Abstract: A sight reduction apparatus includes a sextant, a processor, and a nautical almanac, preferably all provided in an unitary housing. The sextant includes a fixed telescope which is pointed at a known celestial body, and a radial arm is moved against an arc graduated in degrees until a mirror mounted on the sextant reflects an image of the horizon down the telescope to coincide with the known celestial body. The angular elevation of the celestial body, corrected for the exact time and date, gives the position of the user on an imaginary circle. The nautical almanac provides essential data for determining the location of a predetermined list of celestial bodies relative to a fixed location. The processor is programmed to determine the position of a user based upon measurements made with respect to two celestial bodies using the sextant and information provided in the nautical almanac and to further provide the position of a user in terms of latitude and longitude.

Abstract: A method and apparatus for plotting a boat's position relative to a rhumb line when tacking. The apparatus includes three independently rotatable disk members. A first disk member presents a compass rose, the second of the disk members presents an indicator that aligns on the compass rose along with a grid, and the third of the disk members presents a rhumb line. The starting and ending positions are plotted on the rhumb line. The rhumb line is then aligned with the compass rose in accordance with the boat's true course. An initial course is set by rotating the indicator with respect to the compass rose on the first disk. The boat's first tack position is located and plotted on the grid by counting grid lines from the starting position. The second disk is then rotated and the next tack position is plotted away from the first tack position. The tack positions are plotted on the third disk to provide the boat's position relative to the rhumb line.

Abstract: A directional plotter for underwater searches, land searches, land orienting, or the like includes a pair of first and second relatively rotatable discs with the first disc including first, second and third concentric sets of compass degrees in radially adjacent relationship to each other. The second disc includes first, second and third sets of apertures associated with the first, second and third concentric sets of compass degrees. The two discs are relatively rotatable such that different search patterns can be established by rotating the discs relative to each other and viewing the required degrees for a particular search pattern through the associated apertures.

Abstract: A navigational calculator (10) for establishing the ratios of time, or distance, to be spent on port or starboard tacks, respectively, during the maneuvering of a yacht to a windward destination. A plurality of disk members are carried on a central support (11). The first disk member (14) has a true wind indicator (30) imprinted thereon. The second disk member (15) has a compass rose (34) imprinted thereon. The third disk member (16) has a course indicator (35) and two sets (38 and 39) of tack ratio indicia imprinted thereon. The fourth and fifth disk members (18 and 19) have starboard and port heading indicators (46 and 55, respectively) imprinted thereon. The sixth disk member (20) has included tacking angle indicia imprinted thereon and a tack ratio indicator (61) alignable with one set (38) tack ratio indicia. The seventh disk member (21) has included tacking angle indicia imprinted thereon and a tack ratio indicator (66) alignable with the other set ( 39) of tack ratio indicia.

Abstract: A menu-driven, hand-held navigation and flight performance computer having a keyboard, display, and CPU. The display includes a menu region for displaying the names of navigation and flight performance functions, one or more parameter name regions and a data region. The keyboard includes a first cursor key for selecting among the navigation and flight performance functions on the menu portion of the display. The keyboard additionally includes a key for triggering the start of a specific function selected by the cursor key, a plurality of arithmetic operator keys, a plurality of number keys, and a conversion key for converting data from one unit of measure to another. A timer is included for upcounting and downcounting and for triggering the automatic shut-off of the computer after a specific period of time expires since the last keyboard entry. The CPU retains outputs of select programs to be used as default inputs to select subsequently executed programs.

Abstract: There is disclosed a marine calculator of the slide rule type whereby the running distance to a destination station over a dogleg or zig zag course may be readily determined from knowledge of the rhumb line course distance and the departure angle of the dogleg or zig zag course.

Abstract: A wind and course calculator for navigation is provided comprising two superimposed disks made from a transparent material, a mobile disk 1 movable in rotation and in translation carrying a network of concentric circles corresponding to the speeds and of converging straight lines corresponding to the angular values of headings and a supporting disk 2 having a mark 5 indicating the heading and, at its periphery, graduations corresponding to the angular values of sailing trims of the boat and a scale of speeds 7 carried on the radius directed towards the indication of the heading, on the reverse side of which supporting disk is fixed a pointer 10, 11 having a slider 12 carrying a reference dot 13 serving as display and reading point. The upper face of the supporting disk has two parallel guides 3 between which the mobile disk 1 slides.

