Abstract: The invention relates to a management module for a sailing boat, said sailing boat comprising a wind angle sensor configured to measure the wind angle value of the boat indicating the angle between the wind direction and the sailing direction of the sailing boat, said wind angle value being comprised between ?180° and +180°, and an autopilot module configured to receive control commands and to control the trajectory of said sailing boat using said control commands, said management module being configured to receive the wind angle value from said wind angle sensor, generate a control command to control the wind angle of the boat between a first angle threshold and a second angle threshold wherein said first angle threshold and said second angle threshold are greater than or equal to 0° and smaller than or equal to +180° when the wind angle value is between 0° and +180° and greater than or equal to ?180° and smaller than or equal to 0° when the wind angle value is between ?180° and 0°, and send said generated c

Abstract: Techniques are disclosed for systems and methods to provide perimeter ranging for navigation of mobile structures. A navigation control system includes a logic device, a perimeter ranging sensor, one or more actuators/controllers, and modules to interface with users, sensors, actuators, and/or other elements of a mobile structure. The logic device is configured to receive perimeter sensor data from the perimeter ranging system. The logic device determines a range to and/or a relative velocity of a navigation hazard disposed within a monitoring perimeter of the perimeter ranging system based on the received perimeter sensor data. The logic device then generates a display view of the perimeter sensor data or determines navigation control signals based on the range and/or relative velocity of the navigation hazard. Control signals may be displayed to a user and/or used to adjust a steering actuator, a propulsion system thrust, and/or other operational systems of the mobile structure.

Abstract: An aircraft airflow sensor probe includes an airflow assembly or a cone assembly configured to sense a direction of local airflow outside an aircraft; a shaft configured to rotatably hold the assembly and allow rotational movement of the assembly; and a motor connected to the shaft and configured to generate a torque to damp the rotational movement of the shaft as well as the assembly. The sensor probe further includes an angle of attack processor configured to control the motor to generate the torque to damp the rotational movement of the shaft as well as the assembly and a sensor configured to sense a position of the assembly and provide the position of the assembly to the angle of attack processor. An aircraft airflow sensor process is disclosed as well.

Abstract: A boat basically includes a hull, at least one propulsion unit, a heading sensor, a position sensor and a controller. The at least one propulsion unit is movably mounted to the hull, and has a propulsion axis. The heading sensor is configured to detect a heading of the boat. The position sensor is configured to detect a position of the boat. The controller is programmed to turn the at least one propulsion unit relative to the hull such that the propulsion axis moves away from a center point of the boat to correct the heading of the boat upon determining that the boat is drifting in a drift direction based on detection results of the heading sensor and the position sensor.

Abstract: An aircraft is provided. The aircraft comprises: a fuselage; and a laser transceiver configured to transmit one or more laser light beams, wherein the laser transceiver is mounted to the aircraft at a waterline location along the center of the fuselage of the aircraft, wherein the center is between the top and bottom of the fuselage, and wherein the laser transceiver is configured to measure at least one air data parameter.

Abstract: Example methods and apparatus to determine downhole fluid parameters are disclosed herein. An example method includes determining a velocity of a portion of a downhole tool moving in a well and determining a response of a fluid sensor disposed on the portion of the downhole tool. The fluid sensor includes a resistance temperature detector at least partially immersed in a fluid in the well. The example method further includes determining a velocity of the fluid based the velocity of the portion of the downhole tool and the response of the fluid sensor.

Abstract: An atmospheric turbulence data optical LIDAR system for computation of wind velocity includes a laser (16) to transmit one or more beams to a target, an optical head (10) including a transmitting optics (12) and a collecting lens (14) for receiving one or more corresponding beam returns from the target. A detection system (18) includes a multi-element detector array at near a focal plane of the collecting lens. For each element of the multi-element detector array there is a specific optical path in the atmosphere leading from the laser to the target and back from the target to the element. A processor measures (20) signal fluctuations of an element of the multi-element detector array and computes therefrom crosswind velocity of wind in the atmosphere. The processor calculates turbulence strength changes.

