Abstract: A hand-held through-skin (HHTS) sensor for determining the location of an underlying aperture in a support structure suited to mount a skin or surface. In an embodiment, the HHTS sensor includes a sensor disposed in a housing and configured to determine a location of an aperture disposed in an adjacent surface through electromagnetic, x-ray, ultrasonic or other means. The HHTS sensor further includes an alignment assembly having an alignment orifice disposed in the housing and configured to be maneuvered in an x-y plane within the housing. The HHTS sensor also includes a processor coupled to the sensor and configured to receive a signal from the sensor indicating the location of the aperture and configured to control first and second actuators to maneuver the alignment orifice within the x-y plane to be co-axially located with the aperture in response to the sensor signal.

Abstract: Electronic devices may be provided with compasses for detecting the Earth's magnetic field. Electronic devices may be provided with other electronic components. A compass may include a magnetic sensor and control circuitry configured to apply offsets or other compass calibration data to compass data to compensate for magnetic interference from the other electronic components. Other electronic components may include components such as cameras, auto-focus lens mechanisms, light sources, and displays. The control circuitry may be configured to apply compass calibration data that is specific to an electronic component and that is specific to an operational status of the component. The control circuitry may be configured to recognize a replacement electronic component and revert to an average compass calibration correction. The control circuitry may be configured to output interference-corrected compass data to applications running on the electronic device.

Abstract: A thermoelectrically cooled GMR sensor having a first thermoelectric layer with an array of nanowires, wherein the nanowires include a diameter of about 1 nanometer to about 1000 nanometers. A plurality of alternating layers of magnetic and nonmagnetic material are positioned over and extend the nanowires to form a GMR assembly. A second thermoelectric layer is positioned over the GMR assembly and extends the nanowires, such that the nanowires have a length of between about 100 nanometers and about 500 microns. Conductors are placed in contact with the first and second thermoelectric layers for connecting the thermoelectric layers to a voltage source.

Abstract: A calibration method for calibrating a compass system suitable for use in a vehicle includes sampling data points of a magnetic field with a magneto-responsive sensor and processing output signals of the sensor via compass circuitry. The compass circuitry includes an analog-to-digital converter for converting analog signals of the sensor to digital signals and a digital-to-analog converter for converting digital signals to analog signals that are supplied to the sensor for adjusting the sensor. The output signals of the sensor are adjusted to be within an operable range of an analog-to-digital converter via an initial calibration mode. After completion of the initial calibration mode, output signals of the sensor are processed to determine when the output signals are outside a range of the analog-to-digital converter. An output of a digital-to-analog converter is adjusted to reposition the output signals of the sensor to be within the range of the analog-to-digital converter.

Abstract: A compass compensation system is provided for automatically and continuously calibrating an electronic compass for a vehicle, without requiring an initial manual calibration or preset of the vehicle magnetic signature. The system initially adjusts a two axis sensor of the compass in response to a sampling of at least one initial data point. The system further calibrates the compass by sampling data points that are substantially opposite to one another on a plot of a magnetic field and averaging an ordinate of the data points to determine a respective zero value for the Earth magnetic field. The system also identifies a change in magnetic signature and adjusts the sensor assembly.

Abstract: A motion estimation method and system for a mobile body are provided. The method includes: obtaining magnetic field information from compass information of the mobile body; comparing the magnetic field of the mobile body with a predetermined value and determining whether a position of the mobile body belongs to a specific region according to the comparison result; and estimating a direction of the mobile body by determining whether a compass azimuth angle is used for direction estimation of the mobile body according to the determination result.

Abstract: In a magnetic data processing device, an input part sequentially inputs magnetic data outputted from a two-dimensional or three-dimensional magnetic sensor. The magnetic data is two-dimensional or three-dimensional vector data that is a linear combination of a set of fundamental vectors. The magnetic data processing device stores a plurality of the inputted magnetic data as a data set of statistical population in order to update an old offset of the magnetic data with a new offset. An offset derivation part derives the new offset based on the old offset and the data set of statistical population under a constraint condition that the new offset be obtained as the sum of the old offset and a correction vector.

Abstract: A compass compensation system is provided for automatically and continuously calibrating an electronic compass for a vehicle, without requiring an initial manual calibration or preset of the vehicle magnetic signature. The system initially adjusts a two axis sensor of the compass in response to a sampling of at least one initial data point. The system further calibrates the compass by sampling data points that are substantially opposite to one another on a plot of a magnetic field and averaging an ordinate of the data points to determine a respective zero value for the Earth magnetic field. The system also identifies a change in magnetic signature and adjusts the sensor assembly.

