Abstract: Disclosed herein is a Fault-Tolerant Inertial Navigation System comprising, in a preferred embodiment, a Redundant Set of at least two Inertial Navigation Systems, from which one may identify and isolate at least one instrument within an Inertial Navigation Unit which shows substantial performance degradation. The two inertial navigation units are fully capable of performing navigational functions. Each of these inertial navigation units has a plurality of navigational instruments, including at least three linear sensors (such as accelerometers) and three angular change sensors (such as gyroscopes or ring laser gyroscopes). No two linear sensors nor any two angular change sensors of either unit are aligned colinearly. Each of the inertial navigation units produces a set of independent navigational solutions at each of their respective outputs.

Abstract: A terrain profiling apparatus for quick and inexpensive profiling of relatively large areas of ground. A prime mover pulls a sled across a terrain to be profiled. A gyroscope on the sled indicates slope and a measuring device records distances moved. Slope and distance signals are used by a computer to indicate terrain profile.

Abstract: In order to eliminate gyro errors of electrically caged, two-axis gyros, which have a pick-off (52,54) and a torquer (46,48) on each input axis, and each pick-off (52,54) arranged on one input axis energizes the torquer (48,46) on the other input axis, a first measurement is made with a first direction of rotation of the gyro rotor (42). Subsequently, for a second measurement, the direction of rotation of the gyro rotor (42) is reversed and, at the same time, the polarity of the signals from the pick-offs (52,54) is inverted. A measuring value is formed from the gyro signals obtained with both of these measurements.

Abstract: A gyrocompassing system intended for land based equipment requiring north reference information includes a novel gyrocompass implementation which enables utilization of high grade inertial sensors while achieving the desired goal of moderate cost. The north finding system is designed to provide high accuracy with fast reaction time over a wide temperature range without the aid of heaters and other auxiliary equipment. The arrangement is specifically configured to tolerate settling and/or oscillatory base motion without additional reaction time or degradation of gyrocompassing accuracy. The input axis of a gyroscope used in the system is skewed, so it can measure a component of gimbal rotation, thereby eliminating the need for independently measuring the relative gimbal angle. Absolute position alignment between the gimbal and the system case as is required is accomplished by an appropriate stop arrangement, which is an easier task than measuring the relative gimbal angle as aforenoted.

Abstract: A device for marking lines on a piece of sail cloth for cutting out sections therefrom for making a sail, comprising an elongated and horizontally extending table for supporting a length of sail cloth thereon and being wider than the width of the sail cloth, a continuous strip of gearbelt material extending along each side edge of the table whereby the strips of gearbelt material are parallel to each other and to the longitudinal axis of the table, each strip of gearbelt material being pliant and being provided with internal reinforcements to prevent substantial longitudinal stretching thereof, the upper portion of each strip of gearbelt material being provided with uniformly spaced gear teeth for the length of each strip. A longitudinally moveable carriage is mounted on the table, and a transverse rotatable shift is mounted in the carriage.

Abstract: A navigation method and apparatus for reducing substantially the measurement errors such as accelerometer bias, gyro drift rate, gyro scale factor errors, and gyro sensing axis orientation uncertainty. The navigation apparatus includes a first gimbal for rotating a triad of gyroscopes and accelerometers about a first gimbal axis at a predetermined angular rate. The axis is positioned in a plane whose orientation is fixed in inertial space (as, for example, parallel to the earth's equatorial plane). The direction of rotation about the first gimbal axis is periodically reversed. A second gimbal is provided for rotating the triad of gyroscopes and accelerometers at a predetermined control angular rate. The second gimbal axis is directed along an axis orthogonal to the plane described above whose orientation is fixed in inertial space (as, for example, the earth's polar axis if this plane is parallel to the equatorial plane of the earth).

Abstract: A device for stabilizing the inclination of an orientable member mobile in rotation relative to a support which is itself mobile. The device includes, the member, a gyroscope the input shaft of which is rotated on itself by an aiming motor having a casing fastened to a cradle coupled in rotation relative to the support by a transmission linkage determining a constant ratio between the relative rotation of the member and the casing relative to the support. The gyroscope includes a precession detector connected to the inclination motor by an automatic control circuit capable of applying at any time to the motor a signal adapted to compensate the precession induced by angular disturbance of the support about the inclination axis.

