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. 06, 2001
Filed:
Feb. 02, 1998
Richard S. Torkington, Mesa, AZ (US);
Thomas P. Emmons, Jr., Mesa, AZ (US);
Keith Warble, Chandler, AZ (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
A zero-drift constellation (,FIG.,) is used to simplify the tracking and hand-off requirements of terrestrial-based user terminals (,FIG.,). Each satellite (,FIG.,) traces out a common ground track which has a number of southbound segments and an equal number of adjacent northbound segments. This allows user terminals (,) to employ antennas with only one degree of freedom to track satellites (,) in zero-drift constellation (,). User terminals (,) perform hand-offs with satellites (,) that are within a limited field of view with respect to user terminal (,). User terminal (,) tracks a first satellite until a crossover point is reached and then performs a hand-off to a second satellite traveling in the opposite direction along an adjacent segment. User terminal (,) tracks the second satellite until another crossover point is reached and then performs a hand-off to a third satellite traveling in the same direction as the first satellite along an adjacent segment.