Doppler characteristics of sea surface reflected and scattered acoustic signals induced by surface wave motion

Propagation and Scattering Effects in Underwater Acoustic Communication Channels

“…It is interesting to note that measurements of sea-surface backscatter have yielded a negative Doppler shift when transmitting downwind, and a positive shift when transmitting upwind [51]. The present forward-scatter measurement gives a positive shift for downwind transmission.…”

“…The Doppler spectrum in Fig. 5 has a sharp peak at 0 Hz that reflects the static part of the channel, sidelobes at 0.6 Hz corresponding to the dominant frequency of the surface gravity waves [51], and a continuum of weaker sidelobes. The correlation functions fall off rapidly from a value of 1 to 0.6, and then remain practically constant.…”

“…1). Surface gravity waves have a strong effect on signal propagation [12], [42], [45], [49]- [52], including time-varying path lengths [15], [41], [44], [53]- [55] and corresponding frequency shifts [51], [56], [57]. Even hydrodynamically calm surfaces are important scatterers of acoustic energy at high frequencies [45].…”

Simulation of wind-generated surface waves and effects of bubbles on scattering, transmission, and attenuation of low frequency sound at the sea surface

“…The wide range of subjects in this area, e.g., underwater communication channels [2][3][4][5][6][7][8], evaluation of sonar performance [9][10][11], marine life [12][13][14], oceanography [15][16][17] among others, has led to numerous researches which have concentrated on these influential phenomena on the sound. Doppler effects [18][19][20][21], attenuation and absorption [22][23][24][25], bubble population [26][27][28][29], and sound transmission [12,[30][31][32][33] as well as the environmental conditions such as wave propagation in shallow water [2,[34][35][36], surface waves [37][38][39][40], and bottom effects [41][42][43] can be considered as interesting Abstract Sea surface virtual acoustic simulator lab (SSVASL) is a software based on a newly presented reformed Helmholtz-Kirchhoff-Fresnel method developed in FORTRAN programming language. Based on the resonance dispersion model (RDM), bubbles d...…”

Estimation and reduction of effects of sea surface reflection on underwater vertical channel

“…In addition, the simultaneous presence of advancing surface wave front in the surface-reflected arrival signal results in Doppler and time-varying delays [9]- [10]. The method of relating the surface-radiated acoustic signals to the waveheight spectrum can be traced back to [10]- [12]. Walree et al [13] presented measured spectra of the amplitude fluctuations affected by surface waves that have significantly sharper peaks with longer tails than those of Gaussian.…”