Abstract: A railway positioning system provides an on-board speed measurement device (6) inducing eddy currents in the wayside structure at two spots along the travelling direction, measuring the variations of the magnetic field emitted by the wayside structure and determining position and speed by correlating the 2 measured signals known from U.S. Pat. No. 5,825,177 and a wayside coded tag (1) providing a coding recognizable by the onboard speed measurement device (6). The coded tag (1) consists of a bar (4) with several slots (3) in which metal blocks (2) of different sizes are mounted. The block sizes and positions are selected to represent a coding according to Quadrature Amplitude Modulation.

Abstract: A railway positioning system provides an on-board speed measurement device (6) inducing eddy currents in the wayside structure at two spots along the travelling direction, measuring the variations of the magnetic field emitted by the wayside structure and determining position and speed by correlating the 2 measured signals known from U.S. Pat. No. 5,825,177 and a wayside coded tag (1) providing a coding recognisable by the onboard speed measurement device (6). The coded tag (1) consists of a bar (4) with several slots (3) in which metal blocks (2) of different sizes are mounted. The block sizes and positions are selected to represent a coding according to Quadrature Amplitude Modulation.

Abstract: A rail mounted vehicle speed measuring device includes a first magnetic field generating member and a first magnetic field sensing member positioned at a first measuring location on the vehicle; a second magnetic field generating member and a second magnetic field sensing member positioned at a second measuring location on the vehicle, spaced a fixed distance from the first location in the direction of vehicle movement; wherein the magnetic fields generated by the first and second magnetic field generating member are influenced by the rail to produce first and second signal patterns sensed by the first and second sensing member and varying with movement of the vehicle along the rail; and device is provided for correlating the first and second sensed signal patterns to determine the time displacement between the two sensed signal patterns and the velocity of the vehicle.