Monday July 28, 2008


Lecturer: Prof. Marco Luise

University of Pisa (Italy)
e-mail: marco.luise@iet.unipi.it


Title: Topics in Signal Processing for Global Satellite Navigation Systems (GNSS)

Abstract
The blooming and booming of systems and services based on information about the user location is something that everyone is experiencing at the moment. Suffice it to cite car and nautical navigation systems, anti-burglar devices, E-911 (in the States) and E-112 (in Europe) services for emergency and rescue, positioning of wireless terminals for conditional advertising or tourist information (or for optimal network resource allocation such as power and bandwidth), just to stick to the mass market, and not mentioning professional applications , such as cartography, agriculture, etc., and military use. The vast majority of such services are at the moment provided with the aid of satellite positioning services, that is to say, through the American Global Positioning System (GPS). The Russian counterpart, GLONASS (GLObal Navigation Satellite Systems) has practically no relevant commercial application. The European Union is catching up with the growing market of satellite positioning through the development of the Galileo system that will basically provide the same services as the GPS does nowadays, but with enhanced accuracy and availability, starting form the year 2012.
As with wireless communications, the DSP contents of a navigation receiver is ever-increasing. The relevant techniques that are being implemented in precision as well as mass-market equipment are borrowed from the classical subjects of estimation theory and signal detection and synchronization. Amidst the many aspects that are treated by the scientific and technical community dealing with GNSS, this tutorial intends to specifically focus on the main aspects related with signal processing. The aim is in particular that of presenting a simple but rigorous framework that helps understanding the actual DSP contents of satellite navigation equipment. Coming to a more detailed description of the various topics, it is known that reliable and accurate positioning is based on TOA (time of arrival) estimation of the satellite spread-spectrum signals and on triangulation techniques. Therefore, a good GNSS receiver has to implement a number of DSP-based techniques for the (coherent) demodulation of the radio signal, such as carrier frequency/phase offset estimation and correction, time delay estimation and/or tracking, compensation of the signal distortion due to multipath radio propagation, just to cite a few. All such techniques have to keep into account the particular signal format, namely, digital spread-spectrum, and has to cope with the low-signal-to-noise ratio environment that is typical of satellite communications. Therefore, a short seminar that introduces and reviews all such techniques is highly desirable. The tutorial will start with a brief review of the fundamental problem of positioning (from TOA estimation to user coordinates) and of the fundamental aspects related to TOA estimation (Gabor bandwidth, the Cramér-Rao bound), will go through a survey of the main signal formats of positioning systems (GPS and GALILEO) to come to more practical issues related to the implementation of navigation receivers (receiver architecture, carrier Doppler and phase estimation/correction, ranging code acquisition and tracking etc.), and will finally touch upon the main sources of accuracy degradation (multipath, ionosphere) and the main relevant countermeasures in terms of DSP functions.

Index of the arguments

1. The problem of positioning: from TOA estimation to user coordinates:

 

2. Signal design for best TOA estimation:

3. GPS and GALILEO signals:

4. Signal detection and synchronization:

5. Accuracy Degradation sources and relevant countermeasures:

6. Test

Lecturer’s Short Bio
Marco LUISE is a Full Professor of Telecommunications at the University of Pisa, Italy. He was born in Livorno, Italy, in 1960 and received his MSc (cum Laude) and PhD degrees in Electronic Engineering from the University of Pisa, Italy. In the past, he was a Research Fellow of the European Space Agency (ESA) at the European Space Research and Technology Centre (ESTEC), Noordwijk, The Netherlands, a Researcher of CNR, the Italian National Research Council, at the Centro Studio Metodi Dispositivi Radiotrasmissioni (CSMDR), Pisa, and an Associate Professor at the Dipartimento di Ingegneria dell'Informazione (Department of Information Engineering) of the University of Pisa. He chaired the V, VI, VII, and IX editions of the Tyrrhenian International Workshop on Digital Communications, respectively, and he was the General Chairman of the URSI Symposium ISSSE'98. He's been the Technical Co-Chairman of the 7th International Workshop on Digital Signal Processing Techniques for Space Communications and of the Conference European Wireless 2002. Recently, Prof. Luise was the General Chairman of EUSIPCO 2006 held in Florence, Italy, in September 2006. He regularly teaches at the University of Pisa and at the Lucca Institute for Advanced Studies IMT. M. Luise is a senior member of the IEEE, was an Editor of the IEEE Transactions on Communications and has served as the co-editor of the '98 Special Issue on Signal Processing in Telecommunications of the European Transactions on Telecommunications. He's also been co-editor of the IEEE Journal of Selected Areas in Communication special issue on Signal Synchronization in Digital Transmission Systems and Editor for Communication Theory of the European Transactions on Telecommunications, and has co-edited a Special Issue of the Proceedings of the IEEE on Turbo techniques: algorithms and applications. He is the co-Editor-in-Chief of the recently founded International Journal of Navigation and Observation, and acts as General Secretary of the Italian Association GTTI, Gruppo Telecomunicazioni Teoria dell'Informazione. He is also member of the Italian Committee of URSI and of the International Committee on Global Navigation Satellite Systems (ICG) of the UNO. His main research interests lie in the broad area of communication theory, with particular emphasis on wireless communications, and mobile and satellite communication and positioning systems.
A full list of Prof. Luise’s scientific publications is available on his home page or directly at the link http://www2.ing.unipi.it/~d7384/HTML/PubFrm.html


To this category belong also the so-called augmentation systems such as the America WASS (Wide Area Augmentation System) and the European EGNOS (European Geostationary Navigation Overlay satellite Service).