Study Of Time-reversing Mirror Retrofocusing In Shallow Ocean

Acoustic Time Reversing Mirror(TRM) can be implemented with an array of transducers that listens to a remote sound source and then transmits a time reversed version of what was heard. TRM is a promising technique for spatial and temporal focusing of sound in unknown environments.Ocean is a complicated and changeable channel which may distort the signal and degrade the performance of sonar system.The genesis, phylogeny and the study status of TRM is simply introduced in the paper so that this theory is realized as a whole. The principle and the focusing in shallow ocean of TRM are analyzed and simulated.The performance of TRM is deterred by the size, longevity, field amplitude of the array's retrofocus and the correlation of the retrofocus signal with the original signal, and related to many parameters, such as waveguide geometry, sound-speed profiles, reflectivity and attenuation in the ocean.A model of shallow ocean is established. Under the character of ocean channel is unchanged, many parameters which will influence on the performance of the TRM is analyzed , such as the length of original signal,the time of receiving, the number of TRM elements, the aperture of TRM, the shift of original and the noise.The simulation results give some reference to the designing and application of TRM.