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Positioning and Navigation Using the Russian Satellite System GLONASS

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Positioning and Navigation Using the Russian Satellite System GLONASS Positioning and Navigation Using the Russian Satellite System GLONASS von Udo Roßbach Vollst¨andigerAbdruck der von der Fakult¨atf¨urBauingenieur- und Vermessungswesen der Universit¨at der Bundeswehr M¨unchen zur Erlangung des akademischen Grades eines Doktor-Ingenieurs (Dr.-Ing.) genehmigten Dissertation. Vorsitzender: Univ.-Prof. Dr.-Ing. W. Reinhardt 1. Berichterstatter: Univ.-Prof. Dr.-Ing. G. W. Hein 2. Berichterstatter: Univ.-Prof. Dr.-Ing. E. Groten 3. Berichterstatter: Univ.-Prof. Dr.-Ing. B. Eissfeller Die Dissertation wurde am 2. M¨arz2000 bei der Universit¨atder Bundeswehr M¨unchen, Werner-Heisen- berg-Weg 39, D-85577 Neubiberg eingereicht. Tag der m¨undlichen Pr¨ufung:20. Juni 2000 ii ABSTRACT / ZUSAMMENFASSUNG Abstract Satellite navigation systems have not only revolutionized navigation, but also geodetic positioning. By means of satellite range measurements, positioning accuracies became available that were previously unknown, especially for long baselines. This has long been documented for applications of GPS, the American Global Positioning System. Besides this, there is the Russian Global Navigation Satellite Sys- tem GLONASS. Comparable to GPS from the technical point of view, it is suffering under the economic decline of the Russian Federation, which prevents it from drawing the attention it deserves. Due to the similarities of GPS and GLONASS, both systems may also be used in combined ap- plications. However, since both systems are not entirely compatible to each other, first a number of inter-operability issues have to be solved. Besides receiver hardware issues, these are mainly the differ- ences in coordinate and time reference frames. For both issues, proposed solutions are provided. For the elimination of differences in coordinate reference frames, possible coordinate transformations are introduced, determined using both a conventional and an innovative approach. Another important topic in the usage of GLONASS for high-precision applications is the fact that GLONASS satellites are distinguished by slightly different carrier frequencies instead of different PRN codes. This results in complications, when applying double difference carrier phase measurements to position determination the way it is often done with GPS. To overcome these difficulties and make use of GLONASS double difference carrier phase measurements for positioning, a new mathematical model for double difference carrier phase observations has been developed. These solutions have been implemented in a GLONASS and combined GPS/GLONASS processing software package. Zusammenfassung Satelliten-Navigationssysteme haben nicht nur die Navigation, sondern auch die geod¨atische Positionsbe- stimmung revolutioniert. Mit Hilfe von Entfernungsmessungen zu Satelliten wurden vorher nicht gekannte Genauigkeiten in der Positionierung verf¨ugbar.F¨urAnwendungen des amerikanischen GPS Global Po- sitioning System ist dies schon lange dokumentiert. Daneben gibt es das russische Global Navigation Satellite System GLONASS. Vom technischen Standpunkt her vergleichbar zu GPS, leidet es unter dem wirtschaftlichen Niedergang der Russischen F¨oderationund erh¨altdeswegen nicht die Aufmerksamkeit, die es verdient. Aufgrund der Ahnlichkeiten¨ zwischen GPS und GLONASS k¨onnenbeide System auch gemeinsam in kombinierten Anwendungen genutzt werden. Da beide System jedoch nicht vollst¨andigzueinander kompatibel sind, m¨ussenvorher noch einige Fragen der gemeinsamen Nutzung gekl¨artwerden. Neben Fragen der Empf¨anger-Hardware sind dies haupts¨achlich die Unterschiede in den Koordinaten- und Zeit-Bezugssystemen. F¨urbeide Punkte wurden L¨osungenvorgeschlagen. Um die Unterschiede in den Koordinaten-Bezugssystemen auszur¨aumen,werden m¨ogliche Koordinatentransformationen vorgestellt. Diese wurden sowohl ¨uber einen konventionellen als auch mit einem innovativen Ansatz bestimmt. Ein anderer wichtiger Punkt in der Nutzung von GLONASS f¨urhochpr¨aziseAnwendungen ist die Tatsache, daß sich GLONASS-Satelliten durch die leicht unterschiedlichen