Abstract

A navigation system for detecting the position and controlling the movement of an automatically guided vehicle (1) comprises at least one light source (4) and at least one detector (5) responsive to the light emitted from the light source (4), the vehicle (1) be accompanied by either the light source (4) or the detector (5). A signal processing unit (10) has memory means (13) in which path control information (12) corresponding to the path (3) of the vehicle is stored, and comparator means (11) adapted to compare the path control information (12) stored in the memory means (13) with positional information produced by the system, in order, when the path control information and the positional information differ, to emit control signals (15) for the movement of the vehicle. The detector (5) is a position-sensitive semiconductor detector having a substantially planar, extended, continuous sensing area (7) and is adapted to receive light within a restricted part (P) of the sensing area of the detector. In response to the detected light, electric signals are produced from which said positional information (9) corresponding to the actual position of the vehicle (1) in at least one direction is derived.