Motion effect modeling in multipath configuration using warping based lag-Doppler filtering

Abstract

The estimation of the impulse response (IR) of a propagation channel is necessary for a large number of acoustic applications: underwater communication, detection and localization, etc. Basically, it informs us about the distortions of a transmitted signal in one channel. This operation is usually subject to additional distortions due to the motion of the transmitter-channel-receiver configuration. This paper points on the effects of the motion while estimating the IR by matching filtering between the transmitted and the received signals and introduces a new motion compensation method. Knowing the transmitted signal, the "apparent" speed of each propagation path can be estimated using wideband ambiguity function [1]. Indeed, some interference appears in the wideband ambiguity plane because of the multipath propagation. A warpingbased lag-Doppler filtering method is proposed allowing us to accurately estimate the IR of the channel.

Time-varying wideband underwater acoustic channel estimation for OFDM communications

“…To best fit the UWA model with matched time-scale transformations, the dictionary atoms are designed to match the channel propagating nature by selecting them to be time-delayed and Doppler scaled versions of the transmitted signal s(t) as in (3). We can thus choose them using the wideband ambiguity function (WAF) of the transmitted signal [10,12]. Using the MPD, the ith atom in the dictionary will correspond to g i (t) = √ η i s(η i (t−τ i )), η i = 0.…”

On the consideration of motion effects in the computation of impulse response for underwater acoustics inversion

“…A compensation method that considers the speed of each ray individually should lead to a more general result and is one of our short term prospects. 20…”

Wideband discrete transformation of acoustic signals in underwater environments

“…Two additional days of measurements were also conducted by SHOM to collect data for the geoacoustic inversion testing. Results based on the BASE07 experiment can be found in [2], [13], [14]. The real data we used was collected from a shallow water environment on the Malta Plateau.…”