Simultaneous localization of a surface ship and a submerged towed source (L).

The cascade of blind deconvolution and array invariant has been successful for localizing a single source, either a surface ship or a submerged source, using a vertical array without knowledge of the environment or source waveform in shallow water. In this letter, the blind deconvolution is extended to a two-source case where individual Green's functions are separately extracted by exploiting a distinct group of modes strongly excited at different source depths. The subsequent array invariant confirms that a surface ship and a towed source at 50-m depth can be simultaneously localized using a 56-m long vertical array in 100-m deep shallow water.