Abstract: An apparatus is disclosed which is utilized to provide positional information relative to an external magnetic field. The apparatus includes a rotatably mounted slotted disk wherein the slot is continuously varying in width around the circumference of the disk. The continuously variable width of the slot serves as a light attenuating mask. The disk incorporates an elongated magnet means which causes it to rotate in relation to an external magnetic field. The slotted disk may be placed in a fluid filled chamber. A first and second aperture are located on the top and bottom of the chamber, the apertures defining an emission passage through the chamber. The apertures have a rectangular length approximately the maximum width of the slot. The slotted disk is intermediate the apertures. A source detector, source emitter and an area source means is provided. The area source means is caused to emit a continuous uniform light signal which is attenuated by the slotted disk.

Abstract: A gimballed compass apparatus with digital logic is disclosed which provides directional and attitudinal data. The apparatus comprises a rotatably mounted slotted disk wherein the slot is continuously varying in width around the circumference of the disk. The disk incorporates an elongated magnet which cause it to rotate in relation to an external magnetic field. A first and second aperture are located on the top and bottom elements of the chamber defining a light passage. The apertures have a rectangular length approximately the maximum width of the slot. The slotted disk is positioned intermediate the apertures. A light housing is provided below the chamber and includes a light source. A linear array of source detector are provided above the chamber. Each source detector element provides a response proportional to the specific amount of light incident upon it. The light beam is reflected from the aperture by a mirror to a beam focusing device.

Abstract: A real time directional orientation apparatus is disclosed for use in a four pi (4.pi.) geometry. The apparatus is to be affixed to an object which translates in space. A source emitter means, which may be radioactive, is suspended in a fluid in concert with a magnet. A bank of emission detectors registers the orientation of the source emitter or emitters against a known starting value. As the object translates in space, so does its position and orientation, thus causing the magnet to adjust its position in reference to an external magnetic field, such as, but not limited to, the earth's magnetic field. The motion of the magnet causes the emitter or emitters orientation to change which is sensed by the emission detectors as both a change in intensity and position. This data is processed by a computer and with ancillary data provided by other sensors provides real time position, path and other navigational, directional and positional data, such as pitch, yaw, attitude and roll.

Abstract: A real time directional orientation apparatus is disclosed for use in a two pi (2.pi.) geometry. The apparatus is to be affixed to an object which translates in space. A cylindrical disk is suspended in a fluid in concert with a magnet. The cylindrical disk is disposed inside a cylindrical housing. A light source is in communication with the disk and the light is propagated through the disk where it is finally projected from the disk in a radial fashion. The light beam projected is detected by a bank of photon sensitive detectors lining the interior of the cylindrical housing. The light source is propagated through two coplanar, orthogonal light channels which emanate from the center of the disk in a radial fashion. The photon sensitive detectors register the orientation of the light channels against a known starting value.

Abstract: A gimballed compass apparatus is disclosed which provides directional and inclinational data. The apparatus comprises a rotatably mounted slotted disk wherein the slot is continuously varying in width around the circumference of the disk. The disk incorporates an elongated magnet which causes it to rotate in relation to an external magnetic field. A first and second aperture are located on the top and bottom elements of the chamber defining a emission passage. The apertures have a rectangular length approximately the maximum width of the slot. The slotted disk is positioned intermediate the apertures. An emission housing is provided below the chamber and includes an emission source and a first source detector. A second source detector is provided above the chamber. The source detectors provide a response to the intensity of emission incident upon them.

Abstract: A low cost, simple apparatus is disclosed which can be used to provide positional information relative to an external magnetic field. The apparatus comprises a rotatably mounted slotted disk wherein the slot is continuously varying in width around the circumference of the disk. The disk incorporates an elongated magnet which causes it to rotate in relation to an external magnetic field. The slotted disk is placed in a fluid filled chamber. A first and second aperture are located on the top and bottom elements of the chamber defining an emission passage. The apertures have a rectangular length approximately the maximum width of the slot. The slotted disk is intermediate the apertures. A source detector is provided below the chamber proximal an emission source, and a second source detector is provided above the chamber. The source detectors provide a response to the intensity of emission incident upon them.

