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. 28, 2004
Filed:
Apr. 30, 2002
Nikki J. Lawrence, Tucson, AZ (US);
Thomas K. Lo, Oro Valley, AZ (US);
Joshua A. Whorf, Tucson, AZ (US);
Mark S. Moellenhoff, Tucson, AZ (US);
Raytheon Company, Lexington, MA (US);
Abstract
A tracking system controls an aimed device ( ) to keep it aimed at a target ( ). A control system ( ) determines when the tracker has lost its lock on the target ( ) by comparing the target's instantaneous acceleration with its median acceleration. When the difference exceeds a predetermined threshold, the system searches backwards through a chronological buffer until it finds position data which antedate the receipt of inaccurate position data from the tracker. A second-order filter such as a Kalman filter is used to provide estimated target states. The difference between a time updated output from the second-order filter ( ) and the present measured state from the tracking device is low pass filtered to provide a measurement of the instantaneous acceleration of the target. The buffer ( ) stores position, velocity, and median acceleration values covering a span of time at least about twice as long as the time required to determine that a breaklock has occurred.