(19)

(11)

EP 0 271 524 A1

(12)

(43) Date of publication: 22.06.1988 Bulletin 1988/25 (21) Application number: 87903653.0 (22) Date of filing: 21.05.1987

(51) International Patent Classification (IPC):  G01R 31/ 02( . ) (86) International application number: PCT/US1987/001180 (87) International publication number: WO 1987/007730 (17.12.1987 Gazette 1987/28)

(84) Designated Contracting States: DE FR GB (30) Priority: 05.06.1986 US 19860871197 (71) Applicant: HUGHES AIRCRAFT COMPANY Los Angeles, California 90502 (US)	(72) Inventor: CALDWELL, Michael, P. Canoga Park, CA 91307 (US) (74) Representative: Colgan, Stephen James, et al  CARPMAELS & RANSFORD 43 Bloomsbury Square London WC1A 2RA London WC1A 2RA (GB)