A parallel-channel shipboard direction finding system

Abstract

Several parallel-channel receiver configurations are presented and analyzed. From this background a particular direction-finding system suitable for shipboard use is detailed. Use of three modes of operation of the defined system is shown to provide through 360° coarse and find indications of the bearings of each of several stations transmitting simultaneously. It is also shown that this system will provide measures of amplitude and, with some added circuitry, frequency of each of these received signals. It is shown that the gain characteristics of the antennas for each mode of operation are chosen in a manner which makes the parallel-channel receiving system immune to signals reflected from the ship and its rigging . Two different methods of obtaining independent measures of signal frequency and bearing are presented. A brief history of direction finding and an extensive bibliography are provided.