Position location system for vehicles on predetermined routes - contains position coding units and vehicle transducer and computer

摘要

An arrangement for determining vehicle position on a predetermined route contains position code devices transforming instantaneous position to the vehicle point by point. The vehicle has a distance pulse transducer and a computer on board. The system is designed to enable the vehicle to repeatedly and automatically generate correction factors for distance errors. Along the predetermined route the vehicle passes through one or more calibration sections whose beginning and end are communicated to it via the position coding units. The computer automatically derives a correction factor from these inputs and takes account of it in summing the pulses from the distance measurement transducer. The beginning of the section is identified by a special bit pattern from a code unit. The end is identified by a normal message from the next unit.