Abstract: A method for providing functional checking of an inertial sensor, a first test signal having a first frequency being fed in at a test electrode of the inertial sensor for exciting a vibration of a vibration mass and a first response signal corresponding to the vibration mass is recorded, a second test signal having a second frequency different from the first frequency being fed in at the test electrode, a second response signal corresponding to the vibration mass being recorded, and the two response signals being evaluated. Also described is an inertial sensor.

Abstract: A gyroscopic system provides measurements on the basis of a vibrating gyroscope and provides a measurement signal. A periodic control signal is applied to it; in order to rotate the position of vibration, during a half period, according to a first speed profile, from a first up to a second position; and in order to rotate the position of vibration in an opposite direction during the other part of the period, according to a second speed profile, up to a third position. The measurements are based on corrected signals, each of said corrected signals, respectively for each of the vibrating gyroscopes, being obtained by; deducting the control signal from the measurement signal of the vibrating gyroscope; and taking account of errors identified on the basis of a comparison, of the measurements provided by the gyroscopic system as a function of the position of vibration with reference measurements.

Abstract: A long-period vibration sensor includes an overdamped accelerometer including a magnet fixed to the inside of a casing, a detection coil disposed between magnetic poles formed due to the magnet, a bobbin configured to hold the detection coil, and a support spring configured to support the bobbin in the casing so that the bobbin can vibrate in a predetermined direction, a voltage being outputted from the detection coil when the bobbin is damped, a plurality of digital filters having different frequency characteristics from one another, a selection module configured to select one digital filter from the plurality of digital filters based on an output value of the voltage outputted from the overdamped accelerometer, and a correction module configured to correct the output value of the voltage outputted from the overdamped accelerometer using the digital filter selected by the selection module.

Abstract: An acceleration detection device for detecting detected acceleration of a vehicle is provided with a stopped acceleration detector, an acceleration change detector, an acceleration estimating unit and a correcting unit. The stopped acceleration detector detects a detected stationary acceleration value when the vehicle is stopped on a sloping road based on an acceleration sensor signal from an acceleration sensor mounted on the vehicle. The acceleration change detector detects an acceleration change associated with the vehicle transitioning from a stationary state to a driving state on the sloping road based on the acceleration sensor signal. The acceleration estimating unit estimates an estimated stationary acceleration value based on the acceleration change that was detected by the acceleration change detector. The correcting unit corrects the detected stationary acceleration value based on a deviation between the estimated stationary acceleration value and the detected stationary acceleration value.

Abstract: A method for carrying out a self-test for a micromechanical sensor device, and a corresponding micromechanical sensor device. The method has the following steps: exciting the sensor device using a first excitation signal variation in a first self-test; storing a corresponding first response signal variation of the sensor device; exciting the sensor device using a second excitation signal variation in a second self-test; storing a corresponding second response signal variation of the sensor device; analyzing the first and second response signal variations with regard to at least one predefined criterion; and preparing a self-test result based on the analytical result of the first and second response signal variations.

Abstract: A method for calibrating a micro-electro-mechanical system (MEMS) vibrating structure gyroscope is provided. The method includes obtaining an indication of a position of at least one proof mass with respect to at least one drive electrode and applying an electrostatic force to the at least one proof mass as a function of the indication, the electrostatic force configured to position the at least one proof mass in a first position with respect to at least one drive electrode.

Abstract: A microchip system has a package forming a hermetically sealed interior, and MEMS structure within the interior. The system also has a gas sensor for detecting the concentration of at least one of oxygen or hydrogen within the interior.

Abstract: The present invention provides, as one aspect, an apparatus for inspecting a sensor module including at least one held sensor in a housing having a plurality of outer surfaces. The held sensor detects acceleration or angular velocity. The apparatus includes a holding unit that has an apparatus-side surface and holds the housing in a state where one of the outer surfaces of the housing serving as a housing-side surface contacts the apparatus-side surface, a driving unit that moves the holding unit, a first obtaining unit that, in a state where the housing-side surface contacts the apparatus-side surface, obtains an output from the held sensor, at least one reference sensor that has a detection axis and is provided such that a direction of the detection axis matches a direction of a reference axis of the held sensor, and a second obtaining unit that obtains an output from the reference sensor.

