Towards a EUREF Service Providing Real-time GNSS Clock and Orbit Corrections

Transcription

1 Towards a EUREF Service Providing Real-time GNSS Clock and Orbit Corrections G. Weber 1), W. Söhne 1), A. Stürze 1), L. Mervart 2) 1) Federal Agency for Cartography and Geodesy, Frankfurt am Main, Germany 2) Technical University of Prague, Czech Republic

2 Outline Motivation Real-time concept Conclusions and outlook EUPOS Symposium, November 11-14, 2008, Berlin 2

3 Motivation GNSS real-time data streaming has been s uccessfully developed within EUREF Special Project EUREF-IP was created in 2002 Goal: DGNSS infra-structure through the Internet Meanwhile, wide range of geodetic receivers with Ntrip ( Networked Transport of RTCM via Internet ) technology Currently (Nov, 5) 96 EUREF Permanent Network (EPN) stations (out of 218) with real-time capability (52 of them GPS+GLONASS) SP EUREF-IP moved towards EPN routine operations at the end of 2007 EUPOS Symposium, November 11-14, 2008, Berlin 3

4 GNSS development has been accelerated Motivation from daily to hourly files (data) from post-processing to near real-time (products) Current evolution is going towards Real-time data streaming Real-time monitoring and analysis With the improvement of products and models the GNSS analysis has been extended From relative positioning To precise single point positioning (Zumberge et al., 1997) EUPOS Symposium, November 11-14, 2008, Berlin 4

5 Estimation and streaming of orbit & clock corrections State space representation Real-time components BKG Ntrip Client (BNC) GNSS processing engine BKG Ntrip State Space Server (BNS) Precise point positioning using orbit & clock corrections First results RT concept EUPOS Symposium, November 11-14, 2008, Berlin 5

6 Orbit & clock correction concept EUPOS Symposium, November 11-14, 2008, Berlin 6

7 State space representation RTCM SC-104 Differential Global Navigation Satellite Systems WG State Space (chaired by G. Wübbena) State space principle: Provision of information about individual error sources, i.e., state space representation (Wübbena et al., 2005) Satellite signal delay Satellite clock error Satellite orbit error Satellite antenna PCV Ionosphere Troposphere RTCM State Parameters obstacle Multipath Receiver Antenna PCV Receiver clock error Receiver signal delay EUPOS Symposium, November 11-14, 2008, Berlin 7

8 Purpose BKG Ntrip Client (BNC) GNSS data streams available through Ntrip Generation of high-rate RINEX OBS and NAV files Generation of EPH and synchronized OBS via port Monitoring of the performance of a real-time network Version 1.6 under development Reading data from file (offline mode) Reconfiguration on-the-fly RTCM v3 decoder for clock and orbit corrections RTCM v3 stream check for incoming message types EUPOS Symposium, November 11-14, 2008, Berlin 8

9 BKG Ntrip Client (BNC) Various options selected by tabs Streams from different casters Supports several formats EUPOS Symposium, November 11-14, 2008, Berlin 9

10 RTnet Developed by GPS Solutions Inc. / L. Mervart For post-processing as well as real-time application Uses zero-differences observations, ionosphere free linear combination Used for - - GNSS processing engine either estimation of clock corrections (network solution) ambiguity resolution on double difference level or coordinate estimation (PPP) ambiguity resolution on single difference level Uses broadcast or IGS/IGU orbits Successfully tested for GPS only and GPS+GLONASS, for Europe, North America and Australia EUPOS Symposium, November 11-14, 2008, Berlin 10

11 GNSS processing engine EUPOS Symposium, November 11-14, 2008, Berlin 11

12 Purpose BKG Ntrip State Space Server (BNS) Calculate differences between BRDC and IGU orbits in radial, along track and out-of-plane components Model orbit differences through polynomials of low degree Provide model-based estimations of corrections for BRDC orbits Calculate differences between BRDC clocks and improved IGU clocks Model clock differences through polynomials Provide model-based estimations of corrections for BRDC clocks First version since April 2008 EUPOS Symposium, November 11-14, 2008, Berlin 12

13 BKG Ntrip State Space Server (BNS) Various options selected by tabs Mountpoint for clock corrections Different systems supported EUPOS Symposium, November 11-14, 2008, Berlin 13

14 Precise point positioning concept EUPOS Symposium, November 11-14, 2008, Berlin 14

15 Precise point positioning concept = state space representation, orbits & clocks, RTCM v3 messages EUPOS Symposium, November 11-14, 2008, Berlin 15

16 GNSS processing engine results EUPOS Symposium, November 11-14, 2008, Berlin 16

17 GNSS processing engine results EUPOS Symposium, November 11-14, 2008, Berlin 17

18 GNSS processing engine results EUPOS Symposium, November 11-14, 2008, Berlin 18

19 GNSS processing engine results EUPOS Symposium, November 11-14, 2008, Berlin 19

20 GNSS processing engine results EUPOS Symposium, November 11-14, 2008, Berlin 20

21 GNSS processing engine results EUPOS Symposium, November 11-14, 2008, Berlin 21

22 Conclusions & outlook EPN real-time data streaming widely-used Moved to EPN routine operations Strategies of orbit and clock correction computation and dissemination is on an advanced level EUREF is going to start a new SP about the enhancement of real-time data streams EUPOS Symposium, November 11-14, 2008, Berlin 22

23 Thank you for your attention! Information & Downloads: EUPOS Symposium, November 11-14, 2008, Berlin 23