Marine Battlefield Environment Assessment Methods Researches For Submarine Navigation Safety

In the21century, it is a key task to exploit and utilize the ocean, which depends on astrong navy. The activity range of the navy is the ocean battlefield environment. The oceanbattlefield environment assessment is one part of the study on the marine battlefieldenvironment. Additionally, submarine with concealment and many other advantages, is animportant platform for underwater warfare, and it is an important offshore assault power fornavy as well. As a result, it’s a crucial factor to assess how the marine environment hasimpact on the submarine combat capability. Moreover, the submarine navigation safety is thebase of submarine combat. The marine environment assessment for submarine navigationsafety can provide necessary scientific foundation for effective route selection and stand-byregion determination. However, the study of the marine battlefield environment assessment ofsubmarine navigation safety still needs more efforts. There is no systematic, formal andrational evaluation system until so far. Thus, it can’t satisfy the demands of the modernwarfare security. It has not only important academic value but also significance of applicationto establish a complete marine battlefield environment assessment system for submarinenavigation safety. In this thesis, how the various factors infect the submarine navigationsafety is analyzed, and the evaluation index systems for submarine navigation safety andconcealment are established. Submarine navigation safety and concealment are evaluated bymathematical methods. The main works can be summarized as follows:Firstly, the evaluation index systems for submarine navigation safety and concealmentare established, and how the various factors have impact on submarine navigation safety andconcealment is analyzed. Then the indicators are determined, and the evaluation indexsystems for submarine navigation safety and concealment are established based on theseindicators.Secondly, the fuzzy comprehensive evaluation based on improved super-standard weightis proposed. In this thesis, the super-standard weight is introduced into the assessment ofsubmarine navigation safety. According the problems of the present super-standard weightdetermination methods, a new method is proposed where the super-standard weight isdetermined by membership; The Zadeh operator is decided as the fuzzy composite operatormatched with super-standard weight. The weight vector is improved in case that just theweight is taken when the fuzzy composite takes the min operation between the weight vectorand membership matrix, because when there are many evaluation indexes, the weight vector will be very small.Thirdly, weights are determined by index scale. The index weights of submarinenavigation concealment are determined by Analyzed Hierarchy Process (AHP). According tothe index scale which is better in reciprocal scales, the importance ranks are extended, and thevalue range of importance ratio is given; It is proposed to construct totally consistent sensecomparison matrix, and keeping the original information of sense comparison matrix istransformed into a quadratic programming problem. Finally, an algorithm to calculate theindex weight is proposed. This algorithm needs small calculation and fits the actual situation.Fourthly, submarine navigation safety and concealment are assessed. The evaluationgrades are devided into six grades. All membership functions are determined by uniformlydevided gradient function. The fuzzy comprehensive evaluation method based on improvedsuper-standard weight is taken to evaluate the submarine navigation safety; AHP based onindex scale and two-tier fuzzy comprehensive evaluation method are taken to evaluate thesubmarine navigation concealment. The fuzzy synthesis operator adopts weighted averageoperator. Finally, examples demonstrate the assessment process of submarine navigationsafety and concealment. Demonsrated results show that the proposed assessment method ismore accurate.Finally, transmission of membership function under fuzzy mapping and a new idea ofsubmarine concealment evaluation are discussed. At first when the simple fuzzy inversemapping is one-to-many, an algorithm to calculate membership function is given forimproving the transmission of fuzziness. Moreover, under certain assumptions, the fuzzytransmission theorem of general multivariable function is proposed and proved. Based on thisprinciple, the explicit expression of membership function after mapping can be given forconvenient calculation. Then, using calculation formula of marginal probability for reference,if the multivariable membership function is given, one single variable membership functionwill be calculated, and the corresponding proof is given too. This formula is convenient forpractical application and calculation. At last, based on the probability formula of sonarsearching submarine, it is proposed that to evaluate the submarine concealment by using thetransmission of membership function.The study in this thesis is not only the content of marine battlefield environmentalassessment, but also the application and theoretical research of fuzzy comprehensive evaluation and AHP. The marine environment assessment for the submarine navigation safetyin this thesis provides a criterion to decision-makers for decision making.