The following information obtained from UNAVCO's online DOI system:
(https://www.unavco.org/data/doi/search/search.html)

MAGNET - SEMN-SEMN P.S.
Start: 14-Jan-2021
End: 19-Sep-2022
Blewitt, Geoff, Hammond, William C., Kreemer, Corne, 2021, MAGNET - SEMN-SEMN P.S., UNAVCO, GPS/GNSS Observations Dataset, 
https://doi.org/10.7283/HNW6-9R08