Robust range-rate estimation of passive narrowband sources in shallow water
This paper addresses the problem of range-rate estimation of narrowband passive sources in multipath environments. Although range-rate can be derived from a sequence of matched-field range-depth estimates, such an approach requires accurate modeling of the phase differences between normal modes which is difficult to achieve in practice. Alternatively, estimation of range rate by resolving the differential Doppler components in a narrowband multipath return requires exceedingly long observation times. In this work, robust range-rate estimation is achieved by exploiting the complex temporal fading of unresolved narrowband signals which is a function of differential multipath Doppler spread. Different modal components are modeled as independent processes which makes the estimator robust to environmental mismatch. The performance of the proposed Independent Mode Range-Rate Estimator (IMRE) is shown to compare favorably with the Cramer Rao Lower Bound. IMRE results with real SWELLEX-96 are presented with rangerate estimates made at 20 second update rates which compare favorably with GPS ground-truth measurements. © 2005 IEEE.
