These proceedings contain the papers presented during Symposium No. 5, Geodetic Applications of Radio Interferometry, of the International Association of Geodesy General Meeting held in Tokyo, May 7–8, 1982. The symposium, organized by the IAG Special Study Group 2.51 on Radio Interferometry, had eight sessions and 3 6 papers. Radio interferometry on satellites, such as GPS, was not included because this topic had been extensively discussed during other IAG meetings, such as the Third International Symposium on Satellite Doppler Positioning held in Las Cruces, N. Mex., in February 1982.
The first session contained six papers on reference frames. K. I. Kellermann's contribution illustrated source structures and their frequency and time variations, which have significant influence for the maintenance of a celestial radio catalogue at the milliarcsecond level and for the simultaneous use of two frequencies during Very Long Baseline Interferometry (VLBI) sessions. The second paper, by K. J. Johnston and J. S. Ulvestad, was devoted too to celestial frame by comparing several radiosource catalogues. Some useful recommendations are made for future works, particularly by proposing a set of about 40 sources to be observed by all investigators.