Required Time Of Arrival Research Articles

Cooperative task allocation for multi heterogeneous aerial vehicles using particle swarm optimization algorithm and entropy weight method

Reasonable and effective task allocation strategy is the premise to ensure the successful completion of combat missions, which is of great significance to improve the overall operational effectiveness of the cluster. In this paper, a cooperative task allocation method for multi heterogeneous aerial vehicles under strong space-time constraints using particle swarm optimization (PSO) algorithm and entropy weight method is presented. Specifically, the problem of cooperative task allocation is formulated as a multi-objective optimization problem under multi-constraint conditions, and the requirement of required time of arrival (RTA) of time-sensitive targets is considered. Then, the PSO algorithm is applied to solve the task allocation model. Especially, task sequence is introduced into the coding of the feasible solutions, and task urgency is employed to update the particle position. Furthermore, the entropy weight method is introduced into task assignment scheme decision-making. Finally, a simulation is given to illustrate the validity.

Airborne Separation Assistance during Landing - An Approach for Automation

Self-spacing and Required-Time-of-Arrival (RTA) concepts are now being developed to support future Air Traffic Management (ATM) systems. Among many types of separation methods, distance based separation assumes importance form safety point of view. The present study is an attempt to analyze approach proposed by EUROCAE and extend the same for development of guidance laws in the form of acceleration commands instead of speed commands. Objective is to realize an effective implementation of the guidance laws in the Thrust Management Function of onboard Flight Management System. Simulation studies are presented involving actual flight responses for the lead aircraft during terminal phase.

Automated sequencing and merging with dynamic aircraft arrival routes and speed management for continuous descent operations

In this paper, we present a novel methodology to manage arrival traffic in terminal airspace. We define two areas around the airport, aiming to efficiently schedule incoming traffic. A four-dimensional (4D) trajectory negotiation/synchronization process between the air traffic control officer (ATCO) and the aircraft is performed in the pre-sequencing area, while the aircraft are still in the en-route phase of flight. On the other hand, in the dynamic-trajectories area, the ATCO, with the help of a ground support tool, generates dynamic arrival routes that automatically adapt to the current traffic demand. These arrival routes allow the aircraft to fly neutral continuous descent operations (CDOs, descents with idle thrust and no speed-brakes usage) and to ensure a separation throughout the arrival procedure. We choose a mixed-integer-programming approach to generate the arrival routes, while we formulate and solve an optimal control problem to generate a set of candidate CDOs per aircraft. Results show that, with a sufficient look-ahead time, it is possible to assign a required time of arrival (RTA) within each aircraft-arrival time window that would allow to efficiently schedule traffic even in the most challenging and dense scenarios. Besides improving efficiency of current operations in terminal airspace, the methodology presented in this paper could become a technical enabler towards an extended arrival manager (E-AMAN) with extended capabilities and, ultimately, to a fully deployed trajectory based operations (TBO) environment.

Traffic synchronization in terminal airspace to enable continuous descent operations in trombone sequencing and merging procedures: An implementation study for Frankfurt airport

This paper proposes to enhance the current tromboning paradigm with a four dimensional trajectory negotiation and synchronization process with the aim to maximise the number of neutral Continuous descent operations (CDOs, descents with idle thrust and no speed-brakes usage) achieved by the arriving traffic in terminal maneuvering areas (TMAs). An optimal control problem has been formulated and solved in order to generate a set of candidate CDO trajectories per aircraft, while a mixed-integer-linear programming model has been built in order to optimally assign routes of the arrival procedure and required times of arrival (RTAs) to the arriving traffic when still in cruise. The assessment has been performed for Frankfurt am Main airport (Germany), by using arrival traffic gathered from historical data. Results show that, after assigning an RTA and a route to every arriving aircraft, it is possible to maximize the number of aircraft performing CDOs while ensuring a safe time separation throughout the arrival procedure. For low traffic scenarios, the totality of traffic can be successfully scheduled, while for high traffic scenarios this is not the case and not all aircraft can be scheduled if neutral CDOs are flown. However, by assuming different arbitrarily defined arrival times to the TMA or by considering more additional shortcuts in the trombone procedure it is possible to increase the number of aircraft scheduled. Besides improving current operations in the short-mid term, the methodology presented in this paper could become a technical enabler towards a fully deployed trajectory based operations (TBO) environment.

