Methods for processing data from a metrology process and for obtaining calibration data are disclosed. In one arrangement, measurement data is obtained from a metrology process. The metrology process includes illuminating a target on a substrate with measurement radiation and detecting radiation redirected by the target. The measurement data includes at least a component of a detected pupil representation of an optical characteristic of the redirected radiation in a pupil plane. The method further includes analyzing the at least a component of the detected pupil representation to determine either or both of a position property and a focus property of a radiation spot of the measurement radiation relative to the target.

An angular rate sensor. The sensor includes a Coriolis vibratory gyroscope (CVG) resonator, configured to oscillate in a first normal mode and in a second normal mode; a frequency reference configured to generate a reference signal; and a first phase control circuit. The first phase control circuit is configured to: measure a first phase difference between: a first phase target, and the difference between: a phase of an oscillation of the first normal mode and a phase of the reference signal. The first phase control circuit is further configured to apply a first phase correction signal to the CVG resonator, to reduce the first phase difference. A second phase control circuit is similarly configured to apply a second phase correction signal to the CVG resonator, to reduce a corresponding, second phase difference.

A method for determining a current estimated gyroscope bias of a gyroscope, the gyroscope being configured to output rotation rate data, the method comprising: receiving first rotation rate data associated with a first time from the gyroscope, the first rotation rate data comprising a first rotation rate reading that indicates a rotation rate of the gyroscope about a first axis; calculating a rotation rate moving average associated with the first time based on the first rotation rate data and a rotation rate moving average associated with a second time earlier than the first time; calculating a moving standard deviation associated with the first time based on the first rotation rate data, the rotation rate moving average associated with the first time, and a moving standard deviation associated with the second time; determining if the moving standard deviation associated with the first time is less a threshold moving standard deviation; and in response the moving standard deviation being less than the threshold moving standard deviation, using the first rotation rate reading to update the current estimated gyroscope bias.

A wearable computing device, including a device body configured to be affixed to a body of a user. The wearable computing device may further include an inertial measurement unit (IMU) and a processor. The processor may receive kinematic data from the IMU while the device body is affixed to the body of the user. The processor may perform a first coordinate transformation on the kinematic data into a training coordinate frame of a training wearable computing device. At a first machine learning model trained using training data including training kinematic data collected at the training wearable computing device, the processor may compute a training-frame velocity estimate for the wearable computing device based on the transformed kinematic data. The processor may perform a second coordinate transformation on the training-frame velocity estimate to obtain a runtime-frame velocity estimate and may output the runtime-frame velocity estimate to a target program.

A method for identifying a static phase of a vehicle involves a first step of detecting the static phase without using measurements of a satellite geolocation unit, this first detection step involving checking that a first set of one or more conditions is satisfied, checking, repeatedly, that a second set of one or more conditions is satisfied, then so long as the second set of conditions is satisfied, executing a second step of detecting the static phase from the measurements of the satellite geolocation unit, so long as the second set of conditions is not satisfied, executing the first detection step and inhibiting the execution of the second detection step.

Inertial measurement units (IMUs) and methods with adaptations to eliminate or minimize sensor error, offset, or bias shift. More particularly, such IMUs and methods for gun-fired projectiles and particularly adapted to accurately measure forces and to prevent or minimize the error, offset, or bias shift associated with events exhibiting high g shock, and/or high levels of vibration, and/or rotation. Even more particularly, such IMUs and methods utilizing novel IMU packaging adapted to prevent or minimize sensor error, offset, or bias shift, and recalibration adaptations and methods adapted to correct or reset the error, offset, or bias shift from such an event. Ultimately relates to IMUs that are adapted to provide accurate measurements prior to, during and after such event, and to provide continuous accurate measurements during flight of gun-fired projectiles.

The present disclosure relates to methods of enhancing a navigation solution about a device and a platform, wherein the mobility of the device may be constrained or unconstrained within the platform, and wherein the navigation solution is provided even in the absence of normal navigational information updates (such as, for example, GNSS). More specifically, the present method comprises utilizing measurements from sensors (e.g. accelerometers, gyroscopes, magnetometers etc.) within the device to calculate and resolve the attitude of the device and the platform, and the attitude misalignment between the device and the platform.

A level comprising a level body and a bubble vial mounted on the level body. The bubble vial includes a bubble vial body comprising a clear material and an internal cavity containing a liquid. A top opening in the level body that interrupts at least a portion of a top wall to accommodate the bubble vial. An internal support structure disposed within the tubular configuration of the level body and spanning longitudinally along the level body so as to be disposed on both sides of the top opening to provide structural support to the level body in the vicinity of the top opening. A carrier positioned beneath the bubble vial and between the internal support structure and the bubble vial. The bubble vial body has a length that is less than a length of the top opening in the top wall of the level body.

A level comprising a level body and a bubble vial mounted on the level body. The bubble vial includes a bubble vial body comprising a clear material and an internal cavity containing a liquid. A top opening in the level body that interrupts at least a portion of a top wall to accommodate the bubble vial. An internal support structure disposed within the tubular configuration of the level body and spanning longitudinally along the level body so as to be disposed on both sides of the top opening to provide structural support to the level body in the vicinity of the top opening. A carrier positioned beneath the bubble vial and between the internal support structure and the bubble vial. The bubble vial body has a length that is less than a length of the top opening in the top wall of the level body.

A surveying instrument comprises a base; an alidade rotatable about a first axis relative to the base; and an optical measuring instrument having a measuring axis rotatable about a second axis relative to the alidade. A beam path can be provided for a light beam using components including a light source, lenses, mirrors, beam splitters, and a position-sensitive detector. The surveying can be calibrated by performing plural measurements at different orientations of the alidade relative to the base and different orientations of the measuring instrument relative to the alidade using the above components.