Required navigation performance

About: Required navigation performance is a research topic. Over the lifetime, 343 publications have been published within this topic receiving 3477 citations. The topic is also known as: RNP.

Performance of Military Cargo Aircraft Using Required Navigation Performance Departures

Abstract: : Maximum takeoff weight for cargo aircraft is affected by many factors including the aircraft's ability to safely climb out to altitude. When there are obstacles in the departure path, the total weight of the aircraft may have to be reduced to ensure the aircraft will achieve the appropriate climb rate to clear the obstacles. During times of limited visibility, aircrews traditionally rely on predetermined departure paths limited by the aircraft navigation capability and the ground based navigation aids. A Required Navigation Performance (RNP) departure with accuracy down to 0.3 mile could allow the aircraft to safely navigate around obstacles with better precision, allowing a greater takeoff weight. This study compared current instrument departure procedures with predicted RNP 0.3 departures by computing the maximum allowable weight limit for the C-5 aircraft under a range of operating temperatures at three separate locations. The results showed that an increased precision of the RNP 0.3 departures had an operational advantage by allowing an increased cargo, passenger, or fuel load. The amount of weight increase was dependent upon a variety of factors, to include airframe type and location. To receive certification from the FAA to fly RNP 0.3 procedures, specific requirements such as training and equipment are necessary. Current configurations of the C-5 aircraft do not support RNP 0.3 procedures.

Low-cost Vision Sensors and Integrated Systems for Unmanned Aerial Vehicle Navigation

Abstract: A novel low cost navigation system based on Vision Based Navigation (VBN) and other avionics sensors is presented, which is designed for small size Unmanned Aerial Vehicle (UAV) applications. The main objective of our research is to design a compact, light and relatively inexpensive system capable of providing the required navigation performance in all phases of flight of a small UAV, with a special focus on precision approach and landing, where Vision Based Navigation (VBN) techniques can be fully exploited in a multisensory integrated architecture. Various existing techniques for VBN are compared and the Appearance-based Navigation (ABN) approach is selected for implementation. Feature extraction and optical flow techniques are employed to estimate flight parameters such as roll angle, pitch angle, deviation from the runway and body rates. Additionally, we address the possible synergies between VBN, Global Navigation Satellite System (GNSS) and MEMS-IMU (Micro-Electromechanical System Inertial Measurement Unit) sensors and also the use of Aircraft Dynamics Models (ADMs) to provide additional information suitable to compensate for the shortcomings of VBN and MEMS-IMU sensors in high-dynamics attitude determination tasks. An Extended Kalman Filter (EKF) is developed to fuse the information provided by the different sensors and to provide estimates of position, velocity and attitude of the UAV platform in real-time. Two different integrated navigation system architectures are implemented. The first uses VBN at 20 Hz and GPS at 1 Hz to augment the MEMS-IMU running at 100 Hz. The second mode also includes the ADM (computations performed at 100 Hz) to provide augmentation of the attitude channel. Simulation of these two modes is performed in a significant portion of the AEROSONDE UAV operational flight envelope and performing a variety of representative manoeuvres (i.e., straight climb, level turning, turning descent and climb, straight descent, etc.). Simulation of the first integrated navigation system architecture (VBN/IMU/GPS) shows that the integrated system can reach position, velocity and attitude accuracies compatible with CAT-II precision approach requirements. Simulation of the second system architecture (VBN/IMU/GPS/ADM) also shows promising results since the achieved attitude accuracy is higher using the ADM/VBS/IMU than using VBS/IMU only. However, due to rapid divergence of the ADM virtual sensor, there is a need for frequent re-initialisation of the ADM data module, which is strongly dependent on the UAV flight dynamics and the specific manoeuvring transitions performed.

Techniques to Provide Resilient Alternative Positioning, Navigation, and Timing (APNT) Using Automatic Dependent Surveillance - Broadcast (ADS-B) Ground Stations

Abstract: The United States Federal Aviation Administration (FAA) Alternative Positioning, Navigation, and Timing (APNT) program is examining the use of existing FAA terrestrial infrastructure to provide navigation capable of continuing US National Airspace System (NAS) operations should Global Navigation Satellite System (GNSS) position, navigation, and timing (PNT) services be unavailable. The approximately 700 automatic dependent surveillance broadcast (ADS-B) ground stations in the United States, these ground stations represents a key existing infrastructure that can be leveraged to deliver APNT. However, ADS-B was not designed to provide high accuracy/high integrity navigation services – it was designed to provide surveillance to air traffic control (ATC) automation systems to support the safe separation of aircraft and advisory services to pilots. As a result, ADS-B transmissions do not inherently possess features, such as ranging or integrity, necessary to support APNT navigation requirements. This paper describes and analyzes some possible means for aircraft to use ADS-B ground station signals for precise positioning or ranging to support area navigation (RNAV) and potentially required navigation performance (RNP). The paper first provides background on the United States (US) APNT and ADS-B programs. It examines how ADS-B signals can support APNT by either providing positioning directly or by providing ranging. The benefits and drawbacks to using position reports versus ranging from the ground is discussed. The body of this paper examines the two ADS-B protocols implemented in the US: Universal Access Transceiver (UAT) and Mode S Extended Squitter (ES) and how each could be modified to support pseudo and/or true ranging. Additionally, the paper explore ranging based on the combined use of signals from both protocols and how leveraging each protocol’s unique features could help overcome some of the limitations of using a single protocol alone.

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)