DEVICE FOR MEASUREMENT OF MAGNETIC DECLINATION AT SEA Russian patent published in 1996 - IPC

FIELD: geophysics; marine geophysical magnetic survey. SUBSTANCE: similar datum of readings is arranged on board ship and in towed nonmagnetic gondola. Magnitude of angle of magnetic declination is continuously determined relative to this datum. Device has gondola towed by ship with the aid of cable, flux-gate magnetometer, crystal oscillator with frequency divider, zero level discriminator, two selectors, synchronizing circuit, two pulse shapers, flip-flop control device, two counters, memory recorder and course input unit. Mounted in towed nonmagnetic gondola is swivel device which consists of swivel disk, sensor securing unit, step motor with reduction gear and control circuit. Mounted on swivel disk is sensor of flux-gate magnetometer; disk rotates in horizontal plane. At moment of time when sensor of flux-gate magnetometer is located perpendicularly to plane of magnetic meridian, direction to magnetic meridian is noted and direction to geographic meridian is determined on board ship by means of shipboard navigational machine by averaging the measured magnitudes of ship's course within definite period of time effected by means of course input unit. EFFECT: enhanced accuracy of measurement. 3 dwg