Iterative closest contour point for underwater terrain-aided navigation

Behzad (1999) introduced iterative closest contour point (ICCP) from image registration to underwater terrain matching and provided its exact equations and proved its validity with an example. Bishop (2002) proved its validity extensively. However, it was assumed in their research that the matching origin was known exactly while it was seldom satisfied in practice. Simulation results indicated that ICCP diverged easily when the initial INS error was very large (such as 2 nautical miles). Two enhancements, adding the matching origin into matching process and the coarse matching, were put forward to resolve the problem. Simulation results showed that the updated ICCP matches application conditions very well and converges with very high precision. Especially, when INS precision is not high, the updated ICCP matching process is more stable and its precision is higher than TERCOM's.