Wireless Positioning Technologies and Applications

by Alan Bensky

Overview

At last—here's a comprehensive book that puts full details on all short-range wireless-positioning methods at your command for instant access and use. This one-stop resource surveys each technique's theory of operation, advantages and disadvantages, applicability in different domains, implementation procedures, and accuracy to help you select the right technology for any application and ensure the best results possible. Real-life examples together with 161 diagrams help bring all options into sharp focus.

After introducing wireless positioning fundamentals along with various personal, commercial, and industrial applications, the book guides you step by step through radio signal time of flight methods, the signal strength method, the angle of arrival system, and the geometric use of distance measurement to determine location. It discusses location awareness applications and implementations using cellular networks. You are brought up to speed on fast-developing techniques involving local area networks (WLANs), personal area networks (WPANs), and radio frequency ID (RFID). Moreover, you find coverage of the distance measurement features in the new IEEE 802.15.4a spec for low rate wireless personal area networks. This practical resource offers detailed guidance on how to implement important technologies, including direct sequence spread spectrum, frequency hopping spread spectrum, and ultrawideband (UWB). The book also explores ways to counteract accuracy impairments caused by noise, multipath and fading, and limitations of antenna directivity and time measurement precision.

Product Details

ISBN-13:	2901596931304
Publisher:	Artech House, Incorporated
Publication date:	02/28/2008
Edition description:	New Edition

About the Author

Alan Bensky is an internationally recognized expert in radio communication engineering. He is a practicing consultant and university lecturer who has developed products and managed wireless projects in both military and commercial sectors for over 30 years. His experience includes development of algorithms and prototype designs for distance measuring features to be used in short-range communications devices, and he is the author of a book on short-range wireless communications.

Table of Contents

Preface     xiii
Introduction     1
Fundamentals and Terms     1
Basic Measurements     2
Terms     3
Applications     4
Cellular Networks     4
Person and Asset Tracking     5
Wireless Network Security     6
Location-Based Advertising     6
Location Services for Vehicles and Traffic     6
Overview of Distance Measurement and Location Methods     6
Organization of the Book     10
References     11
Basic Principles and Applications     13
Signal Parameters     14
Time Resolution     14
Pulse Width and Duty Cycle     15
Bandwidth     15
Noise     17
Pulse Compression     20
Basics of Location     27
Rho-Theta     27
Theta-Theta or AOA     28
Rho-Rho or TOA     29
TDOA and Hyperbolic Curves     30
Navigation Systems     32
DME     33
VOR     37
Loran-C     38
GPS     44
Conclusions     51
References     52
Spread Spectrum     53
Principles of Direct Sequence Spread Spectrum     53
Transmitter and Receiver Configurations for DSSS     54
DSSS Waveforms     55
Despreading and Correlation     57
Code Sequence Generation     59
Synchronization     60
Velocity Estimation     62
Acquisition     63
Code Acquisition     64
Carrier Acquisition     69
Code Rate Matching     70
Effect of Data Modulation on Acquisition     71
Radiometric Detection     71
Tracking     72
Carrier Tracking     72
Code Tracking     73
Measurement of Elapsed Time     77
One-Way Systems     78
Two-Way Systems     78
The Time Measurement Process     79
High-Resolution Elapsed Time-Measuring Receiver     82
Duplex and Half Duplex Two-Way Ranging Examples     83
Sequence Length and Chip Period     87
Propagation Time Resolution     88
Tracking Accuracy and Noise     88
Multipath     90
Increased Range Resolution Using Carrier Phase      92
Conclusions     93
References     94
Time Transfer     95
Time Transfer Basics     95
Calibration Constants     97
Range Uncertainty     98
Clock Drift and Measurement Time     99
Noise     101
Multipath     102
Relative Motion     102
Ranging Procedure in Wireless Network     103
Conclusions     105
References     105
Multicarrier Phase Measurement     107
Principle of Multicarrier Phase Measurement     107
Phase Slope Method     108
Phase Error Versus Signal-to-Noise Ratio     111
Estimation of Distance Variance Versus SNR     115
Multipath     118
System Implementation     123
Phase Difference Measurements and Analogy to TDOA     125
OFDM     126
The Basics of OFDM     126
OFDM Distance Measurement     130
Location Based on OFDM Distance Measurement     134
Resolution of OFDM Distance Measurement     136
Conclusions     137
References     138
Received Signal Strength     139
Advantages and Problems in RSS Location     139
Propagation Laws     140
Free Space     140
Free-Space dB     140
Open Field     141
Logarithmic Approximation     142
Randomizing Term X     143
Outdoor Area Networks     144
Path Loss and Received Signal Strength     146
RSS Location Methods     146
RSS Location from Range Estimations     146
RSS Location Based on Database Comparison     147
Conclusions     158
References     158
Time of Arrival and Time Difference of Arrival     161
TOA Location Method     162
Overdetermined TOA Equation Solution     163
TOA Method in GPS Positioning     166
TDOA     170
TDOA Measurement Techniques     171
Multilateral and Unilateral Topologies for TDOA     173
TDOA Geometric Model     175
TDOA Example     177
Performance Impairment     181
Uncertainties in Data Measurement     181
Random Noise     182
Dilution of Precision (DOP)     182
Multipath     184
Cochannel Interference      186
Conclusions     186
References     187
Angle of Arrival     189
Triangulation     189
Antenna Performance Terms and Definitions     191
Finding Direction from Antenna Patterns     194
Direction-Finding Methods     198
Amplitude Comparison     198
Phase Interferometer     200
Electronically Steerable Beam Antennas     207
ESPAR Antenna Array     214
Conclusions     220
References     221
Cellular Networks     223
Cellular Location-Based Services     223
Cellular Network Fundamentals     224
GSM Transmissions     226
CDMA     227
UMTS     228
Categories of Location Systems     229
GPS Solution     230
Cell-ID     231
Location Technologies Using TDOA     232
Enhanced Observed Time Differences     234
Observed Time Difference of Arrival     235
Uplink Time Difference of Arrival     236
Angle of Arrival     236
Received Signal Strength and Pattern Recognition     236
Problems and Solutions in Cellular Network Positioning      237
Narrowband Networks     237
CDMA     237
GSM     238
Handset-Based Versus Network-Based Systems     238
Accuracy Factors     239
Conclusions     239
References     240
Short-Range Wireless Networks and RFID     241
WLAN/WiFi     242
TOA     242
TDOA Methods for WLAN Location     248
Fingerprinting     249
WPAN     251
Bluetooth     251
ZigBee     255
Alternate Low Rate WPAN Physical Layer IEEE 802.15.4a     257
ECMA-368 Standard     258
RFID     259
Proximity Location     260
Distance Bounding for Security     260
Accurate RFID Location     262
Conclusions     262
References     263
Ultrawideband (UWB)     265
Telecommunication Authority Regulations     265
FCC Regulations     265
UWB in the European Community     267
UWB Implementation     268
Impulse Radio UWB     268
OFDM     272
IEEE 802.15.4a     274
Physical Layer Characteristics and Synchronization     274
Ranging Protocol     280
Dealing with Multipath and Nonline of Sight     283
Multipath     283
Nonline of Sight     284
Conclusions     286
References     286
Bibliography     289
List of Acronyms and Abbreviations     293
About the Author     297
Index     299