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

Geopentech GPS Network - CLBD-CarlCannonCA2011 P.S.
Start: 22-Jul-2011
End: 14-Nov-2022
Walls, Chris, 2011, Geopentech GPS Network - CLBD-CarlCannonCA2011 P.S., UNAVCO, GPS/GNSS Observations Dataset, 
https://doi.org/10.7283/T5SB43VC