UT1 Formal Errors from the BA 50 Balanced Scheduling Strategy INT01 R&Ds
Abstract
The original operational IVS INT01 scheduling strategy (the ``standard'' strategy or STN) used as few as ∼30 strong but badly distributed sources, resulting in bad source and observation sky coverage at some times of the year. In response, in 2009, we proposed the Maximal Source Strategy (MSS) to maximize sky coverage by using all geodetic sources that are mutually visible at the primary INT01 stations. This yielded an operational INT01 MSS source set that had ∼90 sources but was, on average, weaker than the STN. Increasing sky coverage tends to decrease the UT1 formal error, while decreasing average source strength tends to increase the UT1 formal error by creating longer observations and scheduling fewer observations. To resolve this conflict, we investigated using Sked's Bestsource command to select balanced source sets of varying sizes between the STN and MSS sizes, trying to select enough sources for good sky coverage but not enough to introduce too much weakness. We wanted to balance sky coverage and source strength to try to minimize the UT1 formal errors, while also considering balancing's effect on two other metrics. Our investigation led to the 50 source, balanced ``Balanced 50'' (BA 50) strategy. The IVS Observing Program Committee allocated six 2016 and 2017 R&D sessions for us to compare the BA 50 strategy to the MSS strategy, which had become the sole operational INT01 scheduling strategy in mid-2016. This paper reports the R&Ds' first results, focusing on their UT1 formal errors.
- Publication:
-
International VLBI Service for Geodesy and Astrometry 2018 General Meeting Proceedings: "Global Geodesy and the Role of VGOS - Fundamental to Sustainable Development
- Pub Date:
- September 2019
- Bibcode:
- 2019ivs..conf..209B