A calibration system produces a calibrating signal having an adjustable amplitude, a torque force representative of that amplitude is directly applied to a meridian seeking gyroscope unit that hangs from a suspension band. Prior to each use of the instrument, the signal amplitude is adjusted so the gyroscope unit assumes a predetermined null position. The torque force is applied to the gyroscope unit by inductive field interaction of the first, second, and third coils. A control signal representative of the displacement of the gyroscope unit from the null position is applied to the third coil, which is fixed relative to the null position. The calibrating signal is applied to the first coil, which is also fixed relative to the null position. The axis of the first and third coils are both in an approximately perpendicular relationship to a vertical axis. A reference current is applied to the second coil, whose axis is fixed to the gyroscope unit in approximately a perpendicular relationship to the axis of the first and third coils. The amplitude of the calibrating signal is adjusted until the current applied to the third coil to produce an inductive field coil is reduced substantially to zero, at which time the instrument is calibrated.
