Airborne equipment for geomagnetic measurements

Abstract

The airborne magnetometer AN/ASQ‐3A has been modified and auxiliary equipment has been developed to meet requirements for constructing isomagnetic contours of the total magnetic field over extensive areas for use in magnetic prospecting. The principal features of the instrument system are: (a) a self‐oriented magnetometer which utilizes the output of a system of saturable inductors to provide a d‐c response of low noise level and drift rate; (b) instruments for aiding the pilot to follow predetermined lines of a grid or network covering the area to be explored; and (c) an interlocked group of recorders for automatically correlating a continuous magnetometer record with plane position and altitude. The system described has been used extensively by the United States Geological Survey, the United States Naval Petroleum Reserves, and the United States Naval Ordnance Laboratory in aerial magnetic exploration under a wide variety of conditions. Similar systems are also being used by a few commercial companies.