New ship-borne gravimeter NIPR-ORI Model II installed on board icebreaker SHIRASE

Abstract

A newly-designed ship-borne gravimeter NIPR-ORI Model II to be used for the Japanese Antarctic Research Expedition is described. This meter is a second version of the previously used NIPR-ORI Model I. The new gravimeter is equipped with the inertial grade gyro called TDG (tuned dry gyro). The first performance test was conducted on board the R/V HAKUHO MARU of the Ocean Research Institute, University of Tokyo in 1987,and it was found that the overall accuracy of the meter after the correction for the Eotvos effect caused by ship's speed was better than ±0.5 mgal.