Study on underwater terrain matching positioning based on the integration of TERCOM and MCTM

Based on the current situation of underwater navigation, this paper presents an underwater topographic matching navigation method which is the integration of TERCOM and MCTM algorithm. First of all, we use the TERCOM to acquire a rough position of vehicle. Secondly, a search area is found according to TERCOM positioning result. The multi-contour matching algorithm is implemented in the area. The algorithm is based on the chain code. By means of the code technique, all of contours are coded. Then, each contour coded in the real-time terrain is matched with the corresponding background one. Each matched contour can provide a set of transformation parameters between the real-time terrain and the background. According to all of the transformation parameters acquired from different contour matches, a weighted average is adopted so as to acquire the accurate transformation parameters. Finally, By means of the final transformation parameters, the actual location of underwater vehicle is given out.