Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS) Earth Orientation Parameters Time Series Product from the NASA Crustal Dynamics Data Information System (CDDIS). DORIS is a dual-frequency Doppler system consisting of a receiver flying aboard a satellite and a globally distributed network of ground beacons. The DORIS receiver on-board the orbiting satellite tracks the dual-frequency radio signals transmitted by the network of ground beacons and generates the DORIS data. A measurement is made of either the Doppler shift or absolute phase as the satellite’s orbit moves over the ground-based beacon. DORIS data records contain a time-tagged range-rate measurement with associated ancillary information. DORIS observations from a global network can be utilized for a variety of products. Analysis Centers (ACs) of the International DORIS Service (IDS) retrieve DORIS data on a regular basis to compute various DORIS products from data generated by the DORIS beacons supporting the IDS network, including the time series of Earth orientation parameters (EOPs). The IDS Analysis Center Coordinator combines these solutions to produce an official IDS EOP product. The EOP time series are available in text format.