The present disclosure discloses a submarine position detection method based on extreme points of gravity gradients. A space rectangular coordinate system is established by taking a centroid of the middle cylindrical portion as a coordinate origin, a direction pointing to a bow is taken as a forward direction of the X axis, a direction pointing to a port is taken as a forward direction of the Y direction, and a vertical upward direction is taken as a forward direction of the Z axis. The detection method includes steps of: determining a horizontal position of a submarine, i.e., coordinates (X, Y), according to a position of a central extreme point and a central position between extreme points of non-diagonal components of a gradient tensor; and determining a functional relation between a depth and the extreme points of gravity gradients by using the submarine model.

The present disclosure discloses a submarine position detection method based on extreme points of gravity gradients. A space rectangular coordinate system is established by taking a centroid of the middle cylindrical portion as a coordinate origin, a direction pointing to a bow is taken as a forward direction of the X axis, a direction pointing to a port is taken as a forward direction of the Y direction, and a vertical upward direction is taken as a forward direction of the Z axis. The detection method includes steps of: determining a horizontal position of a submarine, i.e., coordinates (X, Y), according to a position of a central extreme point and a central position between extreme points of non-diagonal components of a gradient tensor; and determining a functional relation between a depth and the extreme points of gravity gradients by using the submarine model.

A method and system for rotating a vector, including at least one lookup table (LUT) including data corresponding to the vector being rotated around a first angle and a second angle, processing circuitry configured for accessing the at least one LUT for incrementally rotating the vector around the first and second angles, where accessing includes identifying an LUT input entry and selecting a corresponding LUT output entry, the corresponding output entry including an incremental angular rotation (IAR) of the vector around the first angle or the second angle, and a comparator configured to generate a comparator signal based upon comparing a counter incremented by the IAR with the first angle or the second angle, the processing circuitry further configured to iteratively access the at least one LUT, based on the comparator signal, for completing the incremental rotation of the vector around the first angle and the second angle.

A method and system for rotating a vector, including at least one lookup table (LUT) including data corresponding to the vector being rotated around a first angle and a second angle, processing circuitry configured for accessing the at least one LUT for incrementally rotating the vector around the first and second angles, where accessing includes identifying an LUT input entry and selecting a corresponding LUT output entry, the corresponding output entry including an incremental angular rotation (IAR) of the vector around the first angle or the second angle, and a comparator configured to generate a comparator signal based upon comparing a counter incremented by the IAR with the first angle or the second angle, the processing circuitry further configured to iteratively access the at least one LUT, based on the comparator signal, for completing the incremental rotation of the vector around the first angle and the second angle.

A method for determining a location of a proppant in a subterranean formation includes obtaining a first set of data in a wellbore using a downhole tool. The proppant is pumped into the wellbore after the first set of data is obtained. The proppant is pumped while or after the subterranean formation is fractured. A second set of data is obtained in the wellbore using the downhole tool after the proppant is pumped into the wellbore. The first set of data and the second set of data include a gravitational field measurement. The first and second sets of data are compared, and in response to the comparison, the location of the proppant in the subterranean formation is determined.

A method for determining a location of a proppant in a subterranean formation includes obtaining a first set of data in a wellbore using a downhole tool. The proppant is pumped into the wellbore after the first set of data is obtained. The proppant is pumped while or after the subterranean formation is fractured. A second set of data is obtained in the wellbore using the downhole tool after the proppant is pumped into the wellbore. The first set of data and the second set of data include a gravitational field measurement. The first and second sets of data are compared, and in response to the comparison, the location of the proppant in the subterranean formation is determined.

Coherent spectroscopic methods are described, to measure the total phase difference during an extended interrogation interval between the signal delivered by a local oscillator (10) and that given by a quantum system (QS). According to one or more embodiments, the method may comprise reading out at the end of successive interrogation sub-intervals (Ti) intermediate error signals corresponding to the approximate phase difference (φ) between the phase of the LO signal and that of the quantum system, using coherence preserving measurements; shifting at the end of each interrogation sub-intervals (Ti) the phase of the local oscillator signal, by a known correction value (.sub.φ(i).sub.FB) so as to avoid that the phase difference approaches the limit of the inversion region; reading out a final phase difference (φf) between the phase of the prestabilized oscillator signal and that of the quantum system using a precise measurement with no restriction on the destruction; reconstructing a total phase difference over the extended interrogation interval, as the sum of the final phase difference (φf) and the opposite of all the applied phase corrections figure (I).

Coherent spectroscopic methods are described, to measure the total phase difference during an extended interrogation interval between the signal delivered by a local oscillator (10) and that given by a quantum system (QS). According to one or more embodiments, the method may comprise reading out at the end of successive interrogation sub-intervals (Ti) intermediate error signals corresponding to the approximate phase difference (φ) between the phase of the LO signal and that of the quantum system, using coherence preserving measurements; shifting at the end of each interrogation sub-intervals (Ti) the phase of the local oscillator signal, by a known correction value (.sub.φ(i).sub.FB) so as to avoid that the phase difference approaches the limit of the inversion region; reading out a final phase difference (φf) between the phase of the prestabilized oscillator signal and that of the quantum system using a precise measurement with no restriction on the destruction; reconstructing a total phase difference over the extended interrogation interval, as the sum of the final phase difference (φf) and the opposite of all the applied phase corrections figure (I).

Disclosed is an optoelectronic measuring device having an electronic magnetic compass for determining an azimuthal alignment of the measuring device and a compensation unit, which is associated with the magnetic compass, for compensating for device-fixed interference fields, wherein the measuring device assumes at least two defined, repeatable operating states, has a different device-fixed interference field in each of the operating states, and the compensation unit carries out an initial compensation of the electronic magnetic compass in a first operating state of the measuring device, wherein the compensation unit has a detection unit for detecting a present operating state, a memory unit for storing a magnetic offset resulting from the different device-fixed interference fields between the first and a second operating state of the measuring device, and a computer unit for computing the azimuthal alignment of the measuring device depending on an ascertained operating state and based on the magnetic offset.

Disclosed is an optoelectronic measuring device having an electronic magnetic compass for determining an azimuthal alignment of the measuring device and a compensation unit, which is associated with the magnetic compass, for compensating for device-fixed interference fields, wherein the measuring device assumes at least two defined, repeatable operating states, has a different device-fixed interference field in each of the operating states, and the compensation unit carries out an initial compensation of the electronic magnetic compass in a first operating state of the measuring device, wherein the compensation unit has a detection unit for detecting a present operating state, a memory unit for storing a magnetic offset resulting from the different device-fixed interference fields between the first and a second operating state of the measuring device, and a computer unit for computing the azimuthal alignment of the measuring device depending on an ascertained operating state and based on the magnetic offset.