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:
Sep. 09, 1997
Filed:
Jul. 18, 1996
Kristine Patricia Maine, Phoenix, AZ (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
A constellation of satellites which are distributed around the earth serves as a communications infrastructure that supports autonomous position determination and reporting of that position to a remote location. Satellites continuously broadcast acquisition signals. Position determining units are remotely programmed to activate upon the occurrence of an activation event. If PDUs can capture an acquisition signal, then they engage in activities which lead to determining their position and they coordinate their communications with the requirements of the communications infrastructure. To determine position, a location pulse may be transmitted on a regular schedule. The location pulse is transported between a fast moving satellite and a PDU. The movement of the satellite causes different location pulses to have different propagation delays and Doppler characteristics. By analyzing changes in propagation delays and Doppler characteristics, a procedure determines a position for a PDU.