Understanding GPS: principles and applications - SAE

Contents Preface Acknowledgments CHAPTER 1 Introduction

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1.1 Introduction 1.2 Condensed GPS Program History 1.3 GPS Overview 1.3.1 PPS 1.3.2 SPS 1.4 GPS Modernization Program 1.5 GALILEO Satellite System 1.6 Russian GLONASS System 1.7 Chinese BeiDou System 1.8 Augmentations 1.9 Markets and Applications 1.9.1 Land 1.9.2 Aviation 1.9.3 Space Guidance 1.9.4 Maritime 1.10 Organization of the Book References

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CHAPTER 2 Fundamentals of Satellite Navigation

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2.1 Concept of Ranging Using TOA Measurements 2.1.1 Two-Dimensional Position Determination 2.1.2 Principle of Position Determination Via Satellite-Generated Ranging Signals 2.2 Reference Coordinate Systems 2.2.1 Earth-Centered Inertial Coordinate System 2.2.2 Earth-Centered Earth-Fixed Coordinate System 2.2.3 World Geodetic System 2.2.4 Height Coordinates and the Geoid 2.3 Fundamentals of Satellite Orbits 2.3.1 Orbital Mechanics 2.3.2 Constellation Design 2.4 Position Determination Using PRN Codes 2.4.1 Determining Satellite-to-User Range 2.4.2 Calculation of User Position

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2.5 Obtaining User Velocity 2.6 Time and GPS 2.6.1 UTC Generation 2.6.2 GPS System Time 2.6.3 Receiver Computation of UTC (USNO) References

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CHAPTER 3 GPS System Segments

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3.1 Overview of the GPS System 3.1.1 Space Segment Overview 3.1.2 Control Segment (CS) Overview 3.1.3 User Segment Overview 3.2 Space Segment Description 3.2.1 GPS Satellite Constellation Description 3.2.2 Constellation Design Guidelines 3.2.3 Space Segment Phased Development 3.3 Control Segment 3.3.1 Current Configuration 3.3.2 CS Planned Upgrades 3.4 User Segment 3.4.1 GPS Set Characteristics 3.4.2 GPS Receiver Selection References

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CHAPTER 4 GPS Satellite Signal Characteristics

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4.1 Overview 4.2 Modulations for Satellite Navigation 4.2.1 Modulation Types 4.2.2 Multiplexing Techniques 4.2.3 Signal Models and Characteristics 4.3 Legacy GPS Signals 4.3.1 Frequencies and Modulation Format 4.3.2 Power Levels 4.3.3 Autocorrelation Functions and Power Spectral Densities 4.3.4 Cross-Correlation Functions and CDMA Performance 4.4 Navigation Message Format 4.5 Modernized GPS Signals 4.5.1 L2 Civil Signal 4.5.2 L5 4.5.3 M Code 4.5.4 L1 Civil Signal 4.6 Summary References

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CHAPTER 5 Satellite Signal Acquisition, Tracking, and Data Demodulation

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5.1 Overview 5.2 GPS Receiver Code and Carrier Tracking 5.2.1 Predetection Integration 5.2.2 Baseband Signal Processing 5.2.3 Digital Frequency Synthesis 5.2.4 Carrier Aiding of Code Loop 5.2.5 External Aiding 5.3 Carrier Tracking Loops 5.3.1 Phase Lock Loops 5.3.2 Costas Loops 5.3.3 Frequency Lock Loops 5.4 Code Tracking Loops 5.5 Loop Filters 5.6 Measurement Errors and Tracking Thresholds 5.6.1 PLL Tracking Loop Measurement Errors 5.6.2 FLL Tracking Loop Measurement Errors 5.6.3 C/A and P(Y) Code Tracking Loop Measurement Errors 5.6.4 Modernized GPS M Code Tracking Loop Measurement Errors 5.7 Formation of Pseudorange, Delta Pseudorange, and Integrated Doppler 5.7.1 Pseudorange 5.7.2 Delta Pseudorange 5.7.3 Integrated Doppler 5.8 Signal Acquisition 5.8.1 Tong Search Detector 5.8.2 M of N Search Detector 5.8.3 Direct Acquisition of GPS Military Signals 5.9 Sequence of Initial Receiver Operations 5.10 Data Demodulation 5.11 Special Baseband Functions 5.11.1 Signal-to-Noise Power Ratio Meter 5.11.2 Phase Lock Detector with Optimistic and Pessimistic Decisions 5.11.3 False Frequency Lock and False Phase Lock Detector 5.12 Use of Digital Processing 5.13 Considerations for Indoor Applications 5.14 Codeless and Semicodeless Processing References