Abstract: A course and heading computer for use with marine charts which includes a transparent planar baseplate having a semicircular edge at one end joined with rectangular edges at the opposite end, the straightedge parallel to the shorter dimension of the baseplate being equal in length to the diameter of the semicircle, a 360.degree. circular scale imprinted on the baseplate with its center at the center of the semicircle, and a printed scaled grid to assure quick, accurate alignment, on the marine charts, and a transparent disk member rotatably attached at its center to the center of said semicircle, and having a 360.degree.

Abstract: A slide rule for solving time/speed/distance problems where distances are measured with a single or universal ruler applicable to all charts or maps regardless of scale. Result is achieved by printing alongside time entries on the slide rule a row of appropriately-spaced numbers constituting indicia of chart or map scale, and which has a range encompassing the largest and smallest scales of charts or maps which are likely to be encountered. When such numbers are properly positioned, it is necessary only to set chart scale opposite speed made good, after which running time will always appear opposite distance travelled, and vice versa. This device eliminates the need to use dividers and mileage or latitude scale, and thus obviates the intermediate steps which their use entails.

Abstract: A template, for use in conjunction with a radar presentation to train an intercept controller in coordinating aircraft movements, defines spatial relationships between aircraft symbols presented on the radar through range and separation scales and position cues imprinted on the template. The template also has a series of apertures which allow direct marking of aircraft position on the radar scope without removing the template.

Abstract: A dead reckoning navigation instrument, consisting of magnetically connected components, for navigation watercraft between known waypoints. A trackline on a transparent trackline plate connects the waypoints. A direction line on a transparent direction line plate, oriented perpendicular to the trackline is used to define the next waypoint along a route. A transparent overlay plate provides the speed and distance traveled scales for the dead reckoning navigation function.

Abstract: A navigational aid device comprising three concentrically mounted relatively moveable scales and at least one centrally mounted rotatable arm defining a moveable radial line intersecting the scales and their axis of rotation, at least the central portion of the device being transparent or cut-away so that when placed on a map the map location appearing on the axis is visible to an operator using the device.

Abstract: A direct reading map plotter for converting grid values to magnetic values and vice versa without having to perform arithmetic calculations. The plotter includes a transparent base having a recess formed therein in which is rotatably supported a transparent disc. A compass rose having its center located at the center of rotation of the disc is imprinted upon the base about the periphery of the recess. A heading line representing magnetic north is also imprinted in the base with the line passing through the center of the rose and being arranged to point at the zero mark on the rose. A second diametrical line representing grid north is imprinted upon the disc so that it is caused to turn therewith. A declination scale is provided on the disc which extends to either side of the grid north line whereby the grid north line can be accurately positioned in relation to the magnetic north line.

Abstract: A graphic vector plotting instrument, particularly suited for marine navigational computations. A cursor disk is surrounded by a concentric compass disk, and both are rotatable about their common center. The cursor disk has a pair of perpendicular cursor lines which intersect at the common center and a plurality of other parallel cursor lines. The compass disk has a 360.degree. compass rose scale thereon. A transparent plotting slide is slidable over the cursor disk and the compass disk and contains scaled markings permitting the plotting and solution of navigational vector problems thereon without the aid of other devices or surfaces or charts.

Abstract: Instruments presently available for stereographic calculations use a single net over which transparent paper is moved. The device of this invention has two nets, one printed on each side of a rotatable disc in a frame and the calculations are made by rotating the nets under transparent paper fixed to the frame.

Abstract: A device utilizing three discs, which are rotatably positionable relative to each other, is provided for computing aerial navigation wind correction angle and ground speed correction for various combinations of aircraft True Course, Wind Direction, Wind Velocity, and True Air Speed. The first disc, which for most effective utilization of the device is referenced to the longitudinal axis of an aircraft outline, has a first series of informational whole number scales running circularly therearound indicating wind correction angles for various wind velocities, and a second circularly arranged series of whole number scales indicating ground speed corrections for various wind velocities. The second of these discs provides a compass rose around its circumference which is positioned in accordance with the aircraft true course set at the longitudinal axis of the aircraft outline of the first disc, and upon which the third disc is positioned in accordance with the wind direction.

