Passive Pulse Source Ranging Using De-dispersion Transform of Power Spectral Density
The low-frequency sound propagating in the shallow water has the multi-mode characteristic and dispersion effect.The de-dispersion transform of signal frequency spectrum can eliminate the dispersion effect to achieve passive ranging.Focusing on the multi-value problem of the de-dispersion transform of frequency spectrum,a passive ranging method based on the De-Dispersion Transform of Power Spectral Density(PSD-DDT)is proposed.First,the field model KRAKEN is used to calculate the horizontal wavenumbers of each normal mode.Next,given the approximate range of waveguide invariant in the shallow water,the dispersion constant between any two modes is estimated.Then,the power spectral density that retains the modal interference term is subjected to the de-dispersion transform.Finally,the estimated value of the source distance is the ratio of the independent variable corresponding to the maximum amplitude of PSD-DDT to the dispersion constant.In addition,when the waveguide parameters are unknown,PSD-DDT is performed separately on the measured source and the guided source,and the distance is determined by the ratio of the independent variables.This condition does not need to calculate the dispersion constant.The effectiveness of PSD-DDT is verified through numerical simulation and sea trial.The effects of waveguide invariant,mode order,and signal-to-noise ratio on the ranging results are analyzed.Based on the trial data in the Northern Yellow Sea of China,compared with the DDT results,the ranging error of PSD-DDT has decreased by about 49.2%,The relative error within a range of 35 km under the best waveguide invariant is approximately 2.55%with high ranging accuracy.
Target detectionRange estimationDe-dispersion transformWaveguide invariantPower spectrum density