The contribution of BeiDou to multi- GNSS Precise Point Positioning

Transcription

1 Javier Tegedor, Ole Ørpen Fugro Satellite Positioning AS The contribution of BeiDou to multi- GNSS Precise Point Positioning Geodesi- og hydrografidagene 2015, Sundvollen, November 2015

2 Fugro Precise Point Positioning services Fugro launched in 2009 the G2 service using GPS and GLONASS: Proprietary worldwide tracking network Real-time estimation of orbits/clocks Broadcast corrections using GEO satellites Maritime professional users Highly redundant service Decimeter level accuracy Following GNSS evolution, new services have been introduced in Q1 2015: G2+: ambiguity-fixed PPP G4: addition of BeiDou and Galileo 2

3 G4 tracking network The legacy G2 reference station tracking network has been upgraded to G4 capability Fugro G4 receivers are tracking all BeiDou and Galileo open signals: Galileo: E1, E5a, E5b, E5a+b BeiDou: B1, B2, B3 3

4 Fugro s first Galileo Only Positioning, 18 March 2013 Four IOV satellites used in Precise Point Positioning (PPP) at 10 cm level Fugro generated high accuracy Galileo orbit/clock data using Fugro s tracking network Fugro tracking network in March 2013, yellow means Galileo capable stations 4

5 Galileo current status G4 system has been qualified for Galileo No Galileo corrections delivered to customers yet Galileo will be added to G4 when operational Satellite PRN Launch Status IOV PFM E11 Oct 2011 OK IOV FM2 E12 Oct 2011 OK IOV FM3 E19 Oct 2012 OK IOV FM4 E20 Oct 2012 Only transmitting in E1 FOC FM1 E18 Aug 2014 Non-nominal orbit FOC FM2 E14 Aug 2014 Non-nominal orbit FOC FM3 E22 Mar 2015 OK FOC FM4 E26 Mar 2015 OK FOC FM5 E24 Sept 2015 OK FOC FM6 E30 Sept 2015 OK 5

6 BeiDou status Regional coverage in Asia 3 MEO (Medium Earth Orbit) 5 IGSO (Inclined Geosynchronous Orbit) 5 GEO (Geostationary Orbit) Full worldwide Coverage (30 satellites) by 2020 Next generation BeiDou-3: First satellite launched on March 31 st 2 additional satellites launched on July 6 The new G4 service: multi-constellation PPP including GPS, Glonass, Galileo and BeiDou

7 BeiDou status Regional coverage in Asia 3 MEO (Medium Earth Orbit) 5 IGSO (Inclined Geosynchronous Orbit) 5 GEO (Geostationary Orbit) Full worldwide Coverage (30 satellites) by 2020 Next generation BeiDou-3: First satellite launched on March 31 st 2 additional satellites launched on July 7 The new G4 service: multi-constellation PPP including GPS, Glonass, Galileo and BeiDou

8 BeiDou status Regional coverage in Asia 3 MEO (Medium Earth Orbit) 5 IGSO (Inclined Geosynchronous Orbit) 5 GEO (Geostationary Orbit) Full worldwide Coverage (30 satellites) by 2020 Next generation BeiDou-3: First satellite launched on March 31 st 2 additional satellites launched on July 8 The new G4 service: multi-constellation PPP including GPS, Glonass, Galileo and BeiDou

9 BeiDou, Chinese Satellite Navigation System Regional coverage in Asia 3 MEO (Medium Earth Orbit) 5 IGSO (Inclined Geosynchronous Orbit) 5 GEO (Geostationary Orbit) Full worldwide Coverage (30 satellites) by 2020 Next generation BeiDou-3: First satellite launched on March 31 st 2 additional satellites launched on July 9 The new G4 service: multi-constellation PPP including GPS, Glonass, Galileo and BeiDou

10 BeiDou challenges Geometry Orbit determination for GEOs is particularly challenging due the static position with respect to the reference station network Satellite attitude: Orbit normal mode used by GEOs, and IGSO/MEOs at low β-angles 10

11 GEO satellites - Orbit normal vs yaw-steering 11

12 Challenges for BeiDou PPP Satellite antenna modelling Phase center offset (PCO) and variations (PCV) are needed for both tranmitting and receiving antennas PCV (mm) Nadir angle (degrees) MEO IGSO 12

13 Challenges for BeiDou PPP Frequency transition from B1 ( MHz) to L1 ( MHz) QPSK to MBOC Pending ICD update Operational challenges for customers Need to upgrade FW in the receivers in the field Source: Navipedia BeiDou TMBOC signals tracked by Javad Source: GpsWorld 13

14 Orbit accuracy BeiDou MEO orbit accuracy is similar to Glonass Slightly worse for IGSOs Meter-level error for GEO (mainly along-track) 14

15 Clock stabillity Short-term BeiDou clock stability is a bit worse than Galileo and GPS IIF clocks Computed Allan-deviations from real-time G4 1Hz clocks: 15

16 Real-time G4 performance Real-time G4 performance on Perth (Australia), September 6 th 2015 Up to 30 satellites contribute to position estimation: G4 is significantly more robust than G2 thanks to the increased number of satellites 16

17 Precise Point Positioning using BeiDou Perth (Australia) The addition of GEO satellites to the G4 service allows to obtain 24/7 PPP using only BeiDou Very good horizontal accuracy (<10cm) Vertical accuracy is a bit more variable due to GEO orbit errors 17

18 Real-time G4 performance The design of the BeiDou constellation allows to obtain 24/7 real-time PPP results in the Far East, when all BeiDou satellites are used Orbit accuracy for BeiDou GEO satellites limits BeiDou-only PPP performance BeiDou-only PPP is slightly worse than GPS, but still at decimeter level 24 hours horizontal position plots for GPS-only, BeiDou-only and G4 18 The new G4 service: multi-constellation PPP including GPS, Glonass, Galileo and BeiDou

19 Satellite visibility from Oslo 31 July 2015 Satellites used in solution: Fugro Broadcast Satellite BeiDou GEO Satellite 19

20 G4 in Oslo July

21 Advantages of multi-constellation PPP Increased accuracy and reduced convergence time More robustness against: Interference Scintillation Partial sky visibility Better RAIM protection 21

22 2 GPS + 2 BeiDou GEOs positioning 22

23 Multi-GNSS Integration When Galileo and BeiDou are fully deployed, new positioning scenarios can be envisaged: Deliver two independent solutions Independent of single-system failure Integrity detection is possible by checking the two positions 23

24 Conclusions Fugro introduced the G4 PPP service in 2015 BeiDou is already an important contribution to multi-gnss PPP Higher accuracy, robustness and availability On-going work B1 to L1 frequency transition Modelling improvements Additional GNSS provides an opportunity for improved performance Higher accuracy, reliability and faster convergence Independent solutions 24

25 Thank you for your attention! Javier Tegedor GNSS Scientist Fugro Survey Division Website: 25