Abstract: A pilot's kneepad for use as an aid to navigation by pilots and navigators of aircraft and other vessels consisting of a plate which has means for attaching it to the upper surface of the thigh of a seated pilot, the plate having on its upper surface information for use in navigational calculations and having hingedly attached to it along one edge a second plate the underside of which also carries information for use in navigational calculations and which has on its upper side means for attachment of a writing pad. Preferably, along one edge of the plate is provided a slide rule that can be used for making inflight calculations.

Abstract: This disclosure pertains to a navigational computer having three arms slideably and pivotably secured to one another. A pair of compass roses are affixed at the intersection of one arm to each of the adjacent arms. Angularly disposed indicia, on the compass roses, and distance and speed indicating indicia disposed on each of the arms, provide computed data resulting from selective angular displacement of the arms and the utilization of selective portions of the lengths thereof.

Abstract: A navigation aid for visually indicating to an aircraft pilot or other user the distance and bearing to a destination by use of radio navigation information from two pre-located sources. The axis of a compass rose representative of the destination is preset spacially and angularly with respect to the two radio stations, each represented by an individual compass rose longitudinally movable along primary elongate arms connecting the three compass roses. Three secondary elongate arms are pivotally movable about the respective compass rose axes. By setting two of the secondary elongate arms to represent the bearing of the aircraft to each of the radio stations, distance to the destination can be read directly from the intersection of the three secondary elongate arms. The desired bearing is indicated by the angular relationship between the compass rose centered about the axis representative of the destination and the secondary elongate arm pivoted about its axis.

Abstract: An apparatus and method of calculating a vehicle's elevation, speed, distance and time to arrive at a predetermined point. The apparatus includes a mechanical spring-driven clock mechanism having a rotating settable pointer passing adjacent a clock face for visually ascertaining time measurement during a specified time interval. The clock face has a prescribed set of indicia formed thereon defining a nomograph which correlates the vehicle's speed and distance to the predetermined point. An outer annular ring movable with respect to the clock face provides indicia showing the vehicle's elevation at specific time points. Tab elements which are slideably moveable on the annular ring provide visual guides to important elevation points. A central pointer on the clock is set at the selected vehicle speed and distance measurements on the nomograph and relates to a proper vehicle elevation mark on the annular ring. At a specific time designation, the clock pointer movement is initiated.

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: An aircraft descent calculator including a central member defining an outer annular dial face about the periphery thereof; an intermediate member defining an intermediate annular dial face about the periphery thereof rotatably mounted on the central member so that the intermediate dial face lies adjacent the inside of said outer dial face; and an inner member defining an inner annular dial face about the periphery thereof rotatably mounted on the intermediate member in juxtaposition with said intermediate dial face where each of the dial faces divided into equal angular spaces, where the intermediate dial face has aircraft altitude indicia recorded thereon increasing in prescribed altitude increments in a first direction around the intermediate dial face and where both the inner and outer dial faces have aircraft DME distance recorded thereon increasing in prescribed distance increments in opposite directions around the dial faces so that said dial faces can be manipulated to determine positions on a prescrib

Abstract: Disclosed is a circular computer and system for determining the sun angle relative to the horizon from any given place and at any time. The computer includes transparent, rotatably mounted discs on both sides of the circular disc member. Printed on one side of the circular disc member are outer and inner circular sets of indicia respectively representative of site longitude and Greenwich Mean Time. Printed on an associated one of the rotatable discs is a set of indicia representative of Solar Time. Printed on the other side of the circular disc member are parallel lines representative of latitude between diametral representations of North and South poles. Elliptical lines extending between the North and South poles are proportionally disposed on the surface to scale Solar Time in hours. Printed on the other associated one of the rotatable discs are parallel lines representative of sun angle and a perpendicularly arranged sun elevation line.

Abstract: A course correction calculator for use in light aircraft includes two arms pivotally connected together and each independently pivoted over a map supported on a base. The pivot connecting the two arms is slidable longitudinally along one of the arms and the other of the arms is slidable longitudinally relative to one of two pivot points. A protractor is provided at the pivot connecting the two arms to indicate the angle between them and hence course correction when the two independent pivots are at the departure and destination points on the map and the mutual pivot is at the aircraft's position on the map.