Required Navigation Performance Research Articles

Curved flight procedure construction with site-specific statistical meteorological data: A Swedish example

This paper presents a study of using site-specific statistical meteorological data in the construction of curved flight procedures to explore its potential in reducing the environmental impact of air traffic near the airports. In the study, the statistical meteorological data which covers a 10-year period of time, from 2009 to 2018, have been collected for the air space centred two major Swedish airports, Arlanda at Stockholm (ESSA) and Landvetter at Göteborg (ESGG). Two procedure design practices, one is an area navigation (RNAV) standard instrument departure (SID) procedure from runway 08 of Arlanda airport and another is a required navigation performance authorization required (RNP AR) approach procedure heading to the runway 03 at Landvetter airport, have been performed and analysed. Applying the 95th percentile wind speed from statistical meteorological data, instead of the ICAO standardized tailwind component (TWC), offers varying benefits depending on the specific case. For the RNAV SID procedure from ESSA, the part of the designed departure path which is outside of the regulated noise dispersion area is significantly reduced. Whilst for the RNP AR approach procedure to ESGG, the smaller turning radius resulted from the lower TWC which is calculated from the local meteorological data makes it possible to avoid flying over an inhabited area. Besides the notable potential of noise impact reduction, flight distance shortening of 3.7 NM (RNAV SID ESSA case) and 1 NM (RNP AR ESGG case) compared to the same procedures designed on ICAO standard TWC have been observed. In general, the presented results are positive in supporting the use of local meteorological data in planning curved flight procedures during departures and approaches. A validation performed using an A320 full flight simulator has confirmed the operability of the ESGG RNP AR procedure from the design practice. In the full flight simulator, even with the 100th percentile wind condition from the collected statistical meteorological data, the designed RNP AR approach procedure can be operable considering RNP 0.3 corridor while a 30° bank angle is required for approximately 20 seconds during the turn.

Adaptive Navigation Performance Evaluation Method for Civil Aircraft Navigation Systems with Unknown Time-Varying Sensor Noise.

During civil aviation flights, the aircraft needs to accurately monitor the real-time navigation capability and determine whether the onboard navigation system performance meets the required navigation performance (RNP). The airborne flight management system (FMS) uses actual navigation performance (ANP) to quantitatively calculate the uncertainty of aircraft position estimation, and its evaluation accuracy is highly dependent on the position estimation covariance matrix (PECM) provided by the airborne integrated navigation system. This paper proposed an adaptive PECM estimation method based on variational Bayes (VB) to solve the problem of ANP misevaluation, which is caused by the traditional simple ANP model failing to accurately estimate PECM under unknown time-varying noise. Combined with the 3D ANP model proposed in this paper, the accuracy of ANP evaluation can be significantly improved. This enhancement contributes to ensured navigation integrity and operational safety during civil flight.

Renewal Study of LoCa Between ATS RO Unit and Approach Combined With Tower Unit Perum LPPNPI Ternate

An Air Traffic Controller (ATC) can be easily disrupted by several factors. At the AirNav Ternate Assistant Branch Office, the author observed several factors that could disturb the performance of an ATC. These factors include the need for ATC to directly monitor the AFTN (Aeronautical Fixed Telecommunication Network) to discover flight plans and flight-related news. Each working unit must have good coordination. In the LOCA (Local Operating Control Area) between ATS RO (Area Control Center) and APP (Approach Control) combined with TWR (Tower), it is not clarified that ATS RO personnel inform the TWR unit about flight plans and flight-related news. Moreover, there is a lack of authority and responsibility for each unit, making it unclear what the exact authority and obligations of each unit are in carrying out their tasks. The research employed by the author involves qualitative observational research methods. The study led to the renewal of the LOCA between ATS RO and the APP combined with TWR in Ternate. This renewal includes the delineation of authority for each unit and the responsibilities that each unit must carry out. There is coordination regarding the notification of an aircraft's capabilities in using PBN (Performance-Based Navigation) or RNP (Required Navigation Performance) from the ATS RO unit to the APP combined with the TWR unit in Ternate. This coordination is achieved using the available communication tools.

