Abstract: A piezoelectric transducer hydrophone comprised of a plurality of longitudinal segments is described. The longitudinal segments allow the transducers to be readily attached to cables to form hydrophone arrays. Should a particular transducer become faulty following testing or use of the hydrophone array, the longitudinal segments allow the transducer to be accessed without the need to remove all of the acoustic transducers on the cable between the end of the cable and the one that is faulty.

Abstract: A hydrophone array to perform passive and active sound imaging is described. The array is comprised of a plurality of acoustic transducers attached to a cable that may be towed behind a geophysical survey vessel. The cable and acoustic transducers are enclosed within a sheath of essentially constant external dimensions, which extends longitudinally the length of the cable and which is effective in minimizing turbulent noise created by the array during its use. The sheath may be circular or elliptical in cross-section and can enclose a jacket of resiliently flexible and positively buoyant material that encases the cable and transducers.

Abstract: A process for predictively modelling potential fields in inhomogeneous media is particularly suited for implementation as a Digital Signal Processing chip, as it rapidly predicts the potential field by repeatedly perturbing a trial field solution by a step approximation to the known inhomogeneous media, and then, with one Fast Fourier Transform and one Inverse Fast Fourier Transform, creates a second estimated field solution; a fixed number of such iterations provides a final potential field model, which may be compared with a sensed field to predictively adapt sensor arrays or beam shaping.

Abstract: An improved hydrophone body, suitable for forming an array of towed hydrophone bodies or "fish", formed by placing an acoustic shield or scatterer in the nose and tail sections of the hydrophone body to reduce noise coupling from the cable into the hydrophone sensor. This resulting hydrophone has significantly reduced background noise interference.

Abstract: The current invention discloses a construction of a hydrophone body and hydrophone sensors which provides a significantly enhanced wide band frequency sensor capability within the construction of a sensor array towed in a cable. This construction extends a tuned resonator or sensor along the hydrophone body and into an adjacent section of interconnecting cable. This elongated sensor, in the form of a tubular sensor, provides an enhanced, very low frequency sensing capability within the overall hydrophone array, supplementing the frequency range of the encased hydrophone sensor.

Abstract: A low noise hydrophone which is towed by a cable and has a smoothly increasing front cross-section to a maximum diameter and a smoothly decreasing rear cross-section. The hydrophone sensor is located in the forward section of the hydrophone such that the varying flexural rigidity and shape of the hydrophone results in low turbulence as the hydrophone moves through water.

Abstract: Coherent noise on seismic records is suppressed by reformatting the common shot gathers to common receiver gathers. Pairs of seismic traces from a common receiver gather are corrected for differential normal moveout, weighted in inverse relation to the RMS signal power, and combined to generate compressed common receiver gathers. The compressed common receiver gathers may be reformatted as common midpoint gathers for further processing.

Abstract: An active, low-profile hydrophone for use in aquatic environments having substantially turbulent flow conditions. The hydrophone is generally pisciform such that it may lie substantially flat on the water bottom and oriented in the current so as to reduce ambient noise associated with the turbulent flow. The enclosed sensors are oriented such that they are insensitive to acceleration and are coupled to a unity gain amplifier network also contained within the hydrophone.