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.

Redundant multi-mode filter for a navigation system

Abstract: An approach is introduced to the design of a multi-mode navigation filter to combine a low-cost skewed redundant inertial measurement unit (SRTMU) with a multifunctional GPS (MF-GPS) receiver in order to implement a fault-tolerant aircraft navigation system, which can achieve the required navigation performance of conventional systems in terms of accuracy, integrity, continuity, and availability. The MF-GPS receiver provides raw GPS measurements for pseudo-range and range rate to compute the navigation solutions (position and velocity) and also multi-antenna carrier phase interferometric measurements to estimate the aircraft attitude solution, if the carrier phase data is reliable. A multi-mode navigation filter is designed which combines state and measurement fusion methods and processes the SRIMU and raw MF-GPS outputs to provide reliable position, velocity and attitude information, and also kinematic parameters required in control, guidance, and navigation applications. The feasibility and performance of this integrated design is assessed and evaluated by using simulation. The accuracy of inertial gyros used in the evaluation ranges from ldeg/h to 30deg/h, including low-cost inertial sensor technologies. The simulation studies presented here show that a multi-mode navigation filter can achieve sufficient reliability and accuracy and that SRIMU/MF-GPS integrated navigation systems may provide a cost-effective system for future regional aircraft, general aviation aircraft, and unmanned aerial vehicles

Autonomous Integrity Monitoring for GPS-Based Precision Landing Using Ground-Based Integrity Beacon Pseudolites

Abstract: The Integrity Beacon Landing System (IBLS), developed and tested at Stanford University, is a high integrity solution to GPS-based Category III precision landing. IBLS is a kinematic GPS system which incorporates ground-based Integrity Beacon pseudolites placed under the approach path. The large geometry change that occurs during pseudolite overtlight ensures observability for direct cycle ambiguity estimation. Once cycle ambiguities have been initialized, position fixes accurate to the centimeter level are possible. The real-time accuracy performance of IBLS has already been demonstrated through flight tests in a Piper Dakota. The large number of redundant measurements resulting from Integrity Beacon overtlight and the great precision of carrier phase measurements provide the leverage for receiver autonomous integrity monitoring @AIM). Extremely tight detection thresholds may be set without incurring high false alarm rates (preserving high continuity). The measurement residual statistic can be used to detect a wide specuum of fault scenarios, including cycle slips, intentional tampering or spoofing, and spacecraft ephemeris errors. The overall level of IBLS system integrity as well as accuracy, continuity, and availability is quantitatively assessed through analysis, simulation, and flight test. Preliminary results show that the Required Navigation Performance (RNP) specification for Category III integrity of one undetected failure in one billion approaches is achievable using RAIM with Integrity Beacons. Flight tests were performed in a Piper Dakota with purposely induced navigation system failures to demonstrate the effectiveness of real-time autonomous integrity monitoring with Integrity Beacons. The results of these experiments are discussed.

Performance Basis for Airborne Separation

Abstract: Emerging applications of Airborne Separation Assistance System (ASAS) technologies make possible new and powerful methods in Air Traffic Management (ATM) that may significantly improve the system-level performance of operations in the future ATM system. These applications typically involve the aircraft managing certain components of its Four Dimensional (4D) trajectory within the degrees of freedom defined by a set of operational constraints negotiated with the Air Navigation Service Provider. It is hypothesized that reliable individual performance by many aircraft will translate into higher total system-level performance. To actually realize this improvement, the new capabilities must be attracted to high demand and complexity regions where high ATM performance is critical. Operational approval for use in such environments will require participating aircraft to be certified to rigorous and appropriate performance standards. Currently, no formal basis exists for defining these standards. This paper provides a context for defining the performance basis for 4D-ASAS operations. The trajectory constraints to be met by the aircraft are defined, categorized, and assessed for performance requirements. A proposed extension of the existing Required Navigation Performance (RNP) construct into a dynamic standard (Dynamic RNP) is outlined. Sample data is presented from an ongoing high-fidelity batch simulation series that is characterizing the performance of an advanced 4D-ASAS application. Data of this type will contribute to the evaluation and validation of the proposed performance basis.

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

Assessment of terminal RNAV mixed equipage

Abstract: Airlines continue to acquire or equip existing aircraft with improved and more capable avionics Improvements such as the flight management system (FMS) allow aircraft to fly preplanned paths with precision Attempts to take advantage of improved aircraft guidance to make approaches, arrivals, and departures in the terminal area more uniform and predictable are consequently a natural development in air traffic control The use of area navigation (RNAV) routes is one example of exploiting the current avionics technology to improve/simplify operations In this study we look at the consequences and implications for arrivals of the fact that not all aircraft are yet RNAV equipped The interplay of equipped aircraft (that fly the route according to the FMS) and non-equipped aircraft (which must be vectored) was studied in terms of controller technique, controller training and familiarization, controller comfort level, and the resultant impact on the efficacy of the air traffic control (ATC) operation The effects of specific factors such as variation in turn execution, variation in speed profiles and airspace use were objectively measured Three arrival routes of increasing complexity were simulated One complex route was examined using a varying mix of equipped and unequipped traffic at a fixed, steady state rate Controller in the loop simulations indicate that the percentage of non-RNAV traffic that can be accommodated on a complex arrival route is about 20 percent, and show at the rates simulated, that it was not necessary to segregate equipped and non-equipped aircraft The simulation results indicate that the tolerance for non-RNAV aircraft may be even higher for simple arrival routes Other results of the controller in the loop simulations are presented in detail: reduced flying distances, reduced communications workload, reduced fuel burn and reduced variance in the inter-aircraft arrival times can all be correlated to increasing the percentage of the aircraft that are RNAV equipped These results argue that there are benefits of aircraft flying RNAV routes