Abstract: The present disclosure is directed to systems and methods for analyzing the motion of a sporting equipment, such as a golf club, a baseball bat, a hockey stick, a football or a tennis racquet, for example. The systems comprises a motion sensing system in communications with the sporting equipment to measure motion parameters, wherein the motion sensing system has at least one at least one accelerometer or at least one gyroscope, and a command station having a data acquisition system to process the measured motion parameters and produce data. The motion sensing system may be located on the sporting equipment or, optionally, within the sporting equipment. The systems and methods described herein can be used to determine the impact location of the sporting equipment with another object, the force of the sporting equipment, the velocity of the sporting equipment and/or the angular orientation of the sporting equipment during a motion.

Abstract: A method of reacquiring a satellite signal within an integrated GP/IG navigation system includes detecting a loss of synchronization between a timing code in the satellite signal and a corresponding reference timing code. The method includes receiving position data from an inertial guidance unit. The position data is representative of an estimated position (and its associated uncertainty) of the navigation system. The method also includes estimating a distance from the navigation system to the satellite, as a function of the position data, and deriving an initial delay from the distance. The method includes delaying the reference timing code, with respect to the timing code embedded in the satellite signal, by an offset delay substantially equal to the initial delay. The method includes incrementally varying the offset delay until the timing code embedded in the satellite signal is synchronized with the reference timing code, or until the offset delay equals a predetermined end limit value.

Abstract: A method of calibrating acceleration data signals from a set of accelerometers, and angular rate data signals from a set of gyroscopes within a combined GPS/IGS includes generating navigation data as a function of the acceleration data signals, the angular rate data signals, and prior navigation data. The method further includes combining the navigation data with GPS data via a Kalman filter, so as to produce corrected navigation data, navigation correction data, acceleration correction data and angular rate correction data. The method further includes modifying the acceleration data signals as a function of the acceleration correction data so as to calibrate the acceleration data signals, and modifying the angular rate data signals as a function of the angular rate correction data, so as to calibrate the angular data signals.

Abstract: A method of calibrating acceleration data signals from a set of accelerometers, and angular rate data signals from a set of gyroscopes within a combined GPS/IGS includes generating navigation data as a function of the acceleration data signals, the angular rate data signals, and prior navigation data. The method further includes combining the navigation data with GPS data via a Kalman filter, so as to produce corrected navigation data, navigation correction data, acceleration correction data and angular rate correction data. The method further includes modifying the acceleration data signals as a function of the acceleration correction data so as to calibrate the acceleration data signals, and modifying the angular rate data signals as a function of the angular rate correction data, so as to calibrate the angular data signals.

Abstract: A method of reacquiring a satellite signal within an integrated GP/IG navigation system includes detecting a loss of synchronization between a timing code in the satellite signal and a corresponding reference timing code. The method includes receiving position data from an inertial guidance unit. The position data is representative of an estimated position (and its associated uncertainty) of the navigation system. The method also includes estimating a distance from the navigation system to the satellite, as a function of the position data, and deriving an initial delay from the distance. The method includes delaying the reference timing code, with respect to the timing code embedded in the satellite signal, by an offset delay substantially equal to the initial delay. The method includes incrementally varying the offset delay until the timing code embedded in the satellite signal is synchronized with the reference timing code, or until the offset delay equals a predetermined end limit value.

Abstract: A method and system for integrating a IGS system and a GPS receiver. A predictive filter can measure signal quality from the GPS receiver and accordingly provide parameter estimates by appropriately weighting signal data from the GPS receiver and the IGS system. When GPS signal quality is high, the GPS signal data can be provided proportionately greater weight than the IGS system data, and the IGS/GPS integrated filter outputs can provide compensation to the IGS system for bias errors, etc. Alternately, if the GPS signal data is degraded or unavailable, the IGS signal data can be provided proportionately greater weight than the GPS signal data to provide higher quality inputs to the GPS receiver trackers than would otherwise be available.

