Handbook – Satellite Time and Frequency Dissemination – 2010
PREFACE
TABLE OF CONTENTS
FOREWORD
ACKNOWLEDGEMENTS
INTRODUCTION
CHAPTER 1 – SATELLITES AND TIME AND FREQUENCY TRANSFER AND DISSEMINATION
1.1 Introduction
1.2 Space radiocommunication services and satellite systems employed for frequency and time transfer and disseminat...
1.2.1 Standard frequency and time signal service
1.2.2 Global navigation satellite systems
References
CHAPTER 2 – GLOBAL POSITIONING SYSTEM
2.1 General description and principles of operation
2.2 GPS basics
2.2.1 PRN codes for CDMA and ranging
2.2.2 GPS spectrum
2.2.3 Navigation message
2.3 GPS segments
2.3.1 Space segment
2.3.2 Control segment
2.3.3 User segment
2.4 Role of timing and synchronization in operations
2.4.1 Ranging measurements and performance factors
2.4.2 Satellite clock stability and prediction
2.5 Assessment of GPS satellite clock performance
2.5.1 Satellite path delays
2.5.2 Relativity
2.6 Receiver clock contributions
2.6.1 Navigation receiver clock
2.6.2 Timing receiver clock
2.7 Determination and maintenance of timing
2.7.1 Control segment operations
2.7.2 GPS time steering
References
CHAPTER 3 –SATELLITE BASED AUGMENTATION SYSTEM TO GPS
3.1 Introduction
3.2 Description of an SBAS
3.3 WAAS description (United States of America)
3.4 MSAS description (Japan)
3.4.1 Overview
3.4.2 Dual pseudo-random noise function
3.4.3 Uplink power control
3.5 EGNOS description (Europe)
3.5.1 EGNOS ground segment overview
3.5.2 EGNOS system overview related to time
3.5.3 RIMS clock synchronization and generation of ENT
3.5.4 Steering of ENT to GPS time
3.5.5 Satellite clock corrections
3.5.6 Broadcast ENT through geostationary Earth orbit (GEO) satellites
3.5.7 Estimation of the difference between ENT and UTC time-scales
3.5.8 SBAS and time
3.5.9 Time and the GEO
3.5.10 SBAS and time transfer
3.5.11 Time transfer between 2 laboratories
3.5.12 Time transfer between 2 SBAS
References
APPENDIX A –Brief description of SBAS message content
CHAPTER 4 –GPS SYSTEM TIME
4.1 Introduction
4.2 Tracking clock measurements and ephemeris determination
4.3 GPS time
4.3.1 Composite clock implementation
4.3.2 Covariance reduction
4.3.3 Partition reconciliation
4.4 UTC (USNO) from GPS
CHAPTER 5 –GLONASS NAVIGATION SATELLITE SYSTEM
5.1 Introduction
5.2 General description and principles of operation
5.3 GLONASS architecture and development
5.3.1 Space segment
5.3.2 Control segment
5.3.3 User segment
5.4 GLONASS time
5.5 Orbit determination and time synchronization (OD & TS) of GLONASS system
5.6 GLONASS signals and radio-frequency spectrum
5.6.1 Frequency requirements
5.6.2 Signal power and spectra
5.7 GLONASS and GPS combined use features
5.8 Conclusion
References
CHAPTER 6 –COMMUNICATION SATELLITE SYSTEMS
6.1 Introduction
6.2 The communication payload
6.2.1 Analog bent-pipe architecture
6.2.2 Regenerative architecture
6.2.3 Digital implementation
6.2.4 The tracking, telemetry and command system
6.3 Timing and synchronization for satellite operation
6.4 Impact of link noise and satellite imperfections in bent-pipe payloads
6.4.1 White noise contribution
6.5 Satellite phase noise and systematic errors
6.6 Conclusion
References
CHAPTER 7 –TIME SCALES
7.1 Introduction
7.2 Universal time
7.3 Ephemeris time
7.4 Atomic time
7.5 Relativistic time scales
7.5.1 Terrestrial time
7.5.2 Geocentric coordinate time
7.5.3 Barycentric coordinate time
7.5.4 Barycentric dynamical time
7.6 International time scales
7.6.1 International atomic time
7.6.2 Coordinated universal time
References
CHAPTER 8 –NATIONAL TIMING CENTRES
8.1 Introduction
8.2 Timing laboratory layout
8.3 Local measurement system
8.4 International traceability
8.5 Time dissemination services
References
CHAPTER 9 –RELATIVISTIC EFFECTS IN SATELLITE TIME AND FREQUENCY TRANSFER AND DISSEMINATION
9.1 The space-time interval
9.2 The principle of relativity
9.2.1 The metric tensor
9.2.2 The gravitational potential of the Earth
9.2.3 Time dilation
9.2.4 Gravitational redshift
