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.

Using RNP AR for Noise-Abating Approach Procedures

Abstract: This paper describes RNP AR approach procedures which have been designed by the German Aerospace Center (DLR) Institute of Flight Guidance in the course of the LufoIV project HETEREX. The approaches purpose is to reduce the noise impact of approaching aircraft at an airport. Approaches with vertical guidance need a straight segment of about 10 NM prior to touchdown due to technical and operational, i.e. safety reasons. In case settlements are located on the extended centreline nearer than 10 NM to the airport, these settlements can not be circumnavigated. With GPS and vertical navigation based on the barometric system, approaches with vertical guidance do not need a straight segment of 10 NM prior to touchdown anymore. Those approaches have first been developed and certified for mountainous regions, where straight segments of up to 10 NM were impossible due to the terrain around the airport. Operations to these airports were limited to good weather situations only. With the precision of GPS in conjunction with a barometric vertical navigation system (BARO VNAV), those airports can now be operated to in much more inclement weather situations regarding visibility and cloud bases. In 2010, ICAO released a certification guideline for those approaches with curved segments nearer than 10 NM to the airport, called RNP AR for Required Navigation Performance, Authorization Required. In Germany, no airports with the need for RNP AR approaches due to mountainous terrain exist. Nevertheless, RNP AR approaches with their possibility of curved segments nearer than 10 NM prior to touchdown provide the possibility to design approaches which avoid settlements that lie under the extended centreline of a runway and are nearer than 10 NM to an airport. In this paper, five approaches to the airport of Nuremberg are presented which lead approaching aircraft around several towns near Nuremberg which with the currently applied approach procedures can not be circumnavigated and thus are impacted by the noise of arrival traffic. These approaches show how RNP AR can be used to improve airports’ acceptance by surrounding communities. The five example approaches at Nuremberg are presented together with the design rules that determine their exact shape as well as the population areas that can be circumnavigated with these approaches. Their potential to further reduce fuel consumption and thus production of CO2 by shortening the length of approach procedures is also presented. The approaches have undergone a first flyability assessment in a full-flight simulator.

Terminal area arrival management concepts using tactical merge management techniques

Abstract: This paper describes operational concept options for 4D trajectory-based arrival management in the terminal area, using Flight Management Systems (FMS) capable of Area Navigation (RNAV), Required Navigation Performance (RNP), Vertical Navigation (VNAV), as well as Required Time of Arrival (RTA) and airplane-based Interval Management (IM). Furthermore, it is assumed that the ATM automation system provides support to the controller to enable the airplane to fully utilize the above capabilities while maximizing the throughput of a large airport. The paper assumes an arrival management process that is consistent with the current FAA automation architecture for Time-Based Metering, and with the capabilities of the NASA Center-TRACON Automation System (CTAS), i.e. the Traffic Management Advisor (TMA) and Efficient Descent Advisor (EDA). The paper refers to the use of these particular capabilities, but many other similar capabilities are already in use or under development across the ATM industry. The paper also assumes the use of an automation capability for efficient operations through the TRACON that supports the airplane capabilities described above. The capability considered in this paper is based on the Relative Position Indicator (RPI) developed by MITRE CAASD, which is scheduled for demonstration in selected FAA TRACON facilities in 2010. The paper discusses the RPI concept in the context of other concepts that involve RNAV/RNP, RTA and IM capabilities. An analysis of the technical performance of these arrival management concepts using the Boeing Trajectory Analysis and Modeling Environment (TAME) is presented. The paper describes how the authors chose to represent the potential application of the RPI in a fast-time simulation of the Denver TRACON airspace. The results show the influence of speed control strategies and scenario design on spacing performance and runway delivery accuracy.

High-performance trajectory prediction for civil aircraft

Abstract: High-performance trajectory prediction is at the core of strategic airspace capacity and safety enhancement. Current state-of-the-art trajectory prediction models are based on a three-dimensional point-mass model, using often predefined settings from existing databases rather than real-time information available onboard the aircraft to determine aircraft dynamics. As a result trajectory prediction performance is limited by the accuracy of these settings. This paper addresses this limitation and proposes a high-performance four-dimensional trajectory prediction model for civil aircraft. The model includes a new flight-control system and an enhanced flight-script. The latter incorporates new taxonomy and content enabling better definition of aircraft intent. The performance of the trajectory prediction model is assessed using data acquired during a real flight trial, and shown to be significantly better than the current models. It has the potential to meet the required navigation performance for departure, en-route and non-precision-approach phases of flight.

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."

GPS/IRS/FMS Integration for RNP Airspace Operations

Abstract: This paper describes tbe approach taken to integrate GPS into an existing multisensor navigation system on a commercial jet transport. The goal has been to develop a certiBable system providing benefits to the airlines without imposing unreasonable constraints or training requirements on a scheduled operator. The accuracy, integrity, availability and continuity of function aspects of Required Navigation Performance (RNP) are discussed. Integrity is defined in terms of a containment surface. Availabiiity of navigation signals and navigation equipment are defmed as well as levels of totaI system availability. The Boeing Specitication GPS Sensor Unit (GPSSU) is described, followed by the mechanization of Receiver Autonomous Integrity Monitoring in the GPSSU. Accuracy and integrity levels are output by GPSSU qsing the ligure of merit (FOM) and horizontal integrity limit (HIL) labels. The general philosophy of multisensor navigation system integration witbin the Flight Management System (FMS) on the 747-400 is presented. The GPSSU interface with the FMS and other navigation/display/crew alerting avionics are shown in a functional block diagram. The FMS mechanization of RNP is described. An alternate integrity function has been implemented to provide integrity when GPS integrity monitoring cannot support the RNP. This allows use of GPS with its high accuracy during most RAIM outages and eliminates the need to frequently revert to less accurate means of navigation. Predictions of GPS/Inertial navigation and integrity availabiiity are presented. First, the various assumptions used in the analysis, such as constellation state are, discussed. RAIM availability and RAIM outage durations for a number of constellation states are shown. Additionally, predictions of RAIM continuity of function at a threshold of 0.3 NM are made. RAIM availability and outage durations are then combined to show the global availability of different levels of RNP for the integrated GPS/IRS/FMS system. Recently completed flight tests in Australia are described, followed by a discussion of various operational considerations.