1 Introduction and Motivation | 25 |
1.1 GSMMobile Phone Localization | 25 |
1.2 Localization in Search and Rescue Scenarios | 28 |
1.3 Key Inventive Concept | 29 |
1.4 Scope of thisWork | 30 |
2 Basic System Architecture and Measurement Setup | 31 |
2.1 Time Difference of Arrival Localization Systems | 31 |
2.1.1 Localization Scenario | 31 |
2.1.2 Major Challenges and Requirements | 33 |
2.1.3 Auxiliary System Components | 34 |
2.2 Time Difference of Arrival Estimation Scenario | 36 |
2.2.1 ElementaryMeasurement Setup | 36 |
2.2.2 Generic Radio ChannelModel | 38 |
3 GSM Signal Characteristics and Modeling | 41 |
3.1 Physical Layer Structure | 41 |
3.1.1 Modulation | 41 |
3.1.2 Burst Types and Structures | 44 |
3.1.3 Power and Spectral Characteristics | 46 |
3.1.4 Multiple Access and Duplexing | 48 |
3.2 Modeling of GSMSignals | 53 |
3.2.1 Single Burst SignalModel | 53 |
3.2.2 Frequency Hopping SignalModel | 54 |
4 Coherent Wideband Signal Acquisition and Modeling | 55 |
4.1 Wideband Signal Acquisition Techniques | 55 |
4.1.1 Wideband Frontend Signal Acquisition | 55 |
4.1.2 Narrowband Frontend Signal Acquisition | 57 |
4.1.3 Mixed Acquisition Schemes | 59 |
4.1.4 Coherence and Phase Relationships | 60 |
4.2 Properties of AcquiredWideband Signals | 61 |
4.2.1 Frequency Hopping Bandwidth | 61 |
4.2.2 Effective Signal Bandwidth | 61 |
4.2.3 Signal to Noise Ratio | 62 |
4.3 Pre-Processing andMultiple Source Separation | 64 |
4.3.1 Burst Isolation Technique | 64 |
4.3.2 Wideband Signal Reconstruction Technique | 67 |
4.3.3 Multiple Source Separation Technique | 68 |
5 Coherent Time Difference of Arrival Estimation Techniques | 69 |
5.1 Wideband Crosscorrelation Technique | 69 |
5.1.1 Definition of the Crosscorrelation Function | 69 |
5.1.2 Decomposition of the Crosscorrelation Function | 70 |
5.1.3 Ambiguity Function of Frequency Hopping Signals | 71 |
5.1.4 Shape of the Ambiguity Function | 72 |
5.1.5 Properties of the Ambiguity Function | 80 |
5.1.6 Application of Concatenated and Stacked Signals | 84 |
5.1.7 Range Limitations | 88 |
5.2 Burst Phase Analysis Technique | 90 |
5.2.1 Derivation for Simple Delay Scenarios | 90 |
5.2.2 Evaluation ofMultiple Burst Signals | 92 |
5.2.3 Influence of Multipath Components | 95 |
5.2.4 Averaging of Burst Phase Differences | 101 |
5.2.5 Range Ambiguities | 104 |
5.3 Realizable Frequency Hopping Signal Configurations | 105 |
6 Numerical Performance Simulation and Evaluation | 107 |
6.1 Simulation Environment and Parameters | 107 |
6.2 Noise Performance inMultipath-Free Scenarios | 110 |
6.2.1 AWGN ChannelModel | 110 |
6.2.2 Cramér-Rao Lower Bound | 110 |
6.2.3 Estimation Standard Deviation | 111 |
6.3 Multipath Performance in Two-Paths Scenarios | 116 |
6.3.1 Two-Path ChannelModel | 116 |
6.3.2 Maximum Estimation Bias | 116 |
6.4 Multipath Performance in Realistic Scenarios | 120 |
6.4.1 Tapped Delay-Line ChannelModel | 120 |
6.4.2 Resolvability of Propagation Paths | 124 |
6.5 Summary of Estimation Technique Performance | 128 |
7 Prototype System Structure and Measurement Results | 129 |
7.1 Structure of the Receiving Stations | 129 |
7.1.1 Main Functional Components | 129 |
7.1.2 Synchronization SourceModule | 130 |
7.1.3 Synchronization and TriggerModule | 131 |
7.1.4 Wideband Signal AcquisitionModule | 133 |
7.1.5 Data and ControlModule | 135 |
7.1.6 Integration of theModules | 136 |
7.2 Characteristics of HardwareModules | 137 |
7.2.1 Phase Noise Profile of Synchronization Signals | 137 |
7.2.2 Synchronicity of Synchronization Source Signals | 138 |
7.2.3 Synchronicity of Synchronization and Trigger Signals | 140 |
7.2.4 Frequency Response of Wideband Signal Acquisition Modules | 142 |
7.2.5 Symmetry of Wideband Signal Acquisition Modules | 144 |
7.3 Time Difference of ArrivalMeasurement Results | 146 |
7.3.1 Static Offset Compensation Procedure | 146 |
7.3.2 Measurement Setup and Evaluation Procedure | 147 |
7.3.3 Originating GSMSignal Configuration | 150 |
7.3.4 Delay-LineMeasurement Results | 150 |
7.4 Summary of Hardware andMeasurement Results | 154 |
8 Summary and Outlook | 157 |
8.1 Major Achievements and Contributions | 157 |
8.2 FutureWork and Development | 158 |
8.3 Patents, Scientific Publications and Theses | 161 |
Appendices | 163 |
A Frequency Hopping Sequence Generation in GSM Systems | 165 |
B Logical and Physical Channels in GSM Systems | 167 |
B.1 Definition of Resources and Channels | 167 |
B.2 Structure of the 26-Multiframe | 167 |
B.3 Structure of the 51-Multiframe | 168 |
C Frequency Hopping Signal Transmission Initiation in GSM Systems | 171 |
C.1 Requirements for Signal Transmission Initiation | 171 |
C.2 Voice and Data Connection | 171 |
C.3 Modified Handover Procedure | 174 |
D Time Difference of Arrival Estimation for Narrowband GSM Signals | 177 |
D.1 Narrowband Crosscorrelation Technique | 177 |
D.2 Model-based Estimation Techniques | 179 |
D.3 Incoherent Integration withMultipath Rejection Technique | 180 |
D.4 Successive Cancellation Technique | 182 |
D.5 Further Applicable Techniques | 183 |
D.6 Comparative Summary | 186 |
E Localization System Architecture for Search and Rescue Scenarios | 187 |
References | 189 |