Aeronautical Scenarios Research Articles

About the combination of high and low frequency methods for impact detection on aerospace components

This paper presents an analysis of state-of-the-art of impact detection techniques for aerospace structural components as well as a study about the combination of two promising approaches for localizing an incidental impact event on a typical metallic aerospace structural component as test article. In the aeronautical scenario, some typical damaging events that may occur during service life are runway bird-strike, tool drop and debris impact. The last two cases produce generally high-frequency vibrations that are usually well predicted by ultrasonic techniques. The impacts from birds on the other hand produces vibrations in the lower or modal frequency range. The present work is focused on the possible combination of two methodologies: the first one, related to impacts inducing low-frequency vibrations, is based on the implementation of a Neural Network, while the second one, related to impacts inducing higher-frequency stress waves, is based on an acoustic source localization approach. Both numerical and experimental analyses were implemented on the same isotropic aluminum flat panel, and a possible combination of the experimental sensors arrangement will be discussed within the paper. The results have confirmed the positive performance of the neural network, opening to a more extended experimental campaign mainly oriented to the definition of the system precision, possible fault reconstruction and optimization in the data handling and reduction of computational effort. On the other hand, the main advantage of the acoustic emission formulation is that it does not require the knowledge of the wave velocity profile in the panel. Dependence of the guided wave velocity on the signal frequency for isotropic plates and, also on the wave propagation direction for anisotropic plates are the two major obstacles for acoustic source localization in a plate. Both these obstacles are avoided in this latter formulation.

Structural Life Management in a Combat Aircraft

The paper briefly describes some of the underlying concepts, issues and strategies for ensuring efficient management of structural integrity of an airframe throughout the useful life of an aircraft—especially that of a military combat aircraft. Much of the discussion in the paper is based on the experience of the authors during the design and development phase of the Indian light combat aircraft, namely, LCA Mk-I Tejas, and the information available about the LCA in the open literature or public domain. Even though not an ageing aircraft, LCA is taken as an example to facilitate bringing out various issues and strategies to resolve them, particularly with relevance to the Indian aeronautical scenario. The use of both metallic and composite materials in modern combat aircraft structures necessitates different design strategies to be adopted for their structural integrity throughout their lifetime. In this respect too, the LCA serves as a good example. Within the limited scope of the paper, the description and discussions are primarily limited to some of the important aspects, such as the fatigue degradation in metallic materials and impact damage in composites—which do form the bulk of the effort of life management of airframe structures. Other issues such as corrosion in metals and environmental degradation in composites are also briefly mentioned. A brief description of the aircraft and its structure is given initially. Major steps in designing for structural life management, such as, estimation of static loads, derivation of fatigue spectra for the intended usage, degradation through fatigue or impact damage, lifing philosophies, estimation of life and monitoring of health and usage of individual aircraft are described. A brief mention is also made about structural health monitoring (SHM) as a future direction in life management. It is expected that the exposition in the paper will help understand issues and strategies that would eventually be required as a combat aircraft gets aged in service.

On Delay-Aware Resource Control With Statistical QoS Provisioning By Dual Connectivity in Heterogeneous Aeronautical Network

In this paper, we explore the effect of dual connectivity (DC) on delay-aware resource control with statistical Quality of Service (QoS) provisioning in heterogeneous aeronautical networks. Firstly, the Software Defined Networking (SDN) controller is introduced to support the DC for aircraft by centralized management of different base stations. In light of the delay analysis of user traffic, the delay-aware resource control of SDN controller is established as a multi-objective stochastic optimization problem to guarantee the statistical QoS provisioning. Secondly, the multi-objective stochastic optimization problem is transformed into a weighted single-objective optimization and relaxed by the Lagrangian relaxation. Then, the Lyapunov optimization theory is utilized to solve the relaxed stochastic optimization for optimal resource control. Finally, the performance of resource control under DC mode is verified in two aeronautical scenarios.

Exploiting Dual Connectivity for Handover Management in Heterogeneous Aeronautical Network

In this paper, by introducing the software-defined networking (SDN) controller, we conduct traffic scheduling under dual connectivity (DC) pattern to support handover management in the heterogeneous aeronautical network. First, we construct a stochastic optimization problem of handover overhead with queue backlog, under the condition of ensuring user fairness and limited resource constraints. Then, we utilize the Lyapunov optimization theory to transform the stochastic optimization problem into a deterministic optimization problem and propose feasible and optimal strategies. Finally, we verify the feasibility and effectiveness of those strategies on handover management by simulations in two different aeronautical scenarios.

