Please complete the protocol for Session 4 " Operability, coordination and maintenance of the ITGRF".
Date
Second part (after the coffee break)
1) Discussion on the definition of reference stations, comparison stations? and core-stations within the ITGRF:
Shall we leave the comparison sites as a category of stations within the ITGRF? If so, we could give up on comparison sties.
We would have just reference stations where monitoring is available and further facilities or attributes for comparisons. Additionally we would have the core-sites in the sense of GGOS.
--> Comparison sites shall be described as additional facilities. For the ITGRF, we would set reference stations with certain attributes.
--> Reference stations should be those where gravity is monitored with an uncertainty of 10^-8 (10 muGal) over time.
---> GGOS core-stations should have gravity reference at some level in the future. TO BE ADDRESSED!
2) Categories of reference stations:
Relax the requirement for the reference stations and allow more stations to be included as reference stations?
---> The measurements requirements should be setup based on the stability of the point. E.g. if you have a stations with low variability, you do not need to measure that often.
---> Repeated measurements at a given station would enable the station to be adopted as a (secondary) reference stations.
- Regional managers for the reference stations: take care to compile the set of stations.
---> Two categories of reference stations.
What is realizing the Frame?
The Frame is realized through absolute gravity measurements traceable at a reference stations or through comparisons. If that is the case, all measurements of that instrument would be in the ITGRF. That would allow to include field absolute stations and would be realizing the ITGRF for a certain epoch and with a given uncertainty.
Task: evaluate existing absolute gravity networks and instruments to trace back if the instruments are traceable. If so, those measurements would be included in the ITGRF.