Abstract: A sensor system uses ground emitters to illuminate a projectile in flight with a polarized RF beam. By monitoring the polarization modulation of RF signals received from antenna elements mounted on the projectile, both angular orientation and angular rate signals can be derived and used in the inertial solution in place of the gyroscope. Depending on the spacing and positional accuracies of the RF ground emitters, position information of the projectile may also be derived, which eliminates the need for accelerometers. When RF signals of ground emitter/s are blocked from the guided projectile, the sensor deploys another plurality of RF antennas mounted on the projectile nose to determine position and velocity vectors and orientation of incoming targets.

Abstract: A self-calibrating laser accelerometer system that continuously removes bias errors from acceleration measurements under dynamic operating conditions has a frame with a pair of essentially identical mass modulated accelerometers positioned within the frame. Each accelerometer includes a proof mass mounted to the sensing element frame by a flexure suspension. The proof mass is arranged to rotate about an output axis in response to acceleration of the sensing element frame along an input axis. The first proof mass includes a secondary mass that is movable between a first stable position on a first side of the output axis and a second stable position on a second side of the output axis to provide mass modulation of the first proof mass and to provide a selectively reversible polarity to the input axis and to provide self-calibration of bias.

Abstract: A beamsplitter is arranged to split an incident laser beam into a pump beam and a detection beam. The pump beam passes through the beam splitter and then reflects from a pair of mirrors to a quarter waveplate into an NMR cell. After passing through the NMR cell, the pump beam reflects from a mirror to a first photodetector. The detection beam reflects from the beam splitter and propagates on a path perpendicular to the path of the pump beam through the NMR cell. After passing through the NMR cell, the detection beam is incident upon a polarizer. The polarized portion of the detection beam then is incident upon a photodetector. Electrical signals output from the first and second photodetectors may then be processed to determine the rotation rate of the NMR cell about a sensing axis.

Abstract: An automatic gain control system for a fiber optic gyroscope control loop includes an adjustable gain applied to the gyro output signal. A pilot signal is injected into the fiber optic gyroscope control loop. A compensation loop receives signals output from the control loop and also receives pilot signals. The compensation loop processes the pilot signal to produce a compensation signal that is combined with signals output from the control loop to provide a compensated fiber optic gyroscope output signal. An automatic gain control loop is connected between the compensation loop and the adjustable gain applied to the fiber optic gyroscope output signal. The automatic gain control loop includes a gain error demodulator that multiplies the compensated fiber optic gyroscope output signal and the compensation signal together to produce a gain error signal used to control the adjustable gain in order to stabilize the gain of the gyro control loop.

Abstract: A fiber optic gyroscope signal process dither system permits application of a low amplitude dither signal for many sampling periods without increasing the noise in the sampled outputs due to residual dither signals. A dither loop and an accumulator are added to a closed loop fiber optic gyroscope rotation sensing system. The dither loop has a delay and a gain that are adjusted to match the gain and delay of the fiber gyro loop. A zero mean dither of amplitude sufficient to break up the deadband is injected into to gyro and the dither loop. The dither loop filters the dither signal in the same manner as the gyro loop to provide a signal that is input to a differencing circuit to remove the dither signal from the gyro output.

Abstract: A wave generator has a circular spline, a flexspline inside the circular spline and a plug inside the flex spline. The plug is asymmetrical and is preferably formed to comprise a semi-elliptical first portion and a semi-cylindrical second portion. The diameter of the semi-cylindrical portion coincides with the major axis of the semi-elliptical portion. Gear teeth on the circular spline and on the flex spline are meshed in only a first zone and unmeshed in a second zone. The flexspline in the harmonic drive gear assembly according to the present invention preferably has only one tooth fewer than the circular spline so that the circular spline rotates through and arc defined by one gear tooth for each complete revolution of the flexspline.