VLBI schedules for Galileo Frame Tie Study

Description

The dataset contains Very Long Baseline Interferometry (VLBI) schedules in form of NGS files that include observations of both quasars and Galileo satellites are were created with the scheduling software VieSched++ (version v1.3.1; Schartner and Böhm 2019, available on GitHub). These schedules are used to find the optimal distribution of VLBI transmitters (VT) in the Galileo space segement for frame ties. Therefore different numbers and distributions of Galileo satellites being equipped with a VT are investigated. The scenarios having either one, two or three satellites of the Galileo space segment equipped with a VT are investigated. 

Context and methodology

In total, six different satellite configurations ("scenarios") are considered, varying in the number and orbital plane distribution of Galileo satellites equipped with a VT:

• 1A – 1 satellite with VT in plane A
• 1A1B – 1 satellite with VT in plane A and 1 in plane B
• 2A – 2 satellites with VT in plane A
• 1A2B – 1 satellite with VT in plane A and 2 in plane B
• 3A – 3 satellites with VT in plane A
• 1A1B1C – 1 satellite with VT in each of the planes A, B, and C

For each scenario, different proportions of satellite observations relative to the total number of observations are tested. These satellite-to-quasar observation ratios range from 10% to 60%, except for scenarios 1A and 1A1B, for which only 10% to 40% are tested due to limited visibility of the satellite(s).

Each schedule file is named according to the scenario and the satellite observation ratio. For example:

• 2A_10p refers to the scenario with two satellites in plane A and 10% satellite observations.
• 1A1B_30p refers to the scenario with one satellite in plane A and one in plane B and 30% satellite observations.