The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 09, 1999
Filed:
Dec. 18, 1997
Charles J Soulliard, Tucson, AZ (US);
Herschel W Ward, Tucson, AZ (US);
Stephen M Matacia, Phoeniz, AZ (US);
Midian Electronics, Inc., Tucson, AZ (US);
Abstract
A vehicle detector comprising a flux gate magnetometer with vertical and horizontal sensing coils is positioned within a roadway. The ambient levels of the earth's magnetic field as sensed by the magnetometer are used to establish reference levels and deviations therefrom are evaluated by a microprocessor which produces a vehicle arrived signal when the vertical component of sensed perturbations exceed a threshold and in an alternate mode when either vertical or horizontal levels exceed threshold values. Both vertical and horizontal levels must fall below threshold levels to determine a departure in either mode. Vehicle arrival and departure events are encoded as NRZ data packets which are transmitted by an edge-fired antenna as FM modulated signals. A remote multi-channel receiver capable of responding to a plurality of magnetometer modulated FM transmitters processes the received data and provides signals that are used by traffic signal controlling computers.