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CHAPTER 6 Interference, Multipath, and Scintillation

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6.1 Overview 6.2 Radio Frequency Interference 6.2.1 Types and Sources of RF Interference 6.2.2 Effects of RF Interference on Receiver Performance 6.2.3 Interference Mitigation 6.3 Multipath

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6.3.1 Multipath Characteristics and Models 6.3.2 Effects of Multipath on Receiver Performance 6.3.3 Multipath Mitigation 6.4 Ionospheric Scintillation References

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CHAPTER 7 Performance of Stand-Alone GPS

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7.1 Introduction 7.2 Measurement Errors 7.2.1 Satellite Clock Error 7.2.2 Ephemeris Error 7.2.3 Relativistic Effects 7.2.4 Atmospheric Effects 7.2.5 Receiver Noise and Resolution 7.2.6 Multipath and Shadowing Effects 7.2.7 Hardware Bias Errors 7.2.8 Pseudorange Error Budgets 7.3 PVT Estimation Concepts 7.3.1 Satellite Geometry and Dilution of Precision in GPS 7.3.2 Accuracy Metrics 7.3.3 Weighted Least Squares (WLS) 7.3.4 Additional State Variables 7.3.5 Kalman Filtering 7.4 GPS Availability 7.4.1 Predicted GPS Availability Using the Nominal 24-Satellite GPS Constellation 7.4.2 Effects of Satellite Outages on GPS Availability 7.5 GPS Integrity 7.5.1 Discussion of Criticality 7.5.2 Sources of Integrity Anomalies 7.5.3 Integrity Enhancement Techniques 7.6 Continuity 7.7 Measured Performance References

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CHAPTER 8 Differential GPS

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8.1 Introduction 8.2 Spatial and Time Correlation Characteristics of GPS Errors 8.2.1 Satellite Clock Errors 8.2.2 Ephemeris Errors 8.2.3 Tropospheric Errors 8.2.4 Ionospheric Errors 8.2.5 Receiver Noise and Multipath 8.3 Code-Based Techniques 8.3.1 Local-Area DGPS

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8.3.2 Regional-Area DGPS 8.3.3 Wide-Area DGPS 8.4 Carrier-Based Techniques 8.4.1 Precise Baseline Determination in Real Time 8.4.2 Static Application 8.4.3 Airborne Application 8.4.4 Attitude Determination 8.5 Message Formats 8.5.1 Version 2.3 8.5.2 Version 3.0 8.6 Examples 8.6.1 Code Based 8.6.2 Carrier Based References

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CHAPTER 9 Integration of GPS with Other Sensors and Network Assistance

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9.1 Overview 9.2 GPS/Inertial Integration 9.2.1 GPS Receiver Performance Issues 9.2.2 Inertial Sensor Performance Issues 9.2.3 The Kalman Filter 9.2.4 GPSI Integration Methods 9.2.5 Reliability and Integrity 9.2.6 Integration with CRPA 9.3 Sensor Integration in Land Vehicle Systems 9.3.1 Introduction 9.3.2 Review of Available Sensor Technology 9.3.3 Sensor Integration Principles 9.4 Network Assistance 9.4.1 Historical Perspective of Assisted GPS 9.4.2 Requirements of the FCC Mandate 9.4.3 Total Uncertainty Search Space 9.4.4 GPS Receiver Integration in Cellular Phones—Assistance Data from Handsets 9.4.5 Types of Network Assistance References

