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:
Dec. 14, 1999
Filed:
Nov. 21, 1997
Clifford Dana Leitch, Coral Springs, FL (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
A communication system (700) comprises a plurality of base sites (702-708) which include a first antenna (712) for transmitting a synchronous communication protocol such as a paging protocol and a second antenna (714) for transmitting a rotating phase signal. A communication device (250) takes the synchronous communication protocol and develops a reference signal (220) from the received protocol. The communication device (250) takes the reference signal (220) and the received rotating phase signal (214) and uses a phase detector (216) to produce a phase difference signal (232) which is substantially equal to the angle of the communication device (250) with respect to the particular base site (702-708) which transmitted the signals. In order to determine the location of the communication device at least two such phase difference signals (232), one phase difference signal from at least two different base sites is determined. In the preferred embodiment, the phase difference signals (232) are transmitted by the communication device (250) to a paging system controller (710) for calculation of the proximate location of the communication device (250).