Airborne magnetometer for determining all magnetic components

The NOL vector airborne magnetometer Type 1A (VAM‐1A), designed for measuring components of the geomagnetic field from aircraft, consists of a modification of the AN/ASQ‐3A equipment employed for geophysical exploration by air. The VAM‐1A continuously records the total intensity of the field and its direction with respect to vertical and horizontal coordinates established by a pendulum. The effects of accelerations of the aircraft on the vertical accuracy of the pendular reference are largely eliminated by averaging the magnetometer data over a period normally required for two phugoid oscillations of the aircraft. The operation of the magnetometer is limited to regions in which the magnetic dip exceeds 45°. The magnetometer is estimated to measure F, H, and Z to an accuracy of 200 gammas.