Fusion of radar tracks, reports and plans

This paper suggests a method that utilizes non-real time information as an aid to improve maritime surveillance. Under certain conditions vessels move in accordance with preplanned routes and possibly also report their own position at certain positions or at certain times during the voyage. The method proposed consists of a statistical route model that describes the movement of the vessel, and includes refinement of the estimated movement based upon reports on the vessel. The estimated movement is then associated with radar tracks using multiple hypothesis techniques. This is due to the fact that the number of vessels with known route plans is small compared to the total number of vessels in an area. The associated radar tracks are also used to improve the estimated movement of the vessels. The problem of generating possible solutions and selecting the best hypothesis is formulated as a constraint satisfaction problem and implemented using a constraint programming technique.