Flight Route Optimization in Required Navigation Performance (RNP) Approach Flight Procedures Based on Experimental Algorithm

ICAO recommends that capacity and efficiency achievement programs be carried out through the Performance Based Navigation (PBN) implementation model. This research aims to obtain an overview of the optimal formula model that can be implemented into flight paths based on the RNP approach procedure for flight path efficiency and fuel efficiency. This research uses quantitative experimental methods. The results of this research are that the optimization model at minimum speed (V=210 knots) produces route effectiveness of 8% and fuel savings of 1.5% compared to the established current procedure. The conclusion is that for straight paths, route optimization is achieved by applying the maximum speed, but for circular (arc) paths, route optimization is achieved by applying the specified minimum speed.

Required Navigation Performance (RNP) - A Navigation Update

In the recent years, air traffic has increased globally. The rate of growth of air traffic has been estimated to be 8% per annum. In India, the international and domestic aircraft movements have posted an increase of 12.1 and 11% respectively, over the previous year’s figures. This growth in air traffic manifests into operational problems like congestion and bottle necks in air traffic affecting the economy of aircraft operations. Recent increase in fuel costs also added to the need for achieving economy in aircraft operations. The aircraft operators felt a need to drive the costs down. In order to sustain the air traffic growth and also to ensure safe, regular and economic flow of air traffic, ICAO, the concerned contracting states of ICAO in Asia and other related organizations like the IATA, SITA etc., joined together and decided to introduce a route structure with more air routes which are parallel and closer. This Revised ATS (Air Traffic Service) Route structure - Europe, Middle East, Asia Route Structure South of Himalayas (EMARSSH) was introduced on the 28th November 2002. However, the inherent drawbacks in navigation along such closely defined air routes had to be tackled. With safety foremost in mind, it is essential to be able to define the requirements for accurate navigation and to use the best tool available to qualify aircraft for today’s demanding operations. This was achieved by suitably defining the Required Navigation Performance (RNP) to be complied by the aircraft.

Design and Testing of a Vertically Guided High-Precision Approach into Salzburg Airport

The approach to landing on runway 33 of Salzburg Airport in Austria is severely impacted by mountainous terrain on the extended runway centerline. This renders all straight-in approaches, except those based on required navigation performance (RNP) with authorization required (AR), impossible. Only the high navigation accuracy available under RNP-AR minimizes the required obstacle protection areas sufficiently to not be penetrated by the terrain. The combination of RNP-AR and localizer performance with vertical guidance makes it further possible to use a more precise angular guidance for the final approach. In Salzburg, this enables a reduction of the decision height from 368 to 218 ft above aerodrome level because the critical terrain and obstacles now fall outside of the protection areas. A level D full flight simulator test with an Airbus A350 showed that advanced RNP 0.1 coding is sufficient to achieve RNP 0.1 performance under all permitted environmental conditions.

Safety analysis of RNP approach procedure using fusion of FRAM model and Bayesian belief network

AbstractThe use of the required navigation performance (RNP) procedure has been increasing for aircraft navigation, since it allows for better optimisation of the airspace, which is increasingly congested. The present work aims to investigate the application of the functional resonance analysis method (FRAM), combined with the quantitative analysis provided by the Bayesian belief network (BBN), to demonstrate the existing variability in functions that are part of the complex navigation system based on the RNP procedure, specifically when the aircraft approaches the airport (approach phase). As a result, it is possible to analyse the variability that occurs in the studied system and the BBN complemented the study by allowing a quantitative interpretation of the functions considered most important for the execution of an RNP approach procedure.

A Low-Drift Laser-Driven FOG Suitable for Trans-Pacific Inertial Navigation

We report a laser-driven fiber-optic gyroscope (FOG) with an angle random walk of 0.9 mdeg/√h, an Allan-deviation minimum of 4.9 mdeg/h, and an Allan-deviation maximum (or true drift) of 12.6 mdeg/h. This state-of-the-art performance was achieved by implementing an optical gate and a power-control feedback loop to suppress several sources of drift in the FOG, namely optical spikes that result from the square-wave biasing modulation, the nonlinear Kerr effect, drift in the detected power arising from spurious interferometers in the fiber circuit and laser-power fluctuations, and bias offset drift in the demodulation electronics. The measured output of this FOG was used to simulate 20 10-h trans-Pacific flights of an aircraft guided solely by inertial sensors. 95% of the flights landed within ±10 nmi of their intended destination. To our knowledge, this is the first report of a laser-driven FOG that meets the Federal Aviation Administration's Required Navigation Performance 10 criteria for aircraft navigation.

