Accurate Positions of 120 Radio Sources with Declinations Above −45°

Abstract

Development of a catalogue of approximately 100 radio sources having positional accuracy of ~0.005 arcseconds is one goal of the DSN radio reference frame program. This objective is set by the navigation requirements of the Galileo Project for reconstruction of the probe entry angle into the atmosphere of Jupiter. These radio positions are determined by VLBI observations using the antennas of the NASA Deep Space Network on two intercontinental baselines – California-Spain and California-Australia. Since 1978, measurements have been made simultaneously at 2.3 and 8.4 Ghz. Sixteen to twenty-four hours of data on each of the two baselines are usually obtained within a few days of each other, and since mid-1982 these pairs of observations have been made at approximately six week intervals.