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Search Publications by:

Displaying 1 - 25 of 199

Type-B uncertainty analysis of gravity-based determinations of triaxial-accelerometer properties by simulation of measurement errors

January 4, 2022

Author(s)

Jon Geist, Michael Gaitan

We simulate the effect of gimbal-alignment errors and rotational step-size errors on measurements of the sensitivity matrix and intrinsic properties of a triaxial accelerometer. We restrict the study to measurements carried out on a two-axis accelerometer

Calibration of Triaxial Accelerometers by Constant Rotation in the Gravitational Field

December 13, 2021

Author(s)

Michael Gaitan, Jon Geist

We extend the use of the intrinsic properties calibration method for triaxial accelerometers that we reported earlier from discrete angular steps to using a constant rotation rate to produce a time varying excitation in the earth's gravitational field. We

A Dynamic Uncertainty Protocol for Digital Sensor Networks

November 1, 2021

Author(s)

Michael Gaitan, Richard A. Allen, Jon Geist, Akobuije Chijioke

We propose a concept of the use of dynamic uncertainty to improve the accuracy and robustness of digital sensor networks. The digital smart transducer is integrated with a microcontroller that reads the binary data from the calibrated sensor, performs an

Accurate localization microscopy by intrinsic aberration calibration

June 24, 2021

Author(s)

Craig Copeland, Craig McGray, Robert Ilic, Jon Geist, Samuel Stavis

A standard paradigm of localization microscopy involves extension from two to three dimensions by engineering information into emitter images, and approximation of errors resulting from the field dependence of optical aberrations. We invert this standard

Reduction of Calibration Comparison Uncertainty due to Mounting for 3-Axis Accelerometers using the Intrinsic Properties Model

April 13, 2021

Author(s)

Michael Gaitan, Iris M. Lopez Bautista, Jon Geist

We provide experimental results showing that the calibration of tri-axis accelerometers based on the device's intrinsic properties alleviates the uncertainty due to misalignment of the device under test in comparison to the use of the sensitivity matrix

CHARACTERIZATION OF LASER DOPPLER VIBROMETERS USING ACOUSTO-OPTIC MODULATORS

December 31, 2020

Author(s)

Michael Gaitan, Jon C. Geist, Benjamin J. Reschovsky, Akobuije Chijioke

We report on a new approach to characterize the performance of a laser Doppler vibrometer (LDV). The method uses two acousto-optic modulators (AOMs) to frequency shift the light from an LDV by a known quantity to create a synthetic velocity shift that is

Shock Measurements Based on Pendulum Excitation and Laser Doppler Velocimetry: Primary Calibration by SI-Traceable Distance Measurements

April 10, 2020

Author(s)

Muhammad Afridi, Jon Geist, Michael Gaitan

A new method is described to provide a primary calibration of shock measurements produced by a shock measurement system consisting of pendulum excitation and laser Doppler velocimetry. The method uses the laser Doppler velocimeter to determine the total

Particle Tracking of a Complex Microsystem in Three Dimensions and Six Degrees of Freedom

January 18, 2020

Author(s)

Craig Copeland, Craig McGray, Robert Ilic, Jon Geist, Samuel Stavis

We exploit the intrinsic aberrations of an optical microscope to track single particles in three dimensions. We combine information from multiple particles on a rigid body of a microelectromechanical system to measure its motion in six degrees of freedom

Particle tracking of microelectromechanical system performance and reliability

October 25, 2018

Author(s)

Craig R. Copeland, Craig D. McGray, Jon C. Geist, Samuel M. Stavis

Microelectromechanical systems (MEMS) that require contact of moving parts to implement complex functions have demonstrated critical limits of performance and reliability. Here, we advance a particle tracking method to measure MEMS motion in operando at

Subnanometer localization accuracy in widefield optical microscopy

July 11, 2018

Author(s)

Craig R. Copeland, Jon C. Geist, Craig D. McGray, Vladimir A. Aksyuk, James A. Liddle, Bojan R. Ilic, Samuel M. Stavis

The common assumption that precision is the limit of accuracy in localization microscopy and the typical absence of comprehensive calibration of optical microscopes lead to a widespread issue - overconfidence in measurement results with nanoscale

Aperture Arrays for Subnanometer Calibration of Optical Microscopes

September 28, 2017

Author(s)

Craig Copeland, Craig McGray, Jon Geist, James Alexander Liddle, Robert Ilic, Samuel Stavis

We fabricate and test subresolution aperture arrays as calibration devices for optical localization microscopy. An array pitch with a relative uncertainty of approximately three parts in ten thousand enables magnification calibration with subnanometer

Gravity-based characterization of three-axis MEMS-accelerometers in terms of intrinsic accelerometer parameters

July 13, 2017

Author(s)

Jon C. Geist, Muhammad Y. Afridi, Craig McGray, Michael Gaitan

Cross-sensitivity matrices are used to translate the response of three-axis accelerometers into components of acceleration along the axes of a specified coordinate system. For inertial three-axis accelerometers, this coordinate system is often defined by

ANALYSYS AND PROTOCOL FOR CHARACTERIZING INTRINSIC PROPERTIES OF THREE-AXIS MEMS ACCELEROMETERS USING A GIMBAL ROTATED IN THE GRAVITATIONAL FIELD

May 30, 2017

Author(s)

Michael Gaitan, Muhammad Y. Afridi, Jon C. Geist

Three-axis MEMS accelerometers are typically characterized in terms of their cross-sensitivity matrix. We present an analysis and protocol to characterize them in terms of their intrinsic properties, which we define as the responsivity of each