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

MAGNET - PORC-PORC P.S.
Start: 24-Sep-2011
End: 20-Oct-2021
Blewitt, Geoff, Hammond, William C., Kreemer, Corne, 2012, MAGNET - PORC-PORC P.S., UNAVCO, GPS/GNSS Observations Dataset, 
https://doi.org/10.7283/T5GX48R5