in more detail below in order to realign itself with the target the missile 201 will perform calculations based on a number of parameters including the u201c target range u201d u201c missile range u201d and u201c closing range u201d the target range defines the true distance along the line of sight of the target 203 from the optical sight 205 whilst the missile range defines the distance of the missile 201 along the line of sight from the laser transmitter 209 the target range may be measured on one of several ways known in the art for example the target range may be determined using a separate laser range finder provided in the same unit as the missile launcher optical sight alternatively the target range may be determined by use of a radar based system again associated with the same unit as the missile launcher optical sight other conventional means for determining the distance from the optical sight to the target may also be employed the target range may be communicated to the missile using the laser transmitter 209 that is in addition to the spatial information encoded in the inter pulse separation the laser beam emitted from the laser transmitter 209 may also be used to transmit data to the missile 201 indicating the target range as discussed above the optical sight 205 and laser transmitter 209 are co located with one another and the missile launcher 211 this means that the target range and missile range are both measured from the same point of origin in practice the nature of these devices means that the optical sight and.