(19)

(11)

EP 0 965 055 A1

(12)

(43) Date of publication: 22.12.1999 Bulletin 1999/51 (21) Application number: 98909585.0 (22) Date of filing: 05.03.1998

(51) International Patent Classification (IPC):  G01S 7/ 41( . ) G01S 13/ 88( . ) (86) International application number: PCT/GB1998/000698 (87) International publication number: WO 1998/039670 (11.09.1998 Gazette 1998/36)

(84) Designated Contracting States: DE FR GB IT NL (30) Priority: 06.03.1997 GB 19970004637 (71) Applicant: Marconi Electronic Systems Limited Stanmore, Middlesex HA7 4LY (GB)

(72) Inventors: TAIT, Peter, Donald, Fraser Chelmsford, Essex CM1 2PD (GB) KYTE, Adrian, Peter Chelmsford, Essex CM1 7RX (GB) STEWARD, Peter, James Chelmsford, Essex CM1 6FL (GB) SHEPHARD, David, John Chelmsford, Essex CM2 9LA (GB) FFRENCH, Timothy, Edward Chelmsford, Essex CM1 7RX (GB) (74) Representative: Cockayne, Gillian  GEC Patent Department Waterhouse Lane Chelmsford, Essex CM1 2QX Chelmsford, Essex CM1 2QX (GB)