Abstract: An accelerometer (22) includes sense elements (24, 26, 28) for measuring acceleration (30, 32, 34) and a processor (36) in communication with the sense elements (24, 26, 28). The processor (36) executes an auto-calibration process (46) that entails collecting (94) acceleration datasets (96) and identifying a subset (130) of acceleration datasets (132) in which each of the acceleration datasets (132) represents a scenario in which the accelerometer (22) is in a static position and in which the acceleration datasets (132) represent a variety of orientations of the accelerometer (22). The subset (130) of acceleration datasets (132) is utilized to compute updated calibration parameters (184). Current calibration parameters (48) are compared to the updated parameters (184) to determine validity of the current parameters (48). When the current parameters (48) are invalid, they are replaced with the updated parameters (184), and the updated parameters (184) are implemented to calibrate the accelerometer (22).

Abstract: The invention relates, in general, to the field of magnetic sensors and accelerometers and the utilization of the same as magnetometers, magnetic compasses, range finders, navigational systems and other applications. More particularly, the invention relates to effective, simplified and highly accurate techniques for calibration of magnetic sensors and accelerometers.

Abstract: A method of detecting activity in a MEMS accelerometer captures an acceleration bias, measures acceleration at a predetermined time, calculates a change in acceleration using the measured acceleration and the acceleration bias, and compares the change in acceleration to a threshold to detect activity. A method of detecting inactivity uses a similar technique along with a timer. The method of detecting inactivity in a MEMS accelerometer captures an acceleration bias, measures acceleration at a predetermined time, calculates a change in acceleration using the measured acceleration and the acceleration bias, and compares the change in acceleration to a threshold to detect inactivity. The method further determines if the change in acceleration is less than the threshold and, if so, determines if a predetermined period of time has elapsed to detect inactivity.

Abstract: A MEMS stiction testing method applies a first electrical signal to a MEMS device having two opposing surfaces to cause the two opposing surfaces to make physical contact. The two opposing surfaces produce a second electrical signal when in physical contact. The method then substantially mitigates the first electrical signal after detecting that the second electrical signal has reached a prescribed maximum value.

Abstract: An inertial sensor includes an oscillator, a drive unit for oscillating the oscillator, a sensor for sensing the amount of inertia applied to the oscillator, and a failure diagnosis unit disposed between the oscillator and the drive unit. The drive unit includes a reference potential supply unit for supplying a reference potential to the oscillator, and a drive signal supply unit for supplying a drive signal to the oscillator based on a monitor signal received from the oscillator. The failure diagnosis unit includes a diagnosis unit for diagnosing a failure based on the value of a current supplied by the reference potential supply unit to the oscillator. The inertial sensor having this structure can detect a failure in the drive unit or the oscillator.

Abstract: A method of processing signals from an accelerometer/gyroscopic-based input device includes providing the input device within a vehicle. An accelerometer/gyroscopic-based second device is also provided within the vehicle. The input device is manually actuated while the vehicle is in motion. First signals are transmitted from the input device in response to the manually actuating step. Second signals are transmitted from the second device in response to the motion of the vehicle. The first signals are adjusted dependent upon the second signals.

Abstract: An accelerometer open loop control system comprising a variable capacitance accelerometer having a proof mass movable between fixed capacitor plates, drive signals applied to the capacitor plates, a charge amplifier amplifying an accelerometer output signal representing applied acceleration, and an autoranging facility for monitoring the output signal, and for adjusting the drive signals in dependence on the output signal in order to restrict the amplitude of the accelerometer output signal, thus maintaining sensitivity of the accelerometer while permitting response to a wide range of g values. Corrections are applied by means of look up tables to compensate for inaccuracies arising from movement of the proof mass and temperature variations.

Abstract: An error-correction method for an acceleration sensor having a plurality of electrodes and a seismic mass. The error-correction method which makes it possible to correct systematic errors at low expense includes the following steps: applying a voltage in order to deflect the seismic mass; measuring a first current caused by the deflection of the seismic mass; measuring a second current caused by the deflection of the seismic mass; and determining a correction variable on the basis of the first current and the second current.

