Abstract: A system and method of determining a magnetic field and magnetic compass calibration is disclosed. One embodiment is a method of determining a magnetic field vector, the method comprising storing, for each of a plurality of sensor orientations, one or more calibration components, determining, for a sensor orientation not included in the plurality of sensor orientations, a magnetic field vector and a gravity vector, iteratively estimating one or more calibration coefficients based on the stored components, the determined magnetic field vector, and the determined gravity vector, wherein the calibration coefficients are updated during each of a plurality of iterations, and determining a sensor-orientation-independent magnetic field vector based on at least one of the calibration coefficients.

Abstract: Calibration systems and methods simultaneously calibrate a magnetic compass and gyroscopes. An exemplary embodiment rotates the field calibration system. Based upon the rotation sensed by the magnetic compass and the gyroscopes, the field calibration system determines compensation for both the magnetic compass and the gyroscopes.

Abstract: The invention relates to a method for defining a compass direction by means of an electronic compass device. In the method at least two field components of an external magnetic field are measured, from which a set of data points is formed, which correspond to the different orientations of the device relative to the external magnetic field, so that the location of the data points in a set of co-ordinates depends on the Earth's magnetic field and the magnetic disturbances of the environment. From the data points it is determined whether the set of data points correspond to a measurement, in which the device has remained on the horizontal plane with a predefined accuracy, or the tilting of the device is detected relative to the horizontal plane during measurement and the set of data points is corrected to correspond to a measurement in which the device has remained on the horizontal plane with a predefined accuracy.

Abstract: A nanowire magnetic sensor and position sensor for determining the position of a magnetic object and direction of magnetic field is disclosed herein. The magnetic compass includes a number of magnetic nanosensor printed on a flexible substrate, which covers 360-degree angle at equal intervals. Each magnetic nanosensor generally includes magneto-resistive nanowires with high magnetic sensitivity printed in sets e.g. of ten on the flexible substrate. The flexible substrate can also be bent to form a circular configuration to detect the azimuth direction of the magnetic field. The individual nanosensors can be connected into resistive Wheatstone bridge configurations by metalization. The magnetic nanosensors can be utilized as a position sensor of a magnetic object for position determination. Additional electronics can also be mounted or printed on the flexible substrate from other type of nanowires.

Abstract: A parameter related to the Earth's magnetic field can be used to determine accuracy of a magnetometer of a mobile device. In one aspect, a first instance of a parameter related to Earth's magnetic field is determined using data generated by the magnetometer. The magnetometer data can be based in part on a position of the mobile device with respect to the Earth. A second instance of the parameter can be determined using data generated by a model of Earth's magnetic field. The model data can also be based in part on the position of the mobile device with respect to the Earth. The first instance of the parameter can be compared with the second instance of the parameter. An accuracy metric for the magnetometer can be determined based on a result of the comparison. An indication of the accuracy metric can be presented by the mobile device.

Abstract: An apparatus and method for compensation of the effects of various bias errors encountered by inertial rate gyroscopes, particularly vibrating element gyroscopes, configured to detect heading relative to true north. Certain embodiments are suitable for reducing rotational dynamic errors associated with rotating gyroscopes. Other embodiments may include compensation of biases not related to rotational dynamics, such as thermal drift. The various methods disclosed may also account for the bias by sampling the rotational vector of the earth at an arbitrary heading, and at a heading that is 180° offset from the arbitrary heading. The sequence may be repeated numerous times to compensate for bias drift. The bias drift may be constant with respect to time (linear) or changing over time (non-linear) during the data acquisition sequence. Some embodiments include methods that utilize data from accelerometers to infer the bank and elevation angles as well as earth latitude location relative to the equator.

Abstract: Provided is a hybrid sensor module including first and second sensors that are attached on one surface of a printed circuit board (PCB) so as to detect two-axis signal components parallel to the PCB; a third sensor that is attached on one surface of the PCB such that the axial direction of the third sensor is tilted at a predetermined angle from a vertical direction of the PCB, the third sensor detecting a signal component sensed in the axial direction; and a signal correction unit that is connected to the first to third sensor and corrects signal components, detected from the respective sensors, into signal components of an orthogonal coordinate system.

