Analysis of antenna position measurements and weather station network data during the ALMA Long Baseline Campaign of 2015
Todd R. Hunter, Robert Lucas, Dominique Broguiere, Ed B. Fomalont,, William R. F. Dent, Neil Phillips, David Rabanus, Catherine Vlahakis

TL;DR
This study analyzes antenna position measurements and weather data during ALMA's 2015 campaign, highlighting challenges in vertical accuracy and exploring atmospheric correction methods to improve positional repeatability.
Contribution
It introduces a comprehensive analysis of weather station data and antenna measurements, proposing potential improvements in atmospheric delay modeling for better positional accuracy.
Findings
Vertical position errors are more than three times larger than horizontal errors.
Current atmospheric correction models do not fully account for vertical residual errors.
Adding weather station data alone does not significantly improve antenna position repeatability.
Abstract
In a radio interferometer, the determination of geometrical antenna positions relies on accurate calibration of the dry and wet delay of the atmosphere above each antenna. For the Atacama Large Millimeter/Submillimeter Array (ALMA), which has baseline lengths up to 16 kilometers, the geography of the site forces the height above mean sea level of the more distant antenna pads to be significantly lower than the central array. Thus, both the ground level meteorological values and the total water column can be quite different between antennas in the extended configurations. During 2015, a network of six additional weather stations was installed to monitor pressure, temperature, relative humidity and wind velocity, in order to test whether inclusion of these parameters could improve the repeatability of antenna position determinations in these configurations. We present an analysis of the…
Peer Reviews
No public reviews on file for this paper yet. If you reviewed it on a platform where reviews are public (OpenReview, ICLR, NeurIPS, ICML), you can paste yours below so the community can read it here.
Videos
No videos yet. Explain this paper in a talk, walkthrough, or lecture? Add one.