9.2.5 Time transfer by clock transport
9.2.6 Earth-Centered Inertial coordinate system
9.2.7 Earth-Centered Earth-Fixed coordinate system
9.3 Clock onboard a satellite
9.4 Time transfer by an electromagnetic signal
9.4.1 Earth Centered Inertial coordinate system
9.4.2 Earth-Centered Earth-Fixed coordinate system
9.4.3 Inter-satellite link
9.4.4 Relativistic Doppler effect
9.5 Conclusion
References
CHAPTER 10 – EARTH ORIENTATION AND GEODETIC SYSTEM
10.1 Introduction
10.2 Earth orientation
10.2.1 Precession/nutation
10.2.2 Polar motion
10.3 Universal Time (UT)
10.4 Geodetic systems
10.5 Reference surfaces
10.5.1 Geoid
10.5.2 Ellipsoid
10.5.3 Types of coordinates
References
CHAPTER 11 –PROPAGATION AND ENVIRONMENTAL FACTORS
11.1 Introduction
11.2 Comparative range delay of the Earth's troposphere and the ionosphere
11.3 Modeling the range delay of the Earth's troposphere
11.3.1 Variability of the ionospheric and the tropospheric range delay
11.4 The time delay of the ionosphere, its worldwide behavior, day-to-day variability and solar cycle variability
11.4.1 Methods of correcting for ionospheric time delay, monthly mean models, updated models, use of SBAS/WAAS/IGS ...
11.4.2 Higher order ionospheric effects on time delay
11.4.3 Scintillation effects
11.5 Conclusion
References
CHAPTER 12 – GLOBAL NAVIGATIONAL SATELLITE SYSTEMS – AS A PRIMARY TOOL FOR TIME TRANSFER
12.1 Introduction
12.2 GPS and time
12.2.1 How does GPS distribute time?
12.2.2 How does GPS synchronize clocks over large distances?
12.3 Applications of GPS time transfer
12.3.1 GPS C/A-code single-channel common-view time transfer
12.3.2 One-site comparisons (zero baseline)
12.3.3 GPS differential calibration
12.3.4 Closure around the world
12.4 Comparison of GPS with other time transfer techniques
12.4.1 Comparison with two-way satellite time and frequency transfer
12.4.2 Comparison with laser time transfer
12.5 Recent developments in GPS time transfer
12.5.1 Multi-channel common-view GPS time transfer
12.5.2 Temperature stabilized antennas
12.5.3 Use of GPS carrier phase
12.6 Use of GLONASS
12.7 Conclusion
References
CHAPTER 13 –GEODETIC TECHNIQUES USING GPS PHASE AND CODE MEASUREMENTS
13.1 Introduction
13.2 Instrumental and hardware considerations
13.2.1 GPS satellite components
13.2.2 GPS tracking antenna installations
13.2.3 Antenna cables and connections
13.2.4 GPS receivers
13.2.5 Evaluating multipath effects and system testing
13.2.6 Calibration of tracking station delays
13.3 Data analysis strategies
13.3.1 GPS observation equation
13.3.2 Methods for global solutions
13.3.3 Reference frames and models for correction terms
13.3.4 Precise point positioning
13.3.5 Effects of errors on clock solutions
13.4 IGS clock products and timescales
13.4.1 Available product sets
13.4.2 IGS timescales
13.5 Evaluation of performance by day-boundary discontinuity analysis
13.6 Comparisons with independent two-way time transfer results
13.7 Assessment of time transfer performance
13.8 Future trends
References
CHAPTER 14 –TWO WAY SATELLITE TIME AND FREQUENCY TRANSFER (TWSTFT)
14.1 Introduction
14.2 Description of TWSTFT technique
14.3 Measurements of TWSTFT
14.4 Station laboratory equipment
14.4.1 Spread spectrum modem
14.4.2 Time interval counter
14.5 Link dependent measurements (path and equipment)
14.5.1 The Sagnac effect
14.5.2 Second-order relativistic correction to the Sagnac effect
14.5.3 Difference in up-link and down-link frequencies
14.6 Calibration methods
14.6.1 Station calibration using a satellite simulator
14.6.2 Station calibration using a transportable Earth station
14.6.3 Calibration campaigns of 1993 and 1998
14.6.4 X-band calibration campaign
14.7 Problems arising when using different satellite transponders
14.8 Problems arising when using different satellite transponders
14.9 Long term stability of TWSTFT
14.9.1 Long term comparisons between GPS and TWSTFT
14.10 Conclusion
References
CHAPTER 15 –SUMMARY TIME AND FREQUENCY DISSEMINATION