Dardari — 01-fm-i-iv-9780123820846 — 2011/9/23 — 2:10 — Page 1 — #1 Satellite and Terrestrial Radio Positioning Techniques Dardari — 01-fm-i-iv-9780123820846 — 2011/9/23 — 2:10 — Page 3 — #3 Satellite and Terrestrial Radio Positioning Techniques A Signal Processing Perspective Edited by Davide Dardari Emanuela Falletti Marco Luise AMSTERDAM • BOSTON • HEIDELBERG • LONDON NEW YORK • OXFORD • PARIS • SAN DIEGO SAN FRANCISCO • SINGAPORE • SYDNEY • TOKYO Academic Press is an imprint of Elsevier Dardari — 01-fm-i-iv-9780123820846 — 2011/9/23 — 2:14 — Page 4 — #4 Academic Press is an imprint of Elsevier The Boulevard, Langford Lane, Kidlington, Oxford, OX5 1GB, UK 225 Wyman Street, Waltham, MA 02451, USA First edition 2012 Copyright c  2012 Elsevier Ltd. All rights reserved. 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ISBN: 978-0-12-382084-6 For information on all Academic Press publications visit our web site at www.elsevierdirect.com Printed and bound in the UK 11 12 13 14 15 10 9 8 7 6 5 4 3 2 1 Dardari — 03-pre-ix-x-9780123820846 — 2011/9/23 — 2:34 — Page ix — #1 Preface Reliable and accurate positioning and navigation is critical for a diverse set of emerging applications calling for advanced signal-processing techniques. This book provides an overview of some of the most recent research results in the field of signal processing for positioning and navigation, addressing many challenging open problems. The book stems from the European Network of Excellence in Wireless Communications NEWCOM++, in which I was privileged to be involved as both an external observer and a contributor. The Network of Excellence is an initiative of the European Commission, which gives an opportunity to excellent researchers across the continent to build new levels of collaboration. Within the framework of this initiative, there has been an activity focused on the development of signal-processing techniques to provide high-accuracy location awareness. This book considers many different aspects and facets of positioning and navigation techniques. It begins with “classical” technologies for positioning in satellite systems (e.g., GPS and Galileo) and in terrestrial cellular networks. The reader will also find new topics including the ultimate bounds on the accuracy of positioning systems determined by noise and interference; the description and performance of some new techniques such as direct positioning that aim at making GPS work with very weak received radio signals (e.g., indoors); as well as the techniques to optimally combine the measurements coming from radio signals and from different sensors like inertial platforms (e.g., gyroscopes). The new field of cooperative positioning is also discussed, wherein many nodes exchange signals and information to increase the accuracy of their positions, and finally the exciting field of super-accurate indoor ranging with ultra-wide bandwidth (UWB) radio signals is thoroughly addressed. The combination of theory and experimentation in the NEWCOM++ project has led to practical results that the readers can find in the last part of the book. As an example of the direct application of the research forefront to real-world problems, fusion techniques for integration of multiple sensor measurements based on experimental data are explored. I hope this book can serve as a reference for anyone who is interested in the field of positioning and navigation. Moe Z. Win Associate Professor Massachusetts Institute of Technology ix Dardari — 04-fore-xi-xiv-9780123820846 — 2011/9/23 — 2:41 — Page xi — #1 Foreword Many of the readers of this book may have had the occasion to get acquainted with the adventures of Harry Potter in the best-selling works by J.K. Rowling. If so, they will have noticed that young Harry has got something that is called the “Marauder’s Map”: a piece of parchment that shows every inch of the magical school of Hogwarts, as well as the ever-changing, real-time location of Harry’s friends and foes. Wow, if it is in Harry Potter’s book, it must be something magic, the layman wonders. But, the readers of this book know better: it is not magic, but technology. In the cold language of engineers, the Marauder’s map is a geographic information system (GIS) with a dedicated positioning plug-in that tracks real-time, a set of authorized users, and show their locations upon a the map on a display. The GIS is something that anyone can have on his/her smartphone at a small cost. But, something that heavily relies on a number of different techniques ranging from radio transmission to geometric com- putation, from data mining to Kalman filtering, and all of them deriving from the common, unifying umbrella of signal processing, that represents the common background of