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:
Feb. 12, 2002
Filed:
Jan. 05, 2000
John W. Smay, Redondo Beach, CA (US);
John F. Yocum, Rancho Palos Verdes, CA (US);
Salma Saeed, Santa Monica, CA (US);
Hughes Electronics Corporation, El Segundo, CA (US);
Abstract
A method, apparatus, article of manufacture, and a memory structure for controlling an attitude and a nutation of a spacecraft spinning about a first axis. The method comprises the steps of measuring a spacecraft attitude rate &ohgr; (t) about a second axis substantially orthogonal to the first axis; generating a rate correction value &agr;&ohgr; (t)/&lgr; , wherein &lgr; is an inertial nutation frequency of the spinning spacecraft, and &agr; is a proportionality factor; determining a spacecraft attitude angle &phgr; (t) about a third axis substantially orthogonal to the first axis and the second axis; generating an error signal e(t) as &phgr; (t)+&agr;&ohgr; (t)/&lgr; ; and applying a torque to rotate the spacecraft along the second axis. The article of manufacture comprises a program storage device storing instructions implementing the instructions described above. The apparatus comprises an attitude rate sensor for measuring the spacecraft attitude rate &ohgr; (t) about a second axis substantially orthogonal to the first axis; means for measuring a spacecraft attitude angle &phgr; (t) about a third axis substantially orthogonal to the first axis; a processor, in communication with the attitude rate sensor, for generating an error signal e(t)=&phgr; (t)+&agr;&ohgr; (t)/&lgr; , wherein &lgr; is an inertial nutation frequency of the spinning spacecraft, and a is a proportionality factor; and a torquer for applying a torque to the spacecraft along the second axis in accordance with the generated error signal e(t).