Abstract: Systems, methods, and apparatuses for a self-locating compass for use in navigation are disclosed. The self-locating compass is operable to provide position and/or velocity without information from a global positioning system (GPS) device. The self-locating compass includes a direction finder and a Lorentz force detector. The method includes determining orientation with respect to Earth's magnetic field, measuring a Lorentz force proportional to rate of change of location with respect to the field, determining a change in location, and updating location.

Abstract: Methods of calibrating strapdown heading sensors and strapdown heading sensors are provided. The methods include compensating raw sensor data generated by sensors of an uncalibrated strapdown heading sensor to compensate for errors in an instrument frame of the strapdown heading sensor. The strapdown heading sensor is put in a target apparatus and output data is compensated to compensate for errors in an apparatus frame relative to the instrument frame. The strapdown heading sensors include a housing and a compass module having a first sensor configured to detect a magnetic field of the Earth and a second sensor configured to detect a gravitational force of the Earth. The first sensor and the second sensor are each passively isolated from bending and/or flexing of the housing such that an alignment between the first sensor and the second sensor is not disturbed due to the bending and/or flexing.

Abstract: Methods of calibrating strapdown heading sensors and strapdown heading sensors are provided. The methods include compensating raw sensor data generated by sensors of an uncalibrated strapdown heading sensor to compensate for errors in an instrument frame of the strapdown heading sensor. The strapdown heading sensor is put in a target apparatus and output data is compensated to compensate for errors in an apparatus frame relative to the instrument frame. The strapdown heading sensors include a housing and a compass module having a first sensor configured to detect a magnetic field of the Earth and a second sensor configured to detect a gravitational force of the Earth. The first sensor and the second sensor are each passively isolated from bending and/or flexing of the housing such that an alignment between the first sensor and the second sensor is not disturbed due to the bending and/or flexing.

Abstract: The disclosure relates to the field of drilling tool attitude measurement, and particularly to a dynamic testing device suitable for a drilling tool attitude measurement module. The dynamic testing device may comprise a test fixture for attitude measurement module, an azimuth rotation device for adjusting an azimuth angle, an inclination angle swing device for adjusting an inclination angle, and a toolface angle rotation device for driving the test fixture for attitude measurement module to rotate, and a rotation speed measurement device for measuring a rotation speed and a self-rotation angle of the test fixture for attitude measurement module in a rotating state. The testing device has characteristics of large bearing weight, high rotation speed which is measurable and controllable, convenient for mounting and fixing a tested module, etc. It can simulate conditions of downhole rotation of a drilling tool, and be used for dynamic testing of the attitude measurement module.

Abstract: A strapdown heading sensor includes an elongated housing and a compass module at least partially positioned within an inner cavity of the elongated housing. The compass module is cantilevered within the inner cavity of the elongated housing.

Abstract: The subject matter disclosed herein relates to the control and utilization of multiple sensors within a device. For an example, motion of a device may be detected in response to receipt of a signal from a first sensor disposed in the device, and a power state of a second sensor also disposed in the device may be changed in response to detected motion.

Abstract: A mobile device configured to be used in a wireless communication network includes: an image capture device; at least one sensor configured to measure a first orientation of the mobile device; and a processor communicatively coupled to the image capture device and the at least one sensor and configured to: identify an object in an image captured by the image capture device; use a position of the mobile device to determine an actual location of the object relative to the mobile device; and use the actual location of the object relative to the mobile device and the image to determine a correction for the sensor.

Abstract: A method for reducing power consumption of an electronic device is disclosed. In one embodiment, an indication that an electronic device is oriented in a first orientation is received. An indication of rotation of the electronic device around an axis is received. A command is then generated to cause an electronic compass module disposed within the electronic device to transition from an idle operating state to an active operating state and to generate a compass heading.

Abstract: Techniques for estimating compass and gyroscope biases for handheld devices are disclosed. The compass bias can be determined by causing a small movement of the handheld device and comparing the data obtained from the compass with the data obtained from the gyroscope. The gyroscope bias can be determined by obtaining a quaternion based angular velocity term of the handheld device when the accelerometer and compass data are reliable, and then comparing the angular velocity term with the gyro data to estimate the gyro bias. When the compass and/or the accelerometer data are unreliable, a previously determined quaternion angular velocity term is used. The gyroscope bias can also be determined by measuring gyroscope biases at various temperatures in a non-factory setting, storing the data in a memory, and using the data to estimate gyro biases when the accelerometer and/or the compass data are unreliable.

Abstract: A test auxiliary device for testing a portable data terminal having a plurality of sensors includes a base, a carrying unit, a driving unit, and a controlling unit. The carrying unit is disposed on the base and includes a carrying platform and a carrying base. The carrying platform and the carrying base form a first angle and a second angle with the base, respectively, and thereby together form a compound slope. The driving unit drives the carrying unit to move, allowing the carrying platform to move with acceleration and at an angular velocity. The controlling unit receives sensing values generated by the sensors, respectively. The test auxiliary device further includes a test matching unit for testing the sensors in operation. Accordingly, the test auxiliary device assists users in determining whether the sensors of the portable data terminal are functioning well.

Abstract: A multi-magnetometer device comprises at least two z-axis aligned and physically rotated magnetometer triads utilized for measuring corresponding earth's magnetic field. The magnetic field measurements are utilized to measure rotation measurements of a single orthogonal axis along the 360 degrees of the complete circle without user's assistance and/or magnetometer movement for magnetometer calibration. The multi-magnetometer device may compute its magnetic heading utilizing the magnetic field measurements if no magnetic perturbations are detected. When magnetic perturbations are detected, a perturbation mitigation process may be performed. The rotation measurements may be generated by selectively combining the magnetic field measurements. Hard-iron components are determined utilizing the rotation measurements, and are removed from the magnetic field measurements.

Abstract: A method of calibrating a device comprising: imaging an object in a viewfinder of a device; obtaining a device location from a location mechanism and a device orientation from an orientation mechanism; and using the obtained device location and device orientation to calibrate one or more of the location mechanism and the orientation mechanism such that a difference between an expected location of the object in the viewfinder and a location of the object in the viewfinder is reduced.

Abstract: A method and system are provided for calibrating a magnetometer. The method comprises determining a current quality level associated with magnetometer readings obtained using an active set of calibration parameters; and lowering a quality threshold for a background calibration of the magnetometer when the current quality level exceeds a threshold quality level needed by an application utilizing the magnetometer readings.

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: Novel techniques for estimating compass and gyroscope biases for handheld devices are disclosed. The handheld devices can include wireless phones, navigational devices and video gaming systems. The compass bias can be determined by causing a small movement of the handheld device and comparing the data obtained from the compass with the data obtained from the gyroscope. The gyroscope bias can be determined by obtaining a quaternion based angular velocity term of the handheld device when the accelerometer and compass data are reliable, and then comparing the angular velocity term to with the gyro data estimate the gyro bias. When the compass and/or the accelerometer data are unreliable, a previously determined quaternion angular velocity term is used, which was determined when the compass and the accelerometer were providing reliable data.

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 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: An embodiment of the invention includes using a set of telescopes to calibrate a three dimensional optical scanner. Three separate calibrations are disclosed for a survey grade calibration: (1) angular calibration, implemented using at least one anti-podal pair of telescopes, (2) range calibration, implemented using at least one telescope mounted fiber recirculator, and (3) tilt calibration, implemented using at least one pair of telescopes not mounted in anti-podal configuration and an integral tilt table. Methods for aligning or measuring the mis-alignment between anti-podal telescope pairs are also described.

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 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: An electronic compass assembly includes a first collection portion and a second collection portion that each collect magnetic field data. The magnetic field data collected by the second collection portion partially overlaps the magnetic field data collected by the first collection portion. A processor module determines a calibration output based upon the magnetic field data from the first collection portion if a first predetermined condition exists and determines the calibration output based upon magnetic field data from the second collection portion if a second predetermined condition exists. An example method for controlling the electronic compass includes calibrating the electronic compass based upon one of a first magnetic field data set or a second, partially overlapping magnetic field data set.

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 method and system is presented for acquiring calibration data for a three-axis electronic compass by positioning and rotating the compass so that each sensitive axis in the compass experiences variation in the magnetic field while rotating the compass. Acquiring the calibration data occurs by measuring output signals that reflect the magnetic fields acting on the electronic compass while rotating the compass. Positioning of the compass includes moving the compass so that at least one of the sensitive axes travels a path that approximately forms a cone when the compass is rotated around a gravity vector. Calibration data from three sensitive axes experiencing variation in the magnetic field is available during a single rotation of the compass.

Abstract: An electronic compass comprises a saturable core sensor (2) with a core (3) made of ferromagnetic material surrounded by an electric winding (3?), a first couple of electric windings (4, 5) around the sensor (2) having reciprocally orthogonal turns, a second couple of electric windings (8, 9) around said first couple (4, 5) having reciprocally orthogonal turns. The gap between the winding (3?) and the first couple of windings (4, 5) and between the first couple of windings (4, 5) and the second couple of windings (8, 9) is filled with a material having a low thermal expansion coefficient, preferably epoxy fiberglass reinforced plastic, supporting the windings of said first (4, 5) and second (8, 9) couple of windings. It is also provided an electronic control circuit (20, 21, 22).

Abstract: A correcting mechanism for an electronic azimuth meter has an X-direction magnetic sensor and a Y-direction magnetic sensor for detecting a magnetic field in two orthogonal directions X and Y and for calculating an azimuth of a main body of an electronic azimuth meter. An azimuth change inducing unit provides a display of an induction mark to induce a continuous change of the azimuth of the electronic azimuth meter main body over a range of rotation of at least 360 degrees.

Abstract: A method for dynamic auto-calibration of a multi-sensor tracking system and apparatus incorporating it therein are presented. The method and apparatus utilize information from complementary sensors, filtered by a simultaneously running filter that combines the sensor data into an estimate of the state of the monitored system to iteratively tune the bias estimate. To track a dynamic system, complimentary or redundant sensors may be combined with a model of the system so that the uncertainty in the estimated state of the dynamic system is less than the noise in the individual sensors. In addition to noise, the sensors may have bias, which has the same value whenever the system is in a particular state. While estimating the actual value of the state, the present invention allows the estimator to determine the bias. The present invention, in its most general embodiment requires complex computations.

Abstract: To reduce a dispersion in a sensitivity of a magnetism detecting circuit driving, by current, a magnetism sensor comprising magnetism resistance elements in a bridge constitution to a dispersion in a sensitivity of a magnetism sensor. An electronic azimuth meter is provided with EEPROM and drive current set values are previously stored to EEPROM. The drive current set values are calculated by a predetermined calculation by measuring bridge resistance of a magnetism sensor of the electronic azimuth meter. In detecting magnetism by the magnetism sensor, CPU controls a sensor drive circuit based on the drive current set values stored to EEPROM. Thereby, the sensor drive circuit supplies a magnetism sensor with optimum drive current in accordance with a bridge resistance value thereof.

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.