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

PBO GPS Network - P319-HogHoleRdgCN2004 P.S.
Start: 15-Sep-2004
End: 14-Nov-2022
UNAVCO Community, 2005, PBO GPS Network - P319-HogHoleRdgCN2004 P.S., UNAVCO, GPS/GNSS Observations Dataset, 
https://doi.org/10.7283/T5S180F5