On 31 October 2020, anonymous ftp access will officially be discontinued at CDDIS. Beginning October 1, 2020, CDDIS will bandwidth limit ALL IPs using anonymous ftp to just 50KB/s and will limit simultaneous downloads to only 3 per IP address. CDDIS is STRONGLY recommending all users begin to transition to using alternate method of access to the CDDIS archive. Examples of alternate methods can be found at: https://cddis.nasa.gov/Data_and_Derived_Products/CDDIS_Archive_Access.html.

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Campaign data

The CDDIS also provides an archive of regional experiment data, previously funded by NASA and international cooperative programs. Starting in 1990, studies in the geophysical integrity of the NASA SLR and VLBI sites were undertaken utilizing GPS. Small networks of GPS sites were selected in an approximate 10-20 km radius around the main observing monuments at several of key sites. The measurements taken at these "footprint" sites allow analysts to estimate the local tectonic stability of the area they encompass, assuring the integrity of the space geodetic measurements taken at these critical sites. In addition to the surrounding footprint sites, measurements are taken at the reference monuments placed at a distance of 50 to 100 meters to the main marker. GPS measurements at the reference monuments allow analysts to continue to monitor the physical stability of the main observing monuments and provide additional data for the estimation of the regional tectonic stability of the area.

Summary of CDDIS GNSS experiment data holdings