Collision and Detection Performance with Three Overlap Signal Collisions in Space-Based AIS Reception

Abstract

A space based receiving system for signals of the Automatic Identification System (AIS) will extend the coverage of the existing ground network which is limited to the coastal zone (around 40 nautical miles) to open seas. With newly available satellite-based AIS receivers, the complete global ocean shipping fleet of about 60,000 ships (AIS Class A, that is, terminals with a transmitted power of 12 W and report messages with a rate that ranges from two seconds to three minutes, depending on their navigation status (speed, course,)) can be tracked. In the previous theory analysis on performance of AIS receiver, it is assumed that signal collisions cannot be resolved. Each message collision event results in the loss of all colliding messages, while any message without collision is successfully detected. In this paper we investigate a theory analysis model on three signals overlap collision scenario in space-based AIS receiver. In comparison to the previous works which assumed signal collisions could not be resolved, this paper discusses three signals overlap collision probability and detection probability which assumes that signal collisions can be resolved by some special methods. In fact, the problem of message collision can be mitigated by applying some innovative technologies, such as a satellite antenna architecture optimization strategy and an innovative receiver scheme. Simulation are used to validate the proposed analysis model of computing collision probability and detection probability. The results show that simulation results have good consistent with that of the theory model. The analysis model can be used to guide the computing of the collision and detection probabilities for three signals overlap collision situations when signal collisions can be resolved by using some innovative technologies.