Abstract: A gyrocompassing system intended for land based equipment requiring north reference information includes a novel gyrocompass implementation which enables utilization of high grade inertial sensors while achieving the desired goal of moderate cost. The north finding system is designed to provide high accuracy with fast reaction time over a wide temperature range without the aid of heaters and other auxilliary equipment. The arrangement is specifically configured to tolerate settling and/or oscillatory base motion without additional reaction time or degradation of gyrocompassing accuracy.

Abstract: A plurality of two-axis rate gyros are arranged in relation to an aircraft-fixed coordinate system such that they redundantly supply angular rate information. A plurality of accelerometers supply correspondingly redundant acceleration information. First signal processing means comprise means for failure detection and elimination, such that angular rate and acceleration information subjected to error are eliminated. The angular rate and acceleration information thus cleared from errors supply stabilization signals for the autopilot. Second signal processing means obtain the angular rate and acceleration information cleared from errors and integrated if required, and therefrom supply heading and attitude reference signals.

Abstract: Cutter apparatus is provided for sheet material, such as glass, plastic (e.g., plexiglass) or matte boards, particularly designed for use in picture framing, although also usable wherever such sheets need simple and reliable cutting apparatus. The cutter has means for holding a sheet of material in a position to be cut, a guide, and a cutter assembly or slide movable along said guide. The cutter assembly includes a movable cutter carrier resiliently urged toward said material. The cutter carrier holds two separate cutting elements, either one of which can be presented to the sheet material by pivoting the carrier. A lever moves the cutter carrier away from said material. A latch is provided for retaining the lever in a position with said cutter carrier retracted from said material, the latch being normally inoperative.

Abstract: In a method of producing diffraction gratings by feeding either one of a blank or a groove-ruling tool by an amount consisting of the amount of constant transference and the amount of variable transference that is added thereto, or subtracted therefrom, while reciprocally moving the other one of said blank or said groove-ruling tool, in order to rule grooves of irregular intervals on said blank, a method of producing varied line-space diffraction gratings wherein the region of ruling is divided into a plurality of small regions so that the difference between a maximum value and a minimum value of distance between grooves becomes smaller than a predetermined value, and the amount of constant transference is set to the nearly equal to an average distance between grooves in each of said small regions.

Abstract: A stabilized antenna system is disclosed. The stabilized antenna platform includes an acceleration displaceable mass which compensates for linear acceleration forces to inhibit tipping of the antenna platform. The stabilized antenna system may include in combination a gimbal mounting and one or more gyros.

Abstract: An alignment gauge and method of use for aligning a scriber tool, the alignment gauge including a base and a pair of upstanding, at least semi-transparent side walls that extend forward of the front edge of the base. A pair of sight lines extend along the inside surfaces of the side walls in a common plane with the base front edge, and a clamp holds the guide post of the scriber in abutment with the base front edge while the scribing needle is visually aligned with the sight lines.

Abstract: A compositely statically balanced mechanically stabilized platform system including a stabilizing platform having at least one pivotal axis, an equipment platform, a supporting structure, a pendulum, non-rigid means for orienting the platform with respect to the pendulum, a gyro assembly mounted for rotation about a precession axis perpendicular to a pivotal axis of the platform. The gyro assembly itself is statically balanced about its precession axis and has restraining means for orienting the spin axis of the gyro with respect to the gyro assembly supports. The system further includes an equipment platform preferably mounted remotely from the platform and mechanically connected thereto by a linkage assembly which transmits motion of the stabilizing assembly to the equipment platform. In one embodiment the system is constructed as a single integrated unit. In several embodiments the gyro azimuth frame is supported on bearings which permit unrestrained rotation in the azimuth plane.

Abstract: Apparatuses and processes for detecting misalignments between various portions of a deformable body, such as an aircraft, are disclosed. Orientation detection devices, such as potentiometric vertical indicators and gyros, are provided at a master module disposed at a predetermined location on the structure and in a remote module located at a predetermined portion of the structure remote from the reference location. The orientation of the remote portion of the structure, as determined from the remote module is compared to the orientation of the master module to thereby determine the orientation of the remote portion of the structure relative to a fixed reference. The orientation detection devices are secured to the various locations through the use of a standardized track and base assembly, whereby virtually all components of the master and remote modules are interchangeable. The remote module may be disposed on a trammel point assembly wherein the orientation of a predetermined surface may be determined.

