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:
Jul. 27, 1999
Filed:
Apr. 30, 1997
Mark A Birchler, Roselle, IL (US);
Debra A Jones, Schaumburg, IL (US);
Nicholas C Oros, Schaumburg, IL (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
Signals comprising time of transmission indications relative to a common time base (302) are transmitted by at least two fixed transceivers (110-116). When the signals are received by a mobile unit (160), a time of reception indication relative to the common time base is calculated for each signal. Pseudo-ranges are calculated based on the time of transmission and time of reception indications, and a WLS solution location estimate is calculated based on the pseudo-ranges. Essentially the same procedure may be performed on signals transmitted by the mobile unit. Given the common time base between the fixed transceivers and the mobile unit, only two or more signals are required to determine the location estimate. Where GPS receivers are used to supply the common time base, location determinations can still be made when a GPS solution is unavailable.