A combined determination of the Earth rotation parameters for the period 1980 January – 1984 October using data obtained with different techniques

30 Observational series which include the ERP component, latitude or time results of 15 main networks using six techniques (Ast, Doppler, SLR, LLR, VLBI and CEI) have been reduced to give a combined determination of the ERP for the period 1980 Jan 1 – 1984 October 31. The systematic error of each series is modeled by a constant plus a drift, and these are adjusted together with the ERP unknowns. The accuracies and systematic errors of the 15 networks so found are also given.