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2013 Western Australia Surveying Conference 16.05.2013 BeiDou? First Australian results of BeiDou + GPS positioning Dennis Odijk, Robert Odolinski, Nandakumaran.

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Presentation on theme: "2013 Western Australia Surveying Conference 16.05.2013 BeiDou? First Australian results of BeiDou + GPS positioning Dennis Odijk, Robert Odolinski, Nandakumaran."— Presentation transcript:

1 2013 Western Australia Surveying Conference BeiDou? First Australian results of BeiDou + GPS positioning Dennis Odijk, Robert Odolinski, Nandakumaran Nadarajah, Boris Padovan, Peter Teunissen GNSS Research Centre, Curtin University

2 Curtin University is a trademark of Curtin University of Technology CRICOS Provider Code 00301J Presentation Outline  BeiDou What is it? Constellation + Signals Time and Coordinate Systems  First ever results of Beidou+GPS, computed by GNSS Research Centre: Single Point Positioning (SPP) Real-Time Kinematic Positioning (RTK) Attitude determination (Pitch, Roll and Yaw)  Conclusions BeiDou? First Australian results of a combined …

3 Curtin University is a trademark of Curtin University of Technology CRICOS Provider Code 00301J BeiDou – What is it?  北斗  Big Dipper or Plough, Northern Dipper  Chinese satellite navigation system  Demonstration system (BeiDou-1) completed in 2003  Second generation under construction (BeiDou-2; previously known as COMPASS)  SIS ICD released in December 2012  BeiDou signals will be free of charge  Full global constellation expected in BeiDou? First Australian results of a combined …

4 Curtin University is a trademark of Curtin University of Technology CRICOS Provider Code 00301J BeiDou – Constellation  Operational constellation: 35 satellites (GPS currently 31 - MEO) 5 Geosynchronous Earth Obiter (GEO) 3 Inclined GeoSynchronous Orbiter (IGSO) 27 Medium Earth Orbiter (MEO) Global coverage  Current (2013) Constellation: 14 satellites 5 GEO, 5 IGSO and 4 MEO satellites Fully operational in the Asia Pacific region BeiDou? First Australian results of a combined … Sky plots for Perth

5 Curtin University is a trademark of Curtin University of Technology CRICOS Provider Code 00301J BeiDou – Signal Frequencies BeiDou:(Modernized) GPS: BeiDou? First Australian results of a combined … B1: MHz cm B2: MHz cm B3: MHz cm L1: MHz cm L2: MHz cm L5: MHz cm BeiDou, GPS (and Galileo) signals are based on Code Division Multiple Access (CDMA) BEIDOU B1 B3 B2

6 Curtin University is a trademark of Curtin University of Technology CRICOS Provider Code 00301J BeiDou – Time and Coordinate Systems BeiDou Time System:  Beidou time (BDT) is synchronized with UTC within 100 ns  Offset BDT and GPS time (GPST)/Galileo time (GST) is broadcast by satellites BeiDou Coordinate System:  BeiDou uses China Geodetic System 2000 (CGS2000)  Coincides with ITRF at few centimetre level; for most (surveying) applications difference between CGS2000 and ITRF can be ignored BeiDou? First Australian results of a combined …

7 Curtin University is a trademark of Curtin University of Technology CRICOS Provider Code 00301J Combined BeiDou + GPS: Increased model strength and availability BeiDou? First Australian results of a combined … Suitable for e.g.: Developing and operating minesAgriculture (wheat belt in dark yellow)

8 Curtin University is a trademark of Curtin University of Technology CRICOS Provider Code 00301J GNSS Satellite Availability in Challenging Environments “urban canyons” open pit mines BeiDou? First Australian results of a combined …

9 Curtin University is a trademark of Curtin University of Technology CRICOS Provider Code 00301J BeiDou + GPS: Single Point Positioning (SPP)  24 h of data (07/07/12) tracked at Curtin’s permanent GNSS station (Trimble NetR9)  Single-frequency Beidou (B1 code) + GPS (L1 C/A code) data used; cut off = 10 deg  Satellite orbits/clocks from nav. message  Estimate parameters: 3D position + 1 receiver clock error per constellation  Position errors computed by subtracting estimated position from known coordinates BeiDou? First Australian results of a combined … B1 BEIDOU.

10 Curtin University is a trademark of Curtin University of Technology CRICOS Provider Code 00301J BeiDou + GPS: Real-Time Kinematic (RTK) Positioning BeiDou? First Australian results of a combined …  Relative (2 receivers) positioning based on code (pseudorange) and carrier phase  Integer carrier-phase ambiguity resolution (IAR) = key to high-precision (mm-cm level) positioning  Short baseline: elimination of clocks + atmospheric errors  Most challenging: single-frequency BeiDou (B1 code) + GPS (L1 C/A code) single-epoch RTK  Double-differenced observations with unknown parameters: 3D relative position + double- differenced phase ambiguities per constellation CUTA (Left; reference) and CUTT (Right; rover) GNSS antennas, baseline distance ~1 km

