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(11)

EP 0 641 447 A1

(12)

(43) Date of publication: 08.03.1995 Bulletin 1995/10 (21) Application number: 93910255.0 (22) Date of filing: 21.05.1993

(51) International Patent Classification (IPC):  G01S 5/ 10( . ) G01S 11/ 08( . ) (86) International application number: PCT/GB1993/001050 (87) International publication number: WO 1993/023765 (25.11.1993 Gazette 1993/28)

(84) Designated Contracting States: AT BE CH DE DK ES FR GB GR IE IT LI LU MC NL PT SE (30) Priority: 21.05.1992 GB 19920010859 (71) Applicant: RACAL POSITIONING SYSTEMS LIMITED New Malden, Surrey KT3 4NR (GB)	(72) Inventor: WARNER, Edward, Steven 8 Pen-Y-Mor Road Penlan West Glamorgan SA5 7EF (GB) (74) Representative: Cross, Rupert Edward Blount, et al  BOULT, WADE & TENNANT 27 Furnival Street London EC4A 1PQ London EC4A 1PQ (GB)