Depth estimation of an underwater target by the method of time reversal mirror

231-236<span style="font-size:9.0pt;font-family: " times="" new="" roman","serif";mso-fareast-font-family:"times="" roman";mso-ansi-language:="" en-us;mso-fareast-language:ar-sa;mso-bidi-language:ar-sa"="" lang="EN-US">Time reversal mirror (TRM) refocuses the received signal back to the original source location regardless of the complexity of the medium of propagation. When the medium contains several reflectors, the time reversal process can be used to focus on the desired target. Two arbitrary scatterers are positioned in the oceanic waveguide at different ranges and depths. Assuming that range of the focused scatterer is known approximately, the converged transmission vector through TRM may be matched against the computed eigenvector corresponding to the largest eigenvalue of the modeled channel transfer matrix between the transmitter and a test scatterer (at test depth) in order to determine the depth of the focused scatterer. Note that this approach of matching with the focused transmission vector leads to an improved depth estimation performance due to better SNR gain over a conventional matched field processor without TRM.