A system for determining the distance between a target (4) and a laser guided weapon traveling towards the target (4). The system (1) comprises a laser designator (5) on a remote platform (2) for radiating a first train of pulses (l1) on a set wavelength in the direction of the target (4). In the weapon (3) a receiver (6) is arranged to receive and detect pulses on the set wavelength reflected from the target (4). There is also a direction sensing means in the weapon (3) for determining the direction of the target (4). A transmitter (7) is arranged in the weapon (3) to periodically transmit a second train of pulses (l2) on the set wavelength in the direction of the target (4). There are means in the receiver (6) to extract a reflection from the target (4) of the second train of pulses (l2). There are further timing means to determine the period of time from transmitting the second train of pulses (l2) to receiving the reflection from the target (4) of the second train of pulses (l2). Computing means (8) are arranged for determining a distance corresponding to said period of time.