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

COCONet GPS Network - NARA-NARA_IGN_GT_2009 P.S.
Start: 16-May-2010
End: 16-Feb-2016
UNAVCO Community, 2014, COCONet GPS Network - NARA-NARA_IGN_GT_2009 P.S., UNAVCO, GPS/GNSS Observations Dataset, 
https://doi.org/10.7283/T5FF3QM7