Abstract: A method for controlling an electronic compass includes receiving raw magnetic field data into a calibration module and determining a calibration output based upon the raw magnetic field data. The raw magnetic field data is also received into a compass heading module for determining compass heading outputs based upon the raw magnetic field data. The calibration module filters the raw magnetic field data and validates the calibration outputs independently from output data filtering and results validation in the compass heading module.

Abstract: A geomagnetic sensor which informs a user that information with respect to a distorted azimuth angle may be detected. The geomagnetic sensor includes a geomagnetism detection module including an X axis fluxgate and a Y axis fluxgate orthogonal to each other and detecting a predetermined amount of electrical signals corresponding to a geomagnetism of each of the fluxgates; a signal processing unit for converting the electrical signal output from the geomagnetism detection module to predetermined X axis and Y axis output values and outputting them; a display unit for displaying a predetermined warning message on a screen; and a control unit for determining whether the output values of the X and Y axes are distorted, and controlling the display unit to display the predetermined warning message upon determination that the output values are distorted. Accordingly, the possibility of a distorted azimuth angle may be detected and informed to a user.

Abstract: An electronic compass system includes a magnetic sensor circuit having at least two sensing elements for sensing perpendicular components of the Earth's magnetic field vector. A processing circuit is coupled to the sensor circuit to filter, process, and compute a heading. The processing circuit further selects an approximating geometric pattern, such as a sphere, ellipsoid, ellipse, or circle, determines an error metric of the data points relative to the approximating pattern, adjusts the pattern to minimize the error, thereby obtaining a best fit pattern. The best fit pattern is then used to calculate the heading for each successive sensor reading provided that the noise level is not noisy and until a new best fit pattern is identified. The electronic compass system is particularly well suited for implementation in a vehicle rearview mirror assembly.

Abstract: A compass compensation system is provided for automatically and continuously calibrating an electronic compass for a vehicle, without requiring an initial manual calibration or preset of the vehicle magnetic signature. The system initially adjusts a two axis sensor of the compass in response to a sampling of at least one initial data point. The system further calibrates the compass by sampling data points that are substantially opposite to one another on a plot of a magnetic field and averaging an ordinate of the data points to determine a respective zero value for the Earth magnetic field. The system also identifies a change in magnetic signature and adjusts the sensor assembly.

Abstract: A method for adjusting an electronic azimuth meter comprising the steps of performing a magnetic field generating sequence by generating a sequence of magnetic fields used for adjusting the electronic azimuth meter, the sequence of magnetic fields commencing with generation of a strong magnetic field having a magnitude larger than that of the Earth's geomagnetism, and providing, within the strong magnetic field, an electronic azimuth meter having a magnetic detector and a control unit for performing a data acquisition and adjustment process in response to detection of the strong magnetic field, so that the control unit commences the data acquisition and adjustment process when the strong magnetic field is detected and the electronic azimuth meter is not electrically connected to a magnetic field generating apparatus which generates the sequence of magnetic fields.

Abstract: The compass system of the present invention utilizes an improved calibration routine in which a processing circuit of the compass recalibrates the compass each time three data points are obtained from a magnetic field sensor that meet predetermined criteria. One such criterion is that the three data points define corners of a triangle that is substantially non-obtuse. When three data points have been obtained that define a triangle meeting this criterion, the processing circuit calculates a center point for a circle upon which all three data points lie by solving the equation 2+y2+Ax+By+C=0 for A, B, and C, using the coordinate values (x,y) for the three data points and defining the center point as (−A/2, −B/2).

Abstract: An electronic compass system includes a magnetic sensor circuit having at least two sensing elements for sensing perpendicular components of the Earth's magnetic field vector. A processing circuit is coupled to the sensor circuit to filter, process, and compute a heading. The processing circuit further selects an approximating geometric pattern, such as a sphere, ellipsoid, ellipse, or circle, determines an error metric of the data points relative to the approximating pattern, adjusts the pattern to minimize the error, thereby obtaining a best fit pattern. The best fit pattern is then used to calculate the heading for each successive sensor reading provided that the noise level is not noisy and until a new best fit pattern is identified. The electronic compass system is particularly well suited for implementation in a vehicle rearview mirror assembly.