Abstract: An electromagnetic boat speedometer includes a boundary layer velocity compensating arrangement comprising a primary coil for producing a primary electromagnetic field within a relatively large first volume of water, a secondary coil for producing a secondary electromagnetic field within a relatively small portion of the first volume of water immediately adjacent the hull of the boat, and a set of first electrodes removably mounted in one or more openings in the hull of the boat, such that the tips of the first electrodes extending into the relatively small water portion. In one embodiment, the coils are simultaneously energized in opposition, so that the primary and secondary electromagnetic fields are in opposition. In a second embodiment, the coils are energized alternately, and the signals produced by the electrodes are modified to achieve the desired boundary layer compensation. A second set of second electrodes may be included in the second embodiment.

Abstract: The object of the present invention is to provide an air data sensor that does not require an external input of a reference velocity as a Doppler LIDAR, has a function of autonomously determining the absolute airspeed, and has no position error.

Abstract: A gear position detecting system includes structure which facilitates mounting of the system, and minimizes direct contact of other objects with the system. The outer circumferential surface of a shift drum, turned by operation of a change pedal, is provided with lead grooves. Shift forks, engaged with the lead grooves, are moved in the left-right direction by turning of the shift drum, whereby shift gears are changed over, and a speed change desired by the rider is performed. A detection pin of a neutral safety switch, which is one of gear position sensors, is pushed in by a detection cam of a cam surface provided at the outer circumferential surface of the shift drum in the speed change operation position, whereby a neutral position is detected.

Abstract: A method for synthetically calculating redundant attitude and redundant heading for an aircraft using data existing in the aircraft, including angular rates p, q, r around x-, y- and z-coordinates of an aircraft-fixed (body frame) coordinate system, air data information including speed, altitude and angle of attack, includes the steps of calculating attitude and heading based on the body-frame angular rates p, q, r, estimating errors in measured body-frame magnetic field vector components, deriving a measured body-frame field magnetic field vector, estimating errors in calculated attitude and heading using the air data and the derived measured body-frame magnetic field vector components, and correcting the calculated attitude and heading using the estimated errors in attitude and heading.

Abstract: To provide a speed detecting device mounting structure for a vessel in which a paddle is prevented from being entangled with rubbish and seaweed in the sea, and the paddle is prevented from being damaged or picking-up mud or the like from the sea bottom. In a vessel, a water jet pump is provided at a rear portion thereof. A ship bottom plate is provided below the water jet pump. A speed detecting device is mounted on the ship bottom plate. A paddle of the speed detecting device detects the flow rate of water flow and obtains the propelling speed of the vessel. The speed detecting device mounting structure for a vessel is constructed in such a manner that the paddle of the speed detecting device is disposed on the upper surface of the ship bottom plate, an opening is formed at the portion of the ship bottom plate forwardly of the speed detecting device, and water taken through the opening is guided to the speed detecting device.

Abstract: A nose cone overlay for determining air data quantities. The overlay is adapted for removable mounting to a conventional radome or nose cone of a typical aircraft. The overlay includes transducers for measuring data with respect to pressure from which quantities of the aircraft such as angles of attack, side slip are derived, which quantities are transmitted wirelessly to the interior of the cabin or a secondary location.

Abstract: The fluid flow meter of the present invention includes a ramp inclined to the surface of a vessel so as to form a recess in the surface. A dynamic port surface extends from the lower end of the ramp to the surface of the vessel. A dynamic port is formed in the surface of the vessel, and a static port is formed in the ramp. The differential pressure between the dynamic and static ports is measured and is related to the flow velocity of fluid over the surface. The inventive flow meter has advantages of reduced drag, reduced likelihood of fouling and reduced likelihood of impact damage compared to conventional flow meters.

Abstract: A data processing system for automating the process of managing flight data and generating reports based on that data. The system accesses flight data transmitted on an airborne databus, where the data represents sensor readings indicative of various flight parameters. The accessed flight data is sampled, filtered, decoded, encrypted, and subjected to an adaptive compression process prior to being stored on a portable, self-protected secure memory device. After the flight ends, the portable, self-protected secure memory device is transferred to ground personnel. The data stored on the memory device is then accessed by authorized personnel, decompressed and decrypted. The flight data is analyzed and used to evaluate pilot performance and monitor the operation of the aircraft through the generation of flight reports. Various data analysis techniques, