ESOC Navigation Support Office IGS Workshop 2008 Miami IGS Real Time Pilot Project: Analysis Centre Activities Loukis Agrotis 4 June 2008

ESOC Navigation Support Office IGS Workshop 2008 Miami Outline  Objectives  Schedule  Analysis Centre Status  RT Processing Issues and Challenges  Conclusions

ESOC Navigation Support Office IGS Workshop 2008 Miami Objectives  Generation and Dissemination of a Real Time Combination Product –Accurate (clocks < 0.5 ns, predicted orbits <5 cm ) –With low latency ( <? ) »5-10 sec from observation time should be achievable –High Availability »Low Downtime »Available to a potentially large user set –High Reliability »But with no “service guarantees” –These are for commercial providers to offer

ESOC Navigation Support Office IGS Workshop 2008 Miami Schedule April 08:AC teleconferences and formal PP kick-off June 08:Clock RINEX and SP3 Products from 3 ACs  Start routine comparisons  Develop and validate tools for combination solution  Prototype process on ESOC FTP server (to be eventually transitioned to CDDIS) July 08:Start Disseminating Comparisons Sept 08:Batch Combination Product Jan 09:RT Product Dissemination by ACs All ACs Operational March 09:RT Combination Product Available

ESOC Navigation Support Office IGS Workshop 2008 Miami Analysis Centre Status CentreStatus RT Product Availability ESOC RT Clocks and TZD and NRT Orbits from batch process. Real Time products currently streamed internally. Real Time product dissemination outside ESOC once agreement on formats and protocols for the PP is reached. Immediate NRCan RT Clocks and TZD and NRT Orbits from batch process. Currently distributing RT products via satellite. Immediate BKG with TU Prague RT clocks as double difference clock corrections, using IGS ultra-rapid orbits. RT products and Broadcast ephemeris orbit corrections are disseminated via NTRIP. Immediate IGG RT Clocks based on IGU orbits. Currently generates online comparisons with IGU clocks. IGU orbit residuals in near future Immediate

ESOC Navigation Support Office IGS Workshop 2008 Miami Analysis Centre Status CentreStatus RT Product Availability GMV SP3 and clock RINEX files every hour (with current capabilities). RT system under development. January 2009 (TBC) University of Newcastle RT obits and clocks. Clocks determined with smoothed pseudo ranges. January 2009 KASI Real Time data processing with estimation of orbits, clocks, ionospheric and Tropospheric products. AC for global ionospheric products from RT- IGS stations. January 2009 (TBC) TU CataloniaAC for RT Ionospheric Products.June 2009 Chalmers Emphasis is on a Tropospheric product for weather forecasting. Intend to participate as a RT Analysis Centre using own software for estimation of orbits and clocks. January 2009 (TBC) Geo++Analysis contributions using best efforts.January 2009

ESOC Navigation Support Office IGS Workshop 2008 Miami Issues and Challenges Product and Data Formats  Formats for RT products –Formats still to be defined and agreed –Main issue that could hold back progress of RT PP  Formats for Data –Predominant data formats are RTCM, RT-IGS / SOC and BINEX for GPS –Main challenge for data formats is support for generic GNSS (GLONASS, Galileo, Compass) and higher accuracies –Discussions now taking place on future requirements thanks to the good efforts of NRCan and BKG –Objective is to find the best fit among currently proposed format revisions and to influence their evolution so that our requirements are met.  Transport Protocols –NTRIP via HTTP, TCP or UDP –UDPRelay –Either or both could be used to disseminate the RT Combination Product

ESOC Navigation Support Office IGS Workshop 2008 Miami Issues and Challenges Network Issues  Excellent results are possible thanks to the contributions of a number of agencies  Large area with no network coverage results in network fragmentation. Example from 22 April shows circled stations and satellites which experienced jumps in our solution.  Densification of the network is being actively pursued

ESOC Navigation Support Office IGS Workshop 2008 Miami Issues and Challenges Network Issues  The clock correction plots show that all clocks in the South-East have jumped by the same amount, while the remaining clocks were unaffected  Several similar occurrences of this phenomenon have been observed

ESOC Navigation Support Office IGS Workshop 2008 Miami Issues and Challenges Filter Tuning Issues  Jump experienced in PRN19 at start of new pass with CAS1  CAS1 clock appears to reset with each new pass  Changes needed to the tuning of the filter so that the CAS1 clock behaviour is better modelled

ESOC Navigation Support Office IGS Workshop 2008 Miami Conclusions  RT PP is now active, thanks to the enthusiasm and support of the participating groups, particularly NRCan and BKG.  Success of the AC activity relies on the generation of high quality RT products but also on making the correct decisions on formats and protocols to ensure a wide distribution  Densification of the network in areas of low coverage is a priority  An IGS RT service will complement and increase the usefulness of the various commercial offerings for this type of service - it should not be viewed as competition to any of the current offerings of potential participants.