Three-Dimensional ANP Evaluation Method Based on Spatial Position Uncertainty under RNP Operation

Performance-based navigation (PBN) operations based on the required navigation performance (RNP) operations are the trend for civil aviation in the future. In order to further ensure the safety and efficiency of civil aviation operation, RNP will transition from 2D to 3D/4D. Accurately evaluating the actual navigation performance in three-dimensional directions (3D ANP) under civil aircraft RNP operation is important to guarantee the safe flight of civil aircraft. However, the traditional two-dimensional ANP evaluation method mainly focuses on plane navigation performance along the track, lacks the evaluation of the vertical direction. Moreover, the traditional three-dimensional accuracy evaluation method is based on the assumption of three-dimensional independence and uniformity, which can only carry out approximate calculation, and the evaluation result is inaccurate. Therefore, this paper constructs a three-dimensional ellipsoid error probability (EEP) evaluation model for the spatial position uncertainty of the navigation output of the flight management system in three-dimensional directions, and gives the three-dimensional accurate ANP calculation results through iterative numerical integration. The simulation results show that the evaluation method proposed in this paper can accurately evaluate the actual navigation performance of the airborne navigation system in all directions of 3D space, and has higher evaluation accuracy and precision than the traditional ANP evaluation method, which is of great significance to ensure the flight safety of civil aircraft under 3D/4D RNP operation in the future.

DRL-RNP: Deep Reinforcement Learning-Based Optimized RNP Flight Procedure Execution.

The required navigation performance (RNP) procedure is one of the two basic navigation specifications for the performance-based navigation (PBN) procedure as proposed by the International Civil Aviation Organization (ICAO) through an integration of the global navigation infrastructures to improve the utilization efficiency of airspace and reduce flight delays and the dependence on ground navigation facilities. The approach stage is one of the most important and difficult stages in the whole flying. In this study, we proposed deep reinforcement learning (DRL)-based RNP procedure execution, DRL-RNP. By conducting an RNP approach procedure, the DRL algorithm was implemented, using a fixed-wing aircraft to explore a path of minimum fuel consumption with reward under windy conditions in compliance with the RNP safety specifications. The experimental results have demonstrated that the six degrees of freedom aircraft controlled by the DRL algorithm can successfully complete the RNP procedure whilst meeting the safety specifications for protection areas and obstruction clearance altitude in the whole procedure. In addition, the potential path with minimum fuel consumption can be explored effectively. Hence, the DRL method can be used not only to implement the RNP procedure with a simulated aircraft but also to help the verification and evaluation of the RNP procedure.

Sensing Requirements and Vision-Aided Navigation Algorithms for Vertical Landing in Good and Low Visibility UAM Scenarios

To support the rapid development of the Urban Air Mobility framework, safe navigation must be ensured to Vertical Take-Off and Landing aircraft, especially in the approach and landing phases. Visual sensors have the potential of providing accurate measurements with reduced budgets, although integrity issues, as well as performance degradation in low visibility and highly dynamic environments, may pose challenges. In this context, this paper focuses on autonomous navigation during vertical approach and landing procedures and provides three main contributions. First, visual sensing requirements relevant to Urban Air Mobility scenarios are defined considering realistic landing trajectories, landing pad dimensions, and wind effects. Second, a multi-sensor-based navigation architecture based on an Extended Kalman Filter is presented which integrates visual estimates with inertial and GNSS measurements and includes different operating modes and ad hoc integrity checks. The presented processing pipeline is built to provide the required navigation performance in different conditions including day/night flight, atmospheric disturbances, low visibility, and can support the autonomous initialization of a missed approach procedure. Third, performance assessment of the proposed architecture is conducted within a highly realistic simulation environment which reproduces real world scenarios and includes variable weather and illumination conditions. Results show that the proposed architecture is robust with respect to dynamic and environmental challenges, providing cm-level positioning uncertainty in the final landing phase. Furthermore, autonomous initialization of a Missed Approach Procedure is demonstrated in case of loss of visual contact with the landing pad and consequent increase of the self-estimated navigation uncertainty.

