David M Hull

US Patent:

6404547, Jun 11, 2002

Filed:

Mar 1, 2000

Appl. No.:

09/516798

Inventors:

David A. Hull - Manhattan Beach CA

Assignee:

Raytheon Company - Lexington MA

International Classification:

G02B 2300

US Classification:

359399, 359365, 359366, 359820, 359859

Abstract:

A centrally-obscured reflective telescope having a semi-active focus and thermal compensation system. The telescope has a housing having an input window, a primary mirror, a secondary mirror suspended between the input window and the primary mirror by support struts, an optional tertiary mirror, and an optional fold mirror. The system includes one or more heating elements respectively disposed on each of the support struts. A first temperature sensor (disposed on the primary mirror) generates a reference temperature, a second temperature sensor is disposed on the secondary mirror, and one or more third temperature sensors are disposed on each of the support struts. A temperature compensation controller is coupled to the heating elements and temperature sensors and controls the heat output of the plurality of heating elements to heat the support struts and control the position of the secondary mirror relative to the primary mirror.

US Patent:

6501268, Dec 31, 2002

Filed:

Aug 18, 2000

Appl. No.:

09/641370

Inventors:

Alan S. Edelstein - Alexandria VA
David M. 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 device that senses low frequency magnetic fields by using movable flux concentrators that modulate the observed low frequency signal. The concentrator oscillates at a modulation frequency much greater than the observed magnetic field being sensed by the device. The modulation shifts this observed signal to higher frequencies and thus minimizes 1/f-type noise. This is preferably accomplished by the oscillatory motion of a microelectromechanical (MEMS)âtype 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 modulating flux concentrator is used with the magnetic sensor.

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:

20120257275, Oct 11, 2012

Filed:

Apr 8, 2011

Appl. No.:

13/082860

Inventors:

David A. HULL - Manhattan Beach CA, US

Assignee:

RAYTHEON COMPANY - Waltham MA

International Classification:

G02B 23/02
G02B 23/16

US Classification:

359399

Abstract:

Thermal wake proximate to an optical element of a telescope may be reduced. Signal(s) related to respective temperatures of support struts supporting the optical element may be generated. The respective temperatures of the support struts may be determined based on the signal(s). Individual support struts may be heated based on the respective temperatures of the support struts. Heating a given support strut may cause the given support strut to thermally expand. Individual support struts may be at least partially enclosed with corresponding shrouds. Airspaces may be disposed between individual support struts and the corresponding shrouds. Heat emitted in the airspaces by the support struts may be ejected away from the optical element to prevent a thermal wake from reaching a volume proximate to the optical element.