Thomas Black 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:

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.