Development and evaluation of an RNP AR approach procedure under tight airspace constraints

Required navigation performance authorization required (RNP AR) approach (APCH) procedures are a special form of approaches with vertical guidance (APVs) where stricter navigation system requirements in terms of accuracy, integrity and functionalities allow smaller obstacle clearance areas and the use of curved legs in all approach segments. That leads to very flexible approach design possibilities compared to other instrument approach procedures. This paper guides through the development and initial evaluation of an RNP AR approach on runway 15L at Isa Air Base in Bahrain. The establishment of instrument approaches on this runway has been complicated so far because the final approach would have led straight through the controlled traffic region (CTR) of an adjacent air base. We show that entering the CTR, which ends less than 3.3 NM before the runway threshold, can be avoided with an RNP AR approach by employing a curved leg in the final approach segment and the highest possible navigation accuracy of RNP 0.1—two unique features of RNP AR APCH. We then fly and test the developed procedure in an Airbus A320 full-flight simulator under the wind and weather conditions considered by the procedure design rules. The results show that the actual navigation and flight technical performance met the required one under all conditions without the bank angle and effective glide path limits being exceeded. An initial flight test with a Boeing B737-800 showed that the approach can also be flown with sufficient accuracy in practice.

Fault tolerant multi-sensor data fusion for autonomous navigation in future civil aviation operations

The problem addressed in this paper is that of fault-tolerant multi-sensor data-fusion for flight navigation during approach and landing of a civil jetliner. The work falls within the scope of a large collaborative project on future single pilot operations issues. The proposed methodology is based on a multi-layer hierarchical architecture which can integrate several heterogeneous information sources. The study is restricted to three classical information sources, namely, Inertial Reference System (IRS), Global Positioning System (GPS) and Instrument Landing System (ILS). The system is designed to meet the specified navigation performance requirements in terms of validity, accuracy, continuity and on-board implementation issues. The methodology takes advantage of recently developed set-membership tools, and paves the way toward a new and simple tuning of global merging filter.

Analytic Method for Estimating Aircraft Fix Displacement From Gyroscope’s Allan-Deviation Parameters

The noise and drift requirements for a navigation-grade gyroscope are widely known, yet there is no simple analytic model of how the noise and drift of a gyroscope influence the fix displacement error (FDE) of an inertial navigation system (INS). This work derives simple analytical expressions for the cross-track and along-track errors of an aircraft whose INS consists solely of a three-axis gyroscope system with perfect knowledge of the vertical direction. The error signal of each gyroscope is Gaussian white noise and drift modeled as a first-order Markov random walk. These expressions provide a straightforward mean of calculating the FDE of an aircraft as a function of the flight duration, velocity, noise amplitude, drift amplitude, and drift’s time constant. These expressions are validated with Monte-Carlo simulations of long flights. This model quantifies the noise-versus-drift trade-off for a gyroscope in an inertial navigation system. It can save time when estimating the noise and drift that a gyroscope must exhibit to satisfy a given position-error requirement, or vice versa. They are used in particular to confirm the values, often cited without demonstration, of the noise and drift required to meet the maximum position error of an aircraft imposed by the Federal Aviation Administration’s required navigation performance 10 specification. Finally, it demonstrates that using the minimum in the measured Allan deviation of a gyroscope as a metric of the drift is incorrect, because it fails to capture the drift’s time constant. The proper metric is the maximum in the Allan deviation.

Required Navigation Performance (RNP) Analysis for ADS-B Data of Makassar-Jakarta Flight using Dot Product Method

Required Navigation Performance (RNP) is known as a performance parameter for a navigation system, where its function is to keep an aircraft within a certain radius of containment. During the flight, an aircraft transmits its real-time location-based on Global Navigation Satellite Systems (GNSS) technology via Automatic Dependence Surveillance Broadcast (ADS-B) protocol. However, there are questions about the flight position accuracy. This research aims to analyze the accuracy of ADS-B flight data about RNP requirements. The flight data used is gathered from the FlightRadar24 website and filtered for each flight phase. The selected route used is Makassar (UPG) – Jakarta (CGK) because the route has the highest number of flights per week. The Dot Product method is proposed to calculate the distance between the flight trajectory to the line of flight procedure towards the destination airport. The analysis is conducted based on the compliance of the flight data to the RNP threshold. It is concluded that the majority of evaluated flights in the selected route fly within the RNP boundary. However, some non-complying flights become within the RNP boundary when they are evaluated with other possible published procedures

Performance-Based Navigation Flight Path Analysis Using Fast-Time Simulation

The growing demand for air transportation has led to an increase in worldwide air traffic inefficiency due to capacity constraints. The impacts associated with this situation can be reduced through operational changes. To better handle the problem, the Single European Sky ATM Research (SESAR) and the Next Generation Air Transportation System (NextGen) program suggest Performance-Based Navigation (PBN) as a solution. The Area Navigation (RNAV) and Required Navigation Performance (RNP) approaches belong to the group of PBN procedures. These procedures allow for a more efficient use of airspace by reducing route distances, fuel consumption and perceived aircraft noise. This article quantifies the benefits of PBN systems for two indicator parameters—fuel burn and flight time—and compares PBN systems to conventional instrument navigation procedures. The case studies use five airports in Brazil. The results of this analysis show that the benefits of the PBN approach vary with aircraft type and individual route characteristics.

