1. A Novel Real-Time Precise Positioning Service System: Global Precise Positioning With Regional Augmentation Maorong Ge(maor@gfz-potsdam.de), Xingxing Li, Jan Dousa, Hongzheng Cui, Gerd Gendt, Jens Wickertmaor@gfz-potsdam.de Junping Chen(SHAO), Xuan Zou(WHU) German Research Centre for Geosciences CSNC2011, Shanghai, China, 18-20 May 2011

2. Network Real-Time Kinematic (NRTK) –Using a local/regional reference network –OBS. DOMAIN Representation NRTK Service Covers The Whole Chinese Territory? Global Precise Point Positioning Service –Using a global reference network –STATE DOMAIN Representation Initialization/Re-initialization takes 10-30 Min.. Global PPP + Regional Augmentation For All Real-Time Applications Real-Time Positioning Services

3.  EPOS-RT Software  Global RT-PPP Service  Regional Augmentation  The Novel System Contents

4. EPOS-RT Software –Motivation –Structure –Progress

5. EPOS-RT: Motivation Requirement of:  New IGS Products  Multi-System, Multi-Technologies  LEOs, GEOs, Huge Networks  IGS Real-Time Pilot Project  GFZ Ongoing Projects Decision:  Multi-Technology: GNSS SLR VLBI …  Multi-Function: Real-time/Post-mission; Static/Kinematic/Dynamic

6. EPOS-RT: Structure  Left Side: Post-Processing. Right Side: Real-Time

7. EPOS-RT: Progress  Since Sept. 2007  Already Available –GPS/GLONASS Real-Time Clock Estimation –GPS/GLONASS/LEO POD (Cui et al, EGU2011, Presentation) –Regional Augmentation/NRTK (Li et al, EGU2011, Poster) –Real-Time ZTD (Bender et al, EGU2011, Presentation) –Embeddable User Software  Further Coming –GALILEO/COMPASS –SLR –IONO. Model

8. GFZ Global RT-PPP Service –Hardware –Software –IGS Real-Time Analysis Centre At GFZ –New Development in PPP PPP Ambiguity Resolution Data Gap Connection

9. Real-Time PPP Service (Hardware) GNSS reference stations GNSS-satellites EPOS-RT Generation of correction information Orbit, clock, iono. UPD Internet connection User terminal with GNSS receiver and communication unit and PPP software INTERNET Caster Geostationary Satellite Correction Data Stream Correction data stream GNSS observations

10. EPOS-RT For Real-Time PPP Service RT Orbit RT Clock RT PPP GPS receivers SRIF(Orb) BNCBNC2SRIFSRIF(Clk)‏ SRIF2BNS BNC2SRIFSRIF(PPP)‏ Internet connection Control Unit IGS Hourly Data RT PPP GPS receivers BNC2SRIFSRIF(PPP)‏ OBS Streaming NTRIP Products ORB/CLK/UPD Hourly D a t a RT ORB Pos&Time ZTD/STD Control Unit IGS Real-Time Analysis Center at GFZ

11. Standard PPP Server

12. Standard PPP Client

13. GFZ Real-Time Clock (Valid) IGS RT PPP Online Validation: http://igs.bkg.bund.de/ntrip/ppp

14.  PPP Ambiguity Fixing  To Shorten Convergence & To Improve Position Accuracy  Uncalibrated Phase Delay (UPD)  Data Gap Handling  To Avoid Re-Initialization  Temporal Stability of Atmo. Delays New Development in PPP

15. UPD Generation For PPPAMB

17. PPP+AMBFIX: 1-2 cm in Horizontal, 3-4 cm in Vertical. Initialization Time 15-20 Min.

18. Impact Summary Long (Re)Convergence Integer Ambiguity Fixing Data Gap Handling Expected NRTK Performance

19. Regional Augmentation –System Configuration –Bias Representation Using UnDifferenced Obs. Corrections –Realization of UD-Corrections –Experimental Validation

20. Principal: Unambiguous OMC  OMC of Station k to Satellite i  Unambiguous OMC (Ambiguity Known)

21.  Corrected Obs. Equ == PPP With Integer SD-Ambiguities  How To Get The Integer UD-Ambiguities For L1&L2 ? Principal: Unambiguous OMC  Interpolated User Correction Interpolated Correction User Obs. Equ.Cor. Obs. Equ.

