(19)

(11)

EP 1 005 773 A1

(12)

(43) Date of publication: 07.06.2000 Bulletin 2000/23 (21) Application number: 98940367.0 (22) Date of filing: 24.08.1998

(51) International Patent Classification (IPC)7: H04Q 7/38 (86) International application number: PCT/GB9802/538 (87) International publication number: WO 9911/086 (04.03.1999 Gazette 1999/09)

(84) Designated Contracting States: AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE (30) Priority: 23.08.1997 GB 9717844 (71) Applicant: CAMBRIDGE POSITIONING SYSTEMS LIMITED Cambridge CB1 2JB (GB)	(72) Inventors: DUFFETT-SMITH, Peter Cambridge CB4 4QS (GB) HARROLD, William, Basil Cambridge CB3 7LE (GB) FOGG, Andrew Sandy,Bedfordshire SG19 3AD (GB) (74) Representative: Brunner, Michael John  GILL JENNINGS & EVERYBroadgate House7 Eldon Street London EC2M 7LH London EC2M 7LH (GB)