(19)

(11)

EP 0 772 762 A2

(12)

(43) Date of publication: 14.05.1997 Bulletin 1997/20 (21) Application number: 95934958.0 (22) Date of filing: 28.07.1995

(51) International Patent Classification (IPC):  G01C 19/ 56( . ) (86) International application number: PCT/US1995/009533 (87) International publication number: WO 1996/004525 (15.02.1996 Gazette 1996/08)

(84) Designated Contracting States: DE FR GB IT NL SE (30) Priority: 29.07.1994 US 19940282757 (71) Applicant: LITTON SYSTEMS, INC. Woodland Hills, CA 91367 (US)	(72) Inventors: STEWART, Robert, E. Woodland Hills, CA 91364 (US) WYSE, Stanley, F. Encino, CA 91316 (US) FERSHT, Samuel, H. Studio City, CA 91604 (US) (74) Representative: Maury, Richard Philip  Sommerville & Rushton, 45 Grosvenor Road St. Albans, Herts AL1 3AW St. Albans, Herts AL1 3AW (GB)