A Statistical Model for Vessel-to-Vessel Distances to Evaluate Radar Interference

The maritime traffic is significantly increasing in the recent decades due to its advantageous features related to costs, delivery rate and environmental compatibility. With the advent of the new generation of marine radars, based on the solid state transmitter technology that calls for much longer transmitted pulses, the interference problem can become critical. Knowing the positions and the heights of the ships the mean number of the vessels in radar visibility can be estimated to evaluate the effects of their mutual radar interferences. This paper aims to estimate the probability density function of the mutual distances. The truncation of the density function, within a limited area related to the horizon visibility, leads to a simple single-parameter expression, useful to classify the ships as either randomly distributed or following a defined route. Practical results have been obtained using AIS data provided by the Italian Coast Guard in the Mediterranean Sea.