22. “Consistent” Int. UD Amb. Instead of The True Consistent == "Int. DD Amb. Constrained” Two Ways (Ambiguity Mapping):  Without Precise Sat. Clocks --- New NRTK (Based On Fixed DD-ambiguities)  With Precise Sat. Clocks--- PPP Augmentation, (Based On Fixed UD/SD-ambiguities) Network Solution Not A MUST There is no limitation on the Number of Reference Stations Integer UD Ambiguities

23. Generation Of Augmentation Info.

24. PPP+Regional Augmentation Client

25. New NRTK: Data Processing RECEIVER Data from Regional Reference Network Data Processing for Ambiguity- fixing (PPP Mode) With Reg. Info. Accuracy: < 2cm Initialization: DF < 2min SF < 10min PPP +AMBFIX Orbits & Clocks, UPDs from Global RTPPP Service Fixed DD-ambiguities OMC wrt Orbits & Clocks Ambiguity Mapping CASTER Computation of Unambiguous OMCs Data Processing for Ambiguity- fixing (Baseline Mode) BRD- (or Ultra Rapid) Orbits & Clocks

26. Validation SAPOS: Simulated RT  DATA ( Map: www.sapos.de )  SAPOS Data of 290 stations  Various receiver types  30 seconds sampling rate  Reference Network  Selected 22 reference stations  Inter-station distance 184 km  Others are user stations  Software  EPOS-RT

27.  Lw+L1 can be fixed with 1 epoch data, On average 1.6 epochs, half of Lw (3 epochs)  LW+L1+ION.PAR can furthermore reduce the fixing time but slightly. Improvement found for cases where long fixing time needed. Results: Fixing Time (Lw+L1)

28.  Lw+L1 8, 6 and 21 mm in ENU, the same as L1 7, 6, and 20 mm  Lw+L1+ION, slightly worse than Lw+L1, but fixing is improved Results: Position Accuracy Accuracy of the Positions at the first fixed epoch Using Lw+L1

29. Validation (CORS): Real Time  DATA  A Regional CORS Network. with 70 stations  Stream Data of 1Hz  Reference Network  Selected 13 reference stations Inter-station distance 150 km  User stations  Software  Newly Developed at GFZ in C++ A Regional CORS Net Network

30.  Every Minute Reset Filter  90% Fixed With 1 Epoch, On average 3 s  Lw, 18, 14 and 34 mm ENU  Lw+L1 in development Validation: Real-Time Results

31. Summary of Augmentation  UD-OMC Based On “Integer UD Ambiguity”  Casted Station-By-Station  Instantaneous Ambiguity Fixing Achievable  Network Solution Not A MUST  Augmented PPP To Replace NRTK

32. Global PPP With Regional Augmentation –System Configuration –Regional Augmentation –PPP Clients

33. Augmentation of PPP Service Global Ref. Network IONOS ORBIT CLOCK CASTER Regional Ref. Network Obs.Resid uals/OMC CASTER Global Info ORBIT, CLOCK IONOS Regional Info Obs. corrections Without Reg. Info. Accuracy: DF < 10 cm SF < 40 cm Initialization: < 20 min With Reg. Info. Accuracy: < 2cm Initialization: DF < 2min SF < 10min PPP +AMBFIX Standard PPP Services Regional Augmentation / Network RTK Global Real-Time Precise Point Positioning With Regional Augmentation

34. Generation Of Augmentation Info.

35. PPP Clients

36. Performance Of The Augmented PPP Service –Without Regional Augmentation Open Ocean, … 5-10 cm, after 30 min., 3-5 cm after Ambiguity-Fixing (15 min) –With Regional Augmentation Developed Cities, … 1-2 cm, within 1-2 min. depends on … –Also For Single-Frequency And Low-Cost Receivers

37. Further Work  As New Activity Under IGS-RTPP, EUREF  Operational Test For China With About 800 Reference Stations.  Operational Test As For Europe.