Tr¨agerfrequenzenihrer Sig- nale unterscheiden, und nicht durch unterschiedliche PRN-Codes. Dies bringt Komplikationen mit sich bei der Anwendung doppelt-differenzierter Tr¨agerphasenmessungen,wie sie bei GPS h¨aufigver- wendet werden. Um diese Schwierigkeiten zu ¨uberwinden und auch doppelt differenzierte GLONASS- Tr¨agerphasenmessungenf¨urdie Positionsbestimmung verwenden zu k¨onnen,wurde ein neues mathema- tisches Modell der Doppeldifferenz-Phasenbeobachtungen hergeleitet. Die gewonnenen Erkenntnisse wurden in einem Software-Paket zur Prozessierung von GLONASS und kombinierten GPS/GLONASS Beobachtungen implementiert. CONTENTS iii Contents Abstract / Zusammenfassung ii Contents iii List of Figures vi List of Tables viii 1 Introduction 1 2 History of the GLONASS System 3 3 GLONASS System Description 7 3.1 Reference Systems . 7 3.1.1 Time Systems . 7 3.1.2 Coordinate Systems . 7 3.2 Ground Segment . 8 3.3 Space Segment . 9 3.4 GLONASS Frequency Plan . 10 3.5 Signal Structure . 12 3.5.1 C/A-Code . 12 3.5.2 P-Code . 14 3.5.3 C/A-Code Data Sequence . 14 3.5.4 Time Code . 14 3.5.5 Bit Synchronization . 15 3.5.6 Structure of Navigation Data . 15 3.5.7 GLONASS-M Navigation Data . 16 3.6 System Assurance Techniques . 19 3.7 User Segment and Receiver Development . 24 3.8 GLONASS Performance . 29 4 Time Systems 31 4.1 GLONASS Time . 31 4.2 GPS Time . 31 4.3 UTC, UTCUSNO, UTCSU and GLONASS System Time . 32 4.4 Resolving the Time Reference Difference . 33 4.4.1 Introducing a Second Receiver Clock Offset . 33 4.4.2 Introducing the Difference in System Time Scales . 34 4.4.3 Application of A-priori Known Time Offsets . 35 4.4.4 Dissemination of Difference in Time Reference . 36 4.5 Conclusions . 36 5 Coordinate Systems 39 5.1 PZ-90 (GLONASS) . 39 5.2 WGS84 (GPS) . 39 5.3 Realizations . 40 5.4 Combining Coordinate Frames . 40 5.5 7-Parameter Coordinate Transformation . 42 5.6 Transformation Parameters . 42 5.6.1 Methods for Determination of Transformation Parameters . 42 iv CONTENTS 5.6.2 Russian Estimations . 43 5.6.3 American Estimations . 44 5.6.4 German Estimations . 44 5.6.5 IGEX-98 Estimations . 45 5.7 Applying the Coordinate Transformation . 46 5.8 Coordinate Frames in Differential Processing . 50 5.9 GLONASS Ephemerides in WGS84 . 53 6 Determination of Transformation Parameters 55 6.1 Preparations and Realization of IfEN’s Measurement Campaign . 55 6.2 Data Analysis . 57 6.2.1 Single Point Positioning . 58 6.2.2 Double Difference Baselines . 61 6.3 Direct Estimation of Transformation Parameters . 62 7 Satellite Clock and Orbit Determination 73 7.1 Satellite Clock Offset . 73 7.2 Satellite Orbit Determination . 74 7.2.1 Orbital Force Model . 74 7.2.2 Orbit Integration . 77 7.2.3 Integration Error . 78 7.3 Satellite Positions from Almanac Data . 83 8 Observations and Position Determination 85 8.1 Pseudorange Measurements . 85 8.1.1 Single Point Positioning . 85 8.1.2 Single Difference Positioning . 91 8.1.3 Double Difference Positioning . 96 8.2 Carrier Phase Measurements . 103 8.2.1 Single Point Observation Equation . 103 8.2.2 Single Difference Positioning . 105 8.2.3 Double Difference Positioning . 106 8.3 GLONASS and GPS/GLONASS Carrier Phase Positioning . 111 8.3.1 Floating GLONASS Ambiguities . 111 8.3.2 Single Difference Positioning and Receiver Calibration . 111 8.3.3 Scaling to a Common Frequency . 112 8.3.4 Iterative Ambiguity Resolution . 113 8.4 A Proposed Solution to the Frequency Problem . 114 8.5 Ionospheric Correction . 120 8.5.1 Single Frequency Ionospheric Correction . 120 8.5.2 Dual Frequency Ionospheric Correction . 123 8.6 Dilution of Precision . 126 9 GPS/GLONASS Software Tools 135 10 Summary 139 Appendix 141 A Bibliography 141 B GLONASS Launch History 149 CONTENTS v C Symbols 151 C.1 Symbols Used in Mathematical Formulae . 151 C.2 Vectors and Matrices . 151 C.3 Symbols Used as Subscripts . 152 C.4 Symbols Used as Superscripts . 152 D Abbreviations and Acronyms 153 Dank 157 Lebenslauf 159 vi LIST OF FIGURES List of Figures 2.1 Number of available satellites in 1996 through 1999 . 5 2.2 Current status of the GLONASS space segment . 5 3.1 Locations of GLONASS ground stations . 9 3.2 Model of GLONASS satellite . 11 3.3 GLONASS frequency plan . 13 3.4 GLONASS C/A-code generation.
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