Altratek, Inc.

Schlumberger Technology Corporation

Orhan Arikan

Ahmet Kemal Ozdemir

David J Rossi

Michael P Ekstrom

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.

System and method for CDMA communications

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.

System and method for detection and tracking of targets

A system and method for evaluating a geological formation is described which compares actual wireline log measurements from a number of wireline logging tools to predicted tool response logs. The system and method uses a forward model of each tool response, given a formation description, to predict a set of wireline logs. Comparing the predicted logs with the actual measured logs yields a mismatch error. The system and method iteratively adjusts the formation description to minimize the mismatch error to obtain a 'best' formation description. In one form, the formation description includes petrophysical properties (porosity, density, saturation) and geometry properties (dip, bedding, invasion). In a more complicated form, the formation description also includes a model of petrophysical mixing laws and formation material content. In the special case of a horizontally layered formation and linear tool response models, there exists a computationally efficient version of the system and method.

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Ankara, Turkey

Orhan Arikan