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:
Jun. 28, 1994
Filed:
Sep. 18, 1992
Applicant:
Inventor:
Yukiharu Shimizu, Tokyo, JP;
Assignee:
NEC Corporation, Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
B64G / ;
U.S. Cl.
CPC ...
356230 ; 2502521 ;
Abstract
A calibration system for periodically calibrating an optical instrument on board a satellite with reference light. In the disclosed system, a calibration unit has two photodetectors one of which is positioned near the light source which radiates reference light and the other near the aperture from which the reference light emerges toward optics of the instrument. Therefore, it is possible to discriminate between contamination or degradation of the optical instrument and contamination of the calibration unit. Two identical and independent calibration units are employed to provide redundancy and enhance the accuracy of calibration.