Abstract: Method and apparatus are disclosed for compensating a magnetic compass in a vehicle for magnetic deviation. With the compass installed, the angle indicated by the magnetic compass relative to a direction axis of the vehicle is measured. A test magnetic field is added at a known angle relative to the direction axis of the vehicle. The strength of the test magnetic field required to displace the direction indicated by the compass through a predetermined angle is memorized. Then, the strength of the resultant magnetic field is calculated using the measured angle, the predetermined angle and the memorized strength of the magnetic field. After determining the strength of the resultant magnetic field with the vehicle oriented in any selected direction, the vehicle is then reoriented in a direction one hundred eighty degrees away from the selected direction and the strength of the resultant magnetic field in that orientation is determined in the same way.

Abstract: Disclosed is an electronic magnetic compass which is to be mounted on a small ship and which is reduced in cost and improved in performance. The electronic magnetic compass is provided with an angle sensor interlocked with a compass card so as to produce a code signal at every predetermined angle, a code converter for converting the code signal into a compass indication angle, and a signal conversion circuit for producing a deviation signal indicating a deviation between an azimuth angle signal and an indication angle signal. The compass azimuth measurement is performed with a simple configuration of an open loop system, so that the structure of an encoder for the angle sensor is so simple that the cost can be reduced so much. The azimuth angle signal and the indication angle signal can be automatically calibrated so that the measurement accuracy can be improved.

Abstract: A magnetic compass in which a conventional compass card provides an analog readout of compass heading and a binary coded digital disk together with fiber optic sensing technology provides a digital readout of compass heading contained within a single housing, together with a gravity driven inclinometer providing a measurement of the inclination of the ground. The compass magnet is shielded by Faraday type shielding from the electronics that processes the digital reading. An analog electronic readout of both compass heading or inclination, capable of remote display, is provided by a tapered iris disk and fiber optic reader combination. A magnetic compass employing a compass disk with a reflecting tapered iris on one side of the disk sensed by a reflecting fiber optic reader and a standard compass card on the other side which can be read visually provides an improved magnetic compass being very compact and providing both analog and digital readouts.

Abstract: A sensor provides remote angular orientation sensing. A rotational signal transmitted to a rotatable input shaft mounted in an encoder body causes the shaft to rotate. Light signals are transmitted through a digital code wheel mounted to the shaft. As the code wheel and shaft rotate, the light signals passing through the code wheel are superimposed with light pulses corresponding to incremental and directional changes of angular position of the code wheel with respect to the encoder body. The light signals are propagated through an optical fiber to a remote combination digital and analog circuit which converts them into a digital representation of the angular position of the code wheel.

Abstract: A method for remotely detecting the angular position of a rotatable code wheel is provided by generating two sine wave modulated light beams which are orthogonally polarized with respect to each other. The beams are combined and then directed through a polarization filter mounted on the code wheel. The combined beam incurs a phase shift with respect to a reference signal which depends upon the position of the code wheel. The combined polarized beam provides angular position resolution between zero and ninety degrees, but lacks quadrant resolution. Two other light beams are directed to a two channel digital mask pattern imprinted on the code wheel. The mask pattern encodes these latter beams with "on" or "off" pulses to provide quadrant resolution. The beams are converted to digital electric signals which are received by a programmable read oly memory (PROM). The PROM provides an output corresponding to the angular position of the code wheel to a display.

Abstract: A magnetic compass is disclosed which is especially adapted for use in automotive vehicles and which is provided with an optical angular position encoder. The housing comprises a cylindrical cup and a hollow cylindrical rim; a compass rotor is disposed in the housing with the magnet in the cup and an encoder disk in the rim. The hollow rim has a base plate defining a vehicle orientation axis and a cover plate. The rotor is provided with a reference position aperture and a plurality of displacement angle apertures disposed in a single circumferential track. The transducer comprises optical transmitters and receivers mounted opposite each other on the plates for detecting the apertures in the encoder disk. Support arms for the compensation coils and the search coil are disposed on the cup opposite the magnet in a predetermined angular location relative to the orientation axis.

Abstract: An electronic compass (10) comprising a circular semi-transparent wheel (12) mounted for rotation in a horizontal plane and carrying a bar magnet (14) mounted radially with the magnets south pole oriented outwardly to cause the wheel to function as a compass. The wheel (12) is provided with a gray scale (16) located around the wheels periphery. One or more light-emitting diodes (LEDs) (18) are mounted below the wheel (12) and a photoresistor (20) is mounted above the wheel in position to receive the light from the LEDs (18) passing through the wheel. The photoresistor provides a signal, indicative of the intensity of the light received to a voltage comparator circuit (22). The circuit (22), in turn, passes signals to a suitable display means (24) to provide a directional indication related to the position of the bar magnet (14).