the many positioning appli- ances that are now widespread in developed countries, like the GPS car navigators. Such ubiquitous positioning devices, in cars or in smartphones, are the basis for a number of innovative context-aware services that are nowadays already available. For example, looking for a pharmacy in a chaotic big city is no longer like treasures hunting, but we are only at the beginning: in the coming years, we will see the advent of high-definition situation-aware applications, based on the availability of positioning information with submeter accuracy, and required to operate even in harsh propagation environments such as inside buildings. The number of newly offered services is only limited by phantasy, and is expected to grow exponentially, together with the corresponding market revenues. However, the path towards this goal is still challenging. Some of the current positioning technolo- gies were primarily designed for different applications (e.g., managing a communication network), and are not optimized for providing accurate and ever-available location information. In addition, none of the positioning technologies currently available or under development ensures service coverage in dif- ferent heterogeneous environments (e.g., outdoor, indoor, at sea, and on the road), and high-definition positioning accuracy. In conclusion, the integration of different positioning technologies is the piv- otal aspect for future seamless positioning systems, and the key to ignite a new era of ubiquitous location-awareness. So far, most books related to positioning address the topic focusing on a specific system, for exam- ple, satellite-based or terrestrial, or are single-technology oriented (GPS or RF Tags just to mention a few). However, the mechanism with which the different positioning systems derive information about the user location share, in many cases, the same fundamental approach. In addition, the design of future seamless positioning systems cannot leave aside a global knowledge of different technologies if their efficient integration has to be pursued. With this in mind, we tried to provide in this book a broad overview of satellite and terrestrial positioning and navigation technologies under the common denominator of signal processing. We are convinced that every positioning problem can be ultimately cast into the issue of designing a signal pro- cessor (to be specific, a parameter estimator) which provides the most accurate user’s location, starting from a set of noisy position-dependent measurements collected through signal exchanges between the wireless devices involved. Our aim was not to simply give a mere description of the various current xi Dardari — 04-fore-xi-xiv-9780123820846 — 2011/9/23 — 2:41 — Page xii — #2 xii Foreword positioning standards or technologies. Rather, we intended to introduce and illustrate the theoretical foundation that lies behind them, and to describe a few advanced practical solutions to the positioning issue, strengthened by case studies based on experimental data. This book takes advantage of the contribution of several experts participating to the European Net- work of Excellence NEWCOM++, of which it represents one of the main outcomes. Most of the material has been originated from a bunch of enthusiastic young researchers working in a coopera- tive environment. The readers may have noticed that this is an edited book, with many contributors. Although, it may be difficult to coordinate and homogenize the work of so many researchers (and we hope we succeeded in this goal), this is a case where “diversity” shines. The different approaches to the general issue of positioning coming from different institutions and research “schools” will be apparent to the readers – we do hope that such diversity (that in our opinion is the added-value of the book) will contribute widening his/her perspective on the subject. This book is intended for PhD students and researchers who aim at creating a solid scientific background about positioning and navigation. It is also intended for engineers who need to design positioning systems and want to understand the basic principles underlying their performance. Even if less importance is given to an exhaustive description of available literature, the table of contents is also designed to provide a book useful for the beginners. For a brief survey of the basic theory of positioning and navigation, the first three chapters may be read, whereas more advanced concepts and techniques are provided in the successive chapters. Specifically, Chapter 1 introduces the concept of radio positioning and states the mathematical problem of determining the position of a mobile device in a certain reference frame, using