Accurate Doppler velocity estimation using a non-linear frequency-modulated acoustic pulse

This paper presents a novel method for estimating the Doppler velocity using complex broadband waveforms such as non-linearly chirped waveforms in SONAR systems. For such waveforms, even when the Doppler velocity is constant, the Doppler shift on these waveforms varies across the bandwidth, resulting in a frequency spread, and traditional Doppler velocity estimators based on estimating a single frequency shift do not perform well. The new method uses Evolutionary Algorithms to relate the spread in the spectrum of most complex wide bandwidth signals to the Doppler velocity that caused it. Furthermore, if the signal return is affected by multiple targets, each with Different velocities, the method will resolve each Doppler velocity. The use of this method as a novel means of mitigating range-Doppler coupling is also presented.