Abstract: The invention relates to a target tracking system comprising two identical stationary and mutually distant sub-systems (5, 6), each sub-system including a laser source (7, 8) and two perpendicularly pivotable mirrors (10, 11), such that a laser beam can be directed by each sub-system towards the moving target (4). Each sub-system further includes a lateral effect photodetector (18) receiving the light beam after its reflection on the target, which is a reflecting target (4) of the cat's eye type. The pivot positions of the mirrors (10, 11) are adjustable in accordance with control signals derived from the detector (18) such that the respective beam tends to approach the center of the target (4) and that it is reflected in itself. Each mirror is pivoted by a brushless DC motor (12, 13). The common pivot shaft of the motor and of the mirror is further coupled to a digital angle encoder (16, 17) which delivers signals to calculator means (27, 29) for evaluating the present 3D coordinates of the target.