Abstract: The effects of IMU gyro and accelerometer bias errors are significantly reduced in accordance with the present teachings by a system or method for commanding an IMU or vehicle through a series of preprogrammed maneuvers. The maneuvers can be designed to minimize the effects of other gyro errors including scale factor errors, nonlinearities, cross coupling/misalignment, and scale factor asymmetries. A sample maneuver is provided which demonstrates performance based on a sequence of roll and yaw maneuvers resulting in zero build up of error at the end of a maneuver cycle period as a result of these errors. Modification of the system involves the addition of control logic to determine the maneuver period, maneuver rate, and vehicle orientation. No additional hardware beyond possible fuel required to perform the maneuver is required.

Abstract: To calibrate an accelerometer, a seismic cable that carries the accelerometer is rotated. Data measured by the accelerometer as the seismic cable is rotated is received, and at least one calibration parameter according to the received data is computed. The at least one calibration parameter is for use in calibrating the accelerometer.

Abstract: A method and apparatus for calibrating or adjusting an accelerometer, wherein the accelerometer is held stationary to obtain the signal outputs from the accelerometer, representing component vectors making up the composite vector of 1 g. Thus, gain or sensitivity, and the zero-g signal offset along for each axis of the accelerometer is determined and adjustable.

Abstract: A sensor system having a substrate and a mass which is movably suspended relative to the substrate is described, the sensor system including detection arrangement for detecting a deflection of the seismic mass relative to the substrate along a deflection direction, the detection arrangement including a first measuring electrode affixed to the substrate and a second measuring electrode affixed to the substrate, and a first overlap, which is perpendicular to the deflection direction, between the first measuring electrode and the seismic mass along the deflection direction is greater than a second overlap, which is perpendicular to the deflection direction, between the second measuring electrode and the seismic mass.

Abstract: A method of identifying and imaging a high risk collision object relative to a host vehicle includes arranging a plurality of N sensors for imaging a three-hundred and sixty degree horizontal field of view (hFOV) around the host vehicle. The sensors are mounted to a vehicle in a circular arrangement so that the sensors are radially equiangular from each other. For each sensor, contrast differences in the hFOV are used to identify a unique source of motion (hot spot) that is indicative of a remote object in the sensor hFOV. A first hot spot in one sensor hFOV is correlated to a second hot spot in another hFOV of at least one other N sensor to yield range, azimuth and trajectory data for said object. The processor then assesses a collision risk with the object according to the object's trajectory data relative to the host vehicle.

Abstract: Compensating for the misalignment of a navigation device with respect to a vehicle is described. In one example, the compensation is made by applying a high pass filter to a measured acceleration of the vehicle to produce a motion acceleration signal, weighting the motion acceleration signal with a measured steering rate of the vehicle, and deriving misalignment parameters for the navigation device with respect to the vehicle using the weighted motion acceleration signal.

Abstract: Systems and methods for controlling a closed-loop accelerometer system. A system includes an accelerometer with a driver that responds in a nonlinear manner and a rebalancing controller in signal communication with the driver. The rebalancing controller includes a proportional-integral-derivative (PID) control portion having at least one variable gain component. A method includes sensing a movement of a proof mass, determining a static g field based on the sensed movement, setting at least one variable gain component of a PID controller based on the determined static g field, and rebalancing the proof mass using the PID controller.

Abstract: An electronic device can include an inertial measurement unit (IMU) operative to monitor the movement of the electronic device. The IMU used in the device can be inaccurate due to the manufacturing process used to construct the IMU and to incorporate the IMU in the electronic device. To correct the IMU output, the electronic device in which the IMU is incorporated can be placed in a testing apparatus that moves the device to known orientations. The IMU output at the known orientations can be compared to an expected true IMU output, and correction factors (e.g., sensitivity and offset matrices) can be calculated. The correction factors can be stored in the device, and applied to the IMU output to provide a true output. The testing apparatus can include a fixture placed in a gimbal movable around three axes.

Abstract: An inertial measurement unit (IMU) contains three linear acceleration sensors and three rotational speed sensors. For the sensors there are desired installation directions parallel to the co-ordinate axes of a Cartesian co-ordinate system which is fixed to the vehicle. The actual installation directions of the sensors may differ from the desired installation directions owing to incorrect orientations. By comparing accelerations which are measured by the linear acceleration sensors for different attitudes of the vehicle with acceleration values which are known for these different attitudes in the Cartesian co-ordinate system which is fixed to the vehicle, the actual installation directions of the linear acceleration sensors are determined. By using a co-ordinate transformation it is then possible to convert the measured accelerations into the actual accelerations.

