Data
The data from NASA’s Space Geodesy Project systems can be downloaded from the CDDIS. These data sets include:
- SLR: Laser ranging data consist of a distance or range (round-trip, station to satellite and back) and time, together with data correction information such as atmospheric effects, which are to be applied to the data. Raw laser ranges are formatted at the remote station before transmission to operational data centers where the data are translated into the appropriate format. Data are archived by satellite and time period and are available at: ftp://cddis.nasa.gov/slr/data. More information about these products can be found at:
- VLBI: The globally distributed networks of VLBI antennas participate in highly coordinated experiments in order to perform simultaneous measurements, which are compared and correlated, generating VLBI database files. The VLBI experiment data consist of the observing site parameters, source information, correlated delay and delay rate between the observing antennas as a function of time, along with meteorological data and system parameters that must be applied to the correlated measurements. VLBI data are archived by format type and experiment and are available at: https://cddis.nasa.gov/archive/vlbi/ivsdata/db (dat afiles) and https://cddis.nasa.gov/archive/vlbi/ivsdata/aux (auxiliary files such as schedules and station log files). More information about these data files can be found at:
- GNSS: The GNSS data consist of the receiver’s observation data, the broadcast orbit information of the tracked satellites, and supporting data, such as meteorological parameters, collected from co-located instruments. GNSS data are archived by type (daily, hourly, high-rate) and year/day of year; these data are available at: https://cddis.nasa.gov/archive/gnss/data. More information about these products can be found at:
- DORIS: DORIS data records contain a time-tagged range-rate measurement with associated ancillary information. The data records also contain information about any corrections that may have been applied during the processing phase, such as for the ionosphere, troposphere, and satellite center of mass, among others. DORIS data are archived by satellite and are available at: ftp://cddis.nasa.gov/doris/data. More information about these products can be found at:
