測位衛星用高精度軌道・ 時計決定ソフトウェアの開発 Development of Precise Orbit/Clock Determination Software for GPS/GNSS

1. 第49回宇宙科学技術連合講演会 測位衛星用高精度軌道・時計決定ソフトウェアの開発Development of Precise Orbit/Clock Determination Software for GPS/GNSS 技術コンサルタント　高須　知二 笠井デザインオフィス　笠井　晶二 Tomoji TAKASU, Shoji KASAI

2. 内容Contents • GT：GPS/GNSS Precise Analysis SW FeaturesStructureModels • Accuracy EvaluationGPS Satellite Orbit/ClockStation Pos/Tropos DelayLEO Satellite Orbit

3. GpsTools (GT) ver.0.5.6

4. 特徴Features • GPS/GNSS Precise Analysis • Uses Undifferenced Carrier Phase Measurements • EKF(Forward/Backward)+Smoother • Precise Measurement Models • Precise Satellite Orbit Models • GUI for Setting/Execution/Utilities • Matlab/C Environment/Libraries

5. Precise Sat Orbit Processing Params. Precise Sat Clock Station Position RINEX OBS Data RINEX NAV Msg. Ocean Loading Pred. (GOTIC2) Observation Data Editor Interpolate Ephemeris Multipath Profiler Ocean Loading Params. Clean OBS Data Interp. Sat Orbit PCV Parameter Estimator Data/Products Downloader Residuals/ Log ERP/ Geocenter Position Clock Tropos. Orbit GUI I/F Plot Estimation Results 構成図Block Diagram

6. Observation Data Editor Parameter Estimator Estimated Params (Forward) Carrier Phase OBS Forward Filter (Meas Update) Clock-Jump Detect/Repair RINEX OBS Data Forward Filter (Temp Update) Cycle-Slip Detect/Repair Estimated Params (Backward) Clean OBS Data Backward Filter (Meas Update) Carrier Smoothing Code OBS Smoother Backward Filter (Temp Update) Sta Pos Rcv Clk Point Positioning Measurement Models RINEX NAV Msgs. Precise Sat Orbit/Clock Satellite Orbit Models Estimated Params (Smoothed) Station Position 処理フロー Processing Flow

7. 観測モデルMeasurement Models • Light-Time Equation • Ionos Delay : Ionosphere-Free LC • Tropos Delay :ZTD/Gradients+Mapping Function • Antenna Phase Center Offset/PCV • Site Displacements ：Solid Earth Tide, Ocean Loading etc • Phase Wind-up/Relativity Effects

8. 設定 Model Settings

9. 衛星運動モデルSat Orbit Model • Geopotential : JGM-3 • Tidal Effect : Solid Earth,Ocean Tide etc • 3rd Body : Moon/Sun, DE405 • Eclipse : Penumbra/Umbra, Earth/Moon • SRP : ROCK4/42, CODE, GSPM etc • Relativity : IERS Conventions • Nutation/Precession:IAU1980,IERS1996 • ERP : IERS Bul.B,C04,IGS,or Estimated

10. 設定 Model Settings

11. 推定パラメータEstimated Params • GPS/GNSS Satellite Orbit • GPS/GNSS Satellite Clock • Receiver Position (Static/Kinematic) • Receiver Clock • Tropospheric Delay (ZTD, Gradients) • ERP, Geocenter Offset FIXED or ESTIMATED

12. 設定Parameter Settings

13. GPS衛星軌道・時計決定精度評価GPS Satellite Orbit/Clock Accuracy

14. 条件 Estimation Settings • GPS 29 Satellites • GPS Week 1291 (2004/10/3-10/9) • Unit:24H+Overlap24H, Interval:300sec • 3Pass Filter/Smoother • Tracking Stations : IGS 40 Stations • Elevation Cutoff : 10 deg • Station Pos : Fixed to Prev. Week PPP • Reference Clock : AMC2

15. 観測局Stations (IGS 40Stas)

16. 推定パラメータ Estimated Params

17. GPS衛星軌道精度 Orbit Accuracy Average of All Sats, wrt IGS Final Orbit

18. 衛星毎軌道精度 Average 5.2cm

19. REF: IGS Final MEAN: 0.0345m RMS: 0.0385m 0.4 0.3 Position Error 3D (m) 0.2 0.1 0 0.2 Radial Along-Track 0.1 Cross-Track 0 Position Error R/A/C (m) REF: IGS Final -0.1 MEAN R: 0.0045m A:-0.0038m C:-0.0083m -0.2 RMS R: 0.0121m A: 0.0321m C: 0.0175m 10/3 10/4 10/5 10/6 10/7 10/8 10/9 GPS PRN01軌道精度