Abstract: A method for calibrating an acceleration sensor includes the following sequential steps: ascertaining acceleration values as a function of three spatial directions; for each of the three spatial directions, generating a comparison value from the acceleration values; comparing each of the comparison values to a first threshold value; calculating a cumulative value as a function of at least one acceleration value for each of the three spatial directions; comparing the cumulative value to a second threshold value; and calibrating the acceleration sensor when, in the third method step, for each of the three spatial directions, the comparison value is less than the threshold value, and when, in the fifth method step, the cumulative value is greater than the further threshold value.

Abstract: An integrated calibration system and process for a three-axis (X, Y, Z) accelerometer estimates Z-axis bias, Z-axis bias drift and determines X, Y, and Z-axes error sources based on measurements taken when the accelerometer is static, i.e., sensing only the earth's gravitational acceleration. Optimal on-the-fly error estimates for the three-axis accelerometer are obtained so that the measurements provided by the three-axis accelerometer remain error-free.

Abstract: A transducer test system for testing accelerometers or velocity transducers includes a signal conditioner and a shaker that can be used in a field environment, for example by an avionics technician at an aircraft. A test transducer and a reference transducer, which is a known-good version of the test transducer, are mounted onto the shaker and electrically connected to the signal conditioner. The technician shakes the two transducers simultaneously by manually shaking the shaker. The signal conditioner receives and compares the signals output from the test and reference transducer in order to determine the operating condition of the test transducer.

Abstract: The present invention relates to a traveling direction measuring apparatus usable as a pedestrian navigation system in locations where it is difficult to obtain high positioning accuracy such as inside buildings or around multistory buildings where a GPS cannot be used. An acceleration detecting section (1) detects 3-axes acceleration of the traveling direction measuring apparatus, which varies with the walking of the pedestrian. An acceleration data acquiring section (2) obtains 3-axes acceleration data repeatedly by the number of prescribed times or more, said 3-axes acceleration data varies with the walking of the pedestrian. A first gravity acceleration calculating section (3) calculates, when the pedestrian is walking with holding the traveling direction measuring apparatus in a generally fixed attitude, gravity acceleration by averaging acceleration data sets during several steps obtained by the acceleration data acquiring section (2).

Abstract: A method of navigation includes providing an angular rate sensor and a direction-of-gravity reference. The method also includes determining bias error of the angular rate sensor about a vertical axis based on data substantially from the angular rate sensor and from the direction-of-gravity reference. In one embodiment, the first angular rate sensor is moved from a first position around a substantially horizontal axis to a second position around the substantially horizontal axis. The first angular rate sensor provides angular rate data for attitude at the first position and for compass heading at the second position. Data from the first angular rate sensor and from the direction-of-gravity reference is processed with a program for determining a bias error correction for the first angular rate sensor while the first angular rate sensor is in the first position.

Abstract: A method for monitoring human activity using an inertial sensor includes obtaining acceleration measurement data from an inertial sensor disposed in eyewear. The acceleration measurement data is processed to determine a user activity statistic. The user activity statistic includes at least one of a current user activity, periodic human motion count, total distance traveled, vertical distance traveled, current speed and average speed.

Abstract: A self-calibrating laser accelerometer system that continuously removes bias errors from acceleration measurements under dynamic operating conditions has a frame with a pair of essentially identical mass modulated accelerometers positioned within the frame. Each accelerometer includes a proof mass mounted to the sensing element frame by a flexure suspension. The proof mass is arranged to rotate about an output axis in response to acceleration of the sensing element frame along an input axis. The first proof mass includes a secondary mass that is movable between a first stable position on a first side of the output axis and a second stable position on a second side of the output axis to provide mass modulation of the first proof mass and to provide a selectively reversible polarity to the input axis and to provide self-calibration of bias.

Abstract: The transduction scale factor for a MEMS gyroscope is calibrated without moving the MEMS device based on measurements of the resonator resonance frequency and the accelerometer resonance frequency as well as a distance value that may be a fixed distance value or a measured distance value. The measured distance value may be obtained by measuring the quality factor of the resonator or accelerometer and deriving the measured distance value from the quality factor measurement.

