ABSTRACT
In general, the ocean has a complicated channel structure. Two basic channels have received wide attention when conducting passive source location and motion estimation. In one basic type, the raypath linking the source to the receiver's subarrays is situated in the azimuthal or horizontal plane that is parallel to the ocean boundaries. In the other type, the raypaths are in the vertical plane which is normal to the reflecting boundaries, and this type is referred to as the multipath channel. For both channels, passive localization has relied on the relative delay in signal arrival times at the sensors. In general, the existence of a multipath channel lends itself to long-range estimation due to the comparatively increased separation between the effective subarrays. The statistical quality is defined for the snapshot estimates that result in multipath ranging. The similarity between this ranging mechanism and that of wavefront curvation ranging is determined also.
