Determination of the inner planet frame tie using VLBI data

The problem of connecting the independent reference frames formed by the planetary ephemeris and the radio source catalog is one of growing importance to spacecraft navigation. Using quasar-relative VLBI delay data collected by the Deep Space Network, and Soviet coherent data from the Venus flyby of the Soviet Vega 1 and 2 spacecraft, a self-consistent estimate of the frame tie offset has been found, along with its uncertainty.