A system comprises a plurality of sensors, a sensor processor, and a sampling rate engine. The sensor processor is coupled to an output of each sensor of the plurality of sensors. The sensor processor estimates user dynamics in response to a first output signal of a first sensor of the plurality of sensors. The sampling rate engine is coupled to an output of the sensor processor. The sampling rate engine determines a sampling rate value of a second sensor of the plurality of sensors in response to a user dynamics value from the sensor processor. The second sensor comprises a selectable sampling rate. The selectable sampling rate is configured in response to the sampling rate value determined by the sampling rate engine.

Technology for determining a position of a device based on an acceleration of the device sensed by an accelerometer, an angular velocity sensed by a gyroscope, and a distance of the device from a fixed magnetic field source determined from a magnetic field strength sensed by a magnetometer.

A GPS-aided inertial navigation method includes providing multiple sensors including multiple inertial measurement units (IMUs) and at least one global positioning system receivers and antennas (GPSs) and computer with embedded navigation software. The computer interfaces with all IMUs and all GPS receivers; running, in parallel, in multiple standard inertial navigation (IN) schemes; computes the mean of all the INSs to obtain a fused IN solution for the IMUs' mean location; computes the mean of all the GPS solutions to obtain a fused GPS solution for the GPS antennas' mean location; applies a lever-arm correction, with the vector from the mean IMU location to the mean antenna location, to the fused GPS solution; feeds the fused IN solution and the lever-arm corrected fused GPS solution to a single navigation filter, as if there were a single IMU and a single GPS; and runs an IMU/IN/GPS correction module.

Included are methods and systems for marine geophysical surveying. A system includes a streamer; a sensor package coupled to the streamer, wherein the sensor package comprises a primary orientation sensor and a complimentary orientation sensor, wherein the complimentary orientation sensor comprises a magnetometer, wherein the primary orientation sensor and the complimentary orientation sensor are capable of collecting data indicative of the orientation of the streamer; and geophysical sensors distributed on the streamer.

A method of calibrating an inertial measurement unit, the method comprising: (a) collecting data from the inertial measurement unit while stationary as a first step; (b) collecting data from the inertial measurement unit while repositioning the inertial measurement unit around three orthogonal axes of the inertial measurement unit as a second step; (c) calibrating a plurality of gyroscopes using the data collected during the first step and the second step; (d) calibrating a plurality of magnetometers using the data collected during the first step and the second step; (e) calibrating a plurality of accelerometers using the data collected during the first step and the second step; (f) where calibrating the plurality of magnetometers includes extracting parameters for distortion detection and using the extracted parameters to determine if magnetic distortion is present within a local field of the inertial measurement unit.

An inertial measurement unit (IMU) includes an inertial sensor assembly including a plurality of accelerometers and a plurality of rate gyroscopes, an inertial sensor compensation and correction module, and a Kalman estimator module. The inertial sensor compensation and correction module is configured to apply a set of error compensation values to sensed acceleration and rotational rate to produce a compensated acceleration and a compensated rotational rate of the IMU. The Kalman estimator module is configured to determine a set of error correction values based on a difference between a change in integrated acceleration of the IMU and a change in true airspeed of the IMU. The inertial sensor compensation and correction module is further configured to apply the set of error correction values to each of the compensated acceleration and the compensated rotational rate to output an error-corrected acceleration and an error-corrected rotation rate.

A device includes a memory and processing circuitry coupled to the memory. The processing circuitry, in operation: estimates an angular rate of change and determines a rotational versor based on the rotational data; and estimates a gravity vector based on the angular rate of change and the rotational versor. The processing circuitry generates a dynamic gravity vector based on the estimated gravity vector, a correction factor and an estimated error in estimated gravity vector. The processing circuitry estimates a linear acceleration and determines an acceleration versor based on the acceleration data, and determines the correction factor based on the linear acceleration. The processing circuitry estimates the error in the estimated gravity vector based on the acceleration versor.

A system comprises a plurality of sensors, a sensor processor, and a sampling rate engine. The sensor processor is coupled to an output of each sensor of the plurality of sensors. The sensor processor estimates user dynamics in response to a first output signal of a first sensor of the plurality of sensors. The sampling rate engine is coupled to an output of the sensor processor./ The sampling rate engine determines a sampling rate value of a second sensor of the plurality of sensors in response to a user dynamics value from the sensor processor. The second sensor comprises a selectable sampling rate. The selectable sampling rate is configured in response to the sampling rate value determined by the sampling rate engine.

A borehole logging instrument sonde employs a case in which support electronics including a processor are mounted. A rotatable platform is mounted within the case and carries an inertial measurement unit (IMU) and a roll axis gyroscope. A motor is adapted to rotate the rotatable platform within the case. The processor receives an input from the roll axis gyroscope and provides an output to the motor responsive to the input for control of rotation of the platform to space stabilize and isolate the IMU from the roll of the instrument sonde.

An inertial measurement system for a longitudinal projectile comprising: a first, roll gyro to be oriented substantially parallel to the longitudinal axis of the projectile; a second gyro and a third gyro with axes arranged with respect to the roll gyro such that they define a three dimensional coordinate system; a controller, arranged to: compute a current projectile attitude from the outputs of the first, second and third gyros, the computed attitude comprising a roll angle, a pitch angle and a yaw angle; compare the computed pitch and yaw angles with expected values for the pitch and yaw angles; calculate a roll angle error and a roll scale factor error based on the difference between the computed pitch and yaw angles and the expected pitch and yaw angles; and apply the calculated roll angle error and roll scale factor error to the output of the roll gyro.