Abstract: A technique includes representing actual measurements of a seismic wavefield as combinations of an upgoing component of the seismic wavefield and ghost operators. Interpolated and deghosted components of the seismic wavefield are jointly determined based at least in part on the actual measurements and the representation.

Abstract: A technique includes determining a displacement of an acoustic sensor while in tow. Based on the determined displacement of the sensor, a measurement that is acquired by the sensor is compensated to remove noise from the measurement.

Abstract: A technique includes towing a particle motion sensor in connection with a seismic survey and controlling the survey to cause a notch in a frequency response of the particle motion sensor to substantially coincide with a frequency band at which aliased vibration noise appears in a seismic signal acquisition space of the particle motion sensor.

Abstract: System and method for detection and tracking of targets, which in a preferred embodiment is based on the use of fractional Fourier transformation of time-domain signals to compute projections of the auto and cross ambiguity functions along arbitrary line segments. The efficient computational algorithms of the preferred embodiment are used to detect the position and estimate the velocity of signals, such as those encountered by active or passive sensor systems. Various applications of the proposed algorithm in the analysis of time-frequency domain signals are also disclosed.

Abstract: To calibrate an accelerometer, a seismic cable that carries the accelerometer is rotated. Data measured by the accelerometer as the seismic cable is rotated is received, and at least one calibration parameter according to the received data is computed. The at least one calibration parameter is for use in calibrating the accelerometer.

Abstract: A technique includes estimating propagation parameters that are associated with a towed seismic survey based at least in part on seismic signal measurements and noise measurements.

Abstract: A technique includes obtaining particle motion data and pressure data that are acquired by seismic sensors while in tow. The sensors are part of a plurality of streamers, and the pressure and particle motion data contain surface ghosts. The technique includes processing the particle motion data and the pressure data to generate a data set that is indicative of a pressure wavefield at positions between the streamers and is substantially free of the surface ghosts.

Abstract: A technique for decomposing a recorded wave field represented in a set of multicomponent, marine seismic data centers around a computer-implemented method including: estimating the statistics of the noise terms in each one of a predetermined group of seismic measurements in a seismic data set acquired in a marine survey; modeling the physical propagation of a recorded wave field represented in the seismic data set from the estimated statistics; and estimating a directional component of the recorded wave field from the physical propagation model that minimizes error relative to the seismic measurements.

Abstract: A technique includes obtaining a noise measurement, which is acquired by a seismic sensor while in tow. Based on the noise measurement, a compensation for at least one of an alignment of the sensor and a calibration of the sensor is determined.

Abstract: The present invention provides a method and apparatus for seismic data acquisition. One embodiment of the method includes accessing data acquired by at least two particle motion sensors. The data includes a seismic signal and a noise signal and the at least two particle motion sensors being separated by a length determined based on a noise coherence length. The method may also include processing the accessed data to remove a portion of the noise signal.

Abstract: The present invention relates to active sensor applications, and more particularly is directed to efficient systems and methods for detection and tracking of one or more targets. The invention provides a method for receiving signals reflected from one or more targets, processing the received signals and the transmitted signal to compute two or more slices of the cross ambiguity function associated with the signals, and estimating the signal delay and the Doppler shit associated with the targets from the computed slices.

Abstract: A system and method for spread spectrum communication primarily for use in mobile CDMA communication systems. The system receiver has simplified architecture, comprising a channel compensator and correlation detector. The channel compensator has a channel estimator and signal constructor. In a preferred embodiment, the channel estimator periodically computes the cross-ambiguity function of the transmitted and received pilot signals of the CDMA system using computationally efficient processing algorithms. The signal constructor uses the estimated multipath parameters to construct a new signal on which effects of the multipath channel is considerably mitigated.

Abstract: System and method for detection and tracking of targets, which in a preferred embodiment is based on the use of fractional Fourier transformation of time-domain signals to compute projections of the auto and cross ambiguity functions along arbitrary line segments. The efficient computational algorithms of the preferred embodiment are used to detect the position and estimate the velocity of signals, such as those encountered by active or passive sensor systems. Various applications of the proposed algorithm in the analysis of time-frequency domain signals are also disclosed.

Abstract: System and method for detection and tracking of targets, which in a preferred embodiment is based on the use of fractional Fourier transformation of time-domain signals to compute projections of the auto and cross ambiguity functions along arbitrary line segments. The efficient computational algorithms of the preferred embodiment are used to detect the position and estimate the velocity of signals, such as those encountered by active or passive sensor systems. Various applications of the proposed algorithm in the analysis of time-frequency domain signals are also disclosed.

Abstract: A system and method for spread spectrum communication primarily for use in mobile CDMA communication systems. The system receiver has simplified architecture, comprising a channel compensator and correlation detector. The channel compensator has a channel estimator and signal constructor. In a preferred embodiment, the channel estimator periodically computes the cross-ambiguity function of the transmitted and received pilot signals of the CDMA system using computationally efficient processing algorithms. The signal constructor uses the estimated multipath parameters to construct a new signal on which effects of the multipath channel is considerably mitigated.

Abstract: A method of attenuating noise in three dimensional seismic data using a projection algorithm is disclosed. A frequency—space—space (“f-xy”) projection algorithm is used which is a generalization of the f-x projection algorithm. The predictability of the seismic signals in the f-xy domain constitutes the basis of the algorithm. Specifically it is demonstrated that if the seismic events are planar in the t-xy domain, then in the f-xy domain they consist of predictable signals in the xy-plane for each frequency f. A crucial step of the 2-D spectral factorization is achieved through the helical coordinate transformation. In addition to the disclosed general algorithm for arbitrary coherent noise, a specialized algorithm for random noise is disclosed. It has been found that the disclosed projection algorithm is effective even in extreme cases of poor signal to noise ratio. The algorithm is also signal preserving when the predictability assumptions hold.

Abstract: System and method for detection and tracking of targets, which in a preferred embodiment is based on the use of fractional Fourier transformation of time-domain signals to compute projections of the auto and cross ambiguity functions along arbitrary line segments. The efficient computational algorithms of the preferred embodiment are used to detect the position and estimate the velocity of signals, such as those encountered by active or passive sensor systems. Various applications of the proposed algorithm in the analysis of time-frequency domain signals are also disclosed.

Abstract: System and method for detection and tracking of targets, which in a preferred embodiment is based on the use of fractional Fourier transformation of time-domain signals to compute projections of the auto and cross ambiguity functions along arbitrary line segments. The efficient computational algorithms of the preferred embodiment are used to detect the position and estimate the velocity of signals, such as those encountered by active or passive sensor systems. Various applications of the proposed algorithm in the analysis of time-frequency domain signals are also disclosed.