Signal Processing - September 2017 - 36

off between the level of detection capability and the resulting
authentication latency, and also taking into account that the
receiver independent synchronization is commensurate with
the latency and, therefore, a higher latency also relaxes this
requirement in the receiver.
Finally, it should be recognized that the detection of SCA
bursts based on a simple threshold, as investigated in the previous example, can be still vulnerable to specific attacks. For
instance, a spoofer can try to bypass this check with an overpower transmission of only a portion of SCA chips, correctly
estimated. Aiming to decrease the misdetection probability
of these kind of attacks, more sophisticated defenses can be
implemented in future participant receivers, further increasing
the cost and the complexity at the attacker side.

Conclusions and perspectives
The widespread reliance on civil GNSS signals is pushing for the demand for suitable authentication solutions.
While some user communities are open to innovations and
enhancements (e.g., location-based services), other groups
are more reluctant, due to required procurement and certification processes [2].
Navigation message authentication approaches are expected
to be implemented in a few-year time frame, becoming part of
civil GNSS services (e.g., Galileo OS NMA [13], [46]). Further
evolutions including more sophisticated solutions based on SCA
(e.g., [11], [27], and [32]) may be implemented in the next GNSS
generations, narrowing the current gap between civil and restricted-access signals. However, the feasibility of such solutions and
their possible implementation time line strongly depend on their
levels of complexity and backward compatibility, their impact on
existing systems and receivers, and policy aspects.

Acknowledgments
This article presents some findings of Future Navigation and
Timing Evolved Signals (FUNTIMES), a project funded by the
European Commission under the Horizon 2020 Framework Program (Funding Reference number 435/PP/GRO/RCH/15/8384).
In addition, we thank the anonymous reviewers for their constructive comments, which helped us to improve the manuscript.

Authors
Davide Margaria (margaria@ismb.it) received his B.S. and
M.S. degrees in telecommunication engineering in 2003 and
2007, respectively, from the Politecnico di Torino, Italy. He
currently works as a senior researcher at the Istituto Superiore
Mario Boellam, Torino, Italy, within the navigation technologies research area. His research interests include Galileo and
modernized global positioning system receivers, innovative
signal processing strategies, mitigation of multipath, jamming,
and spoofing signals, and global navigation satellite system
authentication techniques.
Beatrice Motella (motella@ismb.it) is a senior researcher
at the Istituto Superiore Mario Boella, within the navigation
technologies research area. She received her M.S. and Ph.D.
degrees in electronics and communications engineering in
36

2003 and 2008, respectively, from the Politecnico di Torino,
Italy. In 2006, she joined the Satellite Navigation and
Positioning Laboratory group at the University of New South
Wales, Australia, for one year as a visiting researcher. Her
research interests cover different aspects of signal processing
for radio navigation receivers and mainly focus on the design
of algorithms for interference detection and mitigation.
Marco Anghileri (marco.anghileri@airbus.com) received
his M.S. degree in telecommunication engineering from the
Politecnico di Milano, Italy, in 2006. He works as a navigation
systems engineer at Airbus Defence and Space, where he currently leads various research and development activities on the
evolution of navigation systems and signals. Previously, he
was the lead systems engineer at IFEN GmbH and a research
associate at the Institute of Space Technology and Space
Applications of the Universitaet der Bundeswehr in Munich,
Germany. His main research interests include navigation signal and message design and performance as well as navigation
receiver algorithms. From 2009 to 2013, he was personally
involved in the European GNSS Program, supporting the
European Commission and the European GNSS Agency in
different working groups, where he served as technical expert
for Germany.
Jean-Jacques Floch (jean-jacques.floch@airbus.com)
received his engineering diploma in electronics and telecommunications in 1998 from the Institut Supérieur Electronique
Numérique, France. He has been working in the area of mobile
communications for several years. Since 2002, he has been
working in the field of navigation satellites as a system engineer at the Airbus DS GmbH. His work mainly focuses on
Galileo signal design at the system level and the evaluation of
performances and robustness of Galileo signals.
Ignacio Fernández-Hernández (ignacio.fernandezhernandez@ec.europa.eu) received an M.S.E.E. degree from
the Escuela Técnica Superior de Ingeniería ICAI (formerly
known as the Instituto Católico de Artes e Industrias), Madrid,
Spain, in 2001, an M.B.A. degree from the London Business
School, United Kingdom, in 2011, and a Ph.D. degree in electronic systems from Aalborg University, Denmark, in 2015, for
his research on satellite navigation authentication and snapshot
positioning. Currently he is the Galileo commercial service
manager at the European Commission, Directorate-General
GROW, and a visiting scholar at Stanford University, GPS Research Laboratory, California.
Matteo Paonni (matteo.paonni@ec.europa.eu) obtained a
bachelor's degree in information engineering in 2004 and a
master's degree in electrical engineering in 2007, both from
the University of Perugia, Italy. He is a scientific project officer at the Joint Research Centre of the European Commission,
within the Directorate for Space, Security, and Migration, Unit
for Technology Innovation in Security, Ispra, Italy. From 2007
to 2013, he was a research associate at the Institute for Space
Technology and Space Applications at the Universitaet der
Bundeswehr Muenchen, Germany. His research interests are
in satellite navigation signal design, signal processing, and
global navigation satellite system security.

IEEE SIGNAL PROCESSING MAGAZINE

September 2017

Table of Contents for the Digital Edition of Signal Processing - September 2017