Biblio

The FAA proposes Safety Continuum that recognizes the public expectation for safety outcomes vary with aviation sectors that have different missions, aircraft, and environments. The purpose is to align the rigor of oversight to the public expectations. An aircraft, its variants or derivatives may be used in operations with different expectations. The differences in mission might bring immutable risks for some applications that reuse or revise the original aircraft type design. The continuum enables a more agile design approval process for innovations in the context of a dynamic ecosystems, addressing the creation of variants for different sectors and needs. Since an aircraft type design can be reused in various operations under part 91 or 135 with different mission risks the assurance case will have many branches reflecting the variants and derivatives.This paper proposes a model for the holistic, performance-based, through-life safety assurance case that focuses applicant and oversight alike on achieving the safety outcomes. This paper describes the application of goal-based, technology-neutral features of performance-based assurance cases extending the philosophy of UL 4600, to the Safety Continuum. This paper specifically addresses component reuse including third-party vehicle modifications and changes to operational concept or eco-system. The performance-based assurance argument offers a way to combine the design approval more seamlessly with the oversight functions by focusing all aspects of the argument and practice together to manage the safety outcomes. The model provides the context to assure mitigated risk are consistent with an operation’s place on the safety continuum, while allowing the applicant to reuse parts of the assurance argument to innovate variants or derivatives. The focus on monitoring performance to constantly verify the safety argument complements compliance checking as a way to assure products are "fit-for-use". The paper explains how continued operational safety becomes a natural part of monitoring the assurance case for growing variety in a product line by accounting for the ecosystem changes. Such a model could be used with the Safety Continuum to promote applicant and operator accountability delivering the expected safety outcomes.

The full integration of Remotely Piloted Aircraft Systems (RPAS) in non-segregated airspace is one of the major objectives for the worldwide aviation organizations and authorities. However, there are several technological and regulatory issues due to the increase of the air traffic in the next years and to the need of keeping high safety levels. In this framework, a real-time validation environment capable to simulate complex scenarios related to future air traffic management (ATM) conditions is of paramount importance. These facilities allow detailed testing and tuning of new technologies and procedures before executing flight tests. With such motivations, the Italian Aerospace Research Centre has developed the Integrated Simulation Facility (ISF) able to accurately reproduce ATM complex scenarios in real-time with hardware and human in-the-loop simulations, aiming to validate new ATM procedures and innovative system prototypes for RPAS and General Aviation aircraft. In the present work, the ISF facility has been used for reproducing relevant ATM scenarios to validate the functionalities of a Detect and Avoid system (DAA). The results of the ISF test campaign demonstrate the effectiveness of the developed algorithm in the autonomous resolution of mid-air collisions in presence of both air traffic and fixed obstacles (i.e. bad weather areas, no-fly-zone and terrain) and during critical flight phases, thus exceeding the current DAA state-of-the-art.

This paper presents a framework for medium access control (MAC) and physical (PRY) cross-layer security design of wireless avionics intra-communications (WAICs). The paper explores the different options based on the latest results of MAC-PRY cross-layer design and the available standard technologies for WAICs. Particular emphasis is given to solutions based on multiple-input multiple-output (MIMO) systems and recent developments towards a wireless technology with ultra-low latency and high reliability in the context of 5G and machine-type traffic support. One major objective is to improve WAICs technology and thus match the real-time, reliability and safety critical performance of the internal aeronautics bus technologies (e.g., ARINC 664). The main identified vulnerabilities and potential solutions are explored, as well as their impact on system design complexity and feasibility for wireless networks on-board aircraft. The solutions are presented in the context of the European project SCOTT (secure connected trustable things) using the recently released reference architecture for trusted IoT systems. Other aspects of SCOTT such as trust, privacy, security classes, and safety are also discussed here for the aeronautics domain.

With rapid advances in the fields of the Internet of Things and autonomous systems, the network security of cyber-physical systems(CPS) becomes more and more important. This paper focuses on the real-time security evaluation for unmanned aircraft systems which are cyber-physical systems relying on information communication and control system to achieve autonomous decision making. Our problem formulation is motivated by scenarios involving autonomous unmanned aerial vehicles(UAVs) working continuously under data-driven attacks when in an open, uncertain, and even hostile environment. Firstly, we investigated the state estimation method in CPS integrated with data-driven attacks model, and then proposed a real-time security scoring algorithm to evaluate the security condition of unmanned aircraft systems under different threat patterns, considering the vulnerability of the systems and consequences brought by data attacks. Our simulation in a UAV illustrated the efficiency and reliability of the algorithm.

