At present, the criteria for selecting space geodetic sites are random and uncertain internationally. In this paper, we present a new method for selecting rigid geodetic sites of each plate and establishing a present-day relative motion model of global plates: RM2000. Incorporating geomagnetic anomaly data 80 MaBP, the relative Euler vectors of global plates in different ages can be determined, based on, which the spreading, sliding and converging rates of adjacent plates can be obtained. Comparing them shows: (1) in the recent 10 Ma, the relative motions of adjacent plates have been systematically slowing down in the South Hemisphere, and have no, systematical variations in the North Hemisphere; (2) in the entrie 80 Ma, the relative motion trends of Australia-Antarctica, Pacific-Antarctica, Africa-Australia and Australia-Eurasia have been accelerative, the relative motion trends of mid-Atlantic ridge, Africa-Antarctica, Cocos-Pacific, Africa-Eurasia and India-Eurasia have been slowing down, and the relative motion trends of Pacific-Nazca, Nazca-South America, Pacific-Australia and Pacific-North America, have been almost constant.
Two kinds of fading filters and their principles are introduced. An adaptive robust filter is given with corresponding principle. The basic abilities of the fading filters and adaptively robust filter in controlling the influences of the kinematic model errors are analyzed. A practical example is given. The results of the fading filter and adaptively robust filter are compared and analyzed.
Precise vertical total electron contents (VTEC) and its time variation have been obtained by using GPS dual-frequency observations collected by the continuously operating GPS tracking stations distributed over China. Us-ing VTEC data, the wave-motion appearing in the iono-sphere on November 3, 2003 is monitored and analyzed when a small solar flare happened. Detailed discussion with the VTEC and its change rate series, which are derived from the observations (data) from PRN23 satellite, indicates that the wave-motion mainly contains two dominant frequencies and propagates almost along the meridian line toward south. Additionally, the fluctuation of the mean VTEC has been calculated in a regional Single Layer Model (SLM) iono-spheric shell in the range of N28.0°―34.0° and E118.0°―123.0°. The spectral analysis and the multi-resolution analy-sis of mean VTEC time series show that the periods of these two components of the wave-motion at middle altitude are around 60 and 25 min separately, and the amplitudes can be up to 1.0―2.0 TECU and 0.4―0.7 TECU respectively. Mean- while, the relative motion between the wave-motion and the Ionosphere Pierce Points (IPPs), which are defined as the cross points between the line-of-sight of the GPS signals and the SLM thin shell, reveals that the traveling speeds of the two components are about 120―150 m/s and 30―40 m/s respectively.
