抄録
Hydrographic Department is to start the GPS observations on crustal deformation around Sagami Bay from the beginning of 1990. Here we report the results of test observations which were carried out at O Sima. Manazuru and Izu Sirahama in March and July (just after the occurrence of volcanic activity at Teisi knoll on July 13), in 1989. Phase differences of two carrier frequencies were measured, and it was found that if 4 GPS satellites are visible and 6 hours' observation is secured then we can obtain good repeatability of 1 ppm or less.