20. GPS衛星時計精度 Clock Accuracy Average of All Sats, wrt IGS Final Clock

21. 衛星毎時計精度 Average 0.14ns

22. 5 x 10 3.672 3.67 3.668 Clock Bias (nsec) 3.666 3.664 3.662 1 REF: IGS Final MEAN: 0.0218nsec RMS: 0.0906nsec 0.5 Clock Bias Error (nsec) 0 -0.5 -1 10/3 10/4 10/5 10/6 10/7 10/8 10/9 GPS PRN01時計精度

23. IGS AC解比較Comparisons Average of All Sats, wrt IGS Final

24. 測位・対流圏遅延精度評価Position,Tropos Delay Accuracy

25. 条件 Estimation Settings • IGS 85 Reference Frame Stations • GPS Week 1291 (2004/10/3-10/9) • Unit:24H+Overlap0H, Interval:300sec • Strategy : Static PPP (24H) • 2Pass Filter/Smoother • GPS Orbit/Clock/ERP : IGS Final • Elevation Cutoff : 10 deg • Tropos Model : ZTD/Gradients+NMF

26. 観測局Stations

27. 測位精度 Sta Position Accuracy Average of All Stas, wrt IGb00(ITRF2000)

28. 0.05 0.04 0.03 0.02 0.01 0 局毎測位精度 East North Up Average E:3.3mm N:3.1mm U:7.5mm Position RMS Error (m) TIXI BILI PIE1 VILL FLIN KIT3 THTI ALIC TIDB NLIB YELL MALI IRKT JAB1 OHI2 PETP VESL KELY YAR1 JOZE PERT STJO ASC1 CAS1 DAV1 GLSV LHAS RBAY RIOG THU3 TRAB TSKB ZIMM LPGS NYAL ARTU KSTU MATE NICO SANT POL2 MAS1 BRUS CHAT FORT LAMA POTS SCH2 BAHR CEDU GRAS GRAZ UNSA ALGO AUCK BOR1 HOB2 KERG MKEA SYOG WES2 KARR NKLG NRC1 CHUR CRO1 GOLD HOFN ONSA DUBO GODE GUAM DRAO HRAO URUM WSRT WTZR KOUR GOUG MCM4 MDO1 TOW2 MAW1 DARW NOUM Average

29. 水平測位誤差 Horizontal Pos Error １ｃｍ

30. 垂直測位誤差Vertical Pos Error １ｃｍ

31. 対流圏遅延精度Tropos Accuracy Average of All Stas, wrt IGS Final

32. 0.04 ZTD 0.035 0.03 0.025 ZTD RMS Error (m) 0.02 0.015 0.01 0.005 0 BILI TIXI PIE1 VILL FLIN KIT3 THTI ALIC TIDB NLIB MALI YELL IRKT JAB1 OHI2 PETP VESL KELY JOZE PERT STJO YAR1 ASC1 CAS1 DAV1 GLSV LHAS LPGS NYAL RBAY RIOG THU3 TRAB TSKB ZIMM ARTU KSTU MATE NICO POL2 SANT MAS1 BRUS CHAT FORT LAMA POTS SCH2 BAHR CEDU GRAS GRAZ UNSA ALGO AUCK BOR1 HOB2 KERG MKEA SYOG WES2 KARR NKLG NRC1 CHUR CRO1 GOLD HOFN ONSA DUBO GODE GUAM DRAO HRAO URUM WSRT WTZR KOUR GOUG MCM4 MDO1 TOW2 MAW1 DARW NOUM Average 局毎対流圏遅延精度 Average 4.0mm

33. 2.45 2.4 ZTD (m) 2.35 2.3 IGS Monthly 2.25 0.04 REF: IGS Monthly MEAN: -0.0025m RMS: 0.0033m 0.02 ZTD Error (m) 0 -0.02 -0.04 10/3 10/4 10/5 10/6 10/7 10/8 10/9 ALGO対流圏遅延精度

34. LEO衛星軌道決定精度評価LEO Satellite POD Accuracy

35. 条件 Estimation Settings • GRACE A, GRACE B • GPS Week 1280 (2004/7/18-7/24) • Unit:24H+Overlap0H, Interval:300sec • Strategy : Kinematic PPP • 3Pass Filter/Smoother • GPS Orbit/Clock/ERP : IGS Final • Elevation Cutoff : 0 deg • Receiver Attitude : LEO Sat Model

36. GRACE軌道GRACE Orbit Height： ～500km

37. LEO軌道精度 LEO Orbit Accuracy Pos RMS Error, wrt JPL GIPSY Solution

38. GRACE A 軌道精度

39. GRACE B 軌道精度

40. まとめ Conclusions • GT：GPS/GNSS Precise Analysis • Accuracy (RMSE)GPS Sat Orbit : 5.2cm (3D)GPS Sat Clock : 0.14nsecStation Pos : 3.1/3.3/7.5mm Tropos Delay : 4.０mm (ZTD)LEO Sat Orbit : 5.5-7.5cm (3D) See http://gpspp.sakura.ne.jp