| 摘要 |
PURPOSE:To enable determination of the direction of advance of a mobile station in relation to a fixed station by a method wherein a signal obtained by inverting the logic of bits of a unique word is emitted from a separate antenna of the fixed station. CONSTITUTION:Receiving a frame as an input, a unique word inverting element 2 inverts only the logic of bits of a unique word part 22 therein and outputs it. Modulating elements 4 and 5 modulate a carrier wave by outputs of a data constructing element 1 and the inverting element 2. Antennas 4 and 5 transmit the modulated waves through amplifying elements 6 and 7. Patterns 10 and 11 of the antennas 8 and 9 are made to have main emission directions opposite to each other and the line of the main direction is made to coincide with the line of a road, for instance. When a mobile station 12 moves in the direction of an arrow on the road, data containing an identification code of a fixed station is received together with a unique word of a regular bit pattern, and from the time point when the mobile station passes the fixed station, the logic of bits of the unique word is inverted. In the mobile station 12, therefore, the direction of advance in relation to the fixed station can be determined. |