measure- ments extracted from the propagation of radio waves between certain reference points and the mobile device. It presents a classification of the wireless positioning systems based, on one hand, the kind of information (or measurement) they extract from the propagating signal and on the other hand, the kind of network infrastructure established among the devices involved in the localization pro- cess. Then, it goes through an introductory description of the main positioning systems examined in the book, namely satellite systems, their terrestrial augmentation and assistance systems, terrestrial network-based systems (e.g., cellular networks, wireless LANs, wireless sensor networks, and ad-hoc networks). Finally, an overview of the fundamental mathematical methodologies suited to resolve the radio positioning problem in the above-cited contexts is given, in tight association with the signal processing approaches able to implement them in a technological context. Chapter 2 presents an overview of the satellite-based positioning systems, with particular emphasis on the American GPS, the forthcoming European Galileo and the modernized Russian GLONASS, which provide almost global coverage of the Earth Global Navigation Satellite Systems (GNSSs). First, the “space segment” of such systems, in terms of transmitted signal formats and occupied bands is described. Then, the architecture of a typical satellite navigation receiver is discussed in detail, as it has several peculiar requirements and features with respect to a communication-oriented transceiver. A discussion of the main sources of error in the position estimate is then presented. The last part of the chapter is devoted to present the so-called “augmentation systems”, a category of mostly terrestrial network-based systems aimed at providing support to the GNSS receiver to improve the accuracy or the availability of its position estimate. Examples of such systems are: differential GPS, EGNOS, network RTK, and assisted GNSS. Dardari — 04-fore-xi-xiv-9780123820846 — 2011/9/23 — 2:41 — Page xiii — #3 Foreword xiii The fundamental technologies and signal processing approaches to estimate the position of a mobile device using terrestrial networks-based radio communication systems are addressed in Chapter 3. The potential position-related information that can be extracted from a propagating signal is reviewed, namely: received signal strength (RSS), time-of-arrival (TOA), time-difference-of-arrival (TDOA), and angle-of-arrival (AOA). Then the fundamental techniques to derive the position information from a collection of such mea- surements are explained, according to the classification in geometric techniques (either deterministic or statistical) and mapping (or fingerprinting) techniques. The most common sources of error affecting the above-mentioned processes are then analyzed. The chapter continues presenting the positioning approaches typically adopted in different network technologies (i.e., cellular networks, wireless LANs, and wireless sensor networks), addressing the underlying signal format, the most suited kind of measurement and the associated positioning and navigation algorithms. Particular attention is devoted to the ultra-wideband technology, as the most promising signal format to implement high performance terrestrial positioning. Several factors impact in practice on the achievable accuracy of wireless positioning systems. However, theoretical bounds can be set in order to determine the best accuracy, one may expect in certain conditions as well as to obtain useful benchmarks when assessing the performance of practi- cal schemes. Chapter 4 is dedicated to the presentation of several such bounds, mostly derived from the Cram ´ er-Rao bound (CRB) framework. Theoretical performance bounds related to the ranging esti- mation via time-of-arrival from UWB signals are derived and discussed, also taking into account the critical conditions such as the multipath propagation. Also, the improved Ziv-Zakai bound family is introduced as a tighter benchmark in the case of dense scattering, where the CRB falls in the ambiguity region. Then, novel results are presented, related to the derivation of performance limits for innovative positioning approaches, such as direct position estimation (DPE) in GNSS, cooperative terrestrial localization, and a recent analysis on the interference-prone systems, such as multicarrier systems. Chapter 5 presents a collection of the latest research results in the field of wireless positioning, car- ried out within the NEWCOM++ Network of Excellence. It shows a necessarily-partial panorama of the “hottest topics” in advanced wireless positioning, within the applicative and technological framework