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

PBO GPS Network - P240-MillerSlghCN2005 P.S.
Start: 27-May-2005
End: 08-May-2021
UNAVCO Community, 2005, PBO GPS Network - P240-MillerSlghCN2005 P.S., UNAVCO, GPS/GNSS Observations Dataset, 
https://doi.org/10.7283/T57P8WB5