Abstract: A compass and method of operation are disclosed for finding the heading of a vehicle. The heading is found using a compass having a rotor with a compass magnet thereon and means on the rotor defining a reference line in known relation with the polar axis of the magnet. The angular displacement of the rotor is measured between alignment with the direction reference axis and alignment with the local magnetic field. A search coil is used to torque the rotor so that it reaches a reference position in which the reference line thereon is aligned with the direction reference axis. A reference position encoder generates a pulse when alignment is achieved. An angular displacement encoder produces a digital signal which changes with each predetermined increment of rotation of the rotor and which is indicative of the direction of rotation. A microcomputer processes the signals to provide a cumulative count of the increments of rotation.

Abstract: A device to give an indication of the passage of a pig through a pipeline and methods of performing various pipeline operations using the device are described. The device has a magnetic sensor based on a dip needle and the output of the sensor controls a flag actuating mechanism. Passage of a pig beneath a pig indicating device causes a flag to be raised giving a visual indication that the pig has passed that location. Methods are described in which one or more devices are used to find a lost pig, for accurately locating a defect in a pipeline, for determining if a pig has been correctly launched or received, and for determining and controlling the speed of a pig in a pipeline.

Abstract: A control apparatus is disclosed for a sailboat automatic pilot comprised of a rotatable drum connected to a compass member, the drum having a series of light-reflective and light-absorbent stripes. A light source located adjacent to the drum illuminates the drum surface. A pair of light detectors provide signals to circuits which detect the transition between the light-reflective and light-absorbent stripes and determine the direction of rotation of the drum to provide corrective signals to a steering actuator.

Abstract: A remotely readable fiber optic compass. A sheet polarizer is affixed to a magnet rotatably mounted in a compass body, such that the polarizer rotates with the magnet. The optical axis of the sheet polarizer is preferably aligned with the north-south axis of the magnet. A single excitation light beam is divided into four identical beams, two of which are passed through the sheet polarizer and through two fixed polarizing sheets which have their optical axes at right angles to one another. The angle of the compass magnet with respect to a fixed axis of the compass body can be determined by measuring the ratio of the intensities of the two light beams. The remaining ambiguity as to which of the four possible quadrants the magnet is pointing to is resolved by the second pair of light beams, which are passed through the sheet polarizer at positions which are transected by two semicircular opaque strips formed on the sheet polarizer.

Abstract: An error sensing system for use in marine autopilot systems of the type having a photographic film compass disk aligned with the direction North and sensing means associated with the disk is operative to sense relative movement between the disk and the sensors in response to changes in the heading of the vessel. A first direction error surface portion on the disk has opaque and transparent areas defining a zero reference therebetween, a second magnitude error surface portion on the disk has a second zero reference position in predetermined relation to the first zero reference position and an area of variable transparency extending along the second surface portion. The first and second surface portions are defined by images along the peripheral surface of the photographic film disk.

Abstract: A thin-line heading sensor is disclosed having an outside diameter of less than an inch which is accurate to within 1.degree. of arc. The invention includes a magnetic wheel having a reflective multifaceted perimeter. The facets are optically coded for identification. When the wheel is illuminated by a collimated beam of light, a beam is reflected onto an array of photodetectors. The photodetectors are coupled with an electronic circuit which decodes the position and pattern of illumination to determine the position of the magnetic wheel.

Abstract: A pair of referencing coils are mounted in direct association with a rotatable scale having a reference position index and a code strip. A reference position sensor generates a signal in response to alignment of the reference position sensor with the reference position index, and magnetic members are operative to normally align the scale with magnetic north. An electrical drive is provided for alternately energizing the reference coils disposed at predetermined angles to one another and to the magnetic members which respond to the energization of each coil and advance the reference position index toward the reference position sensor. Preferably alignment coils are positioned at equal angles to either side of the reference position sensor so that drive requirements are such that the current applied to each coil is only necessary to draw the magnets and associated scale through an angle which is just greater than one-half the total included angle between the coils.