drawn in the previous chapters. The focus is first oriented to the recent advances in UWB positioning algorithms, considering a frequency-domain approach for TOA estimation, a joint TOA/AOA estimation algorithm, the impair- ment due to interference, and the mitigation of the nonline-of-sight bias effect. Then, an application of MIMO systems for positioning is discussed. Non-conventional geometrical solutions for position- ing are represented by the bounded-error distributed estimation and the projection onto convex sets (POCS) approach. POCS is then revisited in the context of cooperative positioning, together with a cooperative least-squares approach and a distributed algorithm based on belief propagation. Finally, the cognitive positioning concept is introduced as a feature of cognitive radio terminals. After deriving the expected performance bound, optimum signal design for positioning purposes is addressed and positioning approaches are discussed. Chapter 6 is devoted to present the several signal processing strategies to combine together, in a seamless estimation process, position-related measurements coming from different technologies and/or systems (e.g., TOA and TDOA measurements in terrestrial networks, TOA and RSS measurements, or even satellite and terrestrial systems, or satellite and inertial navigation systems). This approach, Dardari — 04-fore-xi-xiv-9780123820846 — 2011/9/23 — 2:41 — Page xiv — #4 xiv Foreword generally indicated as “hybridization”, promises to provide better accuracy with respect to its stand- alone counterparts, or better availability thanks to the diversity of the employed technologies. For example, hybridization between satellite and inertial systems is expected to compensate the respective fragilities of the two systems, namely: the relatively high error variance of the former and the drift of the latter. The mathematical framework where hybridization is developed is Bayesian filtering. The generic structure is reviewed and the well-known Kalman filter and its variants are inserted in the framework, with examples of applications to positioning problems. Then the particle filter approach is explained, with its most used variants. Examples of hybrid localization algorithms are then shown, starting from an hybrid terrestrial archi- tecture, then passing to the architectures that blend GNSS and inertial measurements, using either the Kalman filter approach or the direct position estimation approach. Finally, an example of hybrid localization based on GNSS and peer-to-peer terrestrial signaling is presented. Chapter 7, the final part of this book, is dedicated to some case studies. Real-world applica- tion examples of positioning and navigation systems, which are the results of experimental activities performed by the researchers involved in the NEWCOM++ Network of Excellence, are reported. Dardari — 05-ack-xv-xvi-9780123820846 — 2011/9/23 — 2:35 — Page xv — #1 Acknowledgements The authors would like to thank Sergio Benedetto, the Scientific Director of the NEWCOM++ Net- work of Excellence, for his unique capability of leading and managing this large network during these years. They would also like to explicitly acknowledge the support and cooperation of the Project Offi- cers of the European Commission, Peter Stuckmann and Andy Houghton, that who facilitated the development of the research activities of NEWCOM++. The writing of this book would not have been possible without the contribution of all partners involved in the NEWCOM++ “Localization and Positioning” work package which the authors M. Luise and D. Dardari had the honor to lead. The authors Special specially thanks go to Carles Fern ´ andez-Prades, Sinan Gezici, Monica Nicoli, and Erik G. Str ¨ om, for their invaluable contribution to the structure and organization of the book. xv Dardari — 06-acr-xvii-xxvi-9780123820846 — 2011/9/22 — 5:14 — Page xvii — #1 Acronyms and Abbreviations ACGN additive colored Gaussian noise ACK acknowledge ACRB average CRB ADC analog-to-digital converter AEKF adaptive extended Kalman filter AFL anchor-free localization AGNSS assisted GNSS AGPS assisted GPS AltBOC alternate binary offset carrier AN anchor node AOA angle of arrival AOD angle of departure AP access point API application programming interface ARNS aeronautical radio navigation services ARS accelerated random search A-S anti-spoofing AS azimuth spread ASIC application-specific integrated circuit AWGN additive white Gaussian noise BCH Bose–Chaudhuri–Hocquenghem BCRB Bayesian CRB BIM Bayesian information matrix BLAS basic linear algebra subprograms BLUE best linear unbiased estimator BOC binary offset carrier BP belief propagation BPF band-pass filter bps bits per second BPSK binary phase shift keying BPZF band-pass zonal filter BS base station BSC binary symmetric channel BTB Bellini–Tartara bound BTS base transceiver station C/A coarse/acquisition C/NAV commercial/navigation C/N 0 carrier-to-noise density ratio CAP contention access period CBOC composite binary offset carrier CC central cluster xvii [...]