Benefits for Greek Regional Airports Through Innovative Approach Technology Using an LPV to GLS Converter: A Case Study for Corfu and Thessaloniki

Required navigation performance procedures are a cost-effective and accurate solution for aircraft instrument approaches, especially when combined with a final approach segment utilizing satellite based augmentation. However, transport category aircraft are currently not equipped with the satellite based augmentation for precision guidance. An existing converter technology can provide this final approach segment to aircraft equipped with the GPS landing system. Then, as an added bonus, an automatic landing at pilots discretion is possible after the presented approach. Here, we study Thessaloniki and Corfu airports, both accommodating a large number of transport category aircraft, with many ground infrastructure constraints. Both were recently equipped by the Hellenic air navigation service provider with RNP approaches. We successfully flight tested the satellite based augmentation to GPS landing system converter and show that both airports could benefit from a permanent installation of such a system by having fewer diversions.

Modeling and analysis of civil aircraft top level RNP system architecture

In recent years, the international aviation organization has implemented new performance-based navigation technology and issued the operational requirements of required navigation performance (RNP). It involves the cross-linking of multiple complex systems, which puts forward higher requirements for aircraft development and management. In this paper, the development process of RNP functional architecture model is defined by using magic grid software. The modeling is completed from three aspects: problem domain, solution domain and implementation domain. The decomposition and implementation of complex functions are completed from top to bottom. This method can effectively solve the complexity problem of civil aircraft system, and lay the foundation for demand-based model forward design.

Continuity Enhancement Method for Real-Time PPP Based on Zero-Baseline Constraint of Multi-Receiver

Continuity is one of the metrics that characterize the required navigation performance of global navigation satellite system (GNSS)-based applications. Data outage due to receiver failure is one of the reasons for continuity loss. Although a multi-receiver configuration can maintain position solutions in case a receiver has data outage, the initialization of the receiver will also cause continuous high-precision positioning performance loss. To maintain continuous high-precision positioning performance of real-time precise point positioning (RT-PPP), we proposed a continuity enhancement method for RT-PPP based on zero-baseline constraint of multi-receiver. On the one hand, the mean time to repair (MTTR) of the multi-receiver configuration is improved to maintain continuous position solutions. On the other hand, the zero-baseline constraint of multi-receiver including between-satellite single-differenced (BSSD) ambiguities, zenith troposphere wet delay (ZWD), and their suitable stochastic models are constructed to achieve instantaneous initialization of back-up receiver. Through static and kinematic experiments based on real data, the effectiveness and robustness of proposed method are evaluated comprehensively. The experiment results show that the relationship including BSSD ambiguities and ZWD between receivers can be determined reliably based on zero-baseline constraint, and the instantaneous initialization can be achieved without high-precision positioning continuity loss in the multi-receiver RT-PPP processing.

Integrated constellation design and deployment method for a regional augmented navigation satellite system using piggyback launches

The method proposed in this paper is adopted to solve problem B of the 9th China Trajectory Optimization Competition (CTOC). An accurate and economical constellation design strategy for regional augmented navigation satellite systems (RANSSs) has attracted a substantial amount of research interest owing to the increased demand for navigation services in complex environments. This paper proposes a hybrid method of constellation design and deployment for a RANSS to satisfy the navigation performance requirements and minimize the construction cost. First, the search spaces of the design parameters are determined by analyzing the orbital parameters of piggyback launches. Second, the constellation is designed as a combined Walker constellation and optimized by a differential evolution (DE) algorithm. Finally, optimal strategies for deploying satellites to the desired orbits are obtained using a transfer optimization design. The method was adopted to design a RANSS for servicing the 182 cities in the Asia-Pacific region. The configuration consists of five orbital planes and 80 navigation satellites and achieves a low construction cost with 10 piggyback launches. Furthermore, the constellation can cooperate with an existing navigation satellite system to further improve the navigation accuracy for all cities. The results reveal that the RANSS design and deployment problem can be effectively solved with a low construction cost and high navigation performance.