Detection of affine time-delay multipath striations using a generalized cyclostationary model

An important feature available in certain scenarios for the underwater sonar detection of broadband signals is the formation of "striated" patterns in spectrograms. The observed striations can be modeled by a broadband multipath signal whose time delay between arrivals is slowly varying linearly. This model leads to generalized notion of cyclostationarity where the cyclic frequency varies linearly with frequency. In this paper noncoherent and coherent methods to detect these broadband energy patterns based on this model are presented and demonstrated on a nontrivial example. While noncoherent methods cannot distinguish between the positive and negative delay rates, coherent methods determine both the sign in addition to an estimate of the initial multipath delay.