Simulation And Forecast Of High-frequency Sonar Receiving Signal

The simulation and forecast about receiving signal of high-frequency sonar plays a very important role in different stages of sonar design. As follows, this paper completes four kinds of receiving signals:1. One-way propagation signal: high-frequency sonar emits signal, which transmits single path and received by hydrophone. This kind of transmission is always applied in underwater communication, location, guidance.2. Echo signal of underwater target: high-frequency sonar emits signal on target, such as submarine, torpedo, then the backscattered signal from target transmits to hydrophone. This type of transmission is usually used in detecting and identifying.3. Reverberation of sea bottom: parts of the signal from sound generator are backscattered by sea bottom, which is received by hydrophone as reverberation.4. Echo signal of sea bottom: high-frequency sonar emits signal on sea bottom, then the backscatter signal transmits to hydrophone. This kind of signal is adapted to simulate the signal of bathymeter and side-scanning sonar.In the simulation of four kinds of receiving signals, transmission model is an important part. This paper adopts Gaussian Ray Bundle (GRAB) theory as the modeling method, because that the ray theory is fit for high-frequency. GRAB is a ray-based model, which overcomes the disadvantages of traditional ray theory. In a certain range, every single ray has contribution for any depth.Finally using Visual C++ as platform, this paper programs the man-machine interface, which can display receiving signal wave through the setting of specified marine conditions. It also uses DLL to realize calling Fortran programs, and realize the function of displaying colorful graphic by mixing programming between VC and Matlab.