Foreword by Glen Gibbons About this book Acknowledgments List of abbreviations and acronyms List of definitions

Transcription

1 Table of Foreword by Glen Gibbons About this book Acknowledgments List of abbreviations and acronyms List of definitions page xiii xix xx xxi xxv Part I GNSS: orbits, signals, and methods 1 GNSS ground and space segments Ground segment and coordinate reference frames Space segment and time references GPS time and calendar time Other GNSS time scales Onboard clock error Satellite motion description using Keplerian parameters Algorithm for satellite position calculation using standard Keplerian parameters Theoretical background for the spherical harmonics of the Earth s geopotential Algorithm for transformation of GLONASS almanac parameters into standard Keplerian parameters Medium Earth GNSS orbits GEO and HEO for SBAS GEO HEO Algorithm for GPS, Galileo, and BeiDou for satellite position calculation using ephemeris in the form of osculating elements Algorithm for GLONASS satellite position calculation using ephemerides in the form of Cartesian vectors Algorithm for GLONASS satellite position calculation accounting for lunar and solar gravitational perturbations 36 References 37 v

2 Table of vi 2 GPS, GLONASS, Galileo, and BeiDou signals GNSS signals GNSS signals in general CDMA method GNSS signal structure GNSS spread codes: past, present, and future Shift register and memory codes Strange attractor codes BOC modulation Data Tiered code Pilot channel GPS L1 signals GPS L1 C/A signal GPS L1C signal GLONASS L1 signals Galileo signal BeiDou signal GNSS signal propagation error models Effects of signal propagation through the atmosphere on GNSS Algorithms for tropospheric delay calculation Black and Eisner model Saastamoinen tropospheric delay model Niell mapping function Algorithms for ionospheric delay calculation Single-layer ionosphere model Ionospheric error compensation in GPS and BeiDou receivers Ionospheric error compensation in GLONASS receivers Ionospheric error compensation in Galileo receivers Ionospheric error corrections from GEO/HEO satellites Ionospheric error compensation in multi-frequency GNSS receivers GNSS data GPS and BeiDou navigation messages Galileo navigation message Algorithm for constructing GPS/BeiDou/Galileo pseudorange measurements GPS time mark BeiDou time mark Galileo time mark Pseudorange construction algorithm GLONASS navigation message contents and structure 77

3 Table of vii Subframe of a GLONASS navigation message Algorithm for reading GLONASS subframe Subframes containing immediate information Subframe Subframe Subframe Subframe Subframe What s in a sat s name? Models Signals Geometry Clock 85 References 86 3 Standalone positioning with GNSS Application of pseudorange observables Code phase measurements Carrier phase measurements Pseudorange equations Satellite coordinates Minimum number of satellites for positioning Navigation solution algorithms Least-squares estimation (LSE) solution Analytical solution Kalman-filter solution Brute-force solution Multi-system positioning Generalized equations Time-shift calculation using navigation message data Error budget for GNSS observables Error budget contents Geometrical factors Multipath 108 References Referenced positioning with GNSS Requirements for code and carrier differential positioning Spatial correlations in error budget Decorrelation of satellite orbital errors Decorrelation of tropospheric errors Decorrelation of ionospheric errors 113

4 Table of viii 4.3 Observables Single-difference observables Double-difference observables GLONASS inter-frequency bias Triple-difference observables Double-difference equations for multi-systems Real-time kinematic method Code and carrier phase difference equations RTK positioning algorithm Float solution Integer solution Validation Network RTK method Network of reference stations Control center 124 References 126 Part II From conventional to software GNSS receivers and back 5 Generic GNSS receivers GNSS receiver overview Digest of GNSS receiver operation Receiver specification Specification parameters Accuracy Sensitivity Systems and frequencies Time to first fix Interface Spec specifics for main application fields Geodetic applications Geophysical applications Aviation applications Mobile applications Evaluation of parameters GNSS receiver design Hardware and generic receivers Receiver functional model Receiver structural model Receiver components Correlators Signal acquisition Massive parallel correlation 148

5 Table of ix Coherent signal integration Frequency resolution Receiver channel functions Tracking loop theory Tracking loop implementation PLL-aided DLL Coherent tracking with 20 ms coherency interval Coherent tracking with 1 s coherency interval Lock detectors Bit synchronization Measurements GPS/GLONASS receiver 165 References Receiver implementation on a general processor Development of the software approach Software receiver design Baseband processor implementation Acquisition implementation Advantages of software receivers Software receiver advantages for mobile applications Potential reduction of required hardware Upgradeability Bug fixing Reduction of new product development cycle Adaptability to new signals Change of receiver type Third-party product involvement Software receiver advantages for high-end applications Flexibility Access to baseband processor RF signal post-processing Real-time implementation Concurrency Bottlenecks in GNSS signal processing Algorithmic methods used to speed up processing Early-minus-late discriminator Signal decimation Hardware-dependent methods Software methods Bitwise processing a paradigm for deriving parallel algorithms Pre-calculation of replicas 185

6 Table of x 6.5 Applications of high-end real-time software receivers Instant positioning Ionosphere monitoring Ultra-tightly coupled integration with INS Application in education 187 References Common approach and common components Common approach for receiver design Mobile antennas TCXO and bandwidth Front end Down-converter Analog-to-digital converter Navigation processor 203 References 204 Part III Mobile positioning at present and in the future 8 Positioning with data link: from AGPS to RTK Merging mobile and geodetic technologies Application of external information in the baseband processor Doppler assistance in acquisition Code phase assistance in acquisition Doppler assistance in tracking Navigation data assistance Application of external information in the navigation processor TTFF improvement: snapshot positioning Accuracy improvement: RTK positioning The catch: antennas Network RTK implementation: virtual reference station RTK system External information content Group 1: assistance data Group 2: additional parameters Group 3: differential corrections Pseudolites Pseudolite applications Indoor positioning with carrier phase Repeaters 233 References 235

7 Table of xi 9 Positioning without data link: from BGPS to PPP Advantages of positioning without a data link BGPS: instant positioning without network Advantages of BGPS Instant positioning Power savings Less interruption during cellular operation High sensitivity History of the approach BGPS in a nutshell Formalization Algorithm criteria Required a-priori information Time resolution in real time Task example Heuristic approach to search strategy Preliminary position estimation methods Instant positioning implementation in a device Precise positioning without reference station From a network to the global network Global correction information for mobile devices Free global corrections Orbit prediction Embedded algorithms Satellite ephemeris interpolation procedure inside mobile device Precise error models Filtering The catch Applications Fleet management Bird tracking Positioning with pilot signals 270 References Trends, opportunities, and prospects From Cold War competition to a business model Would you go for a multi-mighty receiver? From SDR to SDR we go SA off, AGPS on, mass market open Convergence of mobile and geodetic applications 283

8 Table of xii 10.6 Synergy of the Internet and GNSS Integration of a mobile device into the Internet The Internet as correction provider The Internet as data link Improvement in GLONASS accuracy Towards a new GNSS paradigm Online updates and upgrades Programmable personality change Full set of online corrections Application of cloud computing technology Third-party tools and services One for all and all for one Offline operation Network position calculation AGPS BGPS 289 References 289 Part IV Testing mobile devices 11 Testing equipment and procedures Testing equipment Multi-channel simulator RPS: record and playback systems Device life cycle Research and development Design Certification Production Consumer testing Test examples General tests AGPS tests Multi-GNSS test specifics Case study: new paradigm SDR simulator 305 References 310 Index 311