1. Mr.Samniang Suttara B.Eng. (Civil), M.Eng. (Survey) Topcon Instruments (Thailand) Co.,Ltd. E-Mail : gps@topcon.co.th Tel. 08-1821-1297 Satellite Surveying

2. Global Navigation Satellite System What is GNSS ? ADVANTAGE - Accuracy from meter to millimeter - Everywhere - Everytime - One system coordination - Many user segment - No expenses

3. NAVSTAR GPS (Global Positioning System) By USA. GLONASS (GLObal NAvigation Satellite System or GLObalnaya NAvigatsionnaya Sputnikovaya Sistema) By Russian. GALILEO By The European Space Agency (ESA) COMPASS By China. GNSS Provider?

4. Launched: 1978 24 Satellite Constellation Launched: 1982 Current Satellite Constellation: 18 Planned Constellation: 24 USA Russia E.U. Test Satellite Launched: Dec. 2005 Current Satellite Constellation: 2 Planned Constellation: 30 Satellites Constellation Technology

5. COMPASS

6. 1.GPS Satellites Satellites 2. GLONASS Satellites

7. Satellites 3. GALILEO Satellites 4. COMPASS Satellites

8. Number of Satellites 24 (24) 24 (27) Launch Vehicle Proton k/DM-2 Delta 2-7925 Satellite Per Launch 3 1 Orbital Planes 3 6 Orbit Inclination 64.8 55 Orbit Altitude 19100 km 20200 km Orbital Period 11 h 15 min 11 h 58 min Ephemerides Pos/Vel/Acc Keplerian Reference Ellipsoid PZ90 WGS84 Carrier Freq. L1 1602.5625 - 1615.5 MHz 1575.42 MHz Carrier Freq. L2 1246.4375 – 1256.5 MHz 1227.60 MHz C/A-code(L1) 0.511 MHz 1.023 MHz P-code(L1,L2) 5.110 MHZ 10.23 MHz GLONASSGPS

9. 24 Satellites, 3 active spares 6 Orbital planes inclined at 55 degrees 1 orbit = 11 hours 58 min. 20,200 kilometers height The Space Segment The GPS Space Segment The GLONASS Space Segment 24 Satellites, 3 active spares 3 Orbital planes inclined at 64.8 degrees 1 orbit = 11 hours 15 min. 19,100 kilometers height

10. GNSS Comparison

11. All the satellite signals are receivedGPSGLONASSGALILEO

12. Increasing satellites of number GPS GLONASS GALILEO

13. 1.Space Segment Constellations of satellites. 2.Control Segment Monitor and control stations for tracking and managing satellites. 3. User Segment Receivers designed to receive, decode and process satellite data. GPS Components

14. Control Segment Space Segment User Segment Bi-directional Information Information in one direction System Overview

15. KWAJALEIN DIEGO GARCIA ASCENSION HAWAII COLORADO SPRINGS (MCS) Control Stations

16. The User Segment

19. Receiver Types 1. Navigation receiver Distance measured with C/A code

20. Receiver Types 2. Geodetic or Surveying receiver

21. Absolute Positioning (Point Positioning) Relative Positioning (Baselines-Vector) SOLUTION: DX, DY, DZ SOLUTION: X,Y,Z Positioning

22. How Does GPS Work? GPS Receiver calculates position by one of the following methods: a) Pseudo-Range Measurements Less Accuracy

23. With codes -C/A code (300 m.) -P code (30 m.) Distance are measured in GPS Positioning

24. a) Pseudo-Range Measurements Receiver Range Range = ( Time Taken for signal to reach Receiver from Satellite) x (Speed of light = 3*10 8 m/s)

25. How Does GPS Work? GPS Receiver calculates position by one of the following methods: b) Carrier-Phase Measurements More Accuracy

26. By signal carriers phase -L1 carriers (19 cm.) -L2 carriers (24 cm.) Distance are measured in GPS Positioning

27. b) Carrier-Phase Measurements Receiver Range Range = ( Whole no. of Wavelengths from Satellite to Receiver) + (Fractional Part of Wavelength)

28. 1.Satellite - Orbit = 5 m. - Clock = 1 m. 2. Signal Propagation – Ionospheric (Dual freq) = cm.- dm. - Troposheric = dm. - Multipath = 5 m. 3.Receiver - Observation noise = 1-10 m. - Hardware delay = m. - Antenna phase center = mm.- cm. Errors in GPS Survey

29. After that...a Geoid (Helmert, 1884) Geoid Ellipsoid Helmert Geoid model accounts for Deflection of the vertical Earth History

30. GEOID (MSL) ELLIPSOID TERRAIN Geoid Ocean surface free of disturbances (Helmert, 1884). Equipotential Surface of the Earth’s Gravity Field. Ellipsoid Geometric representation of the Earth Surface. Earth Surface Representation

31. GEOID (MSL) ELLIPSOID TERRAIN h= Ellipsoidal height H= Orthometric height N = Geoid Undulation N=h-H Heights h N H How EGM works ? -EGM96 -EGM2008

32. Orthometric Heights

33. X (Greenwich Meridian) Z ( CIO ) Normal to Ellipsoid North East Up Station  Y ECEF Coordinate System (X,Y,Z) Topocentric System (N,E,U) Geographic Coordinates (b,l,h) Coordinate System

34. Static Survey Fast or Rapid Static Survey Kinematic Survey Real Time Kinematic (RTK) Survey - Single base - Network RTK (VRS, MAC, FKP) Field Methods Survey

35. GPS Only GPS & GLONASS Mission Planning

36. VDOP =standard deviation in vertical HDOP =standard deviation in horizontal position(2D) PDOP =standard deviation in position(3D) TDOP =standard deviation in Time GDOP =standard deviation in position(3D) and time Dilution of Precision (DOP) (Geometrical)

37. Poor Geometry Dilution Of Precision (DOP) DOP = σ / σ 0 σ = positioning accuracy σ 0 = observation(pseudorange) accuracy

38. Good Geometry

39. Static Survey

40. Static GPS+ Survey

41. Process data

42. Fast Static

43. The RTK Concept

44. Radio Technical Commission for Maritime Services (More than twice as long of a message format) Compact Measurement Record RTCM vs. CMR

45. VRS Network