The present disclosure relates to an apparatus and a method for localizing an underwater anomalous body, which detect, in real time, any one disturbed signal among a disturbed electric field, a disturbed magnetic field, and a disturbed gravity field by means of a detection line installed in the water when an anomalous body such as a submarine passes through the water, calculates a correlation coefficient between the disturbed signal detected in real time and a template in which disturbed signals for each position are calculated and stored in advance, finds a correlation coefficient having highest similarity, and determines a position of the anomalous body from the template.

The present disclosure relates to an apparatus and a method for localizing an underwater anomalous body, which detect, in real time, any one disturbed signal among a disturbed electric field, a disturbed magnetic field, and a disturbed gravity field by means of a detection line installed in the water when an anomalous body such as a submarine passes through the water, calculates a correlation coefficient between the disturbed signal detected in real time and a template in which disturbed signals for each position are calculated and stored in advance, finds a correlation coefficient having highest similarity, and determines a position of the anomalous body from the template.

An atomic interferometer and methods for measuring phase shifts in interference fringes using the same. The atomic interferometer has a laser beam traversing an ensemble of atoms along a first path and an optical components train with at least one alignment-insensitive beam routing element configured to reflect the laser beam along a second path that is anti-parallel with respect to the first laser beam path. Any excursion from parallelism of the second beam path with respect to the first is rigorously independent of variation of the first laser beam path in yaw parallel to an underlying plane.

A gravimeter, a gravimeter system, and a method for measuring gravitational acceleration within a borehole are described herein. The gravimeter includes a proof mass that is constrained by springs and an optical interferometer for measuring displacement of the proof mass. The optical interferometer generates a light path from a light source to a reflective surface on the proof mass. Spatial displacement of the proof mass from a reference position to a position of gravitational equilibrium is determined by measuring a change in length of the light path. In turn, gravitational acceleration can be determined from the spatial displacement of the proof mass. A number of such gravimeters can be used in a gravimeter system to make measurements of gravitational acceleration in variety of different directions.

A gravimeter, a gravimeter system, and a method for measuring gravitational acceleration within a borehole are described herein. The gravimeter includes a proof mass that is constrained by springs and an optical interferometer for measuring displacement of the proof mass. The optical interferometer generates a light path from a light source to a reflective surface on the proof mass. Spatial displacement of the proof mass from a reference position to a position of gravitational equilibrium is determined by measuring a change in length of the light path. In turn, gravitational acceleration can be determined from the spatial displacement of the proof mass. A number of such gravimeters can be used in a gravimeter system to make measurements of gravitational acceleration in variety of different directions.

A microelectromechanical accelerometer includes a support, at least one mass suspended by suspension means relative to the support and configured to move in the plane of the accelerometer, means for measuring the displacement of the seismic mass including at least one first vibrating beam of nanometric cross-section, and first electrostatic coupling means between the seismic mass and said at least one first vibrating beam configured to ensure a mechanical decoupling between the first vibrating beam and the seismic mass. At rest, the first electrostatic coupling means generates traction on the first vibrating beam, so that under the effect of acceleration the state of strain of the first vibrating beam is modified.

A microelectromechanical accelerometer includes a support, at least one mass suspended by suspension means relative to the support and configured to move in the plane of the accelerometer, means for measuring the displacement of the seismic mass including at least one first vibrating beam of nanometric cross-section, and first electrostatic coupling means between the seismic mass and said at least one first vibrating beam configured to ensure a mechanical decoupling between the first vibrating beam and the seismic mass. At rest, the first electrostatic coupling means generates traction on the first vibrating beam, so that under the effect of acceleration the state of strain of the first vibrating beam is modified.

Each atom in a population of atoms can be characterized by a probability density distribution (PDD). Using a shaken-lattice technique, each PDD is split into a pair of sub-PDDs. The sub-PDDs of a pair are propagated along different paths to a common endpoint of the paths, resulting in a matter-wave interference pattern that encodes a net phase between the paths, e.g., due to differential effects associated with a gravity gradient. The matter-wave interference pattern can be measured to yield a respective measurement for each atom. The measurements can be aggregated to yield a result distribution that can serve as a classical domain estimate of the quantum-domain matter-wave interference pattern, and thus of the gravity gradient. Other embodiments can determine gradients for other types of fields.

A method of estimating a parameter of an anomaly in an earth formation includes: disposing a measurement device at at least one measurement location, the measurement device including a frequency standard; estimating a frequency shift of a frequency standard due to a gravitational potential at at least one measurement location; and deriving a relationship between a mass and a depth of a formation anomaly at a distance to the at least one measurement location using the frequency shift.

A method of estimating a parameter of an anomaly in an earth formation includes: disposing a measurement device at at least one measurement location, the measurement device including a frequency standard; estimating a frequency shift of a frequency standard due to a gravitational potential at at least one measurement location; and deriving a relationship between a mass and a depth of a formation anomaly at a distance to the at least one measurement location using the frequency shift.