Systematic Differences between Global or Local Solutions of Polar Motion Derived from Astronomical and Spatial Measurements

Abstract

Global determinations of polar, motion are now made by two kinds of methods: the astronomical method as used by the International Polar Motion Service (IPMS) (Yumi, 1973) or by the Bureau International de l’Heure (BIH) (Guinot, Feissel and Granveaud, 1971), and the method based on Doppler measurements on artificial satellites as used by the Dahlgren Polar Monitoring Service (DPMS) since 1967 (Anderle,1970). In addition, there are local methods used to compute the latitude variations of isolated stations from laser or Doppler measurements.