Please complete the protocol for Session 2 "Realization of the ITGRF".
Date
Presentation by Ezequiel Antokoletz and Andreas Engfeldt
- Reference station classifications
- Rather the prescribe reference station requirements – perhaps start with what kind of stations we already have
- ITGRF proposes 3 types of stations, but perhaps more are needed
- Reference Station
- Provide a long term, stable gravity refereence function (RF)
- SG + AG
- Continuous AG
- ~6 AG observations per years
- Comparison Stations
- Multiple AGs
- Core stations
- GGOS , GNSS, SLR, VLBI
- Need to monitor medium and long term changes in gravity. (RF)
- Argentina example of 30uGal change over 5+ years. (Hungary yesterday, similar). Lucky to have both FG5 and SG
- Matera Italy an example of only AG time series
- Current Station Status
- Core and comparison: 6
- Core and reference: 3
- Comparison: 12
- Reference: 9
- Comparison Status
- CIPM and Regional Key Comparisons. CIPM every 7-8 years, RMO between
- Additional “geodetic” comparisons? How often?
- Need to document equivalence of all AGs
General Discussion
- Comparison site meant to measure at different places at different times
- Reference stations handle same place at different times
- A “monitor” station where you come and compare with local RF
- Mirjam/Alex: reference function is necessary when you don’t have an AG to compare with. If you have AGs you can compare anytime/anywhere
- Vojtech: reference station simply monitors gravity – accuracy may vary widely between RSs. (Let’s figure out comparison stations later). This is enough to access the Frame
- Each RS may have its own “uncertainty” class
- Using local RSs as a control/check when doing a survey in another country/area is another purpose.
- Derek: list of all participating stations with attributes that users can “select” from if they need a local check/confirmation of equivalence
- Sylvain: important to distinguish Comparison stations
- Vicki: ITRF has contributors whose inputs are monitor by a coordination/analysis center. This is how quality/uncertainty is established.
- Alex: reference function can serve as a tie to the frame (metrology)
- Vojtech: Comparisons can happen anywhere – don’t even need to be at RSs.
- Derek: perhaps the ability to host comparisons is simply another attribute of an RS.
- Przemek: we do want as many RSs as possible!
- Ezequiel: not every nation needs an RS
Resolved to Resolve on Wednesday: Frame is defined by RSs and comparisons at RSs. Define stations by collection of attributes and capabilities.