A Novel 3-D TSS-FDTD for Distinguishing Underwater Targets at Low Frequency

A novel three-dimensional total-field scattered-field source finite-difference time-domain (TSS-FDTD) method is presented to analyze the propagation properties of low-frequency electromagnetic wave in underwater. The proposed method includes two-step FDTD calculations. The first calculation space is meshed with a fine cell size. The second is meshed with a coarse cell size. In addition, the ratio of a coarse cell size to a fine cell size is set to an arbitrary positive integer, such as N=11 in this letter. Numerical results prove the accuracy and validity of the proposed method. An analysis of the results shows that the run time spent in TSS-FDTD accounts for 0.35% of that in the conventional FDTD, and the consumed memory is 3.9% of that spent in the conventional FDTD.