21 research outputs found
Satellite-Based Communications Security: A Survey of Threats, Solutions, and Research Challenges
Satellite-based Communication systems are gaining renewed momentum in
Industry and Academia, thanks to innovative services introduced by leading tech
companies and the promising impact they can deliver towards the global
connectivity objective tackled by early 6G initiatives. On the one hand, the
emergence of new manufacturing processes and radio technologies promises to
reduce service costs while guaranteeing outstanding communication latency,
available bandwidth, flexibility, and coverage range. On the other hand,
cybersecurity techniques and solutions applied in SATCOM links should be
updated to reflect the substantial advancements in attacker capabilities
characterizing the last two decades. However, business urgency and
opportunities are leading operators towards challenging system trade-offs,
resulting in an increased attack surface and a general relaxation of the
available security services. In this paper, we tackle the cited problems and
present a comprehensive survey on the link-layer security threats, solutions,
and challenges faced when deploying and operating SATCOM systems.Specifically,
we classify the literature on security for SATCOM systems into two main
branches, i.e., physical-layer security and cryptography schemes.Then, we
further identify specific research domains for each of the identified branches,
focusing on dedicated security issues, including, e.g., physical-layer
confidentiality, anti-jamming schemes, anti-spoofing strategies, and
quantum-based key distribution schemes. For each of the above domains, we
highlight the most essential techniques, peculiarities, advantages,
disadvantages, lessons learned, and future directions.Finally, we also identify
emerging research topics whose additional investigation by Academia and
Industry could further attract researchers and investors, ultimately unleashing
the full potential behind ubiquitous satellite communications.Comment: 72 page
Signals and Images in Sea Technologies
Life below water is the 14th Sustainable Development Goal (SDG) envisaged by the United Nations and is aimed at conserving and sustainably using the oceans, seas, and marine resources for sustainable development. It is not difficult to argue that signals and image technologies may play an essential role in achieving the foreseen targets linked to SDG 14. Besides increasing the general knowledge of ocean health by means of data analysis, methodologies based on signal and image processing can be helpful in environmental monitoring, in protecting and restoring ecosystems, in finding new sensor technologies for green routing and eco-friendly ships, in providing tools for implementing best practices for sustainable fishing, as well as in defining frameworks and intelligent systems for enforcing sea law and making the sea a safer and more secure place. Imaging is also a key element for the exploration of the underwater world for various scopes, ranging from the predictive maintenance of sub-sea pipelines and other infrastructure projects, to the discovery, documentation, and protection of sunken cultural heritage. The scope of this Special Issue encompasses investigations into techniques and ICT approaches and, in particular, the study and application of signal- and image-based methods and, in turn, exploration of the advantages of their application in the previously mentioned areas
Resilient Peer-to-Peer Ranging using Narrowband High-Performance Software-Defined Radios for Mission-Critical Applications
There has been a growing need for resilient positioning for numerous
applications of the military and emergency services that routinely
conduct operations that require an uninterrupted positioning service.
However, the level of resilience required for these applications is difficult
to achieve using the popular navigation and positioning systems available
at the time of this writing. Most of these systems are dependent on
existing infrastructure to function or have certain vulnerabilities that can
be too easily exploited by hostile forces. Mobile ad-hoc networks can
bypass some of these prevalent issues making them an auspicious topic for
positioning and navigation research and development. Such networks
consist of portable devices that collaborate to form wireless
communication links with one another and collectively carry out vital
network functions independent of any fixed centralized infrastructure.
The purpose of the research presented in this thesis is to adapt the
protocols of an existing narrowband mobile ad-hoc communications
system provided by Terrafix to enable range measuring for positioning.
This is done by extracting transmission and reception timestamps of
signals exchanged between neighbouring radios in the network with the
highest precision possible. However, many aspects of the radios forming
this network are generally not conducive to precise ranging, so the
ranging protocols implemented need to either maneuver around these
shortcomings or compensate for loss of precision caused. In particular,
the narrow bandwidth of the signals that drastically reduces the
resolution of symbol timing. The objective is to determine what level of
accuracy and precision is possible using this radio network and whether
one can justify investment for further development. Early experiments
have provided a simple ranging demonstration in a benign environment,
using the existing synchronization protocols, by extracting time data.
The experiments have then advanced to the radio’s signal processing to
adjust the synchronization protocols for maximize symbol timing
precision and correct for clock drift.
By implementing innovative synchronization techniques to the radio
network, ranging data collected under benign conditions can exhibit a
standard deviation of less than 3m. The lowest standard deviation
achieved using only the existing methods of synchronization was over two
orders of magnitude greater. All this is achieved in spite of the very
narrow 10−20kHz bandwidth of the radio signals, which makes producing
range estimates with an error less than 10−100m much more challenging
compared to wider bandwidth systems. However, this figure is beholden
to the relative motion of neighbouring radios in the network and how
frequently range estimates need to be made. This thesis demonstrates
how such a precision may be obtained and how this figure is likely to hold
up when applied in conditions that are not ideal
Sampled-Data Kalman Filtering and Multiple Model Adaptive Estimation for Infinite-Dimensional Continuous-Time Systems
Kalman filtering and multiple model adaptive estimation (MMAE) methods have been applied by researchers in several engineering disciplines to a multitude of problems featuring a linear (or mildly nonlinear) model based on finite-dimensional differential (or difference) equations perturbed by random inputs. However, many real-world systems are more naturally modeled using an infinite-dimensional continuous-time linear systems model, such as those most naturally modeled as partial differential equations or time-delayed differential equations along with a possibly infinite-dimensional measurement model. The Kalman filtering technique was extended to encompass infinite-dimensional continuous-time systems with sampled-data measurements and a technique to approximate an infinite-dimensional continuous-time system model with an essentially equivalent finite-dimensional discrete-time model upon which a filtering algorithm could be based was developed. The tools developed during this research were demonstrated using an estimation problem based on a stochastic partial differential equation with an unknown noise environment