Abstract: An electronic azimuth meter includes an electronic azimuth meter main body and X-direction and Y-direction magnetic sensors for detecting magnetic field components in orthogonal two directions of the main body, the main body includes a magnetic part magnetized by geomagnetism B0 for forming a magnetic field having components in oblique directions relative to directions of the geomagnetism at locations of the magnetic sensors, approximate equation storing means for storing pluralities with regard to respective directions X, Y, of approximate equations calculated based on magnetic field detected values Vx and Vy of the magnetic sensors with regard to a number of azimuths of the azimuth meter in geomagnetism having magnetic field components Bx and By, which are approximate equations representing relationships between the detected values Vx and Vy of the magnetic sensors and the magnetic field components Bx and By of the geomagnetism, and azimuth calculating means for calculating azimuth by selecting specific app

Abstract: An improved vehicle compass calibration obtains magnetic field data measurements from magnetic field sensors mounted in a vehicle. The magnetic field data measurements are stored in memory and, when a sufficient set of data measurements is stored, a calibration calculation attempt is carried out. When a predetermined vehicle accessory that produces a magnetic disturbance is activated, the storage of magnetic field data in memory is interrupted to disable the ongoing collection of data for use in a subsequent calibration calculation while the accessory remains activated.

Abstract: A three-axis algebraic model is used to numerically compensate for magnetic errors in measured magnetic field values in an electronic compass for any orientation of the compass. This model is based on physical principles and uses a linear algebra approach that facilitates computation of the parameters needed for compensation. During a calibration procedure of the electronic compass, magnetic and gravity fields are measured in three axes at each of a variety of combinations of orientations and azimuths. This set of measured magnetic and gravity fields is used to calculate a matrix compensation coefficient and a vector compensation coefficient using a system of equations. These compensation coefficients are stored and then used during normal operations of the electronic compass to correct all subsequently measured magnetometer data to obtain corrected values for the Earth's magnetic field, from which the correct azimuth can be calculated.

Abstract: A compass compensation system is provided for automatically continuously calibrating an electronic compass for a vehicle, without requiring an initial manual calibration or preset of the vehicle magnetic signature. The system initially adjusts a two axis sensor of the compass in response to a sampling of at least one initial data point. The system further calibrates the compass by sampling data points that are substantially opposite to one another on a plot of a magnetic field and averaging an ordinate of the data points to determine a respective zero value for the Earth magnetic field. The system also identifies a change in magnetic signature and adjusts the sensor assembly.

Abstract: A method for calibrating the attitude of a compass in relation to the platform on which the compass is installed. The compass includes an attitude determining device and an optical sighting device and the compass is integrally mounted on a platform. The method includes the steps of determining the angle between the optical sighting device and the attitude determining device, determining the attitude between the optical sighting device and the platform, and determining the attitude between the attitude determining device and the platform.

Abstract: A three-axis algebraic model is used to numerically compensate for magnetic errors in measured magnetic field values in an electronic compass for any orientation of the compass. This model is based on physical principles and uses a linear algebra approach that facilitates computation of the parameters needed for compensation. During a calibration procedure of the electronic compass, magnetic and gravity fields are measured in three axes at each of a variety of combinations of orientations and azimuths. This set of measured magnetic and gravity fields is used to calculate a matrix compensation coefficient and a vector compensation coefficient using a system of equations. These compensation coefficients are stored and then used during normal operations of the electronic compass to correct all subsequently measured magnetometer data to obtain corrected values for the Earth's magnetic field, from which the correct azimuth can be calculated.

Abstract: The compass system of the present invention utilizes an improved calibration routine in which a processing circuit of the compass recalibrates the compass each time three data points are obtained from a magnetic field sensor that meet predetermined criteria. One such criterion is that the three data points define corners of a triangle that is substantially non-obtuse. When three data points have been obtained that define a triangle meeting this criterion, the processing circuit calculates a center point for a circle upon which all three data points lie by solving the equation X2+y2+Ax+By+C=0 for A, B, and C, using the coordinate values (x ,y) for the three data points and defining the center point as (−A/2, −B/2).

Abstract: A system for calibrating an electronic compass for a vehicle of the type employing a Forward and Lateral magnetoresistive magnetic field sensor. As the vehicle changes headings, the system periodically samples and digitally stores the peaks of the sensor outputs. When the stored peaks indicate a minimum change in the output of the sensors, the system microcomputer calculates a “box” surrounding the subscribed arc of heading changes and computes the center of the “box” as the center of the locus of anticipated peaks for all quadrants and shifts the locus (i.e., “box”) to be within the domain of the A/D converter to prevent saturation, which could otherwise occur in the presence of strong remnant magnetic fields in the vehicle. The “box” is updated with each sampling of sensor outputs until the vehicle is eventually headed through all four cardinal compass headings, and the compass is then considered to be fully modeled in the microcomputer.

Abstract: The compass system of the present invention utilizes an improved calibration routine in which a processing circuit of the compass recalibrates the compass each time three data points are obtained from a magnetic field sensor that meet predetermined criteria. One such criterion is that the three data points define corners of a triangle that is substantially non-obtuse. When three data points have been obtained that define a triangle meeting this criterion, the processing circuit calculates a center point for a circle upon which all three data points lie by solving the equation x2+y2+Ax+By+C=0 for A, B, and C, using the coordinate values (x,y) for the three data points and defining the center point as (−A/2, −B/2).

Abstract: An electronic compass system for eliminating magnetic noise which is integrated with an instrument cluster. A vehicle accessory, such as a stepper motor, also located in the instrument cluster, generates a known, consistent, magnetic field of intensity sufficient to cause a static magnetic offset in the electronic compass for each of its' electrical states. A magnetic field sensor detects a combination of The Earth's magnetic field and this stray magnetic field. A controller uses a predetermined correction factor, corresponding to the electrical state, to eliminate the effect of the static magnetic offset. The controller then displays a heading unaffected by the static magnetic offset.

Abstract: An electronic compass system using magnetic signatures to detect a vehicle event which is integrated with an instrument cluster. A vehicle accessory, such as a rear defrost grid, generates a known, consistent, magnetic field of intensity sufficient to cause a static magnetic offset in the electronic compass for each of its' electrical states. This known consistent, magnetic field has a magnetic signature. A magnetic field sensor detects a combination of Earth's magnetic field and the stray magnetic field produced by the vehicle accessory. A controller is coupled to the magnetic field sensor and searches the magnetic field signal for the magnetic signature. The controller then looks up a predetermined correction factor, or uses an algorithm to determine a correction factor, corresponding to the magnetic signature, to eliminate the effect of the static magnetic offset. The controller then displays a heading unaffected by the static magnetic offset.

Abstract: A method for correcting yaw in a DGPS (global positioning system) based guidance system mounted on a vehicle. The method corrects for a yaw induced heading/cross track error due to a DGPS antenna being mounted a significant distance from the point of operation (e.g., the vehicle operator's location, the center of the vehicle, etc.). The method determines a ground track of a vehicle using a DGPS system and a coupled antenna mounted on the vehicle. A heading of the vehicle is also determined using a compass mounted on the vehicle. The heading and the ground track are compared to determine whether a difference exits and the magnitude of the difference. Using the difference, the DGPS determined position is adjusted to be the position of the operator/center of the vehicle. Using this guidance information, an indication is generated operable for directing the vehicle to maintain a desired ground track.

Abstract: A vehicular traveling direction measuring system derives a weighting constant based on a monitored magnitude of the geomagnetic disturbance around a vehicle. Variance values of geomagnetism indicative data and a deviation magnitude from a standard azimuth circle may be used to estimate the geomagnetic disturbance magnitude. Mean data is derived from current cycle data and prior cycle data of the monitored geomagnetism using the weighting constant. The weighting constant determines a rate of dependency upon the current cycle data and the prior cycle data when deriving the mean data. The vehicular traveling direction is derived based on the derived mean data.

Abstract: An electronic compass system and method in which an automatic calibration process is available while the vehicle is in use. The procedure uses a binning process to collect and count data points which automatically triggers the automatic calibration process, and which is also used for manual calibration. Also, there is a procedure for detecting and rejecting anomalous magnetic events outside the vehicle through a jitter phenomenon.

Abstract: A method for determining the direction of the Earth's magnetic field, which may be interfered with by magnetic materials built into equipment and by electric currents, using an electronic magnetic compass which contains three magnetic field sensors and two devices for measuring inclination is provided. The electronic magnetic compass is arranged in N different spatial positions, in each of these N positions, the inclination sensor signals and the magnetic field sensor signals being measured and inclination values and magnetic field values being determined from these signals. On the basis of these inclination values and magnetic field values, the magnitude of the Earth's magnetic field vector is determined using the vector equationconst=b.sub.g =b.sub.E sin(i)=g.sup.T L(b.sub.E)=g.sup.T m(b.sub.mes -b.sub.o)with ##EQU1## N having to be at least equal to the number of parameters to be determined in the vector equation.

Abstract: The invention relates to a method for determining correction parameters for the measured values of a magnetic compass, which is built into a land craft for navigation purposes, and gives the azimuth a of the direction of motion of the vehicle; of a gradiometer giving the elevation e of the direction of motion of the vehicle in relation to the horizon; and of an odometer, giving the distance s travelled. In this method, two visually navigated test drives are carried out in different directions between known point of departure and arrival. The measured values (a, e, s) are replaced by corrected values (a', e', s') in accordance with the following: a'=a+A+B.multidot.sin a+C.multidot.cos a; e'=e-A.sub.2 ; S'=.rho.. The correction parameters are determined by performing a vertorial comparison of the known direction and distance values (a', e', s') with the measured values.

Abstract: A method for converting distorted compass data values into corrected data values which employs linear transforms. A linear transform is formulated and programmed into the read only memory of the microcomputer of the electronic compass system. The microcomputer uses the linear transform to transform compass data readings distorted by ferrous metals in the environment of the vehicle into corrected data readings and then uses the corrected data readings to compute headings.

Abstract: A device for determining the orientation of a vehicle includes a magnetic field sensor (3) which is arranged in the vicinity of a ferromagnetic outer wall of the body of the vehicle and which is rigidly connected to the wall. External magnetic fields could unpredictably magnetize the wall portion (1) of the body, in the vicinity of which the magnetic field sensor (3) is provided, so that the measurements would become inaccurate. In order to achieve a substantial reduction of these adverse effects of external magnetic fields, the relevant wall portion is magnetically stabilized, preferably by including it in a magnetic circuit which also includes at least a magnet (11; 23, 27).

Abstract: In a direction detecting apparatus for a vehicle, when signals input from an earth magnetic sensor into calculating means are judged to be outside a predetermined judging area, an alarm for prompting magnetization correction is given, thereby the direction detecting apparatus can surely display the alarm at any case without the necessity to rotate the vehicle.

Abstract: When the body of an automobile equipped with a stand-alone navigation system is magnetized by an external magnetism, an unknown magnetization vector is determined by correcting the known magnetization vector. Even very small changes in the magnetization vector can be corrected without putting a burden on the user of the automobile. A magnetization vector directed from a reference position toward the center of a magnetic circle which indicates the magnetized condition of the automobile body is detected, and a geomagnetic vector which is directed from the reference position in the direction in which the mobile body progresses is detected. An instantaneous direction vector which is directed from the center of the magnetic circle in the direction in which the mobile body progresses and which has a direction angle is calculated.

Abstract: An electronic compass (10) having at least two sense windings (11, 12) is mounted in a vehicle. The outputs (x(h), y(h)) of the windings are measured for a number of compass directions (headings). From this data an error difference angle (.phi.), from a nominal angle, which actually exists between the output windings is calculated. Preferably a look-up table (21, 39) is created relating actual compass heading (h) to measured sense winding outputs by utilizing the calculated error difference angle (.phi.). This table is then utilized for calculating actual compass heading based on actual measured sense winding outputs. The calculated error angle (.phi.) can also be used to calibrate the compass without creating a look-up table. The calibrated compass compensates for misalignment of the sense windings and provides a more accurate electronic compass without requiring creating a calibration table by orienting the compass in a very large number of exactly known directions.

Abstract: A miniaturized electronic magnetic compass system, or the like, is mounted in a substantially cylindrical gimbal ring unit of about 0.75 in diameter, and 1.25 in length. Critical to the small size is the pendulum that positions the internal magnetic detector by gravity relative to the earth's surface. Thus, a pendulum formed of tungsten has its curved bottom surface formed of a central spherical surface and two flanking cylindrical surfaces meeting in two planes disposed at an angle intersecting with the pendulum axis of rotation. The mass of the detector is centered by resilient conductive spring plates bearing on gimbal pivot shafts, which also serve as electrical connectors for the detector. Thus, two separated shaft ends journalled in one gimbal ring, which is insulated to electrically isolate the shaft ends serve as two conductors. The gimbal system is damped in a perfluorocarbon oil.

