Relative ship positioning based on optimal distributed fusion in the MITS

Marine intelligent transport system, in short MITS, is a wireless sensor networks where the communications of shipping information are frequent. For most of the current ship navigation positioning methods they only consider how to fuse the navigation information obtained by the active integrated positioning system which is composed of GPS, SINS, TNS, and SMS and so on, that is active integrated navigation positioning estimate (AINPE). As a result, the abundant information in the MITS can´t be effectively used. Additionally, GPS possesses the fallibility in the practical application, the uncertainty of practical environment and the insecurity in the control authority. So, in order to improve the accuracy and reliability of the ship integrated navigation positioning system, a novel ship positioning algorithm based on optimal distributed fusion of sensor networks and relative estimates is presented in this paper. The proposed method uses the active integrated navigation positioning estimate from other ship and relative position information between two ships to improve the target ship´s AINPE by use of the distributed information fusion technology. Compared with the target´s AINPE, the proposed relative positioning algorithm has better positioning accuracy, higher stability and better fault-tolerance capability because it uses more positioning information and the information fusion technology. Both the algorithm analysis and a simple simulation example show the validity and advantage of the proposed algorithm.