Rapid inspection and assessment of critical infrastructure after man-made and natural disasters is a matter of homeland security. The primary aim of this paper is to demonstrate the potential of leveraging small Unmanned Aircraft System (sUAS) in support of the rapid recovery of critical infrastructure in the aftermath of catastrophic events. We propose our data collection, detection and assessment system, using a sUAS equipped with a Lidar and a camera. This method provides a solution in fast post-disaster response and assists human responders in damage investigation.

In signed directed graph (SDG) fault diagnosis model, only single fault can be diagnosed. In order to meet the requirements of multiple faults diagnosis, in this paper, improved signed directed graph (ISDG) fault diagnosis model was proposed. The logic and influence between nodes were included in ISDG model. With ISDG model, complex logic can be shown, multiple faults can be diagnosed and the optimal sequence can be determined. Two algorithms are proposed in this paper. One algorithm can obtain the multiple faults combine logic, and the other algorithm can obtain the optimal path of fault diagnosis. According to these two algorithms, the efficiency was improved and the cost was reduced in the multiple fault diagnosis process. Finally, the faults of an aircraft engine bleed system were diagnosed with the interactive algorithm. The proposed algorithms can obtain a diagnosis result effectively. The results of two cases prove that these algorithms can be used for multiple fault diagnosis.

The term "Cyber Physical System" (CPS) has been used in the recent years to describe a system type, which makes use of powerful communication networks to functionally combine systems that were previously thought of as independent. The common theme of CPSs is that through communication, CPSs can make decisions together and achieve common goals. Yet, in contrast to traditional system types such as embedded systems, the functional dependence between CPSs can change dynamically at runtime. Hence, their functional dependence may cause unforeseen runtime behavior, e.g., when a CPS becomes unavailable, but others depend on its correct operation. During development of any individual CPS, this runtime behavior must hence be predicted, and the system must be developed with the appropriate level of robustness. Since at present, research is mainly concerned with the impact of functional dependence in CPS on development, the impact on runtime behavior is mere conjecture. In this paper, we present AirborneCPS, a simulation tool for functionally dependent CPSs which simulates runtime behavior and aids in the identification of undesired functional interaction.

Millions of small Unmanned Aircraft System (sUAS) aircraft of various shapes and capabilities will soon fly at low altitudes in urban environments for ambitious applications. It is critical to ensure these remotely piloted aircraft fly safely, predictably, and efficiently in this challenging airspace, without endangering themselves and other occupants sharing that airspace or in proximity. Concepts, technologies, processes, and policies to solve this hard problem of UAS Traffic Management (UTM) are being explored. But, cyber security considerations are largely missing. This paper bridges this gap and addresses UTM cyber security needs and issues. It contributes a comprehensive framework to understand, identify, classify, and assess security threats to UTM, including those resulting from sUAS vulnerabilities. Promising threat mitigations, major challenges, and research directions are discussed to secure UTM.

The wireless spectrum is a scarce resource, and the number of wireless terminals is constantly growing. One way to mitigate this strong constraint for wireless traffic is the use of dynamic mechanisms to utilize the spectrum, such as cognitive and software-defined radios. This is especially important for the upcoming wireless sensor and actuator networks in aircraft, where real-time guarantees play an important role in the network. Future wireless networks in aircraft need to be scalable, cater to the specific requirements of avionics (e.g., standardization and certification), and provide interoperability with existing technologies. In this paper, we demonstrate that dynamic network reconfigurability is a solution to the aforementioned challenges. We supplement this claim by surveying several flexible approaches in the context of wireless sensor and actuator networks in aircraft. More specifically, we examine the concept of dynamic resource management, accomplished through more flexible transceiver hardware and by employing dedicated spectrum agents. Subsequently, we evaluate the advantages of cross-layer network architectures which overcome the fixed layering of current network stacks in an effort to provide quality of service for event-based and time-triggered traffic. Lastly, the challenges related to implementation of the aforementioned mechanisms in wireless sensor and actuator networks in aircraft are elaborated, and key requirements to future research are summarized.

Unmanned Aerial Vehicles (UAVs) are autonomous aircraft that, when equipped with wireless communication interfaces, can share data among themselves when in communication range. Compared to single UAVs, using multiple UAVs as a collaborative swarm is considerably more effective for target tracking, reconnaissance, and surveillance missions because of their capacity to tackle complex problems synergistically. Success rates in target detection and tracking depend on map coverage performance, which in turn relies on network connectivity between UAVs to propagate surveillance results to avoid revisiting already observed areas. In this paper, we consider the problem of optimizing three objectives for a swarm of UAVs: (a) target detection and tracking, (b) map coverage, and (c) network connectivity. Our approach, Dual-Pheromone Clustering Hybrid Approach (DPCHA), incorporates a multi-hop clustering and a dual-pheromone ant-colony model to optimize these three objectives. Clustering keeps stable overlay networks, while attractive and repulsive pheromones mark areas of detected targets and visited areas. Additionally, DPCHA introduces a disappearing target model for dealing with temporarily invisible targets. Extensive simulations show that DPCHA produces significant improvements in the assessment of coverage fairness, cluster stability, and connection volatility. We compared our approach with a pure dual- pheromone approach and a no-base model, which removes the base station from the model. Results show an approximately 50% improvement in map coverage compared to the pure dual-pheromone approach.

