Sustainability

Research

19 pages, 3938 KiB

Open AccessArticle

A Fractal Dimension Feature Model for Accurate 4D Flight-Trajectory Prediction

by Yuandi Zhao and Kepin Li

Sustainability 2023, 15(2), 1272; https://doi.org/10.3390/su15021272 - 09 Jan 2023

Cited by 1 | Viewed by 1460

Accurate 4D trajectory prediction plays an important role in the sustainable management of future air traffic. Aiming at the problems of inadequate feature utilization, unbalanced overall prediction (OP) result, and weak real-time response in 4D trajectory prediction by machine learning, a fractal dimension [...] Read more.

Accurate 4D trajectory prediction plays an important role in the sustainable management of future air traffic. Aiming at the problems of inadequate feature utilization, unbalanced overall prediction (OP) result, and weak real-time response in 4D trajectory prediction by machine learning, a fractal dimension feature-prediction (FDFP) model is proposed, starting from the airborne quick access recorder (QAR) trajectory data. Firstly, the trajectory features are classified and transformed according to the aircraft operation characteristics. Then, the long short-term memory (LSTM) network is used to construct the prediction model by fractional dimensions; based on the fractal dimension feature (FDF), the different combinations of influencing factors are selected as the feature matrix, and the optimal prediction model of each dimension is obtained. Finally, 671 city pair trajectory data are used to conduct simulation experiments to verify the accuracy and effectiveness of the model. The experimental results show that the FDFP model performs well, with the mean absolute error (MAE) of longitude and latitude both less than 0.0015°, and the MAE of altitude less than 3 m. Compared with the OP model, the MAE of the FDFP model in these three dimensions decreased by 92%, 81% and 79%, respectively. Compared with experiments without feature transformation, the MAE of the FDFP model is reduced by 75%, 82%, and 69%, respectively. Each prediction of the model takes about 30 ms, which satisfies the real-time prediction conditions and can provide a reference for air traffic operation assessment. Full article

(This article belongs to the Special Issue Airspace System Planning and Management)

► Show Figures

Figure 1

23 pages, 3789 KiB

Open AccessArticle

Method of Vertiport Capacity Assessment Based on Queuing Theory of Unmanned Aerial Vehicles

by Honghai Zhang, Yuhan Fei, Jingyu Li, Bowen Li and Hao Liu

Sustainability 2023, 15(1), 709; https://doi.org/10.3390/su15010709 - 30 Dec 2022

Cited by 3 | Viewed by 1486

Abstract

Urban air traffic has gradually attracted attention in recent years, which will bring endless vitality to future urban development. An objective and accurate method of assessing vertiport capacity is the basis for the air traffic flow management of UAVs, which plays an important [...] Read more.

Urban air traffic has gradually attracted attention in recent years, which will bring endless vitality to future urban development. An objective and accurate method of assessing vertiport capacity is the basis for the air traffic flow management of UAVs, which plays an important role in improving the efficiency of urban airspace resources. First of all, this paper establishes a theoretical capacity calculation model for ground facilities such as takeoff and landing platforms, taxiways and aprons, respectively. Next, this paper analyzes the service characteristics of each ground facility and establishes different types of UAV queuing systems to obtain UAV delay curves based on a UAV Poisson flow arrival model. Subsequently, a suitable acceptable delay level is selected to obtain the corresponding UAV flow, which means the actual capacity of UAV operations. Eventually, the validity of the model is verified through actual drone data arithmetic examples. The calculation results show that the combination of “1 landing + 2 takeoffs” can achieve better capacity results and that the landing platform is more prone to congestion than the takeoff platform. Change in average service time has the greatest impact on the apron capacity, and the takeoff platform is the most sensitive to changes in the acceptable delay level. Full article

(This article belongs to the Special Issue Airspace System Planning and Management)

► Show Figures

Figure 1

21 pages, 6809 KiB

Open AccessArticle

Optimal Vertiport Airspace and Approach Control Strategy for Urban Air Mobility (UAM)

by Kyowon Song

Sustainability 2023, 15(1), 437; https://doi.org/10.3390/su15010437 - 27 Dec 2022

Cited by 4 | Viewed by 2306

Abstract

Recently, urban air mobility (UAM), a new transportation system that can expand urban mobility from 2D to 3D, has been in the spotlight all over the world. For successful implementation of UAM, not only eVTOL aircraft development but also various systems such as [...] Read more.