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CHAPTER 10 GALILEO

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10.1 GALILEO Program Objectives 10.2 GALILEO Services and Performance 10.2.1 Open Service (OS) 10.2.2 Commercial Service (CS) 10.2.3 Safety of Life (SOL) Service 10.2.4 Public Regulated Service (PRS) 10.2.5 Support to Search and Rescue (SAR) Service

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10.3 GALILEO Frequency Plan and Signal Design 10.3.1 Frequencies and Signals 10.3.2 Modulation Schemes 10.3.3 SAR Signal Plan 10.4 Interoperability Between GPS and GALILEO 10.4.1 Signal in Space 10.4.2 Geodetic Coordinate Reference Frame 10.4.3 Time Reference Frame 10.5 System Architecture 10.5.1 Space Segment 10.5.2 Ground Segment 10.6 GALILEO SAR Architecture 10.7 GALILEO Development Plan References

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CHAPTER 11 Other Satellite Navigation Systems

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11.1 The Russian GLONASS System 11.1.1 Introduction 11.1.2 Program Overview 11.1.3 Organizational Structure 11.1.4 Constellation and Orbit 11.1.5 Spacecraft Description 11.1.6 Ground Support 11.1.7 User Equipment 11.1.8 Reference Systems 11.1.9 GLONASS Signal Characteristics 11.1.10 System Accuracy 11.1.11 Future GLONASS Development 11.1.12 Other GLONASS Information Sources 11.2 The Chinese BeiDou Satellite Navigation System 11.2.1 Introduction 11.2.3 Program History 11.2.4 Organization Structure 11.2.5 Constellation and Orbit 11.2.6 Spacecraft 11.2.7 RDSS Service Infrastructure 11.2.8 RDSS Navigation Services 11.2.9 RDSS Navigation Signals 11.2.10 System Coverage and Accuracy 11.2.11 Future Developments 11.3 The Japanese QZSS Program 11.3.1 Introduction 11.3.2 Program Overview 11.3.3 Organizational Structure 11.3.4 Constellation and Orbit 11.3.5 Spacecraft Development

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11.3.6 Ground Support 11.3.7 User Equipment 11.3.8 Reference Systems 11.3.9 Navigation Services and Signals 11.3.10 System Coverage and Accuracy 11.3.11 Future Development Acknowledgments References

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CHAPTER 12 GNSS Markets and Applications

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12.1 GNSS: A Complex Market Based on Enabling Technologies 12.1.1 Market Scope, Segmentation, and Value 12.1.2 Unique Aspects of GNSS Market 12.1.3 Market Limitations, Competitive Systems, and Policy 12.2 Civil Navigation Applications of GNSS 12.2.1 Marine Navigation 12.2.2 Air Navigation 12.2.3 Land Navigation 12.3 GNSS in Surveying, Mapping, and Geographical Information Systems 12.3.1 Surveying 12.3.2 Mapping 12.3.3 GIS 12.4 Recreational Markets for GNSS-Based Products 12.5 GNSS Time Transfer 12.6 Differential Applications and Services 12.6.1 Precision Approach Aircraft Landing Systems 12.6.2 Other Differential Systems 12.6.3 Attitude Determination Systems 12.7 GNSS and Telematics and LBS 12.8 Creative Uses for GNSS 12.9 Government and Military Applications 12.9.1 Military User Equipment—Aviation, Shipboard, and Land 12.9.2 Autonomous Receivers—Smart Weapons 12.9.3 Space Applications 12.9.4 Other Government Applications 12.10 User Equipment Needs for Specific Markets 12.11 Financial Projections for the GNSS Industry References

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APPENDIX A Least Squares and Weighted Least Squares Estimates

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Reference

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APPENDIX B Stability Measures for Frequency Sources

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B.1

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Introduction

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B.2 B.3

Frequency Standard Stability Measures of Stability B.3.1 Allan Variance B.3.2 Hadamard Variance References

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APPENDIX C Free-Space Propagation Loss

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C.1 Introduction C.2 Free-Space Propagation Loss C.3 Conversion Between PSDs and PFDs References

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About the Authors

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Index

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