Determination of precise positions of the mainlands and isolated islands in the Japanese territory

Abstract

Precise nautical charts have become indispensable both for determination of the outer limit of jurisdictional sea and for the safety at sea. It is because the United Nations Law of the Sea has come into effect in many countries and also because of the advent of GPS that enables navigators to obtain precise position even in the middle of the ocean. Since 1980, the Hydrographic Department of Japan has carried out space geodetic observations, such as satellite laser ranging (SLR) and global positioning system (GPS), to establish geodetic control network in Japanese islands. This paper briefly reviews our activities and several results in space geodesy for precise nautical charts.