Within a year, NRL reports from the Viking program were diagramming ground-based tracking interferometers, which relieved the Viking of the burden of signal-processing equipment by computing the missile's position from the ground. Two precursors of Minitrack were evident in the interferometer arrangement. First, only a tiny radio beacon needed to be carried on the Viking itself, an important feature of the Vanguard "Minitrack," in which the prefix 'Mini" applied to the minimum-weight satellite transmitter. The second precursor was the "Lff arrangement of the interferometer antennas which persisted in some early designs of Minitrack, although the final deployed version extended the bars of the "L" to make a cross.