A VLF Radio Relative Navigation System

the cruise of the R.V. ATLANTIS II to the Indian Ocean in 1963 presented an opportunity to attempt long-range navigation from the very low frequency (VLF) transmissions of stabilized stations. With a precision oscillator and three phase tracking receivers on board the ship, horizontal movement from known points were indicated as phase differences which were computed to geographical locations, providing relative navigation. Positions were plotted from great circle computations and on a special VLF 30 series of Charts of the Southwestern Indian Ocean provided by the U. S. Navy Oceanographic Office. The relative navigational system was assembled from commercial components at a relatively low cost. Of particular interest to the oceanographer is the long-range navigational capability, the ability to measure the drift of the ship while making hydrographic or current stations, and the inherent precise timing produced by the equipment. This work was supported by the Office of Naval Research.