Abstract: In a stabilized gyrocompass having meridian seeking gyroscopic means and slaved horizontal gryoscopic means disposed upon a common platform, a signal representative of the angle which develops between the meridian seeking gyro and the platform in response to the dynamic effects of the vehicle is generated. The generated angle is proportional to the northerly inertial velocity term and is used to control the platform in azimuth, thereby providing a dynamically correct stabilized gyrocompass without the use of accelerometers or gravity sensors which are conventional in the art.

Abstract: A passive platform stabilization system is disclosed which is suitable for antenna stabilization in maritime communication systems. The stabilization system of the present invention comprises a platform rotatable in a horizontal plane. At least two gyros are suspended from the platform by suspension means which are rotatable about a vertical axis independent of the rotation of the platform in order to avoid undesirable torque components which would result from precession of the gyros. The platform pivots about axes which are parallel to the pitch and roll axes of a vessel on which it is mounted.

Abstract: An instrument including a gyroscopic rotor mounted to precess about a predetermined axis in response to pivotal movement of the rotor about a sensing axis, with the rate of precession being measured and being utilized to determine the amount of said pivotal movement above the sensing axis. Two or more such rotors precessing about different axes can respond to different components of the earth's rotational movement, or to other component movements or torques. Differences in the rates of precession of the two rotors indicate the relative strengths of the corresponding components of the earth's movement, and afford a basis for deriving an indication of azimuth.

Abstract: An inertial platform carries at least one dynamically-tuned free-rotor gyro and is mounted in a three-axis gimbal system. Accelerometers are carried on the platform with their sensitive axes aligned with the two sensitive axes of the gyro. During alignment of the platform, and while the gyro motor is being run up to speed, the output of the gyro pick-off on each axis is combined with the output of the accelerometer on the other axis and applied through a resolver to the appropriate gimbal torque motor.

Abstract: Six sensors are oriented to position their input axes on the surface of a cone. The cone angle is optimized to permit the use of sensors with identical range capacity despite the fact that the maximum input along each of the orthogonal axes differs.The optimization of cone angle minimizes the average total error amplification due to skewing and change of sensor maximum rate capability to provide data closely approximating that derived from a non skewed, orthogonal, sensor array. The sensors may be gyroscope or accelerometer which are packaged in assemblies of two identical sensors each.

Abstract: The azimuth shaft of an internally gimballed, gyro-stabilized platform assembly is maintained rigid by keeping the uniquely structured inertial instrument-mounting components neutrally buoyant in a flotation liquid that is captive within a spherical shaped outermost gimbal member. Unlike the prior art, this internally gimballed, gyro-stabilized platform assembly can be used for precision, and high-"g", applications.

Abstract: A set of two two-degrees-of-freedom rate gyroscopes and three linear accelerometers are assembled in a single module adapted to be mounted within a single aircraft electronics control unit, the unit comprising a strapped-down attitude and heading reference system. The module base provides a common keyed support for the two pre-calibrated gyros and three accelerometers in intimate mechanical and thermal association. The two gyros are oriented in the base and the base oriented in the aircraft so that the spin axis of one gyro is oriented parallel to the aircraft Z axis and that of the other gyro parallel to the aircraft Y axis while the gyro pickoffs and torquers (input and output axes, respectively) are rotated or skewed forty-five degrees about the spin axes to positions such that the input and output axes lie along the slant heights of a forty-five degree half angle right circular cone, the axis of which lies along the aircraft X axis.

Abstract: Survey apparatus and method employs one or more rate gyroscopes having spin axis components directed along an instrument travel axis and in also in directions normal to the travel axis, so that when the gyroscope or gyroscopes are rotated, the earth's rate of rotation will be detected, at all latitudes and at all instrument attitudes.

Abstract: A redundant inertial reference system is provided with four gyroscope units, with the spin axes of the gyroscopes in the units being oriented, respectively, perpendicular to the four faces of an equilateral tetrahedron. Incidentally, a tetrahedron is a four sided body, and an equilateral tetrahedron is a four sided body having equilateral triangles for the four sides. With the four gyroscopes mounted perpendicular to the four sides of an equilateral tetrahedron, each of the gyroscopes is located symmetrically with respect to the others, with an angle of approximately 109.4 degrees between the spin axes of the gyroscopes. The system is particularly applicable to strapdown type inertial guidance systems and can provide three dimensional orientation information even if two of the gyros fail. The system uses four gyro units, a minimum number which can accomplish a foregoing function, with the four gyro units arranged substantially symmetrically with respect to one another.