Recently, urban air mobility (UAM), a new transportation system that can expand urban mobility from 2D to 3D, has been in the spotlight all over the world. For successful implementation of UAM, not only eVTOL aircraft development but also various systems such as UAM traffic management are required; however, research on these areas is still insufficient. Based on the BQA model, in this study, we introduce the balanced branch queuing approach (BBQA) model as a new approach control model that can improve operational efficiency by enabling the landing order to be changed more easily. Through simulation, its effectiveness was verified. The proposed BBQA achieved the identical airspace safety as the BQA model, in addition to showing a superior result to the SBA model in on-time performance (OTP). The vertiport airspace blueprint concept and approach control model proposed in this study are expected to play an important role in future studies in the area of air traffic management in UAM. Full article

(This article belongs to the Special Issue Airspace System Planning and Management)

► Show Figures

Figure 1

23 pages, 4794 KiB

Open AccessArticle

Path Planning of Electric VTOL UAV Considering Minimum Energy Consumption in Urban Areas

by Yafei Li and Minghuan Liu

Sustainability 2022, 14(20), 13421; https://doi.org/10.3390/su142013421 - 18 Oct 2022

Cited by 6 | Viewed by 2301

Abstract

As a new mode of transportation in the future, electric vertical take-off and landing unmanned aerial vehicles (eVTOL UAV) can undertake the task of logistics distribution and carry people in urban areas. It is challenging to carry out research designed to plan the [...] Read more.

As a new mode of transportation in the future, electric vertical take-off and landing unmanned aerial vehicles (eVTOL UAV) can undertake the task of logistics distribution and carry people in urban areas. It is challenging to carry out research designed to plan the path of eVTOL UAVs which can have a safe and sustainable operation mode in urban areas. Therefore, this work proposes a method for planning an obstacle-free path for eVTOL UAVs in urban areas with the goal of minimizing energy consumption. It aims to improve the safety and sustainability of eVTOL UAV operations. Based on variations of air density with height, a more accurate formula for calculating battery energy consumption of eVTOL UAV is derived. It is used in the vertical takeoff and landing phase and horizontal flight phase, respectively. Considering the influence of buildings on eVTOL UAV operation, a path planning method applicable to complex urban environments is proposed. The safe nodes of eVTOL UAV flight are obtained by using Voronoi diagrams based on building locations. Then, the complete shortest and obstacle-free path is obtained by using a Dubins geometric path and Floyd algorithm. After obtaining the obstacle-free paths for all flight height zones, the battery energy consumption of the eVTOL UAV in each flight height zone is calculated. Then, the flight height with the minimum energy consumption is obtained. The simulation results show that the path length obtained by the proposed path planning method is shorter than that obtained by particle swarm optimization; the total battery energy consumption changes in the same pattern in the low-altitude areas and high-altitude areas; the difference between the maximum and minimum energy consumption in the small area enables the eVTOL UAV to cover about 350 m more, and about 420 m more in the large area. Therefore, in future high-frequency UAV mission flights, choosing the altitude with the lowest energy consumption can reduce UAV operator costs. It can also significantly increase UAV transport range and make UAVs operate more sustainably. Full article

(This article belongs to the Special Issue Airspace System Planning and Management)

► Show Figures

Figure 1

17 pages, 3618 KiB

Open AccessArticle

The Method of Trajectory Selection Based on Bayesian Game Model

by Wen Tian, Qin Fang, Xuefang Zhou and Fan Yang

Sustainability 2022, 14(18), 11491; https://doi.org/10.3390/su141811491 - 14 Sep 2022

Viewed by 1172

Abstract

To cope with the problem that most of the en-route spatial-temporal resource allocation in the collaborative trajectory options program (CTOP) only considers the air traffic control system command center (ATCSCC) while ignoring the needs of the airlines, which results in the loss of [...] Read more.

