Litton Systems, Inc.

Other

Tae W Hahn

Daniel A Tazartes

John G Mark

David Barnett Hall

Donald A Frederick

Thomas J Hutchings

Salim N Jabr

Robert A Mitchell

Bruce C Grover

Based upon the equation, BIAS.sub.G .alpha. (I.sub.DE -I.sub.COIL).multidot.(V.sub.DE -V.sub.OFF), where BIAS.sub.G is the bias of a multi-oscillator ring-laser gyroscope (14) as induced by gain medium dispersion effects, I.sub.DE is the proper operating coil current, I.sub.COIL is the actual coil current, V.sub.DE is the proper path length control operating voltage and V.sub.OFF is the actual offset voltage, V.sub.DE is matched by path length control offset voltage and/or I.sub.DE is matched by proper coil current, to produce a zero induced BIAS.sub.G. Matching, through dispersion equalization (DE), is effected by use of clockwise (C) and anticlockwise (A) (or counterclockwise) beams traversing paths with a frame (12). The beams are directed to photodetectors (52, 54) and power meters (56, 58).

Means and method for active dispersion equalization of a multioscillator

A ring laser gyroscope having an alternating Faraday bias includes mode combining apparatus arranged to cause interference between the modes that propagate within the cavity. Signal separating apparatus separates a signal indicative of rotation of the frame from other components of the combined intensity signal. The signal separating apparatus produces two signals indicative of the light intensity in the interference pattern of the combined modes. These two signals have a 180.degree. phase difference in corresponding components that are dependent upon the geometric bias caused by the non-planar optical path to produce a rotation signal that is independent of the spatially uniform interference fringes caused by the geometric bias.

Apparatus and method for detecting rotation rate, Faraday bias and

An electro-optic device is used to detect the position and speed of a golf club head as it passes in front of the device. This information triggers a short optical pulse of light to illuminate the club head, allowing a golfer to see the club head at a desired position as an after-image, and to read the displayed club head speed.

Golf swing trainer

Apparatus for stabilizing the position of the exciting electric component of a radio frequency electromagnetic field within the excited plasma of a ring laser, using two adjacent quarterwave coils, and driving the coils from a radio frequency source to ensure that the adjacent open ends of the two coils have electric field components that produce a steep gradient of electric field within the gas plasma of the ring laser.

Radio frequency excited ring laser gyro

Dispersion in a multi-oscillator cavity is equalized by processing information extracted from the laser beams within the cavity to generate an error signal representative of dispersion bias, and applying a bias control signal to the cavity in such a way as to null the error signal. The bias control signal is preferably a magnetic field applied to the gain medium of the cavity by passing a corresponding current through a coil surrounding the medium. In exemplary embodiments, the laser beams are modulated by modulating the applied magnetic field and/or the path length of the cavity.

Active magnetic field tuning for dispersion equalization of a

A split gain multi-mode ring laser gyroscope is disclosed having a radio frequency excitation induction coil which also serves the magnetic mode suppression system, suppressing undesirable modes of the gain curve to achieve the split gain effect. The induction coil serves as an important common component of both the gain medium excitation and mode suppression systems. The induction coil is suitably configured to carry both AC and DC signals.

Radio frequency excited ring laser gyroscope with common induction coil

Disclosed herein is a Digitally Controlled Cavity Length Control System comprising, in a preferred embodiment, an adaptive servo-loop for cavity length, modulation depth and amplitude control, and of the multioscillator ring laser gyroscope; thereby, permitting the simultaneous control of these elements. The cavity length control of the multioscillator, by including a variable RF detector gain, allows the operation of the gyroscope in a slightly detuned fashion to minimize magnetic sensitivity. In this manner, the multioscillator gyroscope may be maintained at a stable operating point suitable for modeling.

Multioscillator ring laser gyroscope adaptive digitally controlled

A radio frequency excitation system is disclosed for use in conjunction with a ring laser gyroscope. The radio frequency excitation system is comprised of a closed resonant cavity which surrounds a helical coil driven at a high radio frequency at a range of 5 to 550 megahertz. This closed resonant coil surrounds one leg of a ring laser gyroscope which is carved out and exposed so that it may be surrounded by the resonant cavity. Using such a radio frequency excitation system eliminates the need for high power DC discharge components such as cathodes and anodes, as well as problems inherent with properly sealing the cathodes and anodes to the monolithic frame of the ring laser gyroscope.

Radio frequency excited ring laser gyroscope

A rotational sensing system for a Multioscillator ring laser gyroscope is disclosed herein that can operate with a simple upright symmetric optics mechanism, where the required signal separation is performed fully electronically, with the use of a local oscillator. The technique allows for rotational rate and direction detection, as well as cavity length control, with a minimum of cross-talk.

Multioscillator ring laser gyroscope local oscillator-based output

A rotational sensing system for a split gain, multi-mode ring laser gyroscope is disclosed herein that can operate with a simple upright symmetric optics mechanism, where the required signal separation is performed fully electronically. In a preferred embodiment, signal separation circuitry is provided which performs a 180.degree. or .pi. radians phase shift to one of a set of heterodyned signals, A.sub.in, and B.sub.in, with respect to a second set of Split Gain frequency signals, A.sub.out and B.sub.out, in order to extract these Split Gain frequency signals.

Split-gain multimode ring laser gyroscope output optics detection system

An apparatus and method for controlling the length of a multioscillator cavity. A photodiode mixes a pair of beams rotating in the same direction, one of said beams being substantially left circularly polarized, and the other beam being substantially right circularly polarized. A local oscillator causes the mixed beams to be modulated. An amplitude demodulator demodulates the modulated beams. An error detecting device responds to the amplitude demodulators, and an active integrator integrates the detected error. A piezotransducer responds to the output of the integrator for controlling the length of the multioscillator cavity.

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Chatsworth, CA, United States of America

Tae W Hahn