Abstract

Through application of modern technology, aviation systems are becoming more automated and are relying less on antiquated air traffic control (ATC) voice systems. Aircraft are now able to wirelessly broadcast and receive identity and location information using transponder technology. This helps reduce controller workload and allows the aircraft to take more responsibility for maintaining safe separation. However, these systems lack source authentication methods or the ability to check the integrity of message content. This opens the door for hackers to potentially create fraudulent messages or manipulate message content. "br /""br /"This thesis presents a solution to handling many of the potential security issues in aircraft data communication. This is accomplished through the implementation of a Dual Path PKI (DPP) design which includes a novel approach to handling certificate revocation through session certificates. DPP defines two authentication protocols, one between aircraft and another between aircraft and ATC, to achieve source authentication. Digital signature technology is utilized to achieve message content and source integrity as well as enable bootstrapping DPP into current ATC systems. DPP employs cutting-edge elliptic curve cryptography (ECC) algorithms to increase performance and reduce overhead. "br /""br /"It is found that the DPP design successfully mitigates several of the cyber security concerns in aircraft and ATC data communications. An implementation of the design shows that anticipated ATC systems can accommodate the additional processing power and bandwidth required by DPP to successfully achieve system integrity and security. Master of Science

Abstract

large number of stakeholders exist in the modern air traffic management ecosystem. Air transportation studies benefit from collaboration and the sharing of knowledge and findings between these different players. However, not all parties have equal access to information. Due to the lack of open-source tools and models, it is not always possible to undertake comparative studies and to repeat experiments. The barriers to accessing proprietary tools and models create major limitations in the field of air traffic management research. This dissertation investigates the methods necessary to construct an aircraft performance model based on open data, which can be used freely and redistributed without restrictions. The primary data source presented in this dissertation is aircraft surveillance data that can be intercepted openly with little to no restriction in most regions of the world. The eleven chapters in this dissertation follow the sequence of open data, open models, and performance estimations. This order corresponds to the three main parts of the dissertation. In the first part of the dissertation, open surveillance data is explored. Methods are developed to decode and process this data. Extraction of information is also made possible thanks to machine learning algorithms. The second part of the dissertation examines the main components of the open aircraft performance model. Models related to kinematics, thrust, drag polar, fuel flow, and weather are investigated. The third part of the dissertation looks into the possibility of using surveillance data to estimate aircraft performance parameters, for example, aircraft turn performance, aircraft mass, and thrust settings, for individual flights. With the goal of making future air traffic management studies more transparent, comparable, and reproducible, the models and tools proposed in this dissertation are fully open. The final aircraft performance model, OpenAP, proposed in this dissertation has proven to be an efficient open alternative to current closed-source models.

Abstract

Localization is a fundamental technology embedded — often unbeknownst to users — in many devices and services. First, this book reveals how localization systems are driving modern society. The core focus is then on the Global Positioning System (GPS), which is constantly rising in importance due to its global availability and low receiver cost. Still, high energy consumption and susceptibility to fake or reflected signals are challenges for GPS receivers. The limited endurance of battery-powered GPS receivers can be addressed by snapshot receivers which require as little as one millisecond of received satellite signals to determine their location. Using short signals reduces the active time and thus the energy consumption of a GPS receiver drastically. But short signals reduce the received signal energy, which impairs the localization robustness. The collective detection maximum likelihood method performs well with short signals. Furthermore, a tiny and low power snapshot GPS receiver hardware design allows location tracking for months or years using a coin cell. Spoofed GPS satellite signals pose a threat to an increasing number of critical systems relying on GPS. Determining multiple likely localization solutions instead of only one enables correct receiver localization despite malicious signals. Finally, an experimental localization system is presented that leverages status messages transmitted by aircraft. It aims at combining the ubiquitous availability and low receiver cost of GPS with the high signal strength of local localization systems like those based on WiFi or LTE signals. As such, it gives the prospect of robust and possibly indoor localization without the high setup costs of short- range localization systems. This book is suitable for readers with a technical background, but no prior knowledge of localization systems. Readers familiar with GPS can skip the introductory chapters and directly dive into the advanced material.

