Abstract: A three winding induction compass mounted in a host vehicle has each winding output coupled to an analog to digital converter. Each winding output is weighted and accumulated by a push down stack circuit to obtain a time filtered output; the filtered outputs are mapped into equivalent two winding outputs as the vehicle is turned in a 360.degree. circle to form sensitivity values from the windings readings and using these values to obtain measurement parameters which are incorporated into a least squares matrix which is solved for calibration coefficients to obtain the calibration parameters representing the distortions due to the permanent and inducted magnetism of the host vehicle and due to winding imbalance between the three windings and misorientation of the three windings. The calibration parameters are applied to the outputs of the three windings to obtain an equivalent two winding output which is normalized for determining the corrected compass heading.

Abstract: A method for removing bias difference between two or more similarly operated magnetometers is disclosed wherein the inherent bias difference due to the magnetic field of the towing vessel is removed without determining its relative magnitude. Magnetic data is gathered and all time related magnetic events except bias level and slope of the time related magnetic events are removed by mathematical adjustment. Point by point statistical analysis is performed to remove the bias level and the time related slope.

Abstract: A process for automatically correcting alignment errors between the measuring magnetometers of a magnetic gradient meter, consists in adding to such a gradient meter two additional magnetometers perpendicular to each other and to the axis of the measuring magnetometers. The measurements delivered by these additional magnetometers allow, with two coefficients obtained by previous calibration, the two main errors terms to be calculated and the measured value of the gradient to be corrected accordingly, which allows the alignment error to be corrected electronically and automatically.

Abstract: The present invention relates to a method and an apparatus for the reduction of the magnetic identity for such ship parts, primarily ship's guns, the aiming, fire control and possibly firing of which are controlled by a computer. The computer is used to control amplifiers which supply electromagnetic coils built in around the part with the current required for compensation of the magnetic identity of the gun in every specific position. The calculations performed by the computer are based on information on the latitude, course, speed and rolling and pitching position of the ship which it continually fetches from the log of the ship and a gyro reference system as well as on information on the angles of traverse and elevation of the gun which it continuously fetches from angle transducers disposed on the gun.

Abstract: A fluxgate magnetometer with a linear array of three sensors equi-spaced along a support beam and accurately adjustable into the same spatial orientation for sensing magnetic field anomalies and/or for measuring a single axis component of a magnetic field at two or more points in space. The beam is mounted in an elongate housing provided with pairs of wedges, acting in opposition to one another at opposite ends of the beam, for flexing the beam to adjust the sensors, which have drive windings in containers secured to the beam, the drive windings being rotatably adjustable in their containers relative to sense windings and feedback windings.

Abstract: A three winding induction compass mounted in a host vehicle has each winding output coupled to an analog to digital converter. Each winding output is weighted and accumulated by a push down stack circuit to obtain a time filtered output and the maximum and minimum values of each filtered output are determined and stored as the vehicle is turned in a 360.degree. circle. The distortions due to the permanent and induced magnetism of the host vehicle and due to winding imbalance between the three windings and misorientation of the three windings are obtained from the maximum and minimum values to obtain calibration parameters. The calibration parameters for the windings are applied to the outputs of the three windings to obtain an equivalent two winding output which is normalized for determining the corrected compass heading.

Abstract: Magnetic detector apparatus comprises a pair of electrically matched magnetic sensor assemblies supported at opposite ends of a titanium sensor tube of significant length. The sensor tube is supported in a liquid bath so as to resist gravitational forces tending to distort the sensor tube and thereby misalign the magnetic axes of the sensors. The excitation conductors of the sensors are connected in series with an electrically conducting path formed through the sensor tube by spider members in electrical contact with the tube interior and connected to the respective excitation conductors.

Abstract: A device and method producing a compensated gradiometer signal from an uncompensated gradiometer signal having at least one unwanted term which varies as a function of magnetic field. The device is comprised of a sensing unit for sensing the magnetic field. A generator is provided for producing a first vector signal which is representative of the magnetic field. A function generator is provided for producing a second vector signal which represents a component of one of the at least one unwanted term. A mixer is connected to the generator and the function generator for producing a vector output signal which is equal to the one of the at least one unwanted term. Finally, a subtractor unit is provided which is connected to the mixing means for subtracting the output vector signal from the uncompensated gradiometer signal to thereby produce the compensated gradiometer signal.

Abstract: A magnetic field differential probe has field sensors located at spaced intervals along a tensilely stressed diamagnetic wire free of mechanical support between the sensors.

Abstract: 1. A method of correcting errors in the electrical characteristics of a tl field magnetometer after the magnetometer is tested and said errors are measured and resolved, which comprises correcting the core turnover errors in said total field magnetometer by replacing a pair of cores thereof with a new pair of cores having the same total reductance as the first pair and the difference in reductance of the replaced cores different than the difference in reductance of the cores which are replaced, and subsequently correcting the block misparabolism errors in said magnetometer by adjusting at least one of the cores of the magnetometer to a new angular setting thereof so that the indication of field strength will be within prescribed limits of accuracy.