Navigation equipment for a moving vehicle

Claim 1

Navigation equipment for a vehicle comprising, a magnetic field probe (1) for obtaining measured values for the direction of travel, a travel distance meter (2) for obtaining measured values for the distance travelled, a plat memory (4) in which it stores a digitized street may (41) of a region in a coordinate system, a logic means (3) which receives the outputs of said magnetic field probe and of said travel distance meter and calculates position indications of the vehicle referred to the coordinate system, and storing said indications in a position memory (52), a correction stage (5) connected to said plat memory (4) and said position memory (52) and checks every n th position indication and when said n th position indication does not lie on a street of the street map (41), said correction stage corrects said n th position indication to form a position value (X, Y) which corresponds to a point on a neighboring street, said street map (41) of the region is divided into a network (42) composed of network elements (421) of identical size; every network element (421) has an address in the plat memory (4) allocated to it, one of two binary characters being stored under said address, whereby one binary character identifies a positive network element (421) which lies mainly on a street and the other binary character identifies a negative network element which does not lie mainly on a street; said correction stage (5) includes an error memory (51) which contains the respectively m most recent position indications of the checked position indications which fall on a negative network element (421) which has said one binary character that indicates that the vehicle is not on a street; the position indications from the error memory (51) are successively shifted with a shift value until a correction value is found, so that the position indications shifted therewith fall on a network element (421) which lies mainly on a street and the position indications stored in the error memory (51) are subsequently erased; and every position indication is corrected by the correction value and the result is output as said position value.