| 摘要 |
PURPOSE:To improve the discrimination accuracy of a current position of a travelling object by calculating a mean value of plural reception electric field strength values corresponding to each fixed station discriminated by a mobile station at an interval of a prescribed time, comparing the mean values, specifying a fixed station giving the largest mean value and using the value as a position data. CONSTITUTION:A mean value of reception electric field strength values by two times of radio waves sent twice from radio equipments 9A-9C of each fixed station at an interval of a prescribed time respectively is calculated and the radio equipments 9A-9C of the fixed station side giving the largest value are specified to discriminate the current position of fork lifts 1A-1D. Thus, the radio equipments 9A-9C of the fixed station side giving a maximum reception electric field are specified by taking a fluctuation error of the reception electric field due to fading into account. As a result, even when fading may easily take place when the fork lifts 1A-1D are driven, the current position is discriminated with higher accuracy. |
