Honeywell G.m.b.h.

Honeywell International Inc.

US Government As Represented by the Secretary of the Army

James E Lenz

Nick Anthony Demma

Dragutin Milosevic

Joseph J Simonelic

Dale F Berndt

James C Lee

Gordon L Mitchell

Paul E Bjork

Sam DiVita

David A Sandquist

Thomas J Wagener

Lawrence C Vallot

Werner H Egli

Randolph G Hartman

Takeshi Kawai

Kevin D Vanderwerf

Mark T Manfred

Gordon F Rouse

Howard B French

Keith W Nelson

Hisatoshi Fujiwara

Erick C Nehls, Iii

A method for characterizing distortions in the earth's magnetic field caused by a vehicle having a magnetometer affixed therein is described. The method includes repeatedly measuring the distorted magnetic field utilizing the magnetometer and obtaining a three-dimensional orientation of the vehicle axes with respect to the earth at a time of each magnetometer measurement. The method also includes receiving undistorted earth magnetic field data for the vicinity of the vehicle relative to the earth at the time of each magnetometer measurement and characterizing distortions caused by one or more of the vehicle and magnetometer errors utilizing the magnetic field measurements, the orientations of the vehicle, and the undistorted earth magnetic field data.

Methods and apparatus for automatic magnetic compensation

A vehicle detecting system and method for use on a specific location such as an airport, including a sensor string nominally perpendicular to the direction of vehicle travel at the location. The sensor string includes at least one magnetic field sensor and a transmitter for transmitting signals from the at least one sensor to a monitoring point. A plurality of sensors is preferred. The transmitter includes a control unit for receiving the signals and a sender for sending the signals to the monitoring point. The preferred magnetic field sensor is a magnetoresisteive sensor having a field range of at least &plusmn;5 gauss. A preferred location for the sensor string is in a groove in the surface.

Magnetic checkpoint

A magnetoresistive sensor system having resistive elements changing in ohmic value in the presence of a magnetic field of a current being measured. The variant values of the elements are amplified by some electronics that inherently add offset to the resultant values. The elements themselves also add an offset. The output of the electronics is modulated and then buffered as an output. This output is demodulated and integrated. The resultant signal is fed back to the input of the electronics to null out the offsets. The output of the buffer also goes to an inductive coil that is magnetically coupled to the resistive elements to null out the magnetic field from the current being measured. The buffer output indicates the magnitude of the current being measured. An oscillator outputs a signal to actuate the modulator and the demodulator. The oscillator signal also goes to a set/reset circuit for setting and resetting the resistive elements of the magnetoresistive sensor.

Closed-loop magnetoresistive current sensor system having active offset nulling

A proximity sensing circuit is provided with various attributes, including the connection of a proximity sensor coil in a feedback loop of an amplifier, the frequency hopping technique that periodically changes the two frequencies used by its proximity sensor circuit to avoid deleterious interference by constant frequency EMI sources and the provision of a self diagnosis technique. The connection of the proximity sensor coil in the feedback loop of an amplifier results in several advantages including the connection of the coil to a virtually infinite impedance, the reduction of the number of components needed in the proximity sensing circuit and decreased temperature sensitivity of the overall circuit. The frequency hopping technique that periodically changes the two frequencies used by the proximity sensor significantly decreases the likelihood that a constant frequency EMI source in the vicinity of the circuit will have a continually adverse affect on its accuracy and reliability. In applications that require a large number of sensors, the circuit uses a multiplexer with a plurality of sensors and a single filtering network to decrease the necessary number of components in the proximity sensing circuit. Self diagnosis can be performed by using precision resistors or by intelligently monitoring the changing values of the AC impedance, the DC resistance and the compensated resistance, either individually or in combination with each other, to predict certain potential malfunctions.