Abstract: A transducer for sensing the angular position or rate of change of displacement of a housing of a borehole survey instrument with respect to a reference position includes a rotor magnetically suspended within a stator which is in turn secured to the housing. The rotor is constrained by the magnetic suspension to rotate about a single axis relative to the stator. A frame of reference is established for the transducer, against which subsequent measurements are compared. Optical sensing means are included for sensing the movement of the rotor about the axis of motion to develop an indication of the angular position or rate of change of position of the housing.

Abstract: A sailing course computer instantaneously and continuously computes a sailboat's speed towards a predetermined destination. In a first embodiment, a polarizer disk is utilized as a compass card through which a light source may be directed. An analyzer disk is positioned below the polarizer disk, and a photocell below the analyzer disk then provides a signal indicative of the amount of light passing through the two disks in response to the sailboat assuming various headings. A second signal input is provided by a knotmeter, and appropriate electronic circuitry is then used to indicate the speed of the sailboat towards a given destination. In a second embodiment, a light source is provided on one side of a compass card and a photocell is provided on the other, with a circular aperture being positioned tangentially to the center of the card so as to permit light impingement from the light source upon the photocell.

Abstract: A remote-reading compass in which a compass assembly is buoyantly supported within a housing to accommodate a large range of tilt. Buoyancy is provided by a float surrounding the compass assembly and a liquid within the housing chamber. A pivot pin extends from either side of the float along a first normally horizontal axis to permit rotation of the float and compass assembly about the axis. The ends of the pivot pin ride in a circumferentially extending track which is disposed on the interior of the housing. The track permits rotation of the compass assembly and float about a second normally horizontal axis orthogonal to the first axis of the pivot pin. In this manner, the compass assembly is permitted to remain in a normally horizontal orientation during movement of the compass housing without need of gimbals, and rotation about a normally vertical axis is prevented. In addition, the track and the pivot pin together maintain a desired spacing between the float and the interior of the housing.

Abstract: In an orientation arrangement during journeys in vehicles on land, means are provided for the purpose of ascertaining the distance covered by the vehicle and the changes in the direction of the vehicle. The distance covered by the vehicle and its respective location are ascertained and indicated with the aid of the distance measured and the changes in direction which have been ascertained.

Abstract: The angular position of a compass card or like rotary encoder disk includes the utilization of an optical pickoff system in which the accuracy associated with a digitally encoded disk is enhanced through the utilization of a secondary analog optical pickoff system in which the outer periphery or border of the disk carrying the digital code is provided with a series of skewed lines running at an angle to the radius of the disk. A mask having a narrow slot is located to one side of the disk along the radius of the disk. A light source is positioned on the other side of the disk, and a linear array of detectors is positioned above the slot. The use of the skewed lines and slot amplifies the motion of the rotary encoder disk such that fine angular orientation may be detected by virtue of the position along the length of the slot of a line within the slot aperture.

Abstract: A self-contained compass apparatus includes a sensing circuit and power source which are enclosed along with a compass unit within a chamber which is adaptable for suspension at extended distances into a borehole, such as, an oil well, so as to assist in determining direction and orientation of articles, such as tooling, positioned in the well.

Abstract: A digital magnetic compass provides an octant display of magnetic bearing in alphabetic characters and incorporates a magnetic sensor for providing signals representative of the orientation of the sensor with respect to the earth's magnetic field, a microprocessor for processing the signals from the sensor and for providing output signals applied to an alphabetic-type display. In the preferred embodiment of the invention the system is incorporated in a vehicle such as an automobile with the sensor remotely positioned with respect to the display.

Abstract: The device comprises in a preferred embodiment, on one hand, an orienting system comprising a compass provided with two reflecting faces angularly offset 180.degree., an orientable optical system for detecting the angular deviation of the reflecting faces relative to a reference direction and means for displaying the detected deviation and, on the other hand, an automatic piloting system comprising a set of mirrors photocells, a servo-control device, and a cylinder device (32) for steering the steering wheels (33) of the vehicle.Application in particular to agricultural machines.

Abstract: Improvements are disclosed in the pattern cone of the magnetic compass as described and claimed in copending application 769409, Harold T. Lyman, Jr., now U.S. Pat. No. 4,132,113. Simpler apparatus for trimming the sensor outputs of the sine and cosine of the angle between the craft's actual heading and the desired heading, are described and claimed.