Abstract: A short duration test activation signal is applied to the test activation port of a motion sensor module and the test activation status port observed with an error flag being set if a corresponding signal does not appear at the test activation status port within a predetermined time period.

Abstract: A method for manufacturing an acceleration sensing unit includes: providing an element support substrate in which a plurality of element supporting members is arranged so as to form a plane, each of the element supporting members being coupled to the other element supporting member through a supporting part and having a fixed part and a movable part that is supported by the fixed part through a beam, the beam having a flexibility with which the movable part is displaced along an acceleration detection axis direction when an acceleration is applied to the movable part; providing an stress sensing element substrate in which a plurality of stress sensing elements is arranged so as to form a plane, each of the stress sensing elements being coupled to the other stress sensing element through an element supporting part and having a stress sensing part and fixed ends that are formed so as to have a single body with the stress sensing part at both ends of the stress sensing part; disposing the stress sensing element

Abstract: A method for adjusting an acceleration sensor which includes a substrate and a seismic mass, the acceleration sensor having first and further first electrodes attached to the substrate on a first side, counter-electrodes of the seismic mass being situated between the first and further first electrodes, the acceleration sensor having further second electrodes on a second side and further fourth electrodes on a fourth side opposite the second side, an essentially equal first excitation voltage being applied to the first and further first electrodes in a first step for exciting a first deflection of the seismic mass along a first direction, the first deflection being compensated in a second step by applying a first compensation voltage to the further second and further fourth electrodes.

Abstract: The present invention provides a method and an apparatus for in situ test of transducers comprising sensing elements and associated conditioning preamplifiers. The invention makes it possible to evaluate the characteristics of the complete transducer by means of higher integration of the transducer circuitry. Tests can be performed from a remote central location without additional wiring and while the transducer is in operating environment. Testing is performed by superposing test signals and test sequence control signals on the wiring for the transducer output signal, hereby offering flexibility without sacrificing simplicity. Test signalling is by additional circuitry in the transducer interpreted and routed to the input of the conditioning preamplifier based on signalling from the remote test generator, and the signals engendered from the test signals can be analyzed from a remote analyzing system for complete qualifications of the transducer under test.

Abstract: This invention relates to an optical imaging device that includes an elongate housing. An infrared sensor arrangement is arranged in the housing and is configured to sense information printed on a page with infrared ink. The device also includes a radio frequency transceiver arranged in the housing and operatively connected to the sensor arrangement for communicating said information wirelessly. A pair of orthogonal accelerometers mounted in the housing in a plane normal to an elongate axis of the housing. The accelerometers enable the device to sense direction and speed of motion without reference to a location on the page. Also included is a controller circuit for controlling operation of the sensor arrangement, the transceiver, and the accelerometers.

Abstract: The invention relates to a vibration measurement system for frequency-selective oscillation measurement in particular of low frequencies as are relevant in the field of automation and drive technology. The invention proposes coupling a broadband transmitter structure, which is excited directly by the excitation signal to be determined, via an electrostatic or inductive force to a receiver structure. This force coupling results in amplitude modulation of a carrier signal exciting the receiver structure. The actual excitation signal can be extracted from the spectrum of the amplitude-modulated carrier signal, for example by suitably selecting the frequency of the carrier signal. In order to make an oscillation analysis possible which is as unsusceptible to interference possible, an interference signal brought about, for example, by connector excitations is largely eliminated in advance from the amplitude-modulated carrier signal.

Abstract: Illustrative computer-executable methods, systems, and computer software program products compute orientation alignment transfer tool location. Orientation of at least one aerodynamically significant feature of an as-built airplane is automatically determined. Orientation of an orientation monument for the as-built airplane is automatically determined from the determined orientation of the at least one aerodynamically significant feature of the as-built airplane, and motion to align an orientation alignment transfer tool with the determined orientation of the orientation monument is automatically determined.

Abstract: A transducer test system for testing accelerometers or velocity transducers includes a signal conditioner and a shaker that can be used in a field environment, for example by an avionics technician at an aircraft. A test transducer and a reference transducer, which is a known-good version of the test transducer, are mounted onto the shaker and electrically connected to the signal conditioner. The technician shakes the two transducers simultaneously by manually shaking the shaker. The signal conditioner receives and compares the signals output from the test and reference transducer in order to determine the operating condition of the test transducer.

