Abstract: Methods and systems are disclosed for determining information about a position of an object within a distribution of materials having different complex conductivities. The method includes: (i) causing current to flow in the distribution; (ii) measuring an electrical signal at each of multiple locations in the distribution of materials in response to the current flow; (iii) providing spatial information about the distribution of materials with respect to a first reference frame, the spatial information indicative of regions of different complex conductivity in the distribution of materials; and (iv) determining the position of the object with respect to the spatial information about the distribution of materials based on measured electrical signals and the spatial information. In certain embodiments, the object is a catheter inserted into a patients heart cavity for cardiac mapping.

Abstract: A method of determining a physical property of subsurface strata surrounding a borehole. The physical property includes any one or more of stress, strain of fluid pressure of the subsurface strata. The borehole includes a borehole liner having an interior wall. A pair of sensor modules separated by a known distance are clamped to the interior wall of the borehole liner. The clamping induces an acoustic discontinuity in the borehole liner such that a P-wave propagating longitudinally within the borehole liner is at least partially reflected. A respective sensor of each sensor module detecting P-waves propagating in the liner and generating a corresponding sensor output signal indicative of the detected P-waves. A respective sensor output signal from each sensor module is analyzed to detect a resonance in a section of the borehole liner between the sensors. A fundamental frequency of the detected resonance is determined and analyzed to determine the physical property.

Abstract: Methods and systems are disclosed for determining information about a position of an object within a distribution of materials having different complex conductivities. The method includes: (i) causing current to flow in the distribution; (ii) measuring an electrical signal at each of multiple locations in the distribution of materials in response to the current flow; (iii) providing spatial information about the distribution of materials with respect to a first reference frame, the spatial information indicative of regions of different complex conductivity in the distribution of materials; and (iv) determining the position of the object with respect to the spatial information about the distribution of materials based on measured electrical signals and the spatial information. In certain embodiments, the object is a catheter inserted into a patients heart cavity for cardiac mapping.

Abstract: Methods and systems are disclosed for determining information about a position of an object within a distribution of materials having different complex conductivities. The method includes: (i) causing current to flow in the distribution; (ii) measuring an electrical signal at each of multiple locations in the distribution of materials in response to the current flow; (iii) providing spatial information about the distribution of materials with respect to a first reference frame, the spatial information indicative of regions of different complex conductivity in the distribution of materials; and (iv) determining the position of the object with respect to the spatial information about the distribution of materials based on measured electrical signals and the spatial information. In certain embodiments, the object is a catheter inserted into a patients heart cavity for cardiac mapping.