To cope with the problem that most of the en-route spatial-temporal resource allocation in the collaborative trajectory options program (CTOP) only considers the air traffic control system command center (ATCSCC) while ignoring the needs of the airlines, which results in the loss of fairness, this study explores resource allocation methods oriented to airline trajectory preferences with optional trajectory and entry slots of flights over the flow constrained area (FCA) as the research object. Using game theory to analyze airline trajectory preference information and a Bayesian game model based on mixed strategies is constructed, the process of incomplete information game among airlines is studied. The equilibrium theory is used to solve the guarantee strategy of airline trajectory selection, which makes the airline trajectory selection strategy robust and provides a basis for the selection of schemes for ATCSCC to implement en-route network resource allocation under the CTOP. Experimental analysis was carried out to verify the feasibility of the method based on the actual operation data of high-altitude sectors of Shanghai. The results show that the solution obtained by the game can provide airlines with flight trajectory and entry slots over the FCA that are more in line with their actual operational needs and which provide data reference for the ATCSCC to select the final plan in multiple global Pareto optimal solutions in the subsequent process of the CTOP so as to better play the decision-making role of airlines in the CTOP while improving the fairness of en-route resource allocation. Full article

(This article belongs to the Special Issue Airspace System Planning and Management)

► Show Figures

Figure 1

28 pages, 13246 KiB

Open AccessArticle

Multi-Aircraft Cooperative Strategic Trajectory-Planning Method Considering Wind Forecast Uncertainty

by Man Xu, Minghua Hu, Yi Zhou, Wenhao Ding and Qiuqi Wu

Sustainability 2022, 14(17), 10811; https://doi.org/10.3390/su141710811 - 30 Aug 2022

Cited by 1 | Viewed by 1204

Abstract

We address the issue of multi-aircraft cooperative strategic trajectory planning in free-route airspace (FRA) in this study, taking into consideration the impact of time-varying and altitude-varying wind forecast uncertainty. A bi-level planning model was established in response to the properties of the wind. [...] Read more.

We address the issue of multi-aircraft cooperative strategic trajectory planning in free-route airspace (FRA) in this study, taking into consideration the impact of time-varying and altitude-varying wind forecast uncertainty. A bi-level planning model was established in response to the properties of the wind. The upper level focused on minimizing the flight time, while the lower level aimed to reduce potential conflicts. Meanwhile, a heuristic approach based on conflict severity (CS) within the framework of a cooperative co-evolution evolutionary algorithm (CCEA) was proposed to accelerate the convergence speed in view of the complexity of this optimization issue. In order to conduct the experiments, historical data of 1479 flights over western Chinese airspace were retrieved. The number of conflicts, total flight time, total flight time variance, and deviation were used as indicators to evaluate the safety, efficiency, and predictability of the trajectory. When compared to a trajectory in the structured airspace, the optimal solution was conflict-free and reduced the total flight time by about 17.7%, the variance by 11.7%, and the deviation by 37.5%. Additionally, the contrast with the two-stage model demonstrated that the proposed method was entirely meaningful. The outcome of this survey can provide an effective trajectory-planning method, which is crucial for the sustainable development of future air traffic management (ATM). Full article

(This article belongs to the Special Issue Airspace System Planning and Management)

► Show Figures

Figure 1

21 pages, 3938 KiB

Open AccessArticle

Capacity Evaluation Method of Ship Terminal Area Based on Network Maximum Flow

by Gang Zhong, Yuhan Fei, Jia Yi, Dikun Feng and Ouge Feng

Sustainability 2022, 14(17), 10470; https://doi.org/10.3390/su141710470 - 23 Aug 2022

Viewed by 979

Abstract

With the development of modern military ship equipment, the airspace operation environment of shipboard aircraft is becoming increasingly complex. The objective and accurate evaluation of ship-terminal capacity is the basis of air traffic flow management for shipboard aircraft, and it is also the [...] Read more.