Abstract: A method of correcting the gain of a capacitive member having electrodes that are movable relative to each other including the steps of successively applying to one of the electrodes, reduced bias voltages having opposite signs and a common value below a threshold for which a remanent field generated by said reduced bias voltages can be measured, making corresponding measurements of the output signals from the capacitive member; taking an average, and correcting the gain of the capacitive member as a function of the measured output signal.

Abstract: An inertial system is provided. The system includes at least one inertial sensor, a processing unit and a plurality of Kalman filters implemented in the processing unit. The Kalman filters receive information from the at least one inertial sensor, and at most one of the plurality of Kalman filters has processed zero velocity updates on the last cycle. The plurality of Kalman filters is used to optimize system response and performance during periods of intermittent motion.

Abstract: A calibrator includes a moving element having a structural member having a mounting feature for mounting the device to be calibrated. The moving element includes first and second coils at first and second ends. A fixed element supports the moving element and includes at least one magnet magnetically cooperating with the first and second coils. In at least one mode of operation, an amplifier is coupled to the first and second coils in parallel.

Abstract: A method for self-testing a dual-mass linear accelerometer in which a self-test voltage is applied to urge the two masses to move in opposite directions. Self-test signals are then applied to obtain a differential mode signal to detect masses repositioned in opposing directions. During testing, common disturbances to the two masses are rejected as common mode signals.

Abstract: A traveling direction measuring apparatus including 3-axes acceleration detecting means for detecting acceleration, and acceleration data acquiring means for repeatedly obtaining 3-axes acceleration data, said 3-axes acceleration varying with walking of a pedestrian, the traveling direction measuring apparatus including means for calculating, when the pedestrian is walking with holding said traveling direction measuring apparatus in a generally fixed attitude, gravity acceleration by averaging acceleration data sets during several steps obtained by said acceleration data acquiring means, means for calculating frequency components corresponding to duration of one step of the acceleration data sets projected on a plane perpendicular to the calculated gravity acceleration, and means for estimating a moving direction of the pedestrian seen from a terminal coordinate system associated with said traveling direction measuring apparatus according to frequency components.

Abstract: A method and apparatus for calibrating or adjusting an accelerometer, wherein the accelerometer is held stationary to obtain the signal outputs from the accelerometer, representing component vectors making up the composite vector of 1g. Thus, gain or sensitivity, and the zero-g signal offset along for each axis of the accelerometer is determined and adjustable.

Abstract: An accelerometer with improved calibration features, an electronic device having an accelerometer with improved calibration features, and a method of calibrating an accelerometer of an electronic device are provided. In accordance with one embodiment, there is method of calibrating an accelerometer of an electronic device, the accelerometer having at least a primary sensing axis and a secondary sensing axis, the second sensing axis being oriented parallel to the primary sensing axis and in the opposite direction of the primary sensing axis, the method comprising: measuring acceleration calibration data using the primary sensing axis and the secondary sensing axis of the accelerometer; determining calibration parameters in accordance with measured calibration data from the accelerometer; and storing the calibration parameters in a memory of the electronic device.

Abstract: A portable instrument, described in GB2413189, is held between the fingers of one hand and measures the cumulative exposure of a worker to vibration. However, this instrument will not comfortably fit the hands of all workers There is also an administrative problem in administering the allocation of different instruments to respective workers at the beginning of a shift, recording the measurements at the end of a shift and ensuring that instruments are adequately charged. The problem is solved by using a docking station (14) to receive the instruments before and after use, to receive information recorded by or stored within the units, to charge the batteries and to receive identity information concerning a worker requesting access, to a unit. When a worker returns an instrument to the docking station, a processing mechanism collects information about the identity of the worker, and the state of charge of the instrument's battery.

Abstract: A three-axial acceleration sensor inspection device is provided for inspecting a three-axial acceleration sensor that detects acceleration components in three axes crossing perpendicularly with each other and outputs acceleration component signals. The three-axial acceleration sensor inspection device includes a test plate for mounting the three-axial acceleration sensor thereon; a supporting plate for supporting and rotating the test plate; a main rotational shaft for rotating the supporting plate. The supporting plate is arranged radially around the main rotational shaft along a radius direction of the main rotational shaft, and is disposed at each of at least four locations with an equal angular interval along a circumferential direction of the main rotational shaft.