A highly stable crystal oscillator applied to geodetic VLBI experiment

Instead of a hydrogen maser, a carefully selected Crystal oscillator which is phase locked to a Cesium (Cs) frequency standard of a geodetic VLBI experiment. The domestic VLBI experiment with 55 km baseline using the Crystal oscillator at one end was made in Japan and the obtained error of the baseline vector components were 4 cm, and that of the baseline length was 3 cm. This system may be operated after only 2 hours warm up. These results coincides with those of conventional geodetic Laser ranging and VLBI using a hydrogen maser within the formal error. A VLBI experiment with over 1000 km baselines were carried out successfully from October 1988, and over 11000 km baseline between Japan and Antarctica was carried out successfully in January 1990.