Precise Orbit Determination of Global Navigation Satellite System of ...

More documents

Recommendations

Info

Chapter 9 Software and Simulation Results Difference (meter) 1 0.8 0.6 0.4 0.2 0 -0.2 -0.4 -0.6 -0.8 -1 0 24 48 72 96 120 144 168 192 216 240 Tim e (hour) Figure 9-65 Accuracy of Orbit Determination of a GEO Satellite located at λ=20° using Carrier Phase Observation The accuracy of dynamic orbit determination of a GEO satellite located at λ=20° is better than centimeter level. In order to enhance the accuracy of orbit determination of IGSO and GEO satellites, the ambiguity resolution techniques of carrier phase observations are very important. Widely used ambiguity resolution algorithms available at present for GPS may be also suitable for future GNSS-2/Galileo satellite orbit determination. A new method of Three Carrier Ambiguity Resolution (TCAR) is proposed by Harris (1997). If TCAR method is successfully applied for future GNSS-2/Galileo system, it will significantly improve the accuracy of GNSS- 2/Galileo orbit determination. 142 dx dy dz
Conclusion CONCLUSION The GNSS-2/Galileo system should be an open and global navigation satellite system(GNSS), developed by Europe and fully compatible with GPS, but independent of it. Galileo should provide three-dimensional performance, accurate to better than 10 meters horizontally, providing a universal independent time reference on a global basis. The Galileo system is based on a core constellation of MEO satellites. IGSO and GEO satellites are all possible candidates for GNSS-2 satellite constellations such as EGNOS. In the dissertation the orbit determinations of IGSO, GEO and MEO satellites are discussed using dynamic and kinematic methods. The effort focused, however, on IGSO and GEO satellites, because MEO satellites are already adopted by both US and USSR for satellite navigation systems such as GPS and GLONASS and thus there is substantial literature available for GPS/Glonass orbit determination and applications. From the discussion, IGSO satellites have many advantages. Fewer satellites are needed than are used in MEO for global coverage. Using range observations with one meter error, and partial global satellite tracking stations, 1-10 meter accuracy of real-time orbit determination of IGSO satellite can be achieved. When using carrier phase observations, the accuracy of real-time orbit determination will be much better. The disadvantage is that there is no actual application of IGSO satellites, therefore people have no experience of this type of satellite for navigation. GEO satellites can be “fixed” at some point in the sky above the earth surface. For satellite tracking stations on the coverage of GEO, there is no visibility problem. Under the same conditions as IGSO satellites, using range observations, the accuracy of real time orbit determination of GEO satellites is better than that of IGSO satellites. The disadvantage is that the satellite orbit can not be determined using carrier phase observations. This is because of the very slow movement of the GEO satellite relative to the Earth’s surface. Another disadvantage is that maneuver operations are required weekly for GEO satellites due to quick drift. This is a serious problem for navigation and positioning users, because normally satellite orbit information will not be sent to navigation and positioning users during satellite maneuver and thus users can not perform navigation and positioning operations. This serious problem has been solved by using kinematic orbit determination discussed in chapter 8. If the initial ambiguity can be solved, very high accuracy of real time orbit determination can be achieved by using carrier phase observations. For MEO satellites, the same accuracy as the IGSO and GEO satellites could be achieved. The multipath effect has great influence on the initial ambiguity solution and the accuracy of orbit determination. In the dissertation, methods for mitigation of the multipath effect using linear combinations of original carrier phase observations are discussed. 143
Page 1:
PRECISE ORBIT DETERMINATION OF GLOB
Page 4 and 5:
Summary GNSS-2 (Global Navigation S
Page 6 and 7:
3.2.2.1 Principle..................
Page 8 and 9:
9.3.3 The Effect of Distribution of
Page 10 and 11:
Chapter 1 Introduction 1.2 Developm
Page 12 and 13:
Chapter 2 Observations of Orbit Det
Page 14 and 15:
Page 16 and 17:
Page 18 and 19:
Page 20 and 21:
Page 22 and 23:
Page 24 and 25:
Page 26 and 27:
Chapter 3 Orbit Tracking System and
Page 28 and 29:
Page 30 and 31:
Page 32 and 33:
Page 34 and 35:
Page 36 and 37:
Page 38 and 39:
Page 40 and 41:
Chapter 4 Major Error Sources of Sa
Page 42 and 43:
Page 44 and 45:
Page 46 and 47:
Page 48 and 49:
Page 50 and 51:
Page 52 and 53:
Chapter 5 Perturbation Models of IG
Page 54 and 55:
Page 56 and 57:
Page 58 and 59:
Page 60 and 61:
Page 62 and 63:
Page 64 and 65:
Page 66 and 67:
Page 68 and 69:
Page 70 and 71:
Page 72 and 73:
Page 74 and 75:
Chapter 6 Algorithms of Orbit Deter
Page 76 and 77:
Page 78 and 79:
Page 80 and 81:
Page 82 and 83:
Page 84 and 85:
Page 86 and 87:
Page 88 and 89:
Page 90 and 91:
Page 92 and 93:
Page 94 and 95:
Chapter 7 Orbit Determination Using
Page 96 and 97:
Page 98 and 99:
Page 100 and 101: Chapter 7 Orbit Determination Using
Page 102 and 103: Chapter 7 Orbit Determination Using
Page 104 and 105: Chapter 8 Geostationary Orbit Deter
Page 122 and 123: Chapter 9 Software and Simulation R
Page 152 and 153: Conclusion 144
Page 154 and 155: References Carpino M. (1995): SAEG
Page 156 and 157: References Klobuchar, J. A.(1996):
Page 158 and 159: References Traquilla, J. M. and J.
Page 160 and 161: Acknowledgments 152
show all

Precise Orbit Determination of Global Navigation Satellite System of ...

Create successful ePaper yourself

Delete template?

Save as template?