Research On Dipping Sonar Search Technology For Submarine

Because of the high speeds, strong flexibility, high search efficiency, large detectionrange, conceal and security, little-threatened by enemy submarine and good attacking effect,aviation antisubmarine has received more and more attention from every country’s navy, andsimultaneously has become the most effective way to detect, locate, track, and attacksubmarine. By relying on the advantages such as small size, light weight, flexibility, andrepeat applicability, dipping sonar has changed into one of the important airborneanti-submarine equipments at present. In order to search the targeted submarine with thefastest speed in the shortest time, and improve the search effectiveness of antisubmarinehelicopter, the dipping sonar algorithm for searching submarine is thoroughly and specificallyresearched based on the actual situation of army’s aviation antisubmarine in this paper. Themain contents researched in this paper are as follows:Firstly, the research background and significance of this paper are introduced briefly.Along with the development of airborne anti-submarine equipments, the research on thedipping sonar search algorithm has been made accordingly. There are two main directions forthe research of dipping sonar algorithm for searching submarine:(1) submarine searchtechnology—search algorithm design, aiming at researching how to use dipping sonar forsearching the randomly-avoided targeted submarine with the fastest speed in the shortest time;(2) submarine search effectiveness—estimation on the effective submarine search distance ofdipping sonar, aiming at researching the effect of marine environmental changes on theeffective submarine search distance of submarine search equipments on the condition ofmarine environmental noise changes and through simulation analysis. In this paper, submarinesearch technology is researched, namely the design and optimization of submarine searchalgorithm.Secondly, combined with the practical application of airborne anti-submarine, fourtypical dipping sonar algorithms (fan, square, rectangular, and saw-tooth) for searchingsubmarine are modeled and simulated, and also their submarine search probabilities arecalculated respectively with Monte Carlo method. Results are as follows: whatever avoidancestrategy is used in the targeted submarines, the fan and square submarine search algorithmsare better than the rectangular and saw-tooth algorithms, and also the saw-tooth algorithm issuperior to the rectangular algorithm. For the targeted submarine with known losing pointlocation but unknown general movement direction, the selection of dipping multiples is aproblem and two common avoidance ways used in submarine can’t be considered if therectangular search algorithm is applied to searching submarine. Therefore, an improvement isnecessary.Thirdly, the optimal search algorithm of discrete space-time target is researched, and thenthe optimal search strategy when the discrete target distribution function is known and thesearch probability estimation and errors when the discrete target distribution function isunknown are specifically analyzed, so that a direction is clearly shown for optimizing thesubmarine search algorithm. The results of researching the discrete space-time target optimal search technology showthat a distribution function can be assumed and also the optimal search strategy can bedetermined if the distribution function of the target location is unknown. To search based onthis strategy, the probability of searching the actual target depends on the error between theassumed distribution function and the actual distribution function. That is, if the error issmaller, the probability of searching the actual target is much closer to the optimal searchprobability.In the actual tasks searching submarine, the real distribution function of the targetedsubmarines is difficult to be accurately described. It is assumed that targets are uniformlydistributed in all search areas, the optimal search submarine strategy is equally distributing thesearch time of each point. This search strategy is the easiest to implement and also is better inline with the actual situation. Therefore, in the typical submarine search algorithms, it isreasonable to distribute the same search time in each dipping point, and the focus of theoptimization on each point should be placed on the selection of each dipping point, namelythe moving track of the anti-submarine helicopter should be reasonably planned.Fourth, the dipping sonar optimization search algorithm based on spiral lines isresearched. As the dipping multiples of the square algorithm in conscripting anti-submarineare difficult to choose, the submarine search algorithm model based on spiral lines isestablished. According to the submarine search steering angle, this algorithm model isimproved and optimized, and then the submarine avoidance speed scope covered by thisalgorithm and the effect of submarine avoidance course angle on the submarine searchprobability are analyzed, and finally the submarine search algorithm based on spiral lines issimulated. The results show that the submarine search algorithm based on spiral lines featuresshort search time, less steering times, less dipping points, and high submarine searchprobability compared with the square search algorithm in the same conditions.Finally, the anti-submarine search path when dipping sonar is used in anti-submarinehelicopter is optimized by using the genetic algorithm, and also the algorithm model isdesigned and simulated. Results show that the submarine search probability of this is high andalso the search efficiency is ideal after it is optimized by the genetic algorithm. This suggeststhat the application of the genetic algorithm to the optimization of the dipping sonarsubmarine search algorithm is a method with research value, but this method owns thedisadvantages such as complex algorithm, large calculation, and too long operation time, sofurther research and simplification are required in project implementation.