Abstract: The accuracy of underwater terrain aided navigation depends largely on the terrain features of the matching areas. Different matching routes have different effects on navigation performance in the same terrain area and the single terrain characteristic parameter cannot comprehensively evaluate the route navigability of the matching areas. Aiming at this problem, the influence of different terrain on navigation performance is discussed. The navigation coefficient based on the grey fuzzy theory is proposed to analyze the navigability of different matching routes with the terrain characteristic parameters such as the standard deviation of terrain elevation, roughness, correlation coefficient, terrain information entropy and terrain slope comprehensively considered. Subsequently, the point mass filtering 〖JP2〗(PMF) algorithm is used to simulate the navigability of the matching routes with different〖JP〗 navigation coefficients. The simulation results show that the proposed navigation coefficient has better feasibility and strong terrain adaptability in the evaluation of route navigability. In the area whether with rich terrain information or poor terrain information, the navigation coefficient can better evaluate the navigability of the matching route. The method can overcome the problem of incomplete evaluation of navigability with single characteristic parameter and insufficient research on route selection. It has great value in engineering practice for underwater route planning and improving terrain aided navigation performance.

Key words: terrain aided navigation, matching route, terrain characteristic parameters, grey fuzzy theory, navigation coefficient, he point mass filtering (PMF) algorithm