Abstract: Apparatus and method for determining the azimuth (heading), pitch and roll which include a magnetometer-type sensor providing signals measured in three axes relative to a reference frame, and coil elements wound around the magnetometer which selectively impose specific magnetic fields about the sensor. Three axes field components of the magnetic field are measured from the sensor with and without the selective energization of the magnetic coils and stored, from which the azimuth, pitch and roll are calculated. Furthermore, quadrant correction is applied such that a unique reading is produced for all angles through 360.degree. of azimuth, pitch or roll.

Abstract: Disclosed is an electronic magnetic compass which is to be mounted on a small ship and which is reduced in cost and improved in performance. The electronic magnetic compass is provided with an angle sensor interlocked with a compass card so as to produce a code signal at every predetermined angle, a code converter for converting the code signal into a compass indication angle, and a signal conversion circuit for producing a deviation signal indicating a deviation between an azimuth angle signal and an indication angle signal. The compass azimuth measurement is performed with a simple configuration of an open loop system, so that the structure of an encoder for the angle sensor is so simple that the cost can be reduced so much. The azimuth angle signal and the indication angle signal can be automatically calibrated so that the measurement accuracy can be improved.

Abstract: An electronic compass system for determining the heading of an armored vehicle containing a large mass of ferromagnetic material, which system comprises a plurality of sensors, and for real-time computation of the corrections required of actual magnetometer measurements. Part of the values used for the computation are computed in advance, and part in real-time. Some of the computations are based on the perturbation of the earth magnetic field based on an algorithm which takes into account one or two rotational prolate ferromagnetic ellipsoids which have certain dimensions and which are at a predetermined distance from each other either represent the body of an armored vehicle, or when two ellipsoids are used, they represent the hull and turret of a tank.

Abstract: A digital compass system for use in a wide variety of motor vehicle models, especially in the automotive aftermarket, and including various features which simplify installation and calibration by non-professionals. A knowledge of magnetic direction is not required. During calibration, only true geographic directions are used throughout. While searching for a suitable location within the vehicle to mount the magnetic sensor, the installer is advised by the digital display unit of the system as to whether or not a given location contains excessively strong magnetic components.

Abstract: Vehicle position determining apparatus (10) uses dead reckoning to calculate new vehicle position and heading (A2, H2) based on prior position and heading (A1, H1). Computer (11) separately calculates heading changes (.DELTA.H.sub.od, .DELTA.H.sub.c) as measured by a pair of differential wheel sensors (16, 17) and a magnetic compass (15) and uses these heading changes to calculate assoicated lateral accelerations of the vehicle (LA.sub.od, LA.sub.c) over a time and/or distance interval (.DELTA.t, .DELTA.d). If calculated lateral acceleration, or rate of vehicle turn, exceeds a maximum predetermined limit value, and this is therefore indicative of unstable or improbable vehicle operation, heading change data which resulted in calculation of excessive lateral acceleration is probably erroneous and will not be substantially utilized to calculate new vehicle position and heading.

Abstract: In an electronic compass having a plurality of sensors (1, 2, 3), each reacting to a component of the earth field (Hy), it is desired to prevent errors based on variations in the signal amplification and to improve the accuracy of measurement. In accordance with the invention, three identical sensors (1, 2, 3) are disposed at an angle of 120.degree.. The compass may be used, in particular, for the navigation of vehicles.

Abstract: A system for automatically compensating for changes in permanent magnetism in a vehicle in which a flux-gate compass is installed. Calibration is initially performed by rotating the vehicle through a full circle and determining from the flux-gate outputs the degree of distortion suffered by an ideally circular performance characteristic. Subsequent flux-gate readings are compensated in accordance with parameters generated during calibration. Parameters relating to offset or displacement of the characteristic are automatically and continually updated to compensate for changes in permanent magnetism of the vehicle, such as might be caused by loading or unloading the vehicle.

Abstract: A system measures a traveling direction of a vehicle based on a direction toward a coordinate position defined by outputs of a geomagnetic sensor from a first coordinate position of a center of a corresponding output circle. The system utilizes a preliminary coordinate position as a preliminarily corrected value of the first coordinate position, a first value indicative of accuracy of the preliminary coordinate position and a second value which is variable depending on a variation in a magnetization level on a vehicle body. The system derives a finally corrected value of the first coordinate position based on the preliminary coordinate position and a latest value of the finally corrected value which has been derived in a prior execution of the system, by changing a rate which determines a point of the current finally corrected value between the latest finally corrected value and the preliminary coordinate position.

