System for detecting position of moving vehicle

Claim 1

In a system for detecting a position of a moving vehicle wherein light signals radiated from light emitting means provided at at least four reference points apart from the moving vehicle are received, and the position and an advance direction of the moving vehicle are detected on the basis of received signals of the light emitted from three particular reference points of the at least four reference points, said system comprising: light-receiving means mounted on the moving vehicle and rotating in a horizontal plane for receiving the light signals, means for detecting azimuths of the reference points in respect of the advance direction of the moving vehicle on the basis of the light signals at the light-receiving means, means for determining the differential azimuths between the adjoining two reference points of all said four reference points viewed from the moving vehicle, means for calculating the sum for each pair of said differential azimuths adjoining each other, means for selecting a combination of a particular two of said adjoining differential azimuths with which the calculated sum of said two selected adjoining differential azimuths becomes largest among the sums of said other pairs, and means for determining the position and the advance direction of the moving vehicle on the basis of the selected two differential azimuths and the coordinate values of the three reference points forming the selected two differential azimuths.