Optimization of Speed Profile with RTA Constraints under Wind Uncertainty

Four-dimensional (4D) trajectory is considered to be one of the effective means to reduce the environmental impact of aviation while increasing capacity and safety. This paper proposes an approach to optimize cruise speed profile subject to wind uncertainty, aiming to reduce the fuel burn complying with the Required Time of Arrival (RTA) constraints. The approach is based on a probabilistic framework, and the uncertainty propagation is analyzed using a Probability Transformation Method, and the probability distributions of arrival time and fuel consumption are determined. In addition, from an airborne operation perspective, transition profiles need to be considered in the reference speed optimization problem, aiming to improve the rationale of the reference trajectory. Numerical simulations are presented, and the results demonstrate that the speed profiles optimized by this method are able to meet the RTA constraints in the presence of wind uncertainty, with an average reduction of 7.04% in fuel consumption compared with that of the flight data.

Horizontal flight trajectory optimization considering RTA constraints

The increasing of flights around the world has led to various problems for the aeronautical industry such as saturated air space and higher levels of fossil fuel consumption. The way in which en-route flights are handled should be improved in order to increase airways’ capacity. A solution is to make aircraft to arrive at specific waypoints at a time constraint called Required Time of Arrival (RTA). Fossil fuel brings as a consequence the release of polluting particles to the atmosphere such as carbon dioxide and nitrogen oxides. It is thus desirable to compute the most economical trajectory in terms of fuel burn while fulfilling the RTA constraint. This article proposes a horizontal reference trajectory optimization algorithm based on the Particle Swarm Optimization technique in order to reduce fuel burn while fulfilling the RTA constraint. Results showed that for a flight without RTA constraint, up to 4% of fuel can be saved comparing against the trajectory of reference. The algorithm was normally able to meet the RTA constrain. However, aggressive RTA constraints might reduce the optimization levels of fuel compared with flights without RTA constraint.

Fuel-Efficient Trajectories Traffic Synchronization

Continuous descent operations (CDOs) with required times of arrival (RTA) have been identified as a potential solution for reducing the environmental footprint of aviation in the terminal maneuvering area without compromising capacity. This paper assesses the feasibility of replacing current air traffic control sequencing and merging techniques, mainly based on path stretching and air holding, by a control based on RTA over metering fixes on known and fixed arrival routes. Because the remaining distance to the runway threshold is always known by the aircraft crew, this would allow engine-idle CDOs that do not require speed-brake usage and where only elevator control is used to meet the RTA. The assessment has been performed for Barcelona-El Prat Airport (Spain) using historical traffic demand data. The earliest and latest trajectories at a metering fix for each inbound aircraft were computed assuming engine-idle CDOs. Given the attainable RTA window for each aircraft, the aircraft sequencing problem was solved. The results show that assigning RTA allows optimizing the landing sequence when air traffic is low. For scenarios with high-traffic loads and late RTA assignments, path stretching still was found to be necessary. The minimum distance from the runway where inbound aircraft should receive the RTA to fully remove any radar vectoring was also analyzed. It was demonstrated that the assignment of RTA well before starting the descent would favor to enable full CDOs.

Design of Revising Proximity between Space and Time Cues on Flight Deck Displays to Support NextGen – The First Phase

The objective of this study is to develop and evaluate novel display formats to support RTA operations for near to midterm NextGen. Traditional cockpit displays separate space and time information in distant display sources in heterogeneous formats (graphics vs. text). This design composition may cause potential pilot errors when required time of arrival (RTA) obligations are imposed at every waypoint in NextGen. Pilots were randomly assigned to four different display conditions in a simulator – one traditional display with distant space and time cues, and three novel displays with close spatial proximity between the two cues. In the first phase of the experiment for this paper, pilots firstly participated in query tests answering space/time statuses during autopilot RTA flights. The novel displays did not degrade pilots’ situation awareness of space-time as an objective measure. For subjective measure, their situation awareness was significantly higher when the space and time cues were integrated into a single display with graphical temporal conformance indicators. The close spatial proximity between space and time cues and the support of graphical temporal conformance indicator showed a promise for improved RTA navigation.

Flight guidance of aircrafts in continuous descent operation based on 4D trajectory

Continuous descent operation (CDO) is an operating technique to reduce fuel consumption, noise and emissions during descent. Because the uncertainty of trajectory increases with CDO and the traffic density in terminal area decreases, CDO is only applied in the low-density airports or time interval. In order to implement CDO in high traffic density environment, the technique of 4D trajectory-based operation is necessary to reduce the uncertainty of trajectory, and a precise 4D flight guidance oriented to time of arrival can be implemented by 4D trajectory prediction and 4D flight guidance system. In this paper, a scheme of 4D flight guidance system based on 4D trajectory for airliners is proposed, and the describing method about 4D trajectory is given, and the planning procedure of 4D trajectory with multi-constraints is depicted. To improve the predicting precision of ETA (estimated time of arrival), a ground speed calculation method based on pseudo waypoint is proposed, and a speed adjusting strategy according to RTA (required time of arrival) and longitudinal position error is provided in the end. To demonstrate the validation of the algorithms given in the paper, the simulation based on a type of domestically-made carrier is operated, and it is can be drawn from the simulation result that the guidance algorithms and the strategy given in the paper could provide a precise 4D flight guidance oriented to time of arrival for airliners.

