. The concept of Required Navigation Performance (RNP) is introduced and discussed in the context of performance requirements for precision approaches. Considerations for the choice of frequency combinations for multi-frequency modernized GPS and Galileo are evaluated in terms of suitability to provide the required navigation performance. High-level impacts on the avionics receiver of integrating these dual-frequency modernized GPS and Galileo configurations into the current navigation architecture are investigated.