11 Curtin University is a trademark of Curtin University of Technology CRICOS Provider Code 00301J Single-frequency RTK ambiguity resolution + positioning results – cut-off elevation: 35 deg BeiDou? First Australian results of a combined … BeiDou-only B1 System/Ambiguity resolution Frequencysuccess rate % for cut-off [deg] BEIDOU B GPS L COMBINED B1+L h of data (21/04/13)

12 Curtin University is a trademark of Curtin University of Technology CRICOS Provider Code 00301J Single-frequency RTK ambiguity resolution + positioning results – cut-off elevation: 35 deg BeiDou? First Australian results of a combined … GPS-only L1 System/Ambiguity resolution Frequencysuccess rate % for cut-off [deg] BEIDOU B GPS L COMBINED B1+L h of data (21/04/13)

13 Curtin University is a trademark of Curtin University of Technology CRICOS Provider Code 00301J Single-frequency RTK ambiguity resolution + positioning results – cut-off elevation: 35 deg BeiDou? First Australian results of a combined … System/Ambiguity resolution Frequencysuccess rate % for cut-off [deg] BEIDOU B GPS L COMBINED B1+L BeiDou B1 + GPS L1 24 h of data (21/04/13)

14 Curtin University is a trademark of Curtin University of Technology CRICOS Provider Code 00301J Beidou + GPS Attitude Determination BeiDou? First Australian results of a combined … Determination of the relative orientation between reference systems

15 Curtin University is a trademark of Curtin University of Technology CRICOS Provider Code 00301J Beidou + GPS Attitude Determination BeiDou? First Australian results of a combined … Instantaneous ambiguity resolution success-rates LAMBDA: “standard” (RTK) ambiguity resolution; C-LAMBDA: baseline-constrained ambiguity resolution 24 h of data (17/03/13) 8-m baseline

16 Curtin University is a trademark of Curtin University of Technology CRICOS Provider Code 00301J Conclusions  BeiDou is now operational in Asia-Pacific region and signals can be tracked by multi-GNSS receivers  Combined BeiDou+GPS: increased availability of satellites and frequencies  Data quality BeiDou ≈ GPS  First ever Australian combined BeiDou+GPS results were presented, computed using in-house software of Curtin’s GNSS Research Centre  Combined Beidou+GPS seems to be much more robust for single-frequency RTK positioning and attitude determination in challenging environments, compared to one constellation BeiDou? First Australian results of a combined …

17 Curtin University is a trademark of Curtin University of Technology CRICOS Provider Code 00301J Acknowledgments  This work has been executed in the framework of the CRC-SI Positioning Program Project 1.01 ”New carrier- phase processing strategies for achieving precise and reliable multi-satellite multi-frequency GNSS/RSS positioning in Australia”  Curtin PhD student Mr Robert Odolinski for processing the SPP and RTK  Curtin researcher Dr Nanthi Nadarajah for processing the attitude BeiDou? First Australian results of a combined …

18 Curtin University is a trademark of Curtin University of Technology CRICOS Provider Code 00301J More information? BeiDou? First Australian results of a combined … Contact: GNSS Research Centre, Department of Spatial Sciences, Curtin University

19 Curtin University is a trademark of Curtin University of Technology CRICOS Provider Code 00301J Thanks for your attention! BeiDou? First Australian results of a combined … Questions?

20 Curtin University is a trademark of Curtin University of Technology CRICOS Provider Code 00301J BeiDou + GPS: “DGNSS” Positioning  Relative (2 receivers) code (pseudorange) based positioning  Short baselines: reduction/elimination of orbit, clock + atmospheric errors  Single-frequency BeiDou (B1 code) + GPS (L1 C/A code) data used  Double-differenced observations with unknown parameters: 3D relative position  Position errors of CUTT : computed by subtracting estimated position from known coordinates BeiDou? First Australian results of a combined … CUTA (Left; reference) and CUTT (Right; rover) GNSS antennas, baseline distance ~1 km B1 BEIDOU L1 GPSB1 BEIDOU + L1 GPS

21 Curtin University is a trademark of Curtin University of Technology CRICOS Provider Code 00301J Single-frequency RTK ambiguity resolution + positioning results – cut-off elevation: 10 deg BeiDou? First Australian results of a combined … System/Ambiguity resolution Frequencysuccess rate % for cut-off [deg] BEIDOU B GPS L COMBINED B1+L BeiDou-only B1

22 Curtin University is a trademark of Curtin University of Technology CRICOS Provider Code 00301J Single-frequency RTK ambiguity resolution + positioning results – cut-off elevation: 10 deg BeiDou? First Australian results of a combined … System/Ambiguity resolution Frequencysuccess rate % for cut-off [deg] BEIDOU B GPS L COMBINED B1+L GPS-only L1

23 Curtin University is a trademark of Curtin University of Technology CRICOS Provider Code 00301J Single-frequency RTK ambiguity resolution + positioning results – cut-off elevation: 10 deg BeiDou? First Australian results of a combined … System/Ambiguity resolution Frequencysuccess rate % for cut-off [deg] BEIDOU B GPS L COMBINED B1+L BeiDou B1 + GPS L1


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