David Robert Hull

US Patent:

6670809, Dec 30, 2003

Filed:

May 1, 2002

Appl. No.:

10/135392

Inventors:

Alan S. Edelstein - Aalexandria VA
David Hull - Adelphi MD

Assignee:

The United States of America as represented by the Secretary of the Army - Washington DC

International Classification:

G01R 3302

US Classification:

324244, 324225, 324251, 324252, 324259

Abstract:

A magnetic sensing transducer device that senses low frequency magnetic fields by using flux concentrators that modulate the observed low frequency signal, thereby shifting this observed signal to higher frequencies and minimizing 1/f-type noise. This is accomplished by the oscillatory motion of a microelectromechanical (MEMS)-type magnetic flux concentrator operated with a magnetic sensor, preferably made on a common substrate. Such a combined device can be used in a magnetometer. Such a device is small, low-cost and has low-power-consumption requirements. The magnetic sensor can be a Hall effect or other type of magnetic sensor. At least one MEMS-type fabricated flux concentrator is used with the magnetic sensor. The concentrator oscillates at a modulation frequency much greater than the observed magnetic field being sensed by the device.

US Patent:

7411401, Aug 12, 2008

Filed:

Sep 5, 2006

Appl. No.:

11/514980

Inventors:

David M. Hull - Adelphi MD, US
Mark R. Probst - Gaithersburg MD, US

Assignee:

The United States of America as represented by the Secretary of the Army - Washington DC

International Classification:

G01R 29/08
G01R 31/02

US Classification:

324457, 324 72

Abstract:

Systems and methods for reducing electrostatic platform noise in electric-field sensors due to various self-charging and discharging processes are provided. A representative method includes: identifying avoidance regions of an electrostatically-floating sensor platform that have a propensity for self-induced charging and discharging; locating a first electrode and a second electrode on the electrostatically-floating sensor platform, wherein the first electrode and the second electrode are positioned and dimensioned to receive substantially equal amounts of distributed charge via self-charging; and obtaining a differential signal from these two electrodes that is proportional to an external ambient E-field of interest, while at the same time nulling out the common-mode signal that results from sensor platform self-charging and/or discharging.

US Patent:

7529075, May 5, 2009

Filed:

Aug 23, 2006

Appl. No.:

11/513437

Inventors:

David M. Hull - Adelphi MD, US
Stephen J. Vinci - Ellicott City MD, US
Philip N. Repicky - Silver Spring MD, US
Luke E. Sturdevant - Horseheads NY, US

Assignee:

The United States of America as represented by the Secretary of the Army - Washington DC

International Classification:

H01G 7/02

US Classification:

361233

Abstract:

A representative system for providing an electric field comprises an electrically insulated frame, guard members and endplates. The frame incorporates a top, a bottom, opposing sides and opposing ends, with the sides extending between the top and the bottom. Each of the ends engages the top, the bottom and the sides. The frame defines an interior. The guard members are suspended within the interior of the frame, with each of the guard members being formed of metal tubing. The guard members are spaced from each other and located along a length of the frame such that the guard members are oriented substantially parallel to the ends of the frame. The endplates are positioned at the ends of the frame. The frame, guard members and endplates are operative to form an electric field within the interior of the frame responsive to an electric potential being applied to at least one of the endplates.

US Patent:

7701196, Apr 20, 2010

Filed:

Aug 20, 2007

Appl. No.:

11/892151

Inventors:

David M. Hull - Adelphi MD, US
Peter M. Cremona-Simmons - Stafford VA, US

Assignee:

The United States of America as represented by the Secretary of the Army - Washington DC

International Classification:

G01R 25/00

US Classification:

324 7677, 324 67

Abstract:

Methods for detecting and classifying loads on alternating current (AC) lines are provided. One such method includes the steps of placing an AC field sensor in AC electric and magnetic fields generated by an AC line, generating an electric field signal representative of the AC electric field received by the AC field sensor, generating a magnetic field signal representative of the AC magnetic field received by the AC field sensor, generating a relative phase signal representative of relative phase changes between the electric and magnetic fields, and processing the relative phase signal to detect and classify loads on the AC line. In another method, relative load vector signals representative of relative magnitude and phase changes in the magnetic field are generated and processed to detect and classify loads on the AC line.

US Patent:

7920975, Apr 5, 2011

Filed:

Aug 20, 2007

Appl. No.:

11/892152

Inventors:

David M. Hull - Adelphi MD, US
Stephen J. Vinci - Ellicott City MD, US

Assignee:

The United States of America as represented by the Secretary of the Army - Washington DC

International Classification:

G01R 29/08

US Classification:

702 57, 702 58, 702 65, 324117 R, 324249, 32420717, 32420718

Abstract:

Methods of detecting anomalies in ambient alternating current (AC) fields are provided. An exemplary embodiment of such a method includes the steps of placing an AC field sensor in an ambient AC field, generating a signal representative of the ambient AC field received by the sensor, and processing the signal to determine if the ambient AC field includes any anomalies. Various applications for the methods are also provided.

US Patent:

20160327597, Nov 10, 2016

Filed:

May 5, 2015

Appl. No.:

14/704535

Inventors:

- Adelphi MD, US
David M. Hull - Adelphi MD, US

International Classification:

G01R 29/12
G01R 29/24

Abstract:

An electric field sensor having at least a first and second electrically conductive generally planar electrodes that are spaced apart from each other. A circuit is electrically connected to the electrodes which is configured to generate an output signal proportional to a time derivative of a varying electric field surrounding the electrodes. Optionally, three sets of spaced apart electrodes which are arranged perpendicularly relative to each other are used for three-dimensional measurements of the electric field.

US Patent:

20160025666, Jan 28, 2016

Filed:

Jul 22, 2014

Appl. No.:

14/337671

Inventors:

- Adelphi MD, US
David M. Hull - Adelphi MD, US
Gabriel L. Smith - Ellicott City MD, US
Jeffrey S. Pulskamp - Bethesda MD, US
Sarah S. Bedair - Bethesda MD, US

International Classification:

G01N 27/26

Abstract:

According to embodiments, an electric field sensor having a sensor electrode is constructed of an electrically conductive material and having one or more outwardly protruding pillars. A screen electrode overlies the sensor electrode and has one or more openings which register with the one or more pillars on the sensor electrode. At least one piezoelectric actuator is connected to the screen electrode so that, when excited by a voltage signal, the piezoelectric actuator modulates the screen electrode toward and away from the sensor electrode at the frequency of the periodic voltage signal. An output circuit configured to detect a voltage, a current output, or both, between the sensor electrode and the screen electrode which is proportional in magnitude to the strength of the electric field.

US Patent:

20140343878, Nov 20, 2014

Filed:

May 9, 2014

Appl. No.:

14/274259

Inventors:

- Adelphi MD, US
David M. Hull - Adelphi MD, US
James W. Waite - Los Gatos CA, US
Ross N. Adelman - Bethesda MD, US

International Classification:

G01R 25/00
G01R 19/25

US Classification:

702 64

Abstract:

A system and method for estimating the magnitude and phase of magnetic and electrical currents in a power line comprising at least one processor operating to create a model of the power line and derive expected complex magnetic and electric-field values; at least one memory; at least one sensor positioned proximate to the at least one power line for sensing and providing measurements of the magnetic and electric fields of the at least one power line; the at least one processor operating to compute a set of complex magnetic and electric field values based upon the measurements provided by the at least one sensor and to estimate parameters related to the complex voltage and/or current of the at least one power line based upon the measured field values and the set of expected complex electric current and voltage values derived from a model of at least one power line.