Abstract: A remote-indicating magnetic compass system for use with automobiles or the like. The system consists of a dashboard-mounted readout unit, which receives and decodes logic signals provided thereto from a remotely located electro-optical shaft encoder, the latter being responsive to and positioned by the earth's magnetic field. The form of bearing readout is discrete rather than continuous, e. g. 8 or 16 bearing states are described. The bearing readout display may be defined by a plurality of discrete indicators, such as light-emitting diodes, or segmented alpha indicators or so forth may be employed. The electro-optical shaft encoder assembly is preferably located at a point on the vehicle distant from large bodies of iron or steel, and where the earth's field is strong relative to fields associated with permanently magnetized auto parts.

Abstract: Our invention relates to a novel electromechanical method and apparatus for detecting and representing the north direction and/or the heading of an object or vessel in analog and/or digital representation.

Abstract: Apparatus for borehole surveying employing remote reading electro-optical sensors for providing digital signals represenatative of azimuth and multi-axis inclination for direct transmission to the surface for recording or use.

Abstract: A magnetic compass in which the compass magnet is an electromagnet energized only when in a horizontal disposition to provide a correct heading indication without error due to tilting of the compass magnet.

Abstract: A shaft angle transducer particularly suited for use as a magnetic compass card for providing an output signal linear with angular movement over a wide range, such as plus and minus 40.degree., with no zero dead band. A member with a plurality of radial segments, each having relatively opaque and transparent portions, with the proportion of the portions changing from segment to segment to provide an output varying as a predetermined function of angular position. A sensor with radiation source and detector, with the segments moving between the source and detector, with the segments in a disc configuration and in a wheel configuration.

Abstract: A hand-held digital compass employs an incremental encoder including a digit code disc and sensor unit which are so interrelated with a logic circuit as to permit automatic referencing of the compass when power is initially applied; and further permits use of an extremely small digit code disc which in cooperation with the sensor unit will permit digital recording of the direction and degree or extent of displacement of the compass in a given direction. The logic circuit employed is self-correcting for errors caused by input line noise and permits utilization of a simplified counting circuit for reading and digitally displaying degrees of movement between zero and 360.degree..

Abstract: A magnetic compass arrangement for use on a road vehicle consists of two magnets mounted so that tilt or acceleration of the vehicle produces equal and opposite errors in them. The errors are cancelled and a substantially error free output signal representative of direction is provided.

Abstract: An odograph in which calibrated portions of heading and distance signals are used for displaying locations. A magnetic compass is provided including a North-seeking spherical surface carrying a reflective segment, the position of which is sensed by electro-optical components which derive and generate an appropriate heading signal. An odometer generates distance signals which are integrated with the heading signals, calibrated by gating with a probabilistic function. A visual display is driven by means which are responsive to coincidence of the odometer and heading signals but which exclude response to coincidence of an odometor signal and two heading signals.

Abstract: A remote reading magnetic compass in which a coded compass disc is supported for rotation by a single upper pivot bearing which maintains the disc and associated compass magnet submerged in a damping liquid with positive buoyancy and which provides a selected range of tilt without gimbal mounting.

Abstract: A coordinate indicating and plotting system wherein compass heading signals are periodically integrated at frequencies related to the distance traveled by a water, air or land vehicle to obtain coordinate change signals for visual indication of vehicle coordinates. The coordinate change signals can be applied to a plotting system to record the path followed by the vehicle or applied to a counter to indicate the unit changes for the vehicle in each direction. Desirably, the compass heading signals are digitized by converting the heading signals into frequencies and the signals are integrated by summing the pulses for each output direction during each sampling period. A novel crescent-shaped opening whose width approximately follows a sine function between zero and 180.degree. is positioned angularly on the compass card about the center of rotation thereof.

Abstract: Angular displacements are measured relative to either an external magnetic field as in a compass or relative to a vertical reference as in inclinometers or the like by selective orientation of the device. A bistable weight balancing apparatus and a dual bearing support arrangement cooperate to provide two discrete balancing positions. Horizontal positioning of the device results in relatively even weight distribution around a needle bearing support which permits alignment with the polar line of an external magnetic field. Vertical orientation of the device permits an offset redistribution of the weight in the bistable balance to define a vertical reference. Digitally coded apparatus such as a disc permits circuitry to detect instantaneous orientation of the frame relative to a magnetic field or vertical reference. Circuitry logically cooperates with data read from specially coded tracks to insure accurate strobing of the output data free of ambiguities.