Honeywell International Inc.

The Charles Stark Draper Laboratory, Inc.

William Joseph Trinkle, Jr

Ernest Frank John Graetz

William Goethals

Almir D Davis

Donald E Gustafson

Philip S Babcock, Iv

Richard T Berthold

Kirby Kueber

Marc Steven Weinberg

Jonathan Jay Bernstein

Amy Elizabeth Duwel

James Alan Bickford

Joseph M Kinast

John Joseph LeBlanc

Darryl I Parmet

Richard David Elliott, Iii

Michael A Gilbert

Michael J Iannucci

Michael Joseph Tomaino-Iannucci

Arturo D Gossage

Ronald Edmund Gagnon, Jr

Thomas Francis Marinis, Jr

The system and method involve a permanent magnetization induction process for ferromagnetic structures, carried out to the saturation point to overwhelm the intrinsic magnetic fields in the structures. The permanent magnetization to overwhelm the intrinsic magnetization eliminates the effect of intrinsic fields for subsequent measurements. The permanent magnetization along a hollow structure yields two residual magnetic field components: axial and circumferential. The circumferential component varies as a function of depth. Thus, an analysis system can analyze defects and the depth of those defects by detecting the direction of the magnetic flux leakage around the defects. This can further be performed at a distance from the structures.

Method for determining defect depth in ferromagnetic structures based on magnetic flux leakage direction

An ultra-low noise sensor for magnetic fields comprises a mechanically resonant structure having a magnetized proof mass. The displacement of the proof mass due to a magnetic field provides a high resolution and highly amplified measurement of magnetic field fluctuations near the resonance frequency. A flux modulator may be used with the resonant structure to amplify magnetic fluctuations in a non-resonant frequency band. The resonant structure, combined with a high resolution readout device and a frequency-compensating numerical processor, can amplify magnetic fluctuations in a broad range of frequencies. A solenoid coil surrounding the resonant structure may be used to null the quasi-static earth's magnetic field and thereby increase the dynamic range of the sensor. Cryogenically cooling the resonant structure can improve the resolution of the sensor. A magnetometer that embodies features of the present invention is miniaturized and has improved amplification and resolution at room temperature.

Ultra-low noise sensor for magnetic fields

Defects in ferromagnetic materials are detected and characterized by analyzing the items' magnetic fields to find portions of the magnetic fields that differ in characteristic ways from residual magnetic fields generated by non-defective portions of the items. The portions of the magnetic fields that differ in the characteristic ways correspond to locations of the defects. The residual magnetic fields correspond to portions of the items distant from the defects. The defect characterization may include volume of material lost due to each defect and/or width and/or depth of each defect.

System and method of measuring defects in ferromagnetic materials

Embodiments described herein provide for a method of modulating an input light beam of an interferometric fiber optic gyroscope (IFOG). The method includes intermittently jumping a phase step to suppress dead band. During a first cycle, a first cycle raw rate is stored and a feedback signal is generated based on a jumped phase step. During a second cycle, a second cycle raw rate is stored and a feedback signal is generated based on the jumped phase step. During a third cycle, a third cycle phase step is generated by accumulating the first cycle raw rate with a second cycle phase step, and a feedback signal is generated from the third cycle phase step. During a fourth cycle, a fourth cycle phase step is generated by accumulating the second cycle raw rate with the third cycle phase step, and a feedback signal is generated from the fourth cycle phase step.

Fiber optic gyroscope dead band error suppression

Embodiments described herein provide for a method of modulating an input light beam of an interferometric fiber optic gyroscope (IFOG). The method includes intermittently jumping a phase step to suppress dead band. If a bit flip was clocked into a digital to analog converter generating the feedback signal at the beginning of a cycle in which the jumped phase step is implemented, the method includes at least one of re-introducing a rate difference corresponding to the bit flip, altering the timing of the bit flip, or altering the timing of the generating a feedback signal based on the jumped phase step.

Embodiments described herein provide a method of modulating an input light beam of a fiber optic coil of an IFOG. The method includes intermittently jumping the phase step of a feedback signal to suppress dead band. Jumping the phase step includes: creating a jumped phase step during a first cycle of the IFOG, the jumped phase step having a whole value configured to cause a phase jump in the feedback signal and a fractional value corresponding to the fractional value from a phase step of a cycle immediately preceding the first cycle. Jumping the phase step also includes generating the feedback signal from a sum of the bias modulation value and the jumped phase step.

A thermistor amplifier device comprising a first amplifier and a second amplifier is provided. The first amplifier generates an analog temperature signal output based on a voltage across at least one thermistor. The second amplifier generates an offset voltage input to the first amplifier, wherein the offset voltage is based on maintaining the analog temperature signal within a predefined voltage range. The second amplifier selects the offset voltage corresponding to one of a plurality of range levels, wherein each of the plurality of range levels is associated with a temperature range of the at least one thermistor.

High resolution measurement of thermistor thermometry signals with wide  dynamic range

An Interferometric Fiber Optic Gyro (IFOG) device for high accuracy sensing. An example IFOG includes an integrated optics chip (IOC) and a modulation component that modulates one or more light signals passing thru the IOC according to a bias-modulation waveform. A glitch pattern experienced at front-end components of the IFOG includes frequency content that has approximately zero amplitude at predefined sense harmonics. Frequency content of the bias-modulation waveform is below a predefined threshold value at the predefined sense harmonics.

Alternate modulation scheme for an interferometric fiber optic gyroscope

Systems and methods for improving resolution of low-noise signals in an analog-to-digital conversion circuit. A simple, low cost pseudo-noise generating circuit is disclosed that, when connected to the signal conditioning circuitry of A/D conversion circuit, adds pseudo-noise to an analog input voltage signal. Additional pseudo-noise is beneficial for improving the resolution of analog-to-digital conversion when oversampling and summing or averaging are used in post-conversion processing operations. The circuit is composed of a plurality of resistors configured in at least two parallel branches. An individually switchable voltage source output is connected to each branch. A resulting analog voltage can be measured at a common termination point for the branches, depending on the combination of switchable voltage source output turned on, and the branch to which the voltage output is applied. By varying the combination of switchable voltage source outputs turned on over time, a known analog pseudo-noise signal is developed.

Inexpensively improving resolution and reducing noise of low-noise signals

Systems and methods synthesize a signal from the odd harmonic frequency components of an input signal. An exemplary embodiment synthesizes a first signal with a digital to analog converter (DAC), generates a second signal from the first signal, and filters a selected one of the odd harmonic frequency components through a band pass filter to produce an output signal. The first signal is defined by a first frequency. The second signal is defined by the first frequency and includes a fundamental frequency component and plurality of odd harmonic frequency components. The output signal has a frequency substantially equal to the frequency of the selected odd harmonic frequency component.

Growing community of inventors

Arlington, MA, United States of America

William Joseph Trinkle, Jr