Transfer of Detection Contacts to Tracking Contacts in Surveillance

Surveillance of a region is conducted by using a search system to detect targets and a tracking system or force to follow them. After the search system detects a target, the tracking force will attempt to gain contact, usually by a local search. Before the tracking force detects the target, and thereby completes transfer, contact may be lost by the search system. If recontact is made by the search system, the new contact will be used by the tracking force to localize its search for the target. As the local search by the tracking force proceeds, contact by the search system may be lost and regained a number of times. The probability of transfer is obtained under the assumption that the transfer rate decreases as the time since last contact by the search system increases. The particular problem considered is that of sea surveillance for submarines, in which the search system is a fixed field of sensors and the tracking force consists of mobile units, such as ships, aircraft, and helicopters. However, the model can be adapted to other transfer problems, such as the transfer of a contact by a search radar to contact by a tracking radar.