Extending Required Navigation Performance to Include Time Based Operations and the Vertical Dimension

Extending Required Navigation Performance to Include Time Based Operations and the Vertical Dimension

Flight-Deck Surface Trajectory-Based Operations

The results of three piloted simulations investigating flight-deck surface trajectory-based operations (STBO) are presented. Commercial transport pilots were given taxi clearances with time and speed components on the primary flight display and were required to taxi to the departing runway or intermediate intersections. Results show that when pilots were provided with speed-only taxi clearances, pilots either had poor required time of arrival (RTA) conformance with acceptable estimates of attentional distribution and safety, or had good RTA conformance with unacceptable attentional distribution and safety estimates. A flight-deck error-nulling algorithm/display allowed pilots to conform accurately with taxi RTA clearances while maintaining safety. Results are discussed in terms of pilot multitasking in the busy airport surface operations environment.

Air and Ground-Based Methods for Absorbing Delay in Four-Dimensional Trajectory-Based Operations

This paper focuses on pilot and controller issues linked to alternatives for absorbing delay in metering conditions under four-dimensional trajectory-based operations (4D TBO). We specifically explored combining two robust and complex tools, Required Time of Arrival (RTA) and three-dimensional Path Arrival Management (3D PAM) Efficient Descent Advisor (EDA) to yield more accurate and reliable delivery to the meter fix while maintaining operational efficiency. This represents the first time that these two robust and complex tools, one airborne (RTA) and one ground-based (EDA) have been used together. The data demonstrated that the combination of RTA (for speed) and EDA (for path) offered significant capacity for absorbing delay, and these two tools seemed to work well together. Specifically, the speed management of RTA was sufficiently stable and accurate to preserve 3D PAM conflict detection and avoidance and active conflict probe functionality. Potential safety and operational impacts/mitigations and human factors issues requiring further exploration are presented.

Design Options for Advanced Arrival Management in the SESAR Context

At the heart of Advanced Arrival Management (AAMAN) lies the ability to plan and control aircraft along trajectories that incorporate all relevant constraints into an integral solution (clearance) and that can be reliably executed by an aircraft. This paper discusses the AAMAN option of speed schedule / route modification (Speed And Route Advisor - SARA), as well as SARA’s relation to a complementary AAMAN option - Required Time of Arrival (RTA). Results from an operational trial of the speed schedule method at Schiphol airport showed a significant reduction in the variability of track miles flown in the Terminal Area (TMA). This reduction in track mile variability will enable introduction of fixed Precision Area Navigation routes (P-RNAV) in the Schiphol TMA. P-RNAV routes in the TMA are required for noise reduction, with the positive side benefit of providing flight efficiency benefits to airlines through increased predictability and reduced fuel burn. Usage of the RTA and speed schedule methods can be complementary, and is dependent on operational factors, such as traffic conditions, airspace layout, etc.

Airborne Technology for Distributed Air Traffic Management

Worldwide air traffic levels are growing at a rate expected to double the current traffic level by the year 2020. The current technology Air Traffic Control systems are already stretched to their limit and are prone to large delays during the peak summer travel season. There is doubt that the current systems can be scaled up to meet the expected demand levels. Many Air Traffic Management (ATM) automation systems have been proposed to increase the capability of controllers, and some are finding their way into operation. While ATM automation systems will help in handling more traffic, it is still doubtful that they can grow to meet the doubling in traffic levels foreseen. This paper presents an introduction to Distributed ATM – using the capability of airborne electronic systems to further relieve the controller workload. An overview of avionics capabilities is presented, followed by a detailed description of five specific examples of airborne capability that can be used to increase airspace capacity, as listed below. (1) An onboard method to accurately control an aircraft to cross a waypoint in the terminal area at a required time of arrival (RTA). (2) A trajectory negotiation process whereby the ground-based ATM system uses the 4D predicted trajectory computed by the aircraft, gives the aircraft RTA constraints to solve traffic conflicts, and contracts the aircraft to stay within a specified tolerance of the predicted 4D trajectory. (3) A formation flight system whereby multiple aircraft can be flown with reduced separation and controlled as a single aircraft. (4) An onboard alerting system for closely spaced parallel approaches that can increase the capacity of an airport in instrument meteorological conditions. (5) An onboard collision avoidance system that generates a conflict-free trajectory through complex airspace.