Sensor circuit with diagnostic capability

A proximity sensing circuit is provided with various attributes, including the connection of a proximity sensor coil in a feedback loop of an amplifier, the frequency hopping technique that periodically changes the two frequencies used by its proximity sensor circuit to avoid deleterious interference by constant frequency EMI sources and the provision of a self diagnosis technique, The connection of the proximity sensor coil in the feedback loop of an amplifier results in several advantages including the connection of the coil to a virtually infinite impedance, the reduction of the number of components needed in the proximity sensing circuit and decreased temperature sensitivity of the overall circuit. The frequency hopping technique that periodically changes the two frequencies used by the proximity sensor significantly decreases the likelihood that a constant frequency EMI source in the vicinity of the circuit will have a continually adverse affect on its accuracy and reliability. In applications that require a large number of sensors, the circuit uses a multiplexer with a plurality of sensors and a single filtering network to decrease the necessary number of components in the proximity sensing circuit. Self diagnosis can be performed by using precision resistors or by intelligently monitoring the changing values of the AC impedance, the DC resistance and the compensated resistance, either individually or in combination with each other, to predict certain potential malfunctions.

Proximity sensor circuit with frequency changing capability having a

Proximity sensor circuit with frequency changing capability

An optical fiber is releasably held in coil or skein form by a magnetized in film coating on the fiber. Adjacent convolutions are held together by a magnetic field to prevent unintended unravelling of the coil, but the fiber can be rapidly played out at high speed without rupture and with a constant release tension force. The magnetic field has a radial and axial component relative to the coil cylinder. A magnetizing apparatus is disclosed for magnetizing the film. A sensor feedback loop can dynamically adjust the reel-out drag force to dampen vibration modes during reel out which can cause tangle.

Magnetic optical fiber skein

Method of forming an optical fiber

A position sensor is provided which incorporates the first and second magnetic members which are attached to an object whose position is to be determined. First and second magnetic sensors are disposed at positions in association with the two magnetic members. As the object moves along a predetermined path, the first and second magnetic members dispose a predetermined amount of magnetic material in the zones of the two sensors. By measuring the changing impedance of the winding of one of the sensors and comparing that value to the impedance of the winding of the other sensor, corrections can be made to determine the position of the object notwithstanding the fact that external effects may have changed the conditions under which the measurements are being taken. For example, gaps between the magnetic members and the sensors can possibly change from one time to another or the ambient temperature surrounding the sensors and the magnetic members could have changed. By comparing the values of the two sensor readings, these variabilities can be factored out of the determination and the accurate position of the object can be measured.

Apparatus for determining the position of an object

A housing for integrated circuit structures containing magnetic thin film which has permeable protective layers parallel thereto.

Semiconductor device housing with magnetic field protection

An optically powered fiber optic sensor system having a control end sending, with a laser diode or light-emitting diode, optical power and a clock signal exclusively through an optic fiber to a sensing end having sensors, a clock signal picking-off circuit, a return signal light-emitting diode, and needed analog and digital circuitry, all energy dependent upon the optical power transmitted through the optic fiber to the control end. The optically powered sensor end is feasible because of recent advances in technology resulting in micro-powered devices such as the analog-to-digital converter, operational amplifiers, logic circuits, and other low-powered items.

Optically powered remote sensors with timing discrimination

A method of mapping at least a portion of a magnetic field with an interferometer is presented. The interferometer includes an optical fiber clad with a magnetostrictive material. The approximate direction of the magnetic field lines are determined and the optical fiber is placed substantially transverse to the magnetic field lines. The output of the interferometer is recorded for various positions of the optical fiber. The fiber can be maintained substantially transverse to the magnetic field lines during mapping, or the fiber can be positioned substantially transverse to the field lines to precisely determine the direction of field lines and substantially parallel to the field lines to determine field magnitude. In one embodiment the interferometer is adapted to produce a null output for a predetermined value of the integral of the magnetic field along the length of the optical fiber, and the optical fiber is of uniform construction. In this embodiment, the loci of reference points corresponding to null outputs provides a mapping of points of symmetry in the magnetic field. The direction of magnetic field lines at a point in space is also determined by seeking the minimum output of the interferometer by scanning about the point with the optical fiber.

High accuracy mapping of magnetic fields with a fiber optic

Orthogonal components of electromagnetic field perturbations due to objects characterized by electric or magnetic dipoles are measured along orthogonal axes in a plane. The components are proportional with (3 cos.sup.2 .theta.-1) and (3 cos .theta. sin .theta.), where .theta. is the bearing of the dipole center relative to the device for measuring the field components. .theta. is readily determined from these equations and the range of the object can also be determined from knowledge of the dipole moment.

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Brooklyn Park, MN, United States of America

James E Lenz