Research On Several Key Technologies Of Underwater Acoustic Countermeasure

With the development of self-guided and wire-guided torpedoes and the computer's appliance on torpedoes, modern torpedoes have become intelligent gradually. A variety of surface ships and submarines face serious threat, so as to propose new requirements for anti-torpedo technologies and methods. Based on the background above, the dissertation researches on new methods and new programs for anti-torpedo, including three aspects below:1,The academic prediction of bistatic reverberation average strength. Bistatic sonar has many advantages, such as not undermining the sonar platform hidden performance and having well capability of anti-interference. Bistatic reverberation is one of the important interferences limiting sonar's coverage. The paper studies the analytical expressions of horizontal and vertical bistatic reverberation average intensity and deduces simple formulas for prediction. Analyze the characteristics of bistatic reverberation. Finally, discuss the anti-reverberation performance with zero point directivity of vector sensor.2,The researches on signal processing program for suspended emitting while receiving acoustic decoy. Vector sensor and vector signal processing technology have board application prospects with its unique advantages in the field of underwater acoustic warfare. The vector sensor's zero directivity could suppress most interferences effectively while the suspended acoustic decoy emits and receives simultaneously, which makes the emitting while receiving technology be expected to realize easily. Here puts forward an emitting while receiving signal processing program for suspended acoustic decoy, and estimates signal-to-noise ratio of the program, then introduces some key technologies in detail.3,CBF Variance of Instantaneous Frequency detector (CBF-VIF). The radiation noise of small moving target with high speed contains high frequency line spectrum, while other common platforms do not have the feature. The principle of CBF-VIF is to weigh bearing spectrum using the variance of peak frequency and get the bearing-time falling chart of line-spectrum target. Improve the detector above with two line spectrums competition weight and over limit disposing. The CBF-VIF detector is able to suppress multi-target interferes effectively, and detect faint signal in the background of strong interferes. The simulation and trial results show that the CBF-VIF detector has satisfactory detecting capability.The dissertation dedicates to study simple and stable methods to solve several key technologies of underwater acoustic countermeasure, and the studies could be used as the reference in engineering applications.