Risk Analysis of the Future Implementation of a Safety Management System for Multiple RPAS Based on First Demonstration Flights

The modern aeronautical scenario has welcomed the massive diffusion of new key elements, including the Remote Piloted Aircraft Systems (RPAS), initially used for military purposes only. The current decade has seen RPAS ready to become a new airspace user in a large variety of civilian applications. Although RPAS can currently only be flown into segregated airspaces, due to national and international Flight Aviation Authorities′ (FAAs) constraints, they represent a remarkable potential growth in terms of development and economic investments for aviation. Full RPAS development will only happen when flight into non-segregated airspaces is authorized, as for manned civil and military aircraft. The preliminary requirement for disclosing the airspace to RPAS is the implementation of an ad hoc Safety Management System (SMS), as prescribed by ICAO, for every aeronautical operator. This issue arises in the context of the ongoing restructuring of airspaces management, according to SESAR-JU in Europe and NextGen in the USA (SESAR-JU has defined how RPAS research should be conducted in SESAR 2020, all in accordance with the 2015 European ATM Master Plan). This paper provides the basis to implement a risk model and general procedures/methodologies to investigate RPAS safety, according to the operational scenarios defined by EASA (European Aviation Safety Agency). The study is based on results achieved by multiple-RPAS experimental flights, performed within the RAID (RPAS-ATM Integration Demonstration) project.

Design of a Novel Architecture Signaling Network to Provide Internet Multimedia Subsystem Services through Aeronautical Passenger Communication

This article describes a novel architecture signaling network so that an IP Multimedia Subsystem (IMS) user, flying in an aircraft, be able to register with his IMS network of origin and have access to personal services and multimedia, through a Wide-Band Code Division Multiple Access (W-CDMA) link. The proposed architecture integrates the Session Initialization Protocol (SIP), the Network Mobility Basic Support (NEMO BS) protocol and the Mobile Internet Protocol (MIPv6) to enable the usage of IMS services by passenger on board an aircraft, as a type of Aeronautical Passenger Communication (APC) services. In this novel architecture, NEMO and MIPv6 protocols are responsible for the mobility management of smartphones and user notebook and the SIP protocol is responsible for the register and the management of sessions of an IMS user. This novel architecture enables an Air Communication Service Provider (ACSP) be able to supply to an on-board passenger (The IMS user) some APC services through an Universal Mobile Telecommunication System (UMTS). The simulation results indicate the accuracy of the proposed architecture into aeronautical scenarios.

Survey on the Future Aeronautical Communication System and Its Development for Continental Communications

We present in this survey new technologies proposed for the evolution of the aeronautical communication infrastructure. Motivated by studies that estimate the growth of air traffic flow, it was decided to develop a future communication infrastructure (FCI) adapted to the future aeronautical scenario. The FCI development involves researchers, industrials, and aeronautical authorities from many countries around the world, and started in 2004. The L-band Digital Aeronautical Communication System (L-DACS) is the part of the FCI that will be in charge of continental communication. The L-DACS is being developed in Europe since 2007 and two candidates were preselected: L-DACS1 and L-DACS2. In this paper, we first describe the motivations of the FCI. We then give an overview of its development activities from 2004 to 2009. After that, we provide some insights about both preselected L-DACS candidates, at their physical and medium access layers. Finally, we address the challenges on the development of the FCI/L-DACS.

A Secure Correspondent Router Protocol for NEMO Route Optimization

The Network Mobility (NEMO) protocol is needed to support the world-wide mobility of aircraft mobile networks across different access networks in the future IPv6 based aeronautical telecommunications network (ATN). NEMO suffers from the constraint that all traffic has to be routed via the home agent though. The already existing correspondent router (CR) protocol solves this triangular routing problem and permits to route packets on a direct path between the mobile network and the ground based correspondent nodes. We identify security deficiencies of this protocol that make it unsuitable for use within the ATN. We therefore propose a new route optimization procedure based on the CR protocol that provides a higher level of security. We evaluate our new protocol in three ways. We first conduct a simulation based handover performance study using an implementation of a realistic aeronautical access technology. We then investigate the mobility signaling overhead. Finally, we specify a threat model applicable for the aeronautical environment and use it to perform a security analysis of both the old and our new protocol. It is shown that our protocol is not only more secure but also provides better handover latency, smaller overhead in the aeronautical scenario and a higher level of resilience when compared to the original CR protocol.