Abstract: A method and a system for locating objects in a defined area, such as for locating animals in a pen, wherein each segment of the defined area is projected by a narrow angle projection; and the projection is modulated, the modulation including the location of the segment being projected. A self-location-unit is attached to each object for receiving the projection, decoding the modulation having the self-location segment, and transmitting the self-location. A receiver receives each transmission from each self-location-unit, and stores each object's location segment. The system has at least one projector which periodically scans at least part of the defined area, and produces the narrow angle projection that is modulated with information about the location that is being projected. At least one stationary unit receives the self-location information from each object's self-location-unit and displays and/or stores the received locations.