Carl R Nelson

US Patent:

6564741, May 20, 2003

Filed:

May 24, 2002

Appl. No.:

10/155199

Inventors:

Carl V. Nelson - Rockville MD

Assignee:

The Johns Hopkins University - Baltimore MD

International Classification:

B63B 3544

US Classification:

114264, 405205

Abstract:

A telescoping spar structure designed to be scalable for use with very large floating platforms to relatively small floating platforms includes a platform/hull for supporting a payload; a telescoping spar attached to the platform/hull that includes several interlocking tubes extending from a shallow end to a deep end of the spar, the tubes configured to telescope in and out of adjacent tubes such that the tubes are nestable together in a stowed configuration; a buoyancy chamber attached to the spar between shallow and deep ends of the spar; and, a damping chamber attached to the spar between the buoyancy chamber and the deep end of the spar, the damping chamber including: a first compartment for entraining a volume of water, a second compartment for enclosing deployment ballast, and a release mechanism for jettisoning the deployment ballast from the second compartment after the spar structure is deployed, enabling the platform to rise to an operational height relative to the waterline.

US Patent:

6600320, Jul 29, 2003

Filed:

Aug 13, 2001

Appl. No.:

09/928632

Inventors:

Yanping Guo - Silver Spring MD
Harvey W. Ko - Ellicott MD
Carl V. Nelson - Rockville MD
David M. White - Silver Spring MD

Assignee:

The Johns Hopkins University - Baltimore MD

International Classification:

G01V 308

US Classification:

324336, 324334

Abstract:

A unique time-domain electromagnetic system and data processing technique which, using low frequency electromagnetic fields, can localize, in three-dimensions, the position of buried metallic objects is disclosed. The measurement system uses time-domain electromagnetic techniques on a scanning frame similar to a X-Y plotter. The system collects magnetic data over a large area above the buried object. The spatial information of the field detected on the ground is then processed with an unique ânearfield holographicâ data processing method to reconstruct the field image of the buried object.

US Patent:

6661345, Dec 9, 2003

Filed:

Oct 19, 2000

Appl. No.:

09/691893

Inventors:

Matthew G. Bevan - Silver Spring MD
Henry A. Kues - Sykesville MD
Carl V. Nelson - Rockville MD
Paul R. Schuster - Baltimore MD

Assignee:

The Johns Hopkins University - Baltimore MD

International Classification:

G08B 2300

US Classification:

340575, 340576

Abstract:

A system and method for monitoring the alertness of a subject are provided. A Doppler sensor is disposed to sense a parameter pertaining to the subject, the sensor being one of an acoustic sensor and a microwave sensor. Signals from the sensor are processed through an alertness monitoring algorithm for generating processed signals. It is thereafter determined whether an impairment of alertness event pertaining to the subject has occurred based on the processed signals. Feedback is then provided to the subject based on a determination of whether an impairment of alertness event pertaining to the subject has occurred.

US Patent:

6791329, Sep 14, 2004

Filed:

Aug 16, 2002

Appl. No.:

10/222055

Inventors:

Carl V. Nelson - Derwood MD

Assignee:

The Johns Hopkins University - Baltimore MD

International Classification:

G01V 308

US Classification:

324329

Abstract:

A metal detector system including a chassis for supporting electromagnetic sensor components above a medium such as soil or water. A transmitter coil and two receiver coils are attached to the chassis. A propulsion system is attached to the chassis between or adjacent to the receiver coils. The location of the propulsion system causes electromagnetic interference signals emanating from the propulsion system to be received at a nominally equal magnitude by each of the receiver coils.

US Patent:

6809520, Oct 26, 2004

Filed:

Jan 3, 2003

Appl. No.:

10/332095

Inventors:

Carl V. Nelson - Derwood MD

Assignee:

The Johns Hopkins University - Baltimore MD

International Classification:

G01V 311

US Classification:

324329, 324326, 324239, 89 113

Abstract:

A device operative to detect metal objects. The device includes a transmitter circuit, an upper transmitter coil and a lower transmitter coil operatively connected to the transmitter circuit. A current fed through the upper transmitter coil and the lower transmitter coil generates a field that excites eddy currents in metal objects in the vicinity of the upper transmitter coil and the lower transmitter coil. An upper magnetic field detector and a lower magnetic field detector are operative to sense eddy currents generated in the metal objects. Processor elements operatively connected to the upper magnetic field detector and the lower magnetic field detector collect, store and analyze the eddy currents and thereby determine the likelihood that a metal object has been detected. A navigation system operatively connected to the processor elements controls movement of the device. Transporting elements operatively connected to the navigation system are operative to support the device and permit alteration of a position of the device.

US Patent:

6853194, Feb 8, 2005

Filed:

Mar 20, 2001

Appl. No.:

10/181471

Inventors:

Carl V. Nelson - Rockville MD, US
Dexter G. Smith - Columbia MD, US

Assignee:

The Johns Hopkins University - Baltimore MD

International Classification:

G01V003/11

US Classification:

324329

Abstract:

A time-domain electromagnetic target discriminator (ETD) sensor system and method are provided capable of measuring a metal target's time decay response based on the physical parameters of the metal target and its environment and for identifying the metal target. The ETD sensor system includes a pulse transmitter connected to a receiver via a data acquisition and control system. The transmitter and receiver include coil configurations for placement in proximity to a visually obscured, e. g. , buried, metal target (or underground void) for inducing eddy currents within the metal target. The ETD sensor system measures the eddy current time decay response of the metal target in order to perform target recognition and classification. The identification process entails comparing the metal target's (or, underground void or other object's) time decay response with a library of normalized object signatures, e. g. , time decay responses and other characteristics.

US Patent:

6927577, Aug 9, 2005

Filed:

Sep 16, 2004

Appl. No.:

10/942145

Inventors:

Carl V. Nelson - Derwood MD, US

Assignee:

The Johns Hopkins University - Baltimore MD

International Classification:

G01V003/10

US Classification:

324329, 324330

Abstract:

A method of improving pulse inductive metal detector sensitivity by minimizing adverse ground responses and transmitter coil transients is disclosed. The method provides a calibration mode for a typical pulsed EMI metal detector. The purpose of the calibration mode is to determine and record a nulling signal representative of the transmitter coil coupling to the receiver coil and a ground response that has no metal. The nulling signal is then used during normal operation of the metal detector by combining it with the instant receiver coil signal in a difference amplifier. The difference amplifier effectively subtracts the nulling signal from the instant signal yielding a response signal that has removed the ground response that may be present in the instant signal. The metal detector can be periodically re-calibrated. It may also be re-calibrated upon discovery of a metal target to provide the most up to date nulling signal for the ground around the metal target.

US Patent:

6967574, Nov 22, 2005

Filed:

Dec 19, 2003

Appl. No.:

10/742046

Inventors:

Carl V. Nelson - Rockville MD, US

Assignee:

The Johns Hopkins University - Baltimore MD

International Classification:

G08B013/24

US Classification:

340551, 340552, 3405722, 324228, 324239, 342 70

Abstract:

A multi-mode electromagnetic target discrimination sensor system for transmitting an electromagnetic signal and receiving a reflected signal from at least one target is disclosed having a variable inductance antenna having a variable inductance transmitter and a variable inductance receiver for varying at least one of operating bandwidth, sensitivity and size of the antenna, a processor for alternating between a time domain operating mode and a frequency domain operating mode, and controlling the variation of the inductance of the variable inductance antenna based on a current operating mode, and at least one processing algorithm for receiving signals from the receiver, discriminating targets from the received signals, and outputting the discrimination results is disclosed.