(19)

(11)

EP 0 521 945 A1

(12)

(43) Date of publication: 13.01.1993 Bulletin 1993/02 (21) Application number: 91906446.0 (22) Date of filing: 28.03.1991

(51) International Patent Classification (IPC):  G01S 17/ 36( . ) (86) International application number: PCT/GB1991/000480 (87) International publication number: WO 1991/015782 (17.10.1991 Gazette 1991/24)

(84) Designated Contracting States: DE FR GB (30) Priority: 30.03.1990 GB 19900007248 (71) Applicant: IMATRONIC LIMITED Newbury, Berkshire RG14 5SJ (GB)	(72) Inventors: RAPER, Keith 4 Gravel Road Aldershot Hampshire GU13 0BB (GB) STREET, Graham, Stewart, Brandon Impstone House Silchester Reading Berkshire RG7 2NU (GB) (74) Representative: Garratt, Peter Douglas, et al  Mathys & Squire 100 Grays Inn Road London WC1X 8AL London WC1X 8AL (GB)