1. A system for tracking at least one object being illuminated by a laser designator, the system being configured for use in conjunction with an optical apparatus configured for receiving a light beam scattered by the at least one object in response to illumination from the laser designator, the system comprising: a detector having a sensing surface divided into three sectors, each sector being adjacent to two sectors and all sectors meeting at a central point, the sensing surface of the detector being positioned with respect to the optical apparatus such that the laser beam is projected by the optical apparatus onto the sensing surface as an unfocused spot, and each sector being configured for generating a respective signal indicative of an energy of a portion of the spot illuminating the sector; a data processing apparatus configured for receiving the signals from the detector, and processing the signals to determine an orientation of the system with respect to the at least one target.