Antenna and stabilization console for a VLF relative navigational system

Abstract

A VLF relative navigational system makes use of the fact that, at any given point on the earth, phase delay of a received VLF signal is highly stable and predictable. As the receiver is physically moved, phase delay changes linearly with distance from the transmitting station, so that by keeping track of the phase delay of the received signal from several VLF stations, an accurate plot of geographical position is maintained. The paper outlines the development of a relatively simple antenna system, composed of two crossed loops and a whip sense antenna to produce a cardiod shaped radiation pattern, which effectively discriminates against the long-way-around-the world contamination on the short path signal. A means is also devised for electronically rotating the fixed antenna by means of a goniometer which may be stabilized in azimuth by an input from a ship's gyrocompass