Please complete the protocol for Session 5 "Discussion and Summary".
Date
Introduction
Hartmut: need to resolve do: RS define the frame, or all absolute (including Field)? Let’s spend 30 minutes
Next steps? Graham Appleby will present on parallels with ILRS/laser ranging
Let’s discuss publication and outlook for a governing board
Which Stations Realize the Frame?
Vojtech: Single epoch stations
Derek : single epochs are “nodes” of the frame that may “decay” over time
Vojtech: start by assessing traceability multi-epoch stations and instruments. Categorize stations by history, stability.
Frame defined physically by a benchmark and its traceable gravity value
Reference ITGRF stations: either characterized by (traceable) AG and a reference function or multiple AG measurements, etc. A reference station should be able to provide the current gravity value and uncertainty along with the linking/trace information.
Single/multiple epoch stations whose uncertainty needs to include the (initially unknown) site stability.
Derek: need to assess the current inventory to start the ITGRF and also mechanism to enlarge the ITGRF with new instruments and sites
Hartmut: we need to users to be able to access the ITGRF in spite of the sparseness of AGs, etc.
Discussion of what “realizes” the system and the frame?
Frame is realized through absolute gravity measurements that are traceable either via comparisons and/or reference functions.
Access to the frame via traceable observations including field stations, AG observations.
Tradeable measurements are the realization of the system and the benchmark gravity value provides access to the frame
Discussion of ITGRF Operation
Graham to present on parallels with laser ranging ILRS governing board
Nonhomogeneous distribution of stations
Observations stations, center, data centers, analysis centers, a central bureau, a governing board. “Components required to achieve the goals of the service”
Governing board is outward facing component (e.g. to IAG)
Analysis standing committee ensure consistent quality across analysis centers
Network engineering ensures instrument consistency and quality
Graham recommends to start with a governing board (GB)
George Vergios: instead of a service, recommends “coordination center” approach
Hartmut: let’s initiate a core group structure today
Propose to have the ITGRF “Coordination Group” (CG) under the BGI
Four representatives/responsibilities
Comparisons and traceability
Reference Stations and Regional Coordinators. One on the CG
Database / dissemination. Tolouse AGrav
Analysis and processing of gravity. Time series analysis, links to IGETS. Building up reference functions, etc.
Chairperson: general administration, outreach, papers, resolution, etc.
BGI will renew its GB soon, good time to add ITGRF representation
Derek: what tasks will this new group be responsible for?
Ezequiel/Sylvain: we need an immediate roadmap and strategy. Guidelines, list of attributes, future structure, paper and resolution…
Need to reach out for more regional participation: Middle East, Africa, SE Asis/Pacific, Australia, India