Abstract: Apparatus and methods for reducing ghosts from hydrophone signals in a streamer towed underwater close to the sea surface. A multi-axis micro-electro-mechanical-system (MEMS) accelerometer with attitude sensing is used to reduce the frequency spectral notch in the response of the combined hydrophone-accelerometer system and to reduce the sensitivity to ghost-producing downward traveling acoustic waves that are sea-surface reflections of the primary upward traveling acoustic waves. Multi-axis spring load cells provide high compliance and mechanical isolation between stress members and the accelerometer system. The load cells also provide signals representing the vibration of the stress members. The signals can be used with an adaptive filter estimating the mechanical transfer function between the vibration and the motion of the accelerometer system to remove the vibration-induced noise from the accelerometer signals.

Abstract: A method for processing data from dual sensor receivers to produce a combined seismic trace. A first seismic trace is received from a geophone and second seismic trance from a hydrophone in a dual sensor receiver. This first and second seismic traces are transformed into a first and second seismic spectrum. The seismic spectrums are deghosted to obtain deghosted spectrums. The seismic spectra may be added to obtain a deghosted third spectrum. An inverse power is computed for each of the deghosted spectra. The inverse powers for each deghosted spectra are divided by sums of the deghosted spectra to obtain diversity filters. The first and third diversity filters are applied to the first seismic spectrum to obtain a scaled first seismic spectrum. The other scaled spectra are formed in a like manner. The diversity scaled seismic spectrum is inversely transformed to obtain the combined seismic trace.