Abstract: An apparatus and method for measuring a forward direction of a vehicle in which to derive a coordinate position of a center (O.sub.x, O.sub.y) of a directional circle derived from an output of a geomagnetic direction sensor after a magnetization on a vehicle body occurs, the magnetization on the vehicle body is determined from the output of the geomagnetic direction sensor installed in the vehicle and each parameter of a peak quantity (X.sub.max, Y.sub.max), peak direction (D.sub.x, D.sub.y), and a center value of an output circle before the present disturbance occurs is calculated, optimum coefficients are selected and set according to each parameter from among the previously derived coefficients, a magnetization quantity is calculated from each parameter and each optimum coefficient using a linear combination technique, and the coordinate position of the center of the output circle after the magnetization on the vehicle body occurs from the derived magnetization quantity.

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: 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 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: 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 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: An electronic compass for vehicles comprising three magnetic sensors arranged in use to be respectively responsive to orthogonal components of a magnetic field which includes the earth's magnetic field and a spurious magnetic field which is associated with the vehicle, for producing electrical signals corresponding to said components, tilt sensor means responsive to vehicle tilt with respect to the horizontal plane, data processor and storage means arranged to store signals derived from the sensors as the vehicle is turned through a compass setting cycle, and signal processor means responsive to electrical signals produced by the sensors after the setting cycle has been completed and to the signals stored during the setting cycle, for providing compensated signals related to the bearing appertaining to the heading of the vehicle in which the effects of the spurious magnetic field are compensated for and further processor means to which the compensated signals are applied and which is responsive to the tilt se

Abstract: A heading detecting apparatus of the type which is installed in a roof of a vehicle including a magnetic member (a steel body) capable of having a remanence and includes a heading sensor positioned near the magnetic member, whereby the apparatus detects the terrestrial magnetism and thereby detects the forward heading of the moving objects the apparatus includes a permeability member positioned between the magnetic member and the heading sensor so as to reduce the effect of the remanence of the magnetic member on the detection of the terrestrial magnetism by the heading sensor.

Abstract: Mounting structure for a flux-gate sensor used in electrical digital compass for a vehicle includes a cradle assembly for pivotally mounting the sensor for adjustable movement in a vertical plane aligned with the longitudinal axis of a vehicle. A housing includes an arm engaging the cradle assembly for automatically pivoting the sensor to a horizontal position when installed in different vehicles.

Abstract: A magnetometer compensation scheme wherein a magnetizable material adjacent the magnetometer is given a certain permanent magnetization to cancel the effect of the earth magnetic field at the location of the magnetometer.

Abstract: In a correction system for a magnetic field probe, the probe is first moved in a circle for calibration such that respective maximum and minimum values of a measured magnetic field vector or a respective component thereof is determined. By means of a sum formation and halving of the respective maximum and minimum value, a respective additive correction value is derived which is added to the respective measured values during navigation with the magnetic field probe. By so doing, a noise vector superimposed on the external magnetic field is eliminated.

Abstract: The present invention relates to a process for compensating the magnetic disturbances influencing the measurements of a device for determining the magnetic heading, mounted on a land vehicle or aircraft, comprising a magnetometer furnishing analog voltages proportional to the components of the disturbed magnetic field of the earth along its reference axes. It is admitted that the locus of the end of the vector indicative of the field is an ellipse for a land vehicle and an ellipsoid for an aircraft, of which identification from the analog voltages and transformation into a circle or sphere centered at O, origin of the axes of the magnetometer, enable correction coefficients to be calculated which are introduced into the memory of a computer unit associated with the magnetometer in order to define at any instant a vector making with a reference axis of the magnetometer an angle corresponding to the real magnetic heading of the vehicle or of the aircraft.

Abstract: In a magnetic data processing device, an input part sequentially inputs magnetic data outputted from a two-dimensional or three-dimensional magnetic sensor. The magnetic data is two-dimensional or three-dimensional vector data that is a linear combination of a set of fundamental vectors. The magnetic data processing device stores a plurality of the inputted magnetic data as a data set of statistical population in order to update an old offset of the magnetic data with a new offset. An offset derivation part derives the new offset based on the old offset and the data set of statistical population under a constraint condition that the new offset be obtained as the sum of the old offset and a correction vector.