Abstract: The gyroscope operated in a strapdown mode and mounted on a float assembly with its spin axis extending in a vertical direction. The float assembly is free to rotate about any horizontal axis but is constrained from rotating about the vertical to assure an accurate azimuthal reference between the gyroscope and the case in which it is floating. The angle between an azimuthal reference line of the gyroscope and true north is obtained by measuring the amount of torque required to counteract precession of the gyroscope about a horizontal sensitive axis which would occur because of the horizontal component of the rate of rotation of the earth.

Abstract: A four mode ring laser gyro has its four modes at different frequencies combined and applied to a single photo diode. The output from the photo diode is applied to a non-linear device, and the resultant sum and difference frequencies are applied to (1) a laser cavity length control circuit, (2) a rotation rate detection circuit, and (3) a rotation direction determination circuit. The cavity length control circuit operates by the determination of 100% modulation of one of the beat frequencies by a second one. The direction determination circuit utilizes the phase of an AC dithering power supply which varies the anode to cathode plasma current of the laser gyro.

Abstract: A flexure hinge assembly comprising a pair of fixed telescopes inner and outer tubular members separated into at least one driving portion, at least one gimbal portion and at least one driven portion and a plurality of flexure blades all formed by a plurality of slots and apertures through the walls of each tubular member. Flexure blades are formed by pairs of adjacent apertures with the slots interconnecting apertures to separate the tubular members into the driving, gimbal, and driven portions. The four slots of each tubular member which divide that member into these three portions are axially coextensive with the slots in the other member and all extend in the same axial direction from the apertures which form the flexure blades. Such axially coextensive slots displace the driving and the driven portions of the tubular members in the same axial direction from the center of suspension, i.e., from the flexure axes of these portions.

Abstract: A compact and reliable dithered laser gyro utilizes a rectangular laser path geometry to reduce scattering and thereby improve anti-locking capabilities of the laser gyro. In addition, the rectangular geometry serves to reduce the overall package size of the laser gyro and permits the mounting of the anti-lock mechanical dithering drive mechanism within the laser gyro unit. A counterbalance is also provided to reduce vibration from the unit.

Abstract: A cylindrical coil form, for magnetic coupling with an irradiated nuclear magnetic resonance gas sample, is provided with peripheral and longitudinal grooves. The peripheral grooves are not helical in form, but are perpendicular to the axis of the coil form to give a precisely directed longitudinal magnetic field. A first coil for providing strong magnetic coupling along the axis of the coil form is wound in the peripheral grooves, the adjacent turns being interconnected by short longitudinal sections of wire in one of the longitudinal grooves. Additional coils are provided for magnetic coupling transverse to the axis of the coil through the use of wires extending down one of the longitudinal slots and back in another longitudinal slot. The form may be of phenolic material, or may be transparent so that the nuclear magnetic resonance sample may be irradiated directly through the coil form.

Abstract: A universal gyroscope flexure hinge assembly is provided to interconnect the inertial flywheel of a 2-axes free rotor gyroscope to the gyroscope spin shaft, with two symmetrical, axially displaced gimbal elements which allow two axes of angular freedom. Errors which would arise due to axially displaced gimbal elements are compensated for by offsetting the flexure axes of the two gimbal elements. Each pair of flexure blades forming a flexure hinge have a common flexure axis and the flexure hinge assembly has only two orthogonal flexure axes which are axially displaced from one another.

Abstract: The present method involves the detection of variations of the direction of gravity from the mathematical model of the earth, which may be caused by the presence of a discontinuity in the earth's surface, with relatively heavy materials in the earth's crust causing a deflection of gravity toward such heavier material. In accordance with the present method an inertial system is mounted in a mobile vehicle and the vehicle is moved along a survey route from a first control point to a second control point, with the locations and the deflection from the vertical being known at the two control points. The vehicle is stopped periodically between the two control points in order to eliminate accumulate errors in the inertial system, and to record the position of intermediate points to the surveyed.

Abstract: A converter for converting radio teleprinter audio frequency signals from a radio receiver into teleprinter signals which are bipolar pulses for operating an output device. The converter includes a binary pulse decoder, which may be used independently in other applications, and a pair of substantially identical demodulator channels.In radio teleprinter applications the novel decoder is coupled to two substantially identical demodulator chanels which demodulate pulses from incoming information signals at audio frequencies. In the demodulator channels the frequencies of the information signals, which commonly are received by the demodulator channels on different audio frequencies, are shifted to the same audio frequency by mixing them with a signal from a respective local oscillator in each demodulator channel. The demodulator channels each detect a series of DC pulses from the audio signals and apply the DC pulses to the decoder.

Abstract: A universal joint for small angle deflections having a driving element which is rotatable about an axis of rotation wherein the driving element is connected to a driven member by a suspension means which comprises at least two gimbal elements, each gimbal element is connected to the driving element and to the driven element by at least two flexure hinges, each of the longitudinal axes of the flexure hinges forming an angle of the same magnitude with the axes of rotation of the driving and driven elements when the universal joint is in a rest position. A method for fabricating such a multigimbal universal joint for small angle deflections in one-piece wherein integral flexure hinges having such longitudinal axes are provided by forming pairs of adjacent bores in a blank and wherein the driving elements, the driven element and at least two gimbal elements therebetween are formed by electrical discharge machine techniques.