Albert Phillip Simpson

US Patent:

55067026, Apr 9, 1996

Filed:

Apr 7, 1994

Appl. No.:

8/224220

Inventors:

Albert P. Simpson - Rancho Palos Verdes CA

Assignee:

Northrop Grumman Corporation - Los Angeles CA

International Classification:

G02B 532
G01C 2102

US Classification:

359 15

Abstract:

An artificial star is disclosed for use with an optical system (10) that has at least one optical axis (14a). The optical system includes an entrance aperture (14) through which the at least one optical axis passes and a radiation detector (22) having a radiation receiving surface. The optical system also includes an optical train having at least one optical element (16, 18, 20). The at least one optical train is disposed for receiving radiation from the entrance aperture, for directing the received radiation along the at least one optical axis, and for focussing the received radiation onto the radiation receiving surface of the radiation detector. In accordance with the invention the optical system is provided with a source (26) of electromagnetic radiation that outputs a diverging beam (26a); and also with a holographic optical element (28) disposed at the entrance aperture for receiving the diverging beam, for collimating the diverging beam into a collimated beam (26b), and for directing the collimated beam into the at least one optical train to be parallel with the at least one optical axis. As a result, an image of the source is provided at the radiation receiving surface of the radiation detector, the image functioning as an optical reference, or artificial star, for the purposes of calibration, alignment, and/or system operation verification.