Accuracy Estimates of Gravity Potential Differences between Western Europe and United States through Lageos Satellite Laser Ranging Network

摘要

The presently attainable accuracy of connecting the vertical datums of regions, which are separated by oceans, has been investigated. The vertical datum connections are established through geocentric positions of laser tracking stations by estimating the geopotential at these stations, and also utilizing the geopotential differences between stations in each region obtained through leveling. The Western Europe-USA vertical datum connection has been examined in detail. Accuracy estimates of a few other datum connections are also given. Four stations in Western Europe and 14 stations in USA were considered in the Lageos satellite laser ranging (SLR) network (January 1982). The currently available accuracy estimates (December 1981) of the potential coefficients describing the earth's gravity field to degree 180 were used, along with gravity anomalies in a small area around each SLR station. Various anomaly spacing, data cap size, anomaly accuracy were tried to determine the effect on the accuracy of the vertical datum connection. It was found that anomaly spacing need not be more dense than 10'. Different accuracy estimates for the SLR station positions, and any displacement of the SLR coordinate system origin from the geocenter, were considered. The corresponding values for the vertical connection, if anomalies were used in a data cap of 1 deg radius, were 50 and 52 kgal/cm.