Abstract

The ability to meet a controlled time of arrival during a continuous descent operation will enable environmentally friendly and fuel efficient descent operations while simultane- ously maintaining airport throughput. However, if the wind fore- cast used to compute the initial trajectory plan is not accurate enough, the guidance system will need to correct time deviations from the plan during the execution of the descent. Previous work proposed an on-board guidance strategy based on model predictive control, which repeatedly updates the trajectory plan in real-time from the current aircraft state and for the remainder of the descent. However, the wind conditions downstream, at altitudes not explored yet, were difficult to predict due to the lack of data. This paper shows the potential benefits of using wind observations, broadcast by nearby aircraft, to reconstruct the wind profile downstream. The wind profile in the trajectory opti- mization problem is modeled as a spline, which control points are updated to fit the observations before re-planning the trajectory. Results from simulations using realistic wind data show that the performance of model predictive control significantly improves when including up-to-date wind observations, in terms of time and energy errors at the metering fix and fuel consumption. Peer Reviewed

Abstract

The U.S. Next Generation Air Transportation System (NextGen) is designed to increase the capacity, safety and efficiency of the air traffic control via the integration of past experiences and advances in technology. However, the system is expected to greatly increase the amount and types of data generated as well as the knowledge to be managed. Additionally, as with all new technology, U.S. NextGen opens the specter of the potential impacts created by cyberattacks. Given this, it appears logical to view the U.S. NextGen system from the lens of Big Data. This study evaluates the U.S. NextGen system using the five differentiated qualitative characteristics of big data: Volume, Velocity, Variety, Veracity and Value. The results indicate that U.S. NextGen system has several big data challenges that must be addressed in order to obtain its maximal potential. Refereed/Peer-reviewed

Abstract

In Air Traffic Control, ADS-B (Automatic Dependent Surveillance - Broadcast) systems provide surveillance information as obtained by the cooperating airplanes. This usage of air-derived data and of a common link opens various issues: performance in dense traffic area, signals validation and security. A Software Defined Radio (SDR) permits the needed flexibility and modularity in order to easily develop prototypal devices for evaluation and test of novel enhancements of ADS-B receivers. In this frame, a multi-channel receiver for 1090 MHz ADS-B signals was implemented, using an array antenna, a specific designed analog front-end and a software defined receiver. The device is useful to test signal processing algorithms and to analyse the channel traffic. The receiver is also jointly used with another SDR device capable to generate 1090 MHz traffic. With this configuration it is possible to generate specific traffic scenarios characterized by interferences from multiple sources and/or by jammer. This paper deals with the hardware and set-up description, the presentation of the developed software receiver and its functions, and, finally, the results achieved using the system.

Abstract

ft need to be separated from other aircraft by either a minimum vertical distance of 1000ft or by a minimum horizontal distance of 5NM to avoid mid-air collisions. Traffic Alert and Collision Avoidance System (TCAS) work well as a tactical safety backups to avoid collision, but cannot perform separation assurance. This paper presents the design aspects of system that would predict separation infringement and provide flight crew with necessary guidance for maintaining separation. This paper discusses formulation of system function based on ADS-B, mathematical models, simulation and results. A system model has been implemented in MATLAB and various encounters with different speed ratios at various conflict angles has been fed as input to system model with a goal of avoidance and recovery to original waypoint. Both Heading and Speed maneuvers are evaluated and results are presented. The required strength of resolution maneuver as a function of conflict geometry is studied and automatic maneuver selection function is implemented in system model and maneuver selection function is evaluated with discussion of results.

Abstract

To reduce emissions of air traffic, future aircraft will install hybrid-electric propulsion systems. We require the load conditions over the time in service, to design these aircraft. In this paper, we propose a mission profile for a regional aircraft with a hybrid-electric propulsion system. We focused on regional aircraft, which are in service in Ireland and the United Kingdom (UK). The reference aircraft ATR\\,72-600 is a turboprop aircraft with a capacity of 70 passengers. To propose a mission profile, we have analyzed more than 6000 flights of four different aircraft of the same type. Input data is provided by online databases, which collect flight data. We are able to show that the maximum available power is needed for about 52 seconds during take-off and climb phase of the flight. The median flight time is 59 minutes and 30 seconds. The average required power is 53\\,\\% of the maximum power. The average traveled distance is 407\\,km, which is less than one third of the aircraft's maximum reach. These findings are needed for calculating the lifetime of drivetrain components of a hybrid or all electric aircraft. In our further work, we will design an electric machine for regional aircraft. This mission profile will be used to design different power train components.