Future transportation systems highly rely on the integrity of spatial information provided by their means of transportation such as vehicles and planes. In critical applications (e.g. collision avoidance), tampering with this data can result in life-threatening situations. It is therefore essential for the safety of these systems to securely verify this information. While there is a considerable body of work on the secure verification of locations, movement of nodes has only received little attention in the literature. This paper proposes a new method to securely verify spatial movement of a mobile sender in all dimensions, i.e., position, speed, and direction. Our scheme uses Doppler shift measurements from different locations to verify a prover's motion. We provide formal proof for the security of the scheme and demonstrate its applicability to air traffic communications. Our results indicate that it is possible to reliably verify the motion of aircraft in currently operational systems with an equal error rate of zero.

The need for increased surveillance due to increase in flight volume in remote or oceanic regions outside the range of traditional radar coverage has been fulfilled by the advent of space-based Automatic Dependent Surveillance — Broadcast (ADS-B) Surveillance systems. ADS-B systems have the capability of providing air traffic controllers with highly accurate real-time flight data. ADS-B is dependent on digital communications between aircraft and ground stations of the air route traffic control center (ARTCC); however these communications are not secured. Anyone with the appropriate capabilities and equipment can interrogate the signal and transmit their own false data; this is known as spoofing. The possibility of this type of attacks decreases the situational awareness of United States airspace. The purpose of this project is to design a secure transmission framework that prevents ADS-B signals from being spoofed. Three alternative methods of securing ADS-B signals are evaluated: hashing, symmetric encryption, and asymmetric encryption. Security strength of the design alternatives is determined from research. Feasibility criteria are determined by comparative analysis of alternatives. Economic implications and possible collision risk is determined from simulations that model the United State airspace over the Gulf of Mexico and part of the airspace under attack respectively. The ultimate goal of the project is to show that if ADS-B signals can be secured, the situational awareness can improve and the ARTCC can use information from this surveillance system to decrease the separation between aircraft and ultimately maximize the use of the United States airspace.

Recent attention to aviation cyber physical systems (ACPS) is driven by the need for seamless integration of design disciplines that dominate physical world and cyber world convergence. System convergence is a big obstacle to good aviation cyber-physical system (ACPS) design, which is due to a lack of an adequate scientific theoretical foundation for the subject. The absence of a good understanding of the science of aviation system convergence is not due to neglect, but rather due to its difficulty. Most complex aviation system builders have abandoned any science or engineering discipline for system convergence they simply treat it as a management problem. Aviation System convergence is almost totally absent from software engineering and engineering curricula. Hence, system convergence is particularly challenging in ACPS where fundamentally different physical and computational design concerns intersect. In this paper, we propose an integrated approach to handle System convergence of aviation cyber physical systems based on multi-dimensions, multi-views, multi-paradigm and multiple tools. This model-integrated development approach addresses the development needs of cyber physical systems through the pervasive use of models, and physical world, cyber world can be specified and modeled together, cyber world and physical world can be converged entirely, and cyber world models and physical world model can be integrated seamlessly. The effectiveness of the approach is illustrated by means of one practical case study: specifying and modeling Aircraft Systems. In this paper, We specify and model Aviation Cyber-Physical Systems with integrating Modelica, Modelicaml and Architecture Analysis & Design Language (AADL), the physical world is modeled by Modelica and Modelicaml, the cyber part is modeled by AADL and Modelicaml.

Modern military forces are enabled by networked command and control systems, which provide an important interface between the cyber environment, electronic sensors and decision makers. However these systems are vulnerable to cyber attack. A successful cyber attack could compromise data within the system, leading to incorrect information being utilized for decisions with potentially catastrophic results on the battlefield. Degrading the utility of a system or the trust a decision maker has in their virtual display may not be the most effective means of employing offensive cyber effects. The coordination of cyber and kinetic effects is proposed as the optimal strategy for neutralizing an adversary's C4ISR advantage. However, such an approach is an opportunity cost and resource intensive. The adversary's cyber dependence can be leveraged as a means of gaining tactical and operational advantage in combat, if a military force is sufficiently trained and prepared to attack the entire information network. This paper proposes a research approach intended to broaden the understanding of the relationship between command and control systems and the human decision maker, as an interface for both cyber and kinetic deception activity.