Aspects of the disclosure can relate to simulating expected sensor values associated with a drill tool (e.g., a drill assembly) before drilling to monitor the sensor. A planned trajectory for the drill assembly is received, where the planned trajectory is associated with a borehole to be drilled by the drill assembly along a geographic path. Next, an expected position for the drill assembly is determined along the geographic path. Then, an expected sensor value for a sensor associated with the drill assembly is simulated at the expected position. Next, an actual sensor value at an actual position corresponding to the expected position is determined. Then, the expected sensor value and the actual sensor value are dynamically displayed together at a user interface.

Disclosed is a calibration method for a rotating accelerometer gravity gradiometer, wherein linear motion error coefficients, angular motion error coefficients, self-gradient model parameters and scale factors of the rotating accelerometer gravity gradiometer are calibrated once by changing linear motion, angular motion, and self-gradient excitations of the rotating accelerometer gravity gradiometer. The calibrated linear and angular motion error coefficients are used for compensating for motion errors of the gravity gradiometer online, and the calibrated self-gradient model parameters are used for self-gradient compensation. The calibration method provided by the present invention is easy to operate and not limited by any calibration site, thereby being suitable for programmed self-calibration and realizing an important engineering value.

Disclosed is a calibration method for a rotating accelerometer gravity gradiometer, wherein linear motion error coefficients, angular motion error coefficients, self-gradient model parameters and scale factors of the rotating accelerometer gravity gradiometer are calibrated once by changing linear motion, angular motion, and self-gradient excitations of the rotating accelerometer gravity gradiometer. The calibrated linear and angular motion error coefficients are used for compensating for motion errors of the gravity gradiometer online, and the calibrated self-gradient model parameters are used for self-gradient compensation. The calibration method provided by the present invention is easy to operate and not limited by any calibration site, thereby being suitable for programmed self-calibration and realizing an important engineering value.

A method of measuring an acceleration using one or more trapped BECs and at least two atomic field modes within those BECs is described. A density distribution of at least one of the one or more BECs is modified by the acceleration, which leads to a change of the field modes' time evolution. The method comprises: selecting two modes that are differently affected by the acceleration; and measuring the acceleration-induced difference; and using the measured acceleration-induced difference to infer the acceleration. Also described is a method of measuring a field gradient using one or more trapped BECs. Each of the trapped BECs has a density distribution, and at least two atomic modes within those BECs, wherein the density distributions of the one or more BECs are modified by the field, which leads to a change of the atomic modes' time evolution. The method comprises selecting two atomic modes that are differently affected by the field; and measuring a field-induced difference between the selected atomic modes; and using the measured field-induced difference to infer a gradient of the field.

A method of measuring an acceleration using one or more trapped BECs and at least two atomic field modes within those BECs is described. A density distribution of at least one of the one or more BECs is modified by the acceleration, which leads to a change of the field modes' time evolution. The method comprises: selecting two modes that are differently affected by the acceleration; and measuring the acceleration-induced difference; and using the measured acceleration-induced difference to infer the acceleration. Also described is a method of measuring a field gradient using one or more trapped BECs. Each of the trapped BECs has a density distribution, and at least two atomic modes within those BECs, wherein the density distributions of the one or more BECs are modified by the field, which leads to a change of the atomic modes' time evolution. The method comprises selecting two atomic modes that are differently affected by the field; and measuring a field-induced difference between the selected atomic modes; and using the measured field-induced difference to infer a gradient of the field.

Provided is a gravity gradient measurement apparatus and measuring method, wherein a turntable rotates horizontally around an earth-vertical axis, a vacuum layer is arranged on the turntable defining a first chamber, a first three-axis accelerometer and a second three-axis accelerometer are located in the first chamber, the first three-axis accelerometer and the second three-axis accelerometer are arranged symmetrically on an x axis with respect to an origin of coordinates. Both the first three-axis accelerometer and the second three-axis accelerometer have a distance of R from the origin of coordinates. The first three-axis accelerometer and the second three-axis accelerometer are arranged symmetrically on an z axis with respect to the origin of coordinates, and the first three-axis accelerometer and the second three-axis accelerometer are spaced at a distance of h on the z axis. The measurement module uses measurements of the accelerometers to determine gravity gradients on the coordinate axes.

Provided is a gravity gradient measurement apparatus and measuring method, wherein a turntable rotates horizontally around an earth-vertical axis, a vacuum layer is arranged on the turntable defining a first chamber, a first three-axis accelerometer and a second three-axis accelerometer are located in the first chamber, the first three-axis accelerometer and the second three-axis accelerometer are arranged symmetrically on an x axis with respect to an origin of coordinates. Both the first three-axis accelerometer and the second three-axis accelerometer have a distance of R from the origin of coordinates. The first three-axis accelerometer and the second three-axis accelerometer are arranged symmetrically on an z axis with respect to the origin of coordinates, and the first three-axis accelerometer and the second three-axis accelerometer are spaced at a distance of h on the z axis. The measurement module uses measurements of the accelerometers to determine gravity gradients on the coordinate axes.

An attitude sensor system with automatic bias correction having a primary attitude sensor wherein the primary attitude sensor comprises at least one accelerometer and an auxiliary sensor system configured to automatically estimate a bias of the accelerometer of the primary attitude sensor such that the resulting error is removed from an output of the attitude sensor system.

Disclosed is a calibration method for a rotating accelerometer gravity gradiometer, wherein linear motion error coefficients, angular motion error coefficients, self-gradient model parameters and scale factors of the rotating accelerometer gravity gradiometer are calibrated once by changing linear motion, angular motion, and self-gradient excitations of the rotating accelerometer gravity gradiometer. The calibrated linear and angular motion error coefficients are used for compensating for motion errors of the gravity gradiometer online, and the calibrated self-gradient model parameters are used for self-gradient compensation. The calibration method provided by the present invention is easy to operate and not limited by any calibration site, thereby being suitable for programmed self-calibration and realizing an important engineering value.

Disclosed is a calibration method for a rotating accelerometer gravity gradiometer, wherein linear motion error coefficients, angular motion error coefficients, self-gradient model parameters and scale factors of the rotating accelerometer gravity gradiometer are calibrated once by changing linear motion, angular motion, and self-gradient excitations of the rotating accelerometer gravity gradiometer. The calibrated linear and angular motion error coefficients are used for compensating for motion errors of the gravity gradiometer online, and the calibrated self-gradient model parameters are used for self-gradient compensation. The calibration method provided by the present invention is easy to operate and not limited by any calibration site, thereby being suitable for programmed self-calibration and realizing an important engineering value.