Multi-GNSS Opportunities and Challenges

Transcription

1 Multi-GNSS Opportunities and Challenges School of Surveying & Spatial Information Systems Ali Al-Shaery 1,2 Shaocheng Zhang 3 Samsung Lim 1 Chris Rizos 1 1 School of Surveying and Spatial Information System, the University of New South Wales, Sydney, NSW, Australia 2 Umm Al-Qura University, Makkah, Saudi Arabia 3 SPACE Research Centre, RMIT University, Australia

2 Multi-GNSS Opportunities and Challenges Introduction Opportunities Challenges and Solutions Concluding remarks

3 Source:gislounge.com Introduction GLONASS FOC on 8/12/211

4 Introduction FOC since July Operational Satellites in Space since Oct 211 FOC on Operational Satellites in Space since Feb 212 FOC on 22 Source: kelloggreport.com FOC since Dec

5 Opportunities Number of visible satellites increase >>> satellite geometry improves >>> positioning accuracy improves Increasing availability of GLONASS products from IGS analysis centres >>> real-time application becomes possible More and more GPS+GLONASS CORS networks >>> precise GNSS applications in post-mission and real-time

6 Challenges GPS GLONASS

7 Challenges FDMA Receiver Clock Error Inter-channel bias

8 Receiver Clock Error Estimation System 1 Elimination System 2 P P GPS, pq pq pq rm,1 rm,1 rm,1 cdt GLO, x x x rm,1 rm,1 rm rm,1 f N c GPS, pq 1 pq pq pq rm,1 rm,1 rm,1 rm,1 f f f f c c c c P P x y x y GLO, xy 1 x 1 y 1 1 xy xy rm,1 rm,1 rm,1 cdtrm Nrm,1 rm,1 GPS, pq pq pq rm,1 rm,1 rm,1 GLO, xy xy xy rm,1 rm,1 rm,1 c N GPS, pq pq pq pq rm,1 rm,1 rm,1 rm,1 f1 c c N N GLO, xy pq x y xy rm,1 rm,1 x rm,1 y rm,1 rm,1 f1 f1

9 Receiver Clock Error Summary of static RTK test parameters CHUN29 BTRG29 CHPB29 Data length 24 hr 24hr 24hr Obs. Type L1+L2 L1+L2 L1+L2 Baseline Length 4.4km 8.3km 9.7km Receiver Types Leica Trimble Leica Elevation mask 15º 15º 15º Interval 15s 15s 15s (29\12\211)

10 Receiver Clock Error 6: 9: 12: 15: 18: 21: East (m) : 6: 9: 12: 15: 18: 21: Up (m) : 6: 9: 12: 15: 18: 21: -.1 3: 6: 9: 12: 15: 18: 21: : 6: 9: 12: 15: 18: 21: : 6: 9: 12: 15: 18: 21: 2 1 :.1 6: GPS-GLO model CHUN29 System 1 System 2 System 1 System 2 System 1 System 2 12: 18: -.1 : 3: 6: 9: 12: 15: 18: 21: 3: 6: 9: 12: 15: 18: 21: 3: 6: 9: 12: 15: 18: 21: : : Epoch(GPS Time) Baseline CHPB29 18:.1 Epoch(GPS Time) BTRG6 12: North (m) 3: 6: 18: East (m) 12: 15 Up (m) 6: 2 Num Sat Num Sat 15 North (m) Num Sat North (m) East (m) Up (m) 2 1 System 1 System 2 System 1 System 2 System 1 System 2 Standard deviation (m) E N U Epoch(GPS Time)

11 Receiver Clock Error (21\12\211)

12 Northing (m) Receiver Clock Error x 16 System 1 Fixed Float Fix Epochs: 72.3 % Easting (m) x 1 5

13 Northing (m) Receiver Clock Error x 16 System 2 Fixed Float Fix Epochs: % Easting (m) x 1 5

14 Inter-channel Bias Identification estimation calibration

15 Inter-channel Bias - Identification 21/12/211

16 Northing (m) Inter-channel Bias - Identification x LE-LE Fixed LE-LE Float Fixed Epochs: 4.44 % Easting (m) x 1 5

17 Northing (m) Inter-channel Bias - Identification x LE-TR Fixed LE-TR Float Fixed Epochs: 22 % Easting (m) x 1 5

18 Northing (m) Inter-channel Bias - Identification x LE-TO Fixed LE-TO Float Fixed Epochs: % Easting (m) x 1 5

19 Inter-channel Bias - Estimation (29\1\212), 23hr, 15 sec

20 Inter-channel Bias - Estimation c rm P GPS, pq pq pq rm,1 rm rm,1 P k k c GLO, pq pq p q pq rm,1 rm rm rm,1 c N N GPS, pq pq p q pq rm,1 rm rm,1 rm,1 rm,1 f1 c c N N k k c GLO, pq pq p q p q pq rm,1 rm p rm,1 q rm,1 rm rm,1 f1 f1 CPH inter-channel bias expressed in metres by multiplying it by speed of light (c). c rm PR inter-channel bias expressed in metres by multiplying it by speed of light (c). GLONASS channel number for satellite (p) (-7~+6) Average values of inter-channel bias between mixed receivers LEICA - Trimble LEICA - Topcon CPH (m) PR (m)

21 Up (m) East (m) North (m) Num Sat Inter-channel Bias - Calibration 4 CH-TRUN-WCorr (Fixed Sol 92.6%) CH-TRUN-WCorr (Float Sol) : 12: 18: 3: 6: 9: 12: 15: 18: 21: 3: 6: 9: 12: 15: 18: 21: 3: 6: 9: 12: 15: 18: 21: Epoch(GPS Time) LEICA-TRIMBLE Standard deviation (m) E N h With Correction Without Correction

22 Up (m) East (m) North (m) Num Sat Inter-channel Bias - Calibration 4 CH-TOUN-WCorr (Fixed solution 93.8% ) CH-TOUN-WCorr (Float solution) : 12: 18: 3: 6: 9: 12: 15: 18: 21: 3: 6: 9: 12: 15: 18: 21: 3: 6: 9: 12: 15: 18: 21: Epoch(GPS Time) LEICA-TOPCON Standard deviation (m) E N H With Correction Without Correction

23 Concluding Remarks Will these challenges become a real obstacle to an interoperable GNSS world????? Receiver clock error is well mitigated Inter-channel bias still needs more attention from GNSS community. The answer may rely on a collaboration between GNSS analysis centres-academiaindustry.