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

MAGNET - FREN-FREN P.S.
Start: 12-May-2006
End: 27-Sep-2017
Blewitt, Geoff, Hammond, William C., Kreemer, Corne, 2009, MAGNET - FREN-FREN P.S., UNAVCO, GPS/GNSS Observations Dataset, 
https://doi.org/10.7283/T5DZ06GZ