Abstract: A manually manipulatable gyro-stabilized indicating instrument which may be used by pipefitters, carpenters, builders, land and road graders and the like for solving a construction problem involving determining the orientation in space of an unknown geometrical plane with reference to a known geometrical plane, or using a known or unknown geometrical plane as a reference and either establishing in space a geometrical plane having a predetermined orientation with reference to the known or unknown geometrical plane. The instrument has at least one straight planar surface and a gyroscope or gyroscopes operatively connected to the straight planar surface and having motive means for driving the gyroscope or gyroscopes to a continuous stabilized condition relative to the straight planar surface in any fixed position and location assumed by the straight planar surface at the time the gyroscope becomes gyroscopes become stabilized.

Abstract: Gyrocompass heading step-by-step repeater amplifier channels are provided with protection from damage by accidental short-circuits occurring in one or more compass step-by-step data repeaters or in the cables extending to such repeaters. Total shut-down of the affected channel or channels is effected by fast-acting thyristor pulse control circuits and the channels are automatically reset when the fault is removed. A cooperative latching short-circuit alarm is provided.

Abstract: An antenna apparatus comprising a gimbals with two axes crossing at right angles mounted on a fixed stand, an antenna base attached to said gimbals to be rocked with the rotation of said gimbals and holding an antenna, flywheels attached to said antenna base for stabilizing said antenna base applying the principle of precession of gyro, a first driving mechanism for rocking said antenna in the elevational direction, a second driving mechanism for rocking said antenna in the azimuthal direction, and a third driving mechanism for shifting the center of gravity on said gimbals in a direction across the direction of rotation of said first driving mechanism.

Abstract: An assembly of single-component motion sensors consists of four equinumerous groups of sensors. All the sensors in any one group have their measurement axes parallel and the directions of the measurement axes of the four groups are parallel to the diagonals of a rectangular parallelepiped. The edges of the imaginary parallelepiped are parallel to the coordinate axes relative to which it is desired to measure the components of motion. With two sensors per group the assembly can still give results after any two sensors have failed. It is shown how two non-simultaneous failures, and, in some cases, two simultaneous failures, can be located.

Abstract: A mirror or other target-sight element in a military vehicle is subject to oticeable vibration or dislocation relative to inertial space as the vehicle moves over rough terrain. To prevent such vibration or dislocation the mirror is driven by a torque motor that is controlled by a gyroscope that mechanically senses these mirror dislocations. The demodulated gyroscope output signal is amplified and applied to the torque motor, which thereby makes the correct repositionment of the mirror to keep the reflected image in a generally stable position in spite of terrain disturbances. The present invention contemplates a second gyroscope also responsive to vehicle pitch movements. The demodulated output signal of this second gyroscope is applied to a zero cross over detector, which produces a square wave output signal substantially in phase with the signal from the first gyroscope.

Abstract: A multi-axis antenna pedestal with two controlled axes configured with elevation over azimuth on a gravity and gyro stabilized platform. The assembly is suspended with right-angled pivotal axes in substantially the same horizontal plane, and structure pivoted about the upper two controlled axes is statically balanced and the center of gravity of the entire pivotally mounted assembly is on the vertical axis and below the gimbal plane. The platform structure includes at least one gyro motor and rotor system pivotally mounted in the platform structure on an axis parallel to one of the right angled pivotal axes of the platform pivotal mounting. The center of gravity of the one gyro motor and rotor system is below its pivotal mounting in the platform structure, and when two such gyro motor and rotor systems are employed the pivotal mounting axes of each parallels an individual axis of the platform pivotal mounting.

Abstract: An improved second order gyroscopic attitude and heading reference system including separate variable time constant accelerometer integrators for independently controlling the velocity error signals associated with respective east and north acceleration signals to provide velocity damped output signals so that a high acceleration input signal of dubious accuracy will have minimal precessional authority while a lower acceleration input signal of greater accuracy will retain nominal control.