An aerial-and-ground data combined gravity conversion methodincludes the following steps: calculate the first estimated ground gravity by the Runge-Kutta format 1, and calculate the first error between the first estimated ground gravity and the measured ground gravity; calculate the second estimated ground gravity by the Runge-Kutta format 2, and calculate the second error between the second estimated ground gravity and the measured ground gravity; and select the smaller one from the first and second errors, use the corresponding Runge-Kutta format as the Runge-Kutta format for gravity conversion, and finish the gravity data conversion using the mentioned Runge-Kutta format.

Example computer-implemented methods, computer-readable media, and computer systems are described for performing gravity modeling. In some aspects, survey data that includes gravity data of a rifted continental margin is accessed. A value of a geometric parameter is determined, which corresponds to a desired value of a Mohorovicic Discontinuity (Moho) uplift at a specified location of the rifted continental margin. A Moho surface is determined based on a value of Moho uplift at a rift center that is determined based on the value of the geometric parameter. A top basement surface is determined based on a residual gravity data associated with the Moho surface. A crustal model of the rifted continental margin is output. The crustal model includes the Moho surface and the top basement surface of the rifted continental margin.

Example computer-implemented methods, computer-readable media, and computer systems are described for performing gravity modeling. In some aspects, survey data that includes gravity data of a rifted continental margin is accessed. A value of a geometric parameter is determined, which corresponds to a desired value of a Mohorovicic Discontinuity (Moho) uplift at a specified location of the rifted continental margin. A Moho surface is determined based on a value of Moho uplift at a rift center that is determined based on the value of the geometric parameter. A top basement surface is determined based on a residual gravity data associated with the Moho surface. A crustal model of the rifted continental margin is output. The crustal model includes the Moho surface and the top basement surface of the rifted continental margin.

A single arm laser system comprising a first in-phase quadrature modulator, IQM. The first IQM is configured to receive a single frequency fibred laser beam from a frequency locked laser seed, generate a first single side-band frequency based on a carrier frequency of the single frequency fibred laser beam and suppress the carrier frequency, and output a first fibre laser beam having a single side-band suppressed carrier frequency. The single arm laser system also comprises a second IQM in line with the first IQM. The second IQM is configured to receive the first fibre laser beam from the first IQM, generate a second single side-band frequency based on the first single side-band frequency and maintain the first single side-band frequency as the carrier frequency, and output a second fibre laser beam having the first and second single side band frequencies.

An apparatus for generating vertically separated atom clouds. The apparatus comprises an optical system comprising an arrangement of lenses and optics. The optical system is configured to trap and cool atoms to form a cold atom cloud; select the hyperfine level of the atoms; trap atoms of the cold atom cloud in a standing wave optical lattice; and vertically split the cold atom cloud into a high cold atom cloud and a low cold atom cloud. The splitting comprises splitting the cold atom cloud into two clouds by launching atoms of the cold atom cloud in opposite directions to form a high cold atom cloud and a low cold atom cloud, and catching the low cold atom cloud up to reach the same velocity as the high cold atom cloud.

Various implementations disclosed herein include devices, systems, and methods for normal estimation using a directional measurement, such as a gravity vector. In various implementations, a device includes a non-transitory memory and one or more processors coupled with the non-transitory memory. In some implementations, a method includes identifying planar surfaces in an environment represented by an image. Each planar surface is associated with a respective orientation. A directional vector associated with the environment is determined. A subset of the planar surfaces that have a threshold orientation relative to the directional vector is identified. For each planar surface in the subset of the planar surfaces, a normal vector for the planar surface is determined based on the orientation of the planar surface and the directional vector.

Various implementations disclosed herein include devices, systems, and methods for normal estimation using a directional measurement, such as a gravity vector. In various implementations, a device includes a non-transitory memory and one or more processors coupled with the non-transitory memory. In some implementations, a method includes identifying planar surfaces in an environment represented by an image. Each planar surface is associated with a respective orientation. A directional vector associated with the environment is determined. A subset of the planar surfaces that have a threshold orientation relative to the directional vector is identified. For each planar surface in the subset of the planar surfaces, a normal vector for the planar surface is determined based on the orientation of the planar surface and the directional vector.

A gravimeter or inertial sensor system and method of operating such a system is provided. The system comprises a variable frequency signal source (100, 101, 102) configured to provide first and second signals, a resonant sensor (103) connected to receive the first signal, a phase comparator (111) connected to the output of the resonant sensor and to receive the second signal, and a controller (114) connected to the phase comparator. In a first mode, the controller controls the desired frequency of the signals from the variable frequency signal source based on a value of the phase comparator output signal to lock the frequency of the input signals to a resonant frequency of the resonant sensor. In a second mode, the controller disconnects from the variable frequency signal source and records an open loop output signal indicative of the physical parameter to be measured based on the response of the resonant sensor.

Example gravity gradiometers are described that utilize high precision resonant optical cavities to measure changes in gravitational forces at high sensitivities. In one example, a sensing system includes a gravity gradiometer and a controller. The gravity gradiometer includes a first mirror and a second mirror arranged to form an optical cavity having an optical axis. The controller is configured to detect, responsive to displacement of at least one of the first mirror and the second mirror along the optical axis, a change in gravity gradient.

A system and associated methodology determines the porosity and water saturation of a cavity using a joint inversion of gravity and ground penetrating radar data. The system exhibits high accuracy. In one embodiment, the cavity is spherical.