With the development of modern military ship equipment, the airspace operation environment of shipboard aircraft is becoming increasingly complex. The objective and accurate evaluation of ship-terminal capacity is the basis of air traffic flow management for shipboard aircraft, and it is also the premise of improving the efficiency of airspace resources. First of all, this paper divides the airspace and ship terminal areas and realizes the route network planning for the arrival and departure of shipboard aircraft. Following this, according to the airspace characteristics of the ship terminal area and the operation process of the shipboard aircraft, an arrival-and-departure network flow model for shipboard aircraft is established by using capacity-limitation and flow-conservation conditions. Finally, simulated annealing (SA) is used to solve the maximum flow in the arrival-and-departure network flow model, and the capacity evaluation results of the ship terminal area are obtained. The results show that when the number of gates is n_g ≥ 7, the bottleneck in the ship terminal area’s operation capacity is the deck runway. When 3 ≤ n_g < 7, imbalanced take-off and landing tasks lead to a waste of runway resources, and when n_g < 3, the number of gates becomes the bottleneck which limits the capacity. With the number of gates being reduced from seven to three, the capacity is reduced from twenty sorties per hour to six sorties per hour. The model and core idea proposed in this paper can not only quickly evaluate the capacity of the terminal area of ships but also provide a solid foundation for the development of future fleet groups and the full use of maritime airspace. Full article

(This article belongs to the Special Issue Airspace System Planning and Management)

► Show Figures

Figure 1

13 pages, 1700 KiB

Open AccessEditor’s ChoiceArticle

Quantitative Ground Risk Assessment for Urban Logistical Unmanned Aerial Vehicle (UAV) Based on Bayesian Network

by Peng Han, Xinyue Yang, Yifei Zhao, Xiangmin Guan and Shengjie Wang

Sustainability 2022, 14(9), 5733; https://doi.org/10.3390/su14095733 - 09 May 2022

Cited by 10 | Viewed by 2378

Abstract

The Unmanned Aerial Vehicle (UAV) has been used for the delivery of medical supplies in urban logistical distribution, due to its ability to reduce human contact during the global fight against COVID-19. However, due to the reliability of the UAV system and the [...] Read more.

The Unmanned Aerial Vehicle (UAV) has been used for the delivery of medical supplies in urban logistical distribution, due to its ability to reduce human contact during the global fight against COVID-19. However, due to the reliability of the UAV system and the complex and changeable operation scene and population distribution in the urban environment, a few ground-impact accidents have occurred and generated enormous risks to ground personnel. In order to reduce the risk of UAV ground-impact accidents in the urban logistical scene, failure causal factors, and failure modes were classified and summarized in the process of UAV operation based on the accumulated operation data of more than 20,000 flight hours. The risk assessment model based on the Bayesian network was built. According to the established network and the probability of failure causal factors, the probabilities of ground impact accidents and intermediate events under different working conditions were calculated, respectively. The posterior probability was carried out based on the network topology to deduce the main failure inducement of the accidents. Mitigation measures were established to achieve the equivalent safety level of manned aviation, aiming at the main causes of accidents. The results show that the safety risk of the UAV was reduced to 3.84 × 10⁻⁸ under the action of risk-mitigation measures. Full article

(This article belongs to the Special Issue Airspace System Planning and Management)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Airspace System Planning and Management

Share This Special Issue

Special Issue Editors

Special Issue Information

Keywords

Published Papers (8 papers)

Research

Further Information

Guidelines

MDPI Initiatives

Follow MDPI