Thomas G Murdock

US Patent:

6560535, May 6, 2003

Filed:

Jul 3, 2002

Appl. No.:

10/169514

Inventors:

Larry J. Levy - Columbia MD
Thomas Thompson - Silver Spring MD
David S. Hohman - Woodbine MD
Thomas M. Murdock - Eldersburg MD
Edwin E. Westerfield - Silver Spring MD
Thomas M. Hattox - Silver Spring MD
Thomas L. Kusterer - Elkridge MD

Assignee:

The Johns Hopkins University - Baltimore MD

International Classification:

G01C 2126

US Classification:

701213, 701208, 701214

Abstract:

A real-time integrated navigation system for a vehicle includes a GPS receiver, connected to a first antenna, where the GPS receiver receives GPS data from satellites and outputs GPS position data. The system also includes a communications link, connected to a second antenna and to the GPS receiver, receiving range and carrier phase measurements from at least one base station. The system further includes navigation aids which provide relative position data of said vehicle and a Kalman filter, connected to the output of the GPS receiver and the navigation aids, that integrates the GPS position data and the relative position data and outputs smoothed position data. The smoothed position data is used in transportation applications, especially detection of lane departure. This GPS-based positioning system is suitable for highway speeds during all weather conditions.

US Patent:

6898235, May 24, 2005

Filed:

Dec 10, 1999

Appl. No.:

09/457724

Inventors:

Joe Carlin - Ashburn VA, US
Terry Collins - Springfield VA, US
Peter Hays - Fairfax VA, US
Barry E. Hemmerdinger - Annandale VA, US
Robert L. Kellogg - Rockville MD, US
Robert L. Kettig - Herndon VA, US
Bradley K. Lemmon - Herndon VA, US
Thomas E. Murdock - Burke VA, US
Robert S. Tamaru - Reston VA, US
Stuart M. Ware - Silver Spring MD, US

Assignee:

Argon ST Incorporated - Fairfax VA

International Classification:

H04B001/38
H04L005/16

US Classification:

375219, 375316, 342147, 342423

Abstract:

A physically compact, wideband signal activity identification, demodulation and characterization, and direction finding device incorporates multiple and cascadable digital signal processing modules operating in asynchronous real time. The digital signal processing modules include a device for data buffering, a device for digital signal processing (DSP), and a device for high-speed data routing. The module device for data buffering is composed of, among other memory devices, a First In Tap Out (FITO) data buffer that may be accessed at any point for delay or faster than real time resynchronization by the DSP module device. The module device for digital signal processing function incorporates a general purpose digital processor for respective module calculation of overlapped hyperchannelization Fast Fourier Transforms (FFT). Hyperchannels may be combine in a flexible manner to tailor channel bandwidth for optimum signal spectral detection of signal activity, synthesis filter and tuning, demodulation and recognition, and direction finding. The module device for high-speed data routing is composed of one-to-one, one-to-many, or many-to-one digital data routing functions, and allows flexible ordering of digital signal processing modules.

US Patent:

7068362, Jun 27, 2006

Filed:

Jan 22, 2003

Appl. No.:

10/348890

Inventors:

Thomas M. Murdock - Eldersburg MD, US
Kirk S. Decker - Catonsville MD, US
James T. Velky - Baltimore MD, US
Karen D. Rennich - Elkridge MD, US

Assignee:

The Johns Hopkins University - Baltimore MD

International Classification:

G01J 1/44
G01N 21/00

US Classification:

356226, 356432, 356218

Abstract:

The present invention provides apparatus for a beam transmissometer. In an embodiment, the beam transmissometer includes a LED signal source, collimating apparatus, a retroreflector that directs the projected beam, imaging apparatus that directs the beam onto a detector that converts the projected beam into an electrical signal, and signal processing circuitry that enhances the reception of the optical beam. The LED signal source is modulated in a pulsed fashion so that the effects of beam reflection are ameliorated. Signal processing circuitry amplifies, filters, and synchronizes to the electrical signal. A calculating unit uses the processed signal to determine a beam attenuation coefficient, which is indicative of the visibility of a medium in which the transmissometer is immersed. A method is also provided for aligning optics of a beam transmissometer. The method determines an offset and a rotation of a retroreflector housing that causes an optical beam to be centered.