Abstract: A parameter related to the Earth's magnetic field can be used to determine accuracy of a magnetometer of a mobile device. In one aspect, a first instance of a parameter related to Earth's magnetic field is determined using data generated by the magnetometer. The magnetometer data can be based in part on a position of the mobile device with respect to the Earth. A second instance of the parameter can be determined using data generated by a model of Earth's magnetic field. The model data can also be based in part on the position of the mobile device with respect to the Earth. The first instance of the parameter can be compared with the second instance of the parameter. An accuracy metric for the magnetometer can be determined based on a result of the comparison. An indication of the accuracy metric can be presented by the mobile device.

Abstract: Measurement data is collected from a magnetic sensor in a portable device, while the device is being carried by its end user and without requiring the end user to deliberately rotate or position the device while the output data is being collected. For example, the device may be held in the user's hand while walking or standing, or it may be fixed to the dashboard of an automobile or boat. Measurement data may also be collected from one or more positing, orientation or movement sensors. The collected measurement data from one or both of the magnetic sensor and the position, orientation or movement sensor is processed. In response, either a 2D compass calibration process or a 3D process is signaled to be performed. Other embodiments are also described and claimed.

Abstract: Multiple instances of a geomagnetic field are calculated. Multiple instances of an average magnitude of a subset of the instances of the geomagnetic field are also calculated. When the average magnitude changes by more than a first predetermined threshold, the user is informed that compass accuracy has degraded. Other embodiments are also described and claimed.

Abstract: Measurements are acquired from a magnetic sensor during a non-pre-ordered movement, and a plurality of sets of solutions are determined for respective expected values of intensity of the Earth's magnetic field. The solutions are defined by a plurality of parameters, including at least one gain value for each detection axis of the magnetic sensor. For each solution, a figure of merit is determined, correlated to a calibration error, and a partial solution is selected in each set of solutions, based on the figure of merit. Once a gain confidence interval has been defined, a calibration solution is selected based on the figure of merit, from among the partial solutions having respective gain values all falling within the gain confidence interval.

Abstract: The instant invention utilizes two, optionally orthogonal and optionally slightly tilted, horizontal magnetic sensors and, optionally, a 2 or 3 axis accelerometer or inclinometer to calculate a pitch, roll and tilt compensated heading. A vertical, Z, component is relatively constant compared to X and Y components, the Z component can be abstracted from the X and Y sensor when pitch and roll is applied based on Z offset measured with X or Y sensor at high tilt angles. Additional sensors tilted at various ? degrees can be added with a different angle ? to X sensors when additional horizontal and magnetic coverage is desirable.

Abstract: A mobile bearing calculator having a geomagnetic sensor for detecting earth-magnetism and a control unit for calculating a geographical bearing based on detection values of the geomagnetic sensor. The control unit monitors for an event such as a change of operation of electronic parts mounted on the mobile bearing calculator and corrects the geographical bearing in accordance with the occurrence of the event.

Abstract: A compass system comprises a magnetic field sensor for measuring an ambient magnetic field and a magnetic field generator, corresponding to the magnetic field sensor, configured to generate a reference magnetic field. The magnetic field sensor is configured to measure the reference magnetic field. The compass system further comprises a control circuit operably connected to the magnetic field sensor and magnetic field generator, wherein the control circuit is configured to process the ambient magnetic field and the reference magnetic field measurements to determine an absolute reference field strength for use in calibrating the compass system.

Abstract: A system for testing the accuracy of an electronic compass is disclosed. The system includes a circular track, a compass seat, an electromagnetic element, a driver, a power source, a calculator, and a magnetic shielding chamber. The electromagnetic element is disposed on the circular track and powered by the power source to generate a magnetic field. The electronic compass is installed on the compass seat and surrounded by the circular track. As such, the electronic compass can measure the magnetic field of the electromagnetic element and calculate direction relative to the electromagnetic element at different points of the circular track when the electromagnetic element is driven by the driver to move along the circular track. The magnetic shielding chamber is for shielding the electromagnetic element and the electronic compass from interference of external magnetic fields.

Abstract: A bearing calculator provided with a geomagnetic sensor for detecting earth-geomagnetism and a control unit for calculating a geographical bearing based on detection values of the geomagnetic sensor. The control unit can execute offset error correction processing for correcting the offset error to the geomagnetic sensor based on a change in the magnetic field inside the bearing calculator. When detection values of the geomagnetic sensor enter an abnormal state, it performs said offset error correction processing when the abnormal state continues for a predetermined time, while does not perform the offset error correction processing when the abnormal state ends within a predetermined time.

Abstract: A sensor module maintaining high detection accuracy. Correction data of a detected magnetic field is updated only in a case that a fluctuation band acquired from an output signal of an acceleration sensor is less than a threshold value and a difference between an azimuth angle acquired from an output signal of a terrestrial magnetism sensor and an inclination angle acquired from an output signal of acceleration sensor is less than the threshold value. Therefore, the correction data is updated only in a case that a magnetic field at a position of a mobile object is stably detected, and an accuracy of the correction data can be maintained.

Abstract: An electronic device has an orientation sensing system for determining an orientation of the device. The system comprises a magnetometer and an accelero meter. The system further has calibration means to calibrate the sensing system for operational use. The accelerometer supplies measurements used to constrain a range of possible directions of the external magnetic field to be determined. The calibration means numerically solves a set of equations and is equally well useable for a 2D or 3D magnetometer in combination with a 2D or 3D accelerometer.

Abstract: The method estimates movement of a solid mobile in a medium capable of generating disturbances defined by a three-variable vector, wherein the movement is defined by a six-variable vector and the solid is equipped with at least one sensor sensitive to acceleration having at least three sensitive axes and at least one sensor sensitive to the magnetic field having at least three sensitive axes. The method for estimating the movement of a solid includes a step of calculating a nine-variable vector consisting of the six-variable movement vector and of the three-variable disturbance vector and a step of weighting the nine-variable vector capable of transforming the nine-variable vector into a vector with not more than five variables to be estimated.

Abstract: Devices (1) comprising sensor arrangements (2) for providing first field information (11-13) defining at least parts of first fields and for providing second field information (14, 15) defining at least parts of second fields are provided with updaters (4) for updating parameters of the first and/or second fields via criterion-dependent iterations, to become more reliable and user friendly. The fields may be earth gravitational fields and/or earth magnetic fields and/or further fields. The parameters comprise magnitudes of the fields and dot products of the fields. The criterion-dependent iterations comprise magnitude functions and dot product functions. The magnitude functions define new magnitudes being functions of old magnitudes and of updated magnitudes and the dot product functions define new dot products being functions of old dot products and of updated dot products.

Abstract: A portable electronic apparatus able to execute processing concerning calibration of a geomagnetism sensor at a suitable timing and a method of calibration of such a geomagnetism sensor are provided. Further, when a key of a key input part (103) is operated in a power-saving mode, the power-saving mode ends, and the processing concerning the calibration of a detection value of a geomagnetism sensor (110) is executed. Due to this, the processing concerning the calibration is executed in a state where a user tries to view a screen of a display part (107), therefore the calibration processing is executed in a state where an angle of housings with respect to the horizontal plane is suitable, and a calculation precision of a bearing can be improved.

Abstract: A magnetic field sensing device can be realized by using a magnetic sensor in electronic compassing as well as switching. A magnet can be brought in close proximity to the magnetic sensor within an electronic compass to generate a signal that a portable information device has been closed. This signal can be input to a processor or other circuitry to initiate a response to the portable information device being closed. When the magnet is moved out of close proximity to the magnetic sensor, the magnetic sensor can be used in the electronic compass. Thus, a magnetic sensor can serve two functions, namely compassing and switching, reducing the need for separate sensors to perform both functions.

Abstract: An object of the invention is to provide a portable terminal device capable of always providing a precise azimuth if the distance or the direction from a magnetism generation section of a loudspeaker, etc., to a magnetism detector changes as cases are opened/closed or are rotated.

Abstract: A mobile electronic apparatus capable of effectively preventing erroneous recognition of a bearing (azimuth or compass direction) by a user, as a correct display of the bearing is correct when the reliability of the display of the bearing is lowered by a change of the usage environment, and a bearing display method of the same, are provided. If a mobile electronic apparatus (100) is mounted on a charger (200) having a speaker (201), while information on a bearing calculated according to geomagnetism detected by a geomagnetic sensor (108) is displayed on a display part (107), updating of the information on the bearing repeated up to them is stopped, and information on a predetermined bearing is continuously displayed on the display part (107). This enables a user to correctly recognize that the information on the bearing displayed on the display part (107) is incorrect, thereby preventing the user from being misled by the unreliable information on the display part (107).

Abstract: An azimuth calculation program is a computer-executable program that performs an azimuth calculation using output of a magnetic sensor. The azimuth calculation program includes a first step of generating one triangle in three-dimensional space using three output values of a magnetic sensor unit, a second step of determining a circumcircle of the triangle, and a third step of performing an azimuth calculation using center coordinates of the circumcircle and output values of the magnetic sensor.

Abstract: In one embodiment a method and corresponding apparatus are arranged to determine an accurate device heading by continuously combining an average magnetic heading with the compensated inertial heading. The example embodiment obtains the compensated inertial heading by compensating for a time delay of an inertial heading.

Abstract: A method of calibrating a compass sensor in consideration of a magnetic environment is provided. The method includes (a) acquiring magnetic force data by rotating a compass sensor 360 degrees, the compass sensor including a biaxial magnetometer, (b) fitting the acquired magnetic force data to an ellipse function, (c) transforming the acquired magnetic force data and the ellipse function into a circle which is centered on an origin, and (d) calculating a distortion factor based on an inclination of a major axis of the ellipse function or the acquired magnetic force data to a horizontal axis, the distortion factor indicating the degree to which a magnetic field is distorted.

Abstract: In a compass sensor unit, an azimuth data computing method is carried out by the steps of: inputting a signal from a geomagnetic sensor to measure magnetic field; determining whether to store measurement data of the magnetic field based on a distance from the last stored measurement data; calculating an offset value based on the stored data; making a comparison for each component of a plurality of measurement data used for calculating the offset value, and judging the offset value to be valid when a difference between the maximum and minimum values of each component is a given value or more; updating the already stored offset value to the offset value judged to be valid; and correcting newly provided measurement data by the updated offset value to compute azimuth data.

Abstract: A heading sensor includes a housing containing an interferometer having a mirror movable in response to fluctuations in a gravitational force applied to the housing. The interferometer, responsive to a light beam, generates an optical signal modulated according to the relative displacement of the mirror. The housing further includes an electromagnetic coil positioned along an axis of the housing for generating a current signal indicative of fluctuations in a magnetic field applied to the housing. The heading sensor also includes a processor for determining a local gravitational field component according to the optical signal and a local magnetic field component according to the current signal.

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 magnetic azimuth detecting device is easily reduced in size. Three or more magnetic sensors 3 and a control semiconductor 4 controlling these magnetic sensors 3 are attached to and mounted on a surface of a circuit substrate 2, and the magnetic sensors 3 and the control semiconductor device 4 are encapsulated and integrated by an encapsulation member 5. The magnetic sensors 3 are divided into at least two groups, and the terminal forming surface or surfaces 6 of the magnetic sensor or sensors 3 of one group are disposed so as to be perpendicular to the terminal forming surface or surfaces 6 of the magnetic sensor or sensors 3 of another group.

Abstract: A pointing device includes hall elements that detect inclinations of a magnet in first, second and third directions, and a control unit that determines a pointing direction with output voltages of the hall elements depending on the inclinations of the magnet.

Abstract: An interior rearview mirror system for a vehicle includes an interior rearview mirror assembly, a casing having a reflective element, a compass sensor and a control. The compass sensor is disposed within the mirror casing and has a first magnetoresponsive sensing element and a second magnetoresponsive sensing element. The control receives a first signal indicative of a magnetic field sensed by the first magnetoresponsive sensing element and a second signal indicative of a magnetic field sensed by the second magnetoresponsive sensing element. The control determines that the casing is adjusted by an occupant of the vehicle in response to a change in the first and second signals being indicative of an abrupt movement of the casing about the mounting structure by an occupant of the vehicle. The control is operable to enter a rapid compensating mode to compensate for the mirror adjustment.

Abstract: The influence of a magnetic field on a geomagnetic sensor is detected to report a highly reliable bearing, and a 3D geomagnetic sensor (170A) is arranged at a position facing a magnet (190). An external magnetic field detection processing unit (160) detects the approach of the magnet (190) to the 3D geomagnetic sensor (170A), and uses the unit for detecting opening and closing of the housing. In addition, the unit judges whether there is influence by an external magnetic field according to whether the effect of the magnetic field of the magnet (190) is being felt and reflects this in the report of the bearing information.

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 method of controlling an electronic compass assembly includes calibrating magnetic field sensors to produce a calibration product and determining whether a magnetic interference condition exists based upon the calibration product. In one example, the calibration product includes a calibration ellipse. In another example, the method includes determining a first length of time that corresponds to a duration of a magnetic interference condition or a second length of time that corresponds to an elapsed time after the magnetic interference condition. A portion of the electronic compass is controlled based upon the first length of time or the second length of time.

Abstract: A magnetic compass includes a magnetic sensor, an acceleration sensor, respective signal conditioning circuits in electronic communication with the sensors and a microprocessor. These components are arranged and structurally coupled to a single electronic package that supports the sensors, the signal conditioning circuits, and the microprocessor to provide a miniaturized magnetic compass. In addition, a temperature sensor may be coupled to the package to provide temperature compensation for at least some of the above-identified components.

Abstract: The disclosure relates to micro-electromechanical systems (MEMS) and magnetic MEMS sensors. The sensors include a substrate having a surface, a first magnetic field detector positioned on the surface, a second magnetic field detector positioned on the surface proximate to the first magnetic field detector, and a third magnetic field detector positioned on the surface proximate to the first and second magnetic field detectors. Each of the first, second and third magnetic field detector is capable of detecting external magnetic fields that are mutually orthogonal along three directions. In certain embodiments, the magnetic MEMS sensors may be useful as electronic compasses. The disclosure also relates to fabricating a magnetic MEMS device, such as an electronic compass, from or on a single wafer, which includes multiple MEMS sensors.

Abstract: Measurements are acquired from a magnetic sensor during a non-pre-ordered movement, and a plurality of sets of solutions are determined for respective expected values of intensity of the Earth's magnetic field. The solutions are defined by a plurality of parameters, including at least one gain value for each detection axis of the magnetic sensor. For each solution, a figure of merit is determined, correlated to a calibration error, and a partial solution is selected in each set of solutions, based on the figure of merit. Once a gain confidence interval has been defined, a calibration solution is selected based on the figure of merit, from among the partial solutions having respective gain values all falling within the gain confidence interval.

Abstract: In a compass sensor unit, an azimuth data computing method is carried out by the steps of: inputting a signal from a geomagnetic sensor to measure magnetic field; determining whether to store measurement data of the magnetic field based on a distance from the last stored measurement data; calculating an offset value based on the stored data; making a comparison for each component of a plurality of measurement data used for calculating the offset value, and judging the offset value to be valid when a difference between the maximum and minimum values of each component is a given value or more; updating the already stored offset value to the offset value judged to be valid; and correcting newly provided measurement data by the updated offset value to compute azimuth data.

Abstract: The compass system of the present invention utilizes an improved calibration route 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: The invention relates to a method for defining a compass direction by means of an electronic compass device. In the method at least two field components of an external magnetic field are measured, from which a set of data points is formed, which correspond to the different orientations of the device relative to the external magnetic field, so that the location of the data points in a set of co-ordinates depends on the Earth's magnetic field and the magnetic disturbances of the environment. From the data points it is determined whether the set of data points correspond to a measurement, in which the device has remained on the horizontal plane with a predefined accuracy, or the tilting of the device is detected relative to the horizontal plane during measurement and the set of data points is corrected to correspond to a measurement in which the device has remained on the horizontal plane with a predefined accuracy.

Abstract: A magnetic compass apparatus and method to account for magnetic distortion while determining a magnetic heading is disclosed. The method enables a compass module, comprising at least two magnetometers, to characterize its magnetic environment dynamically, while collecting data of a geomagnetic field; a user moves an apparatus through various orientations; the environment may or may not contain magnetic distortion influences. Data gathered by magnetometers and, optionally, accelerometers are processed through at least two filters before being transferred as a processed data set for repetitive measurement calculations. A series of calculations is executed recursively in time by solving one or more linear vector equations using processed data.

Abstract: A sensor module maintaining high detection accuracy. Correction data of a detected magnetic field is updated only in a case that a fluctuation band acquired from an output signal of an acceleration sensor is less than a threshold value and a difference between an azimuth angle acquired from an output signal of a terrestrial magnetism sensor and an inclination angle acquired from an output signal of acceleration sensor is less than the threshold value. Therefore, the correction data is updated only in a case that a magnetic field at a position of a mobile object is stably detected, and an accuracy of the correction data can be maintained.

Abstract: A navigation apparatus mounted on a vehicle is equipped with a first gyro sensor and a second gyro sensor arranged in symmetry with respect to a first axis in a travel direction of the vehicle and to a second axis that passes through the center of gravity of the vehicle, the first and second axes being perpendicular to each other, so that the first and second gyro sensors lean by the same angle from the second axis in opposing directions with respect to a third axis that is perpendicular to the first and second axes. A sensor output circuit is connected to each of the first and second gyro sensors, to output an output signal. A calculator calculates a yaw angular velocity of the vehicle based on the output signal.

Abstract: For compensation of a magnetic field in an operating region a number of magnetic field sensors (S1, S2) and an arrangement of compensation coils (Hh) surrounding said operating region is used. The magnetic field is measured by at least two sensors (S1, S2) located at different positions outside the operating region, preferably at opposing positions with respect to a symmetry axis of the operating region, generating respective sensor signals (s1, s2), the sensor signals of said sensors are superposed to a feedback signal (ms, fs), which is converted by a controlling means to a driving signal (d1), and the driving signal is used to steer at least one compensation coil (Hh). To further enhance the compensation, the driving signal is also used to derive an additional input signal (cs) for the superposing step to generate the feedback signal (fs).

Abstract: Provided are an apparatus and method of calibrating azimuth of a mobile device. The apparatus includes: a motor; a magnetic field measuring unit disposed in the mobile device and measuring magnetic field data indicating magnitudes of a magnetic field in different directions while being rotated by the motor; and a controller driving the motor, generating a calibration table indicating a correspondence between an actual magnetic field trajectory formed by the magnetic field data and a theoretical magnetic field trajectory and calibrating azimuth of the mobile device using the calibration table.

Abstract: An array of three-axis magnetometers used for dynamic magnetic anomaly compensation are located at the corners of a parallelopiped, with pairs of magnetometer outputs used to derive a magnetic anomaly gradient vector used to compensate a compass and/or the output of a gyroscope in an inertial management unit. The system may be used in a neutrally buoyant remotely operated vehicle to permit ascertaining of course and position in the absence of surface control signals.

Abstract: A geomagnetic sensor for computing an azimuth and a method thereof. The geomagnetic sensor includes a geomagnetic sensor module, including X, Y and Z axis fluxgates orthogonal to one another, for performing normalization for mapping output values of the X, Y and Z axis fluxgates onto a previously set normalization range using previously set normalization factors, an operation module for performing operation of new normalization factors based on a plurality of normalization values output from the geomagnetic sensor module when the geomagnetic sensor is swung within a previously set range, a tilt sensor module for computing a pitch angle and a roll angle, and a control module for providing the new normalization factors to the geomagnetic sensor module to allow the geomagnetic sensor module to perform renormalization and computing an azimuth using the output values renormalized by the geomagnetic sensor module and the pitch and roll angles computed during the renormalization.

Abstract: A mobile device or the like having a 3-axis electronic compass is rotated, and the outputs from magnetic sensors disposed in the three axis directions are input to a first arithmetic processing unit (11) so as to obtain the magnetic data X, Y, and Z. By inputting the magnetic data X, Y, and Z to a second arithmetic processing unit (12), gains Gx and Gz can be obtained. A control unit (16) generates access codes x0 and z0 corresponding to the gains Gx and Gz. The correspondence between the access codes x0 and z0 and inclination angle (pitch angle) ? or between the gains Gx and Gz and inclination angle (pitch angle) ? is tabulated and stored in a memory unit (17). The control unit (16) accesses the memory unit (17) so as to obtain an inclination angle (pitch angle) ?0 corresponding to the access codes x0 and z0.