Research On Sonar Pulse Detection And Passive Ranging

Detecting sonar pulse transmitted by an active sonar, it is called "sonar pulse detection" . The main task of it is to measure the working parameter of active sonar and track the target. The key technology of it is passive ranging, while the key of ranging is the high precise time delay estimation, which is the main factor that restricts the precision of ranging.The research work of the dissertation includes the following two parts: researching the passive ranging technology of three elements dissymmetrical array and developing system software of the sonar pulse detection module.The main work of the first part includes: analyzing the theory of measuring direction and distance of the target by three elements symmetrical and dissymmetrical array, comparing the measuring error of two kinds of array, discussing the characteristics of time delay in passive distance measurement, giving valid method of time delay estimation, and discussing the restriction of this method and the distance wrapping in passive ranging.In the thesis, a series of real-time system software of sonar pulse detection is developed on an improved hardware system. The main function of the module is as follows: it can detect the CW signal transmitted by the active sonar, and measure the frequency of target signal and the direction of target. It can execute the tracking order sent by the display and control platform, and track the searched target, measure the target signal repetition intervals and target distance, and give the reliability of estimated distance.The arithmetic of measuring frequency, direction and distance issimulated in Matlab, and the simulating results are given. An experiment on the module is carried out with the target simulator ATANC, and the experiment results shows the performance of sonar pulse detection module is good enough.