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

CALIPSO GPS Network - GERD-Geralds Yard P.S.
Start: 24-Mar-2004
End: 08-Sep-2019
Mattioli, Glen, 2008, CALIPSO GPS Network - GERD-Geralds Yard P.S., UNAVCO, GPS/GNSS Observations Dataset, 
https://doi.org/10.7283/T5TT4PBT