... 1.2 POSITIONING AND NAVIGATION SYSTEMS The positioning and navigation systems analyzed in this book are those for which there exists, or it is expected, a widespread personal use and for which the scientific and technological research has a prominent role in these years Recalling the classifications discussed earlier, we now describe a technological discrimination between satellite and terrestrial positioning. .. FIGURE 1.2 General positioning network recently expanded in a countless set of civil applications In this book, the terms “position location,” positioning, ” and “localization” are interchangeable A fundamental difference exists between position location and (radio) navigation Indeed, navigation refers to “the theory and practice of planning, recording, and controlling the course and position of a vehicle,... and communications devices, applications, and services (NAV/COM systems and services) A frontier of wireless positioning is the hybridization between satellite and terrestrial systems toward the concept of seamless positioning, whose main example is the assisted GPS service, which uses a terrestrial cellular network to improve GPS receiver performance 1.2.1 Satellite- Based Systems The navigation world... Cellular 5–10 m Beyond 30 m Global Satellite (GPS) i-D Tag 0.5–5 m 5–50 m FIGURE 1.4 An illustration of the main positioning technologies, as well as their qualitative level of coverage and accuracy 10 CHAPTER 1 Introduction positioning only The well-known global positioning system (GPS) is nowadays the primary global navigation satellite system (GNSS) Terrestrial positioning systems rely on a network... view of the main positioning technologies currently available and their level of coverage and accuracy is depicted in Fig 1.4 Satellite positioning systems rely on a constellation of artificial satellites rotating in well-known orbits and continuously transmitting signals used by the mobile terminals to perform ranging measurements They are inherently navigation systems, while most recent terrestrial systems... pseudorandom pseudorandom noise public regulated service partial robustness test power spectral density power spatial delay profile physical service data unit phase shift keying position, velocity, and time pulse width pseudo time of arrival position–velocity quadrature phase quadrature phase shift keying quasi-zenith satellite system root derivative minimum variance radio determination satellite service radio. .. 3, when wide bandwidth signals are employed and accurate time measurements are available, time-based ranging can provide high-accuracy positioning capabilities However, time synchronization and measurement errors represent the main issues when designing time-based ranging techniques Time-Sum-of-Arrival systems measure the relative sum of ranges between the agent and the anchor nodes and define a position... several terrestrial systems for maritime and avionic navigation were used: Decca, LORAN-C, TACAN, and VOR/DME just to mention a few [2, 25] They are characterized by very specialized fields of application and high costs of installation and maintenance In the long term, some of them will be superseded by GNSS This generation of terrestrial navigation systems is beyond the scope of this book On the other hand,... recent terrestrial position location systems were born as a sort of by-product of current wireless communications systems One of the main differences between current satellite and terrestrial positioning systems is the fundamental purpose for which the signal traveling from the transmitter to the receiver has been designed: in the satellite case, the purpose is truly localization, whereas in the terrestrial. .. with fire fighters or natural disaster victims), control of home appliances, automotive safety, and military systems It is expected that the global revenues coming from real-time locating systems (RTLSs) technology will amount to more than six billion Euros in 2017 [6] Satellite and Terrestrial Radio Positioning Techniques DOI: 10.1016/B978-0-12-382084-6.00001-5 Copyright c 2012 Elsevier Ltd All rights . #1 Satellite and Terrestrial Radio Positioning Techniques Dardari — 01-fm-i-iv-9780123820846 — 2011/9/23 — 2:10 — Page 3 — #3 Satellite and Terrestrial Radio. technologies and/ or systems (e.g., TOA and TDOA measurements in terrestrial networks, TOA and RSS measurements, or even satellite and terrestrial systems, or satellite