This study investigates how precisely the terrestrial coordinates of the rotational pole can be determined from satellite data from four sites in the United States. The five satellites used are those of the Navy Navigation Satellite System (Transit). Tracking data for these satellites are Doppler observations from sites in Maine, Minnesota, California, and Hawaii. The data used in the study are intermediate data products of the near-real-time orbit determination procedure, which in an integral part of the navigation system operations. Six 5-day intervals were selected fro study, one every other month during 1976. Coordinates were determined daily from five satellites. Five-day averages were used as final estimates. Comparisons were made with extrapolated and final coordinates from the Bureau International de l'Heure (BIH) and final coordinates from the Doppler Polar Motion Service (DPMS). The final coordinates determined in the study agree as well with the final values of BIH as do the results of DPMS. The study implies that low-cost and near-real-time estimates of the terrestrial coordinates of the pole can be made available daily as a by-product of the routine support needed for the Navy Navigation Satellite System. |