Acoustic Wideband Techniques For The Remote Estimation Of The Sea Current Velocity

Abstract

Innovative wideband signals and related echo processing for acoustic remote estimation of sea currents are investigated via doppler profiling techniques. The cur- rent velocity-component along the acoustic beam propaga- tion direction can be obtained by exploiting the frequency shift, with respect to the transmitted signal, of the spectrum of the echo reverberated from the ensonified volume. The problem of deriving the "optimal" wideband waveform to be transmitted, i.e., the waveform that minimizes the statistical fluctuation of the estimate, is addressed. Two particular waveforms, multitone (MT) and frequency shifted keying (FSK), are considered with the aim of reducing the measurement fluctuation. The performances obtainable by applying synthesized echo processors to these waveforms are assessed by means of numerical simulations on syn- thetic model-based echoes.