Abstract: A method for determining the north direction or the travel direction of a vehicle having an electronic compass is proposed by means of which field disturbances at the magnetometer of the compass, occurring during the navigation drive, are measured and evaluated for avoiding angle errors on the direction indication of the compass. For this purpose, the measurement values (Px, y) of the magnetometer are continuously checked by an evaluating circuit of the navigation system and with a deviation (.DELTA.x, y) of several successive measurement values past a predetermined tolerance range (A) of the locus diagram and a simultaneous angle change of the earth's magnetic field vector, an intervention is effected in the direction indication. In this connection, according to the invention, the rate of change (.DELTA..zeta.

Abstract: Apparatus and method for determining the azimuth (heading), pitch and roll which include a magnetometer-type sensor providing signals measured in three axes relative to a reference frame, and coil elements wound around the magnetometer which selectively impose specific magnetic fields about the sensor. Three axes field components of the magnetic field are measured from the sensor with and without the selective energization of the magnetic coils and stored, from which the azimuth, pitch and roll are calculated. Furthermore, quadrant correction is applied such that a unique reading is produced for all angles through 360.degree. of azimuth, pitch or roll.

Abstract: A method for determining the direction of the earth field, the north direction and the travelling direction of a vehicle by way of a magnetometer mounted in the vehicle is based on dynamic compensation or updating of interfering field changes. For this purpose, a resultant vector (v.sub.K) is formed from the magnetic field vector (V.sub.M) effective at the magnetometer, the previous hard-magnetic interfering field vector (H.sub.H) and the nominal vector (V.sub.P) determined from the circle diagram (O) of the magnetic field, as interfering field change in accordance with the equation v.sub.K =V.sub.M -v.sub.B -H.sub.H and this vector is weighted with a factor (k<1). The weighted resultant vector (K.times.v.sub.K) is then added to the previous interfering field vector (H.sub.H). Using the new hard-magnetic interfering field vector (H.sub.H'), thus determined, the direction of the earth field is then calculated in known manner and evaluated for navigation.

Abstract: A hybrid robotic vehicle is provided for use in environments which are hazardous to humans, the vehicle being adapted to carry a payload for use in viewing the area or acquiring other types of sensory data. The hybrid robotic vehicle has a main body and four appendages or legs, each of which has a wheel assembly and a track assembly, and is configured to operate having three degrees-of-freedom about one vertical and two horizontal axes, the three degrees-of-freedom permitting improved capability to cross obstacle-strewn terrain, as well as to traverse inclined surfaces while maintaining the main body and its payload in an upright and level attitude.

Abstract: In an azimuth signal generator for an automobile navigation system a change in the rotational rate of an inertia rotary member, which has its rotary shaft held vertically and is driven at substantially a constant speed, is detected as a direction changing rate of the car and the direction changing rate is integrated by an integrator to obtain an azimuth signal. On the other hand, the azimuth of geomagnetism is detected by a geomagnetic azimuth sensor and a correcting signal is produced based on an error between the azimuth signal and the geomagnetic azimuth signal. The correcting signal is negatively feedback to the input side of the integrator, causing the azimuth signal to follow the geomagnetic azimuth signal.

Abstract: The present invention is a magnetic field measuring system and method for generating a magnetic field signal representative of the Earth's undistorted magnetic field at any given spatial location over a measurement period. The measured undistorted magnetic field is substantially independent of distortions due to any magnetically susceptible material within the measuring system and is substantially independent of internal magnetic fields generated by magnetic field sources within the system.

Abstract: A vehicle compass includes a magnetic field sensor for mounting within a vehicle and providing two output channels of information representing orthogonal direction sensing of the earth's magnetic field within the vehicle. The sensor is coupled to an electrical circuit including a microprocessor for sampling the data from each of the two channels and providing a plurality of tests to determine if the rate of change of data is within a prescribed limit thereby indicating valid data is being received. Further, the data is tested to determine the maximum and minimum signal levels during movement of the vehicle through a completed 360.degree. path of travel and for calculating therefrom the compass compensation information used to provide a corrected heading display.

Abstract: A magnetic compass is disclosed which is especially adapted for use in automotive vehicles and which is provided with an optical angular position encoder. The housing comprises a cylindrical cup and a hollow cylindrical rim; a compass rotor is disposed in the housing with the magnet in the cup and an encoder disk in the rim. The hollow rim has a base plate defining a vehicle orientation axis and a cover plate. The rotor is provided with a reference position aperture and a plurality of displacement angle apertures disposed in a single circumferential track. The transducer comprises optical transmitters and receivers mounted opposite each other on the plates for detecting the apertures in the encoder disk. Support arms for the compensation coils and the search coil are disposed on the cup opposite the magnet in a predetermined angular location relative to the orientation axis.

Abstract: The invention provides various methods for detecting the bearing of a moving vehicle and of processing data in a vehicular navigation system. Provided there is carried out a process of recognizing the present position of the vehicle while the vehicle is moving at a predetermined speed, bearing data obtained from a prestored map is utilized to determine the present position of the vehicle. At that time, the data output from a terrestrial magnetism sensor, which would otherwise be used, is discarded.

Abstract: An apparatus for displaying a travel path of a running body in which a direction detector includes a geomagnetism sensor as well as a rate-type sensor, such as a gyroscope or gas rate sensor (which includes a flow sensor for detecting a degree of displacement of a gas flow produced by an angular velocity applied thereto) for detecting an angular volocity of change of yawing direction of the moving body, in which a difference in angle between directions detected by the rate-type sensor and the geomagnetism sensor is found and temporarily stored when a power source is temporarily turned OFF during operation of the running path displaying apparatus, and then a declination of the direction detected by the geomagnetism sensor is corrected, depending upon the stored difference in angle, when the power source is turned ON again.

Abstract: A method for the determining route angle and for automatically calibrating course accuracy with a three-axis magnetometer fixed to an aircraft despite the presence of interfering vehicle magnetic fields and instrumentation errors. The method is accomplished in flight and includes numerous computations to compensate the magnetometer's principal error sources. A calibration flight includes specified flight maneuvers (without change of position). The method is particularly suitable for helicopters equipped with three-axis magnetometers.

Abstract: A direction finder includes a terrestrial magnetism sensor, a magnetization correction means for correcting an output of the sensor with a magnetic field component produced by a vehicle itself on which the sensor is mounted and a correction amending means for amending a corrected output on the basis of coordinates of a cross point of a line extending perpendicularly from a coordinates corresponding to a correction amount produced by the magnetization correction means onto a perpendicular bisector of a line segment connecting two coordinates points obtained by the sensor at different time instances.

Abstract: A compass and method of operation are disclosed for finding the heading of a vehicle. The heading is found using a compass having a rotor with a compass magnet thereon and means on the rotor defining a reference line in known relation with the polar axis of the magnet. The angular displacement of the rotor is measured between alignment with the direction reference axis and alignment with the local magnetic field. A search coil is used to torque the rotor so that it reaches a reference position in which the reference line thereon is aligned with the direction reference axis. A reference position encoder generates a pulse when alignment is achieved. An angular displacement encoder produces a digital signal which changes with each predetermined increment of rotation of the rotor and which is indicative of the direction of rotation. A microcomputer processes the signals to provide a cumulative count of the increments of rotation.

Abstract: In a location detecting apparatus which detects the location of a moving body on the basis of the heading signal from a terrestrial magnetism heading sensor attached to the moving body and the rotational angle signal from a rotational angle sensor attached to the moving body, a correcting method for correcting errors in a terrestrial magnetism heading sensor, comprising the steps of: detecting the amount of a heading change of the moving body that is made when the moving body turns a curve, and detecting a magnetized amount of the moving body on the basis of the detected amount of a heading change, an output from the terrestrial magnetism heading sensor before the heading change is made and an output from the terrestrial magnetism heading sensor after the heading change is made.

Abstract: A direction finder is disclosed, which comprises a locus amending means which operates such that, when corrected detection signal pairs obtained by correcting detection signal pairs after an initial correction on the basis of coordinates value of a center of an ellipsoidal locus and radii thereof in x and y directions are not on a circle in a perpendicular coordinates system corresponding to the ellipsoidal locus, distances from the circle to the coordinates of the corrected detection signal pairs are divided into perpendicular coordinates components as vector component pair and the center coordinates of the ellipsoidal locus and radii thereof are amended and updated on the basis of the vector component pairs and radii, the magnetism detection signal being amended with using these amending values.

Abstract: A direction finder includes a correction amount amending means which amends automatically correction amounts necessary to cancel out an influence of varying magnetization field of a vehicle on the basis of magnetic detection signals obtained before and after the vehicle changes its moving direction by an angle larger than a predetermined value.

Abstract: A geomagnetic sensor used for vehicle-mount navigational apparatus outputs data indicative of the vehicle's direction. If the output data from the geomagnetic sensor is out of a predetermined range, the data is replaced by predetermined data or corrected on the basis of the predetermined data.

Abstract: The method and system described herein calls for the calibration of an electronic compass without using the operator of the vehicle in the process. This eliminates the need for the operator of the vehicle to help to supply information relating to the earth's unknown magnetic field as sensed from the frame of reference of the vehicle in which the electronic compass resides. The method does not need to make use of the unknown magnetic field due to the earth (as sensed from the frame of reference of the vehicle in which the electronic compass resides) in the process of automatically calibrating the compass. This magnetic field, although unknown, is utilized by viewing the position of the vehicle with respect to the earth's field, thereby eliminating the effect on the compass computation of the earth's magnetic field as sensed in the vehicle.

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 compass dither device for use with a magnetic compass heading sensor unit for marine seismic streamers and the like having interrogating circuitry associated with the heading sensor to periodically provide a trigger pulse for interrogating a compass heading sensing components in the heading sensory unit and provide compass heading signals indicative of the heading of the compass the the time of interrogation, the compass dither device including a housing for the magnetic compass heading sensor unit having a dither coil encircling the portion where the headings sensory unit is positioned.

Abstract: An electronic compass and method. The electronic compass includes circuitry for generating a control signal and circuitry responsive to the control signal for producing reference signals having a frequency established by the control signal. The compass also includes circuitry for phase shifting the reference signals to generate an output signal shifted by a phase shift which is a function of the angle between a reference heading of the compass and the direction of the magnetic flux lines of the earth's magnetic field in a local area. Further, the compass includes circuitry for monitoring the frequency of one of the reference signals, for varying the control signal to thereby cause reference signals having a predetermined frequency, and for measuring the phase shift between the monitored reference signal and the output signal to calculate the angle between the heading of the compass and the direction of the magnetic flux lines of the earth's magnetic field in a local area.

Abstract: In a navigation device for land vehicles the orientation signal which indicates the direction of movement along which the vehicle is moving is measured on the one hand by an electronic compass. A further orientation signal is produced by the variation of the vehicle orientation as determined by wheel sensors. These two orientation signals comprise measuring errors. In order to determine an optimum value for the orientation from said values a digital filter unit is used which comprises low-pass and high-pass filters. The value for the orientation signal measured by the compass is presented to the input of the low-pass filter and the further orientation signal is presented to an input of the high-pass filter. The filter unit further comprises a control unit which generates a filter parameter from received orientation signals and supplies said filter parameter to the low-pass filter and the high-pass filter.

Abstract: To determine the optimal location for a magnetic field sensor in a navigational system in a vehicle, the field sensor is preliminarily and releasably secured at a first location in the vehicle, and then the vehicle is rotated by 360.degree., for example by moving it in a circular course. An evaluation circuit is connected to the field sensor which determines the maximum or minimum value of the entire field vector (H.sub.x, H.sub.y). The level of the disturbance field (Hs.sub.x, Hs.sub.y) is determined by carrying out the calculation by adding half of the respective maximum and minimum values in the respective vectorial directions. The steps are then repeated with a different location of the sensor and, when a minimum disturbance field is determined, the sensor can be secured to the vehicle.

Abstract: A correction apparatus for an azimuth calculation system which includes an azimuth sensor mounted on a moving body for producing two mutually perpendicular magnetic field components relative to the earth's magnetism acting thereon, and wherein the azimuth sensor is moved in a full circle so that an azimuth circle is formed by the two magnetic field components.

Abstract: A quick ranging technique controlled by a microcomputer, makes predetermined stepped adjustments to the charge times in a ranging circuit to bring the charge time into a required range, thusly minimizing calibration time for an electronic compass; a digital filter also controlled by the microcomputer smooths out the magnetic field component signals.

Abstract: A hybrid navigation system for determining a relative position and direction of a vehicle and method therefor. In the hybrid navigation system and method, a magnitization quantity on a vehicle body which affects an output detection result of a geomagnetic sensor is calculated on the basis of a forwarding direction data derived from such as a GPS (Global Positioning System) absolute position calculating circuitry. Furthermore, in order to prevent an erroneous determination of the relative position and direction of the vehicle, the calculation on the relative position and direction of the vehicle on the basis of the detection result of the geomagnetic sensor is halted when the vehicle does not run on a straight road.

Abstract: A method for establishing the driving direction of a motor vehicle is suggested with an electronic compass which is provided with a magnetometer having two probes being turned by 90.degree. with respect to each other and an evaluation circuit. For establishing the ground field (He) and its angle (.phi.') in a vector diagram (X,Y) at first the measuring points (M1 . . . M4) with the maximum and minimum values (x,y) of the elliptical polar frequency (O) of the magnetic field (H) measured on the magnotemeter by turning the vehicle are picked up and from this the vector of a fixed interference field (Hs) with the coordinates of the center point (P) is established as a parameter of the polar frequency (O). Thereafter, the measuring points (M5 . . . M8) of the magnetic field (H) with the maximum and minimum distances of the points on the polar frequency (O) with respect to its center point (P) are picked up and from this the length of the semiaxis (a,b) are established as parameters of the polar frequency (O).

Abstract: Disclosed is an apparatus generating accurate data regarding the heading of a land vehicle as it travels over terrain having changing conditions. The apparatus includes a first sensor means, such as a differential odometer, generating data regarding the relative direction of the vehicle. Also included is a second sensor means, such as a flux gate compass, for generating data regarding the absolute direction of the vehicle relative to the earth. The relative directional data and the absolute directional data are combined in a means for generating accurate data regarding the heading of the vehicle. A means for reducing errors reflected in signals generated by the sensors is provided to insure the accuracy of the output.

Abstract: To calibrate a electronic compass provided with a magnetometer and being fixedly mounted in a motor vehicle the magnitude, and direction of interference magnetic field must be determined. For this purpose, a constant magnetic field Hg containing an earth's field component He' and the interference field component Hs, is measured by the magnetometer in a first position of the vehicle (Hg1) and then in a second position (Hg2) in which the vehicle is turned by 180.degree.. From the measured constant field magnitudes and directions, (Hg1, Hg2) the interference field component Hs is calculated according to vector equation H.sub.s +1/2 (Hg 1+Hg 2).

Abstract: In a process for establishing the driving direction of a vehicle by an electronic compass fixedly mounted in the vehicle and which is provided with a magnetometer having a computerized evaluation circuit the local curve (O) of the earth field (He) is determined from five measuring points (M1 . . . M5) which are established by turning the vehicle and corresponding signals are stored. The parameters for the center point displacement (Hs), the shape (ellipse) and the turning (angle .alpha.) of the local curve (O) in the vector diagram (x,y) are calculated by the computer by means of an algorithm with five unknowns for the five measuring points and thereafter the direction of the earth field (He) is computed. Subsequently, the vehicle is oriented to a predetermined cardinal direction and a correction angle is determined from the difference of angles between the cardinal and north directions and the earth's magnetic field direction measured by the compass.

Abstract: A process for correcting inclination dependent angle errors when establishing the driving direction of vehicles with an electronic compass for navigation is suggested. The compass comprises a magnetometer (10) with an evaluation circuit (11) for computing the driving direction. For compensating inclination dependent angle errors on the indicator of the drive direction the inclination angle of the earth field is fed into the evaluation circuit (11) as a calibration dimension (E), subsequently the inclination angle (.psi.) of the vehicle is established cyclically by means of an inclination measuring device (12) and then the corrected driving direction (.theta.) is established from the computed driving direction (.theta.') as well as from the calibration dimension (E) and the angle of inclination (.psi.) in accordance with the equation .theta.=f (.theta.',.psi.,E). This corrected driving direction can then be further processed or issued to an indicator (13) (FIG. 1).

Abstract: A calibration sequence and method for use with an electronic compass which allows for the separation of the vehicle's magnetic field from the earth's magnetic field so that the earth's field can be measured and used to give vehicle direction; such calibration sequence being done with a mirrored 180 degree re-orientation of the vehicle.

Abstract: A method and apparatus for providing a magnetic compass, and system to accurately calibrate the compass with a rotation of the vessel on which the compass is mounted through a single rotation of 360 degrees. The compass comprises gimballed field sensing elements, and processor to provide a signal which is corrected for compass offsets, for permanent magnetic field anomalies and for induced magnetic field anomalies.

Abstract: An electronic magnetic compass for computing the magnetic heading of a vehicle, such as a tank, having two iron bodies relatively movable with respect to each other about a vertical rotary axis comprises: a non-pendulous triaxial magnetometer outputting magnetic field electrical signals representing the three axial components of the magnetic field at the location of the magnetometer; sensors outputting electrical signals representing the pitch and roll of the vehicle body on which the sensors are mounted; an angle measuring device for outputting electrical signals corresponding to the angle of rotation between the two bodies; a memory for storing a plurality of pre-calibrated correction factors for correcting the effects of the permanent magnetic field and the induced magnetic field on the measurements of the magnetometer for each of a plurality of angles of rotation between the two bodies; and an electronic computer for computing on a real-time basis the magnetic heading of both bodies from the magnetic fiel

Abstract: An aircraft heading correction system utilizing the horizontal field strength of the earth's magnetic field to determine the tangent of the dip angle generally associated with a given field strength. The tangent of the dip angle is then used to generate a signal which corrects the flux valve heading during accelerated flight.

Abstract: Multiplexing a bandpass filter circuit to work with a flux-gate sensor output to minimize the amount of electronic circuitry required to work with the control system and to reduce the effect of gain on the circuit by emphasizing repeatability.

Abstract: A direction detecting system comprises a geomagnetic field sensor for detecting the direction of the earth magnetism by two perpendicular components and a computing circuit for computing a direction and producing a direction signal from the electrical signals associated with the two perpendicular components from the geomagnetic field sensor. The computing circuit detects maximum values of distortions according to the distortion characteristics of the electrical signals associated with the two perpendicular components from the geomagnetic field sensor. Distortion amounts are computed and stored by the maximum distortion values and are used to correct the electrical signals from the geomagnetic field sensor.

Abstract: A correction method for a geomagnetic field sensor (11) of a bearing indication system (10) mounted on a vehicle including a signal processor (13) for processing an output signal (Vx, Vy) of the sensor. The signal processor includes a storing function (15), comprising steps of storing the output signal of the sensor as data (6) of the bearing of the vehicle, while the vehicle is traveling, and computing a bearing correction vector (Xoff, Yoff) for correcting the output signal of the sensor on the basis of the stored bearing data. When the vehicle is judged to be subjected to a strong magnetic field, the bearing data stored may be all cleared. The bearing correction vector may be updated each time when a predetermined period of time is elapsed or the vehicle has traveled a predetermined distance.

Abstract: A magnetic compass comprises: a gimbal mounted direct read card supported on a bearing in the equatorial plane of the compass in a compass bowl; and a housing having a base to which the compass bowl and corrector magnets are mounted; the corrector magnets being positioned above the base beside the bowl for access without moving the compass; means for supporting the corrector magnets located on three axes, one axis parallel to the lubber line and the equatorial plane of the compass in a horizontal orientation of the housing, a second normal to the lubber line and parallel to the equatorial plane and a third normal to the equatorial plane in a horizontal orientation of the housing and parallel to the lubber line and the equatorial plane in a vertical orientation of the housing; said corrector magnets mounted on two of said axes, said second axis and the one of said first and third axes parallel to said lubber line in the horizontal or vertical orientation selected for mounting said compass; the compass card ass

Abstract: A remote indication compass, a sensor of which is formed by a magnetic compass (1) and magnetoresistive sensors (2) attached thereto, by means of which sensors the field created by the magnetic compass is measured. The signal of the sensors is analogous as well as cyclic with respect to the angle between the fastening plate of the sensors and the northern direction indicated by the magnetic compass, the length of a cycle being 360.degree.. The angle between the sensors is selected in such a manner that the flat areas of the signals do not coincide.The sensor signals are amplified and digitalized and scaled. The determination of direction is carried out by comparing the sensor readings to tabulated sensor readings corresponding to different directions or alternatively by comparing the ratio of the sensor readings to the ratios of the tabulated sensor readings. The direction data so obtained is further corrected by means of a deviation correction table created in the operating condition and stored in a memory.

Abstract: A technique is provided to combine software and hardware; the hardware being used to place voltage levels into narrow ranges and the software being used to perform the precise calibration.

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.