Showing papers on "Required navigation performance published in 2000"

An integrated approach to electronic navigation

Abstract: In today's Global Positioning System (GPS) dependent world, some have the notion that navigation is simply and almost solely accomplished through the use of GPS. While GPS is and will continue to be an excellent navigation system, it is neither flawless nor is it the only system employed in the navigation of today's seagoing war fighters. The modern war fighter must operate with dominant maneuverability, precision engagement capability, full dimensional protection and focused logistics. In order to meet these requirements an integration of independent, self-contained, self-initiated and externally referenced systems must be realized. The Navigation Sensor System Interface (NAVSSI) AN/SSN-6 (V) is a system that provides this capability through the real time collection, processing and distribution of accurate and reliable positioning, navigation and timing (PNT) data from varied shipboard sensors and systems. NAVSSI adds to this an electronic navigation capability that provides the ship navigation team with route planning, route monitoring and safety of navigation capabilities. The NAVSSI system is actually an integration of subsystems. The realtime subsystem (RTS) which collects, processes and distributes the PNT data uses a set of navigation source integration algorithms to blend input data from sensors such as GPS and inertial navigation systems (INS) to produce a highly accurate and robust navigation solution. When required, this solution is referenced to the own ship's reference point (OSRP). The display control subsystem (DCS) provides the operator interface to the RTS. It also contains the electronic charting and navigation capabilities as well as a radar interface and chart product distribution capability. The charting software used is the United States Coast Guard developed Command Display and Control Integrated Navigation System (COMDAC INS). The DCS and COMDAC INS software packages are built on the Defense Information Infrastructure Common Operating Environment (DII COE) and together will enable NAVSSI to lead the way to Electronic Chart Display Information System Navy (ECDIS-N) compliance.

RNAV Near-Term Terminal Procedures Development

Abstract: Current terminal operations consist largely of vectoring of aircraft by controllers from the terminal radar approach control (TRACON) boundary to the final approach. The nature of vectoring causes large variations in the flight times and paths of aircraft in the terminal area. En route metering functions include planned terminal flight paths. These large variations make it more difficult to meter aircraft efficiently from the en route to the terminal airspace, which often results in aircraft flying extended paths in the terminal area, costing time and fuel. The large variations in flight times also result in poor schedule predictability for users, which can lead to poor ontime performance, disrupted bank schedules, and passenger delays. Defining arrival and departure routes in the terminal airspace can mitigate many of these problems. MITRE’s Center for Advanced Aviation System Development (MITRE/CAASD) has been working to develop and assess various nearterm terminal area navigation (RNAV) procedures for Philadelphia International Airport (PHL) and Newark International Airport (EWR). These procedures, when implemented, will improve service, reduce required air/ground communications, enhance schedule reliability, improve operational efficiency, reduce flying times, and improve situational awareness for controllers and pilots. A key component to the RNAV procedure development is the collaborative development of the procedure involving the stakeholders. A repeatable implementation process has been defined for developing RNAV terminal procedures based upon overlays of current flight operations. The process identifies stakeholders, data, steps, and schedules to take a procedure from design to public implementation. To support procedure development, CAASD developed the Terminal Area Route Generation, Evaluation, Traffic Simulation (TARGETS) tool. TARGETS allows procedure designers to use current operations as the starting point for designing an overlay route, to visualize the route, and to evaluate operational aspects of the route. Controllers use the traffic simulation capability to assess impact on current air traffic control (ATC) operations, especially mixed equipage issues. In the paper, we discuss the RNAV procedure implementation process and the tools developed to support the process. Results of applying the process to RNAV procedures at PHL and EWR are presented. Lessons learned are reported and preliminary results on benefits obtained from implementing the routes are also reported.

Road Transport Navigation Requirements in Urban Areas: An Assessment of the Performance of GPS and the Design of a LAAS

Abstract: In many countries, the road infrastructure is not expected to increase substantially in the coming years. However, car ownership and travel demand continue to increase at an unsustainable rate. This results in long delays in congested urban areas, a high number of accidents and adverse environmental conditions. There are a number of causes of traffic congestion, one of which is due to the sub-optimal use of existing infrastructure. This is compounded by the lack of information required for planning and executing trips. Advanced Transport Telematics Systems (ATTS) employ state-of-the art computer, communications, navigation and control technologies to ensure an efficient and optimal use of existing infrastructure. The navigation function within an ATTS is responsible for providing geometric and physical location information to support various services. For example, a vehicle equipped with an ATTS receiving real-time updates on the state of the road network can use this information in conjunction with location data to compute optimal routing between a trip’s origin and destination. A pre-requisite to this is that the navigation system adopted must satisfy a wide range of requirements including positional accuracy, integrity, continuity and availability. This is particularly important in physically demanding environments such as cities. This paper presents the results of a study carried out in Greater London to assess and characterise the performance of GPS, and to design a local area augmentation system (LAAS) capable of meeting the required navigation performance (RNP) in urban areas. The study has addressed service coverage and the two RNP parameters of accuracy and integrity. The results highlight the shortcomings of GPS and details the temporal and spatial characteristics to be considered in the design of an augmentation system. These characteristics have been used to specify and justify an architecture for local area augmentation to systems such as GPS, GLONASS and Galileo.