Abstract: The present disclosure is directed to systems and methods for analyzing the motion of a sporting equipment, such as a golf club, a baseball bat, a hockey stick, a football or a tennis racquet, for example. The systems comprises a motion sensing system in communications with the sporting equipment to measure motion parameters, wherein the motion sensing system has at least one at least one accelerometer or at least one gyroscope, and a command station having a data acquisition system to process the measured motion parameters and produce data. The motion sensing system may be located on the sporting equipment or, optionally, within the sporting equipment. The systems and methods described herein can be used to determine the impact location of the sporting equipment with another object, the force of the sporting equipment, the velocity of the sporting equipment and/or the angular orientation of the sporting equipment during a motion.

Abstract: A triangular ring laser gyroscope having a single anode, single cathode, and self-compensating discharge path which cancels gyro bias, bias drift, and noise. The discharge path extends from the anode through a cross channel in the center of the gyro block to the cathode. Counter-propagating laser beams traverse one segment of the discharge path in the direction of the Langmuir flow from anode to cathode, and another segment of the discharge path of equal length in a direction opposite to that flow. The Langmuir return flow from cathode to anode occurs along the walls of the gyro cavity, producing a more uniform gas flow velocity in the central region of the discharge path. Drag effects on the counter-propagating laser beams are equal but opposite, and the laser beams traverse a more uniform region of the Langmuir flow when thermally-induced changes in the gyro cause beam wandering. Gyro bias, bias drift, and noise are substantially cancelled.

Abstract: A dielectric interference film having a central region of one thickness and a peripheral region of a different thickness is superimposed on one of the mirrors of a ring laser gyroscope for the purpose of suppressing off-axis resonant modes that are characteristic of a resonant cavity. The central region is designed to intercept a large portion of the fundamental mode power and a lesser portion of the off-axis mode power. The difference in thickness between the central and peripheral regions causes the reflected light from the two regions to differ in phase by approximately one-half wavelength and destructively interfere. As a result of the imbalance of the fundamental and off-axis mode powers incident on the central region, the reflectivity losses of the off-axis modes are more pronounced than those of the fundamental mode with the result that the off-axis modes are completely suppressed.

Abstract: A laser gyroscope is formed as a sealed, unitary assembly of mirrors optically contacted to a monolithic gyro block without any means, such as Brewster windows, for isolating the laser plasma from any of the mirrors. The mirrors are fabricated with hard multilayer dielectric films which can withstand plasma exposure. A magnetic mirror utilizing the transverse Kerr effect to separate the frequencies of counter-propagating beams, and to avoid lock-in, includes a Ni-Fe alloy layer over which is directly deposited a thin iron or iron alloy layer to form a rotationally switchable Kerr effect combination. The magnetic field for switching is generated by an electric current developed in two pairs of orthogonally disposed wires embedded in the substrate immediately below the iron and Ni-Fe alloy layers.

Abstract: In an optical system such as a ring laser gyroscope cavity, oscillations occur in many transverse modes. The desired modes are allowed to exist by suppressing undesired modes utilizing a light stop apparatus. One light stop is made by treating a dielectric mirror with an electron beam causing a phase change to occur to the undesired reflected waves. An alternative light stop is made by depositing an absorptive material on a dielectric mirror for absorbing some of the energy of the undesired modes. Both light stop embodiments are adjustable with respect to a laser wave in a resonant cavity.

Abstract: In an optical system such as a ring laser gyroscope cavity, oscillations occur in many transverse modes. The desired modes are allowed to exist by suppressing undesired modes utilizing a light stop apparatus. One light stop is made by treating a dielectric mirror with an electron beam causing a phase change to occur to the undesired reflected waves. An alternative light stop is made by depositing an absorptive material on a dielectric mirror for absorbing some of the energy of the undesired modes. Both light stop embodiments are adjustable with respect to a laser wave in a resonant cavity.