Signal Processing - September 2017 - 94

are expected to emerge, provided that the high computations
associated with CS techniques become amenable for realtime implementations.

C/N0 (dB-Hz)

Authors

40
35
30
25
20
50

Time (s)
Standard

STFT Excision

FIGURE 9. A comparison between C/N 0 values estimated in the presence
of jamming with and without TF excision. A drop in C/N 0 is experienced
when the car is close to the jammer.

the receiver operates normally, even without performing TF
excision, and high C/N 0 values are obtained. When the car
approaches the jammer, the C/N 0 value drops significantly,
as shown in the center of Figure 9. The C/N 0 value starts
increasing again once the car goes away from the jammer,
as shown in the last part of Figure 9. The usage of TF excision allows the receiver to operate even in the close proximity of the jammer. When TF excision is used, the receiver
does not experience significant drops in C/N 0 , as clearly
emerges in Figure 9.
The results presented in Figures 8 and 9 demonstrate
the effectiveness of TF excision, which significantly improves the receiver performance at both acquisition and
tracking stages.

Conclusions
In this article, different applications of TF analysis to the field
of GNSS were briefly described, from interference mitigation
to clock and system monitoring. TF analysis techniques can
play a significant role in practically all areas involving the
generation, transmission, reception, and processing of GNSS
signals. TF data representations allow the separation of different desired and undesired signal components and offer
enhanced performance analysis and monitoring capabilities.
Specific focus was devoted to the jamming detection and mitigation problems, and a case study was used to demonstrate the
effectiveness of TF techniques that can maintain a functioning GNSS receiver and uninterrupted operations even in the
presence of significant levels of interference. The development
of CS and sparsity-aware techniques and the availability of
multiantenna systems further improve GNSS receiver performance and create a new paradigm for TF-based jammer excision. Although CS-based jamming suppression methods are
still in the research and academic phase, significant benefits
94

Moeness G. Amin (moeness.amin@villanova.edu) received
his B.Sc. degree from Cairo University, Giza, Egypt, in
1976, M.Sc. degree from the University of Petroleum and
Minerals, Dhahran, Saudi Arabia, in 1980, and Ph.D. degree
from the University of Colorado, Boulder in 1984, all in
electrical engineering. Currently, he is the director of the
Center for Advanced Communications at Villanova University, Pennsylvania. He is a Fellow of the IEEE, the
International Society for Optical Engineering, the Institute of
Engineering and Technology (IET), and the European
Association for Signal Processing. He is the 2017 Fulbright
Distinguished Chair in Advanced Science and Technology,
and a recipient of the 2016 Humboldt Prize, the 2016 IET
Achievement Medal, the 2015 IEEE Warren White Award
for Excellence in Radar Engineering, and the 2014 IEEE
Signal Processing Society Technical Achievement Award. He
has authored more than 700 publications in signal processing
theory and applications.
Daniele Borio (daniele.borio@ec.europa.eu) received
his Laurea Magistrale degree in communications engineering from Politecnico di Torino, Italy, his Diplôme
d'Ingénieur degree in electronics engineering from ENSERG/
INPG de Grenoble, France, in 2004, and the doctoral degree
in electrical engineering from Politecnico di Torino in 2008.
From 2010 to 2013, he was a postdoctoral fellow at the
Joint Research Centre (JRC). From 2008 to 2010, he was a
senior research associate in the Position Location and
Navigation group of the University of Calgary, Canada.
Currently, he is a scientific technical officer at the JRC
of the European Commission. His research interests in clude the fields of location, navigation, and digital and
wireless communications.
Yimin D. Zhang (ydzhang@temple.edu) graduated
from the Northwest Telecommunication Engineering
Institute (Xidian University), Xi'an, China, in 1982, and
received his Ph.D. degree from the University of Tsukuba,
Japan, in 1988. He is currently an associate professor in the
Department of Electrical and Computer Engineering,
Temple University, Philadelphia, Pennsylvania. He has
authored more than 300 publications in the area of array
signal processing, time-frequency analysis, compressive
sensing, and optimization with applications in radar, communications, and satellite navigation. He is an associate
editor of IEEE Transactions on Signal Processing and an
editor of Signal Processing. He is a member of the Sensor
Array and Multichannel Technical Committee of the IEEE
Signal Processing Society. He is a Senior Member of the
IEEE and SPIE.
Lorenzo Galleani (galleani@polito.it) received his
M.S. degree in electrical engineering and his Ph.D. degree
in electrical and communication engineering from Politecnico

IEEE SIGNAL PROCESSING MAGAZINE

September 2017

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