DAILY MEASUREMENTS BY USING GPS AT KYOTO, KOCHI, ASO AND TOTTORI IN SOUTHWEST JAPAN

Daily measurements by using GPS have been carried out at Kyoto, Kochi, Aso and Tottori sites in Southwest Japan since September 1990. The aims of the present measurements are to estimate a long term repeatability of the baseline vectors determined, to investigate effects of error factors and finally to improve the accuracy of GPS measurements.Results for the first six months are as follows:(1) The long term repeatabilities of the baseline lengths of about 150 to 500km were 0.2 to 0.4 ppm.(2) The baseline length in summer was determined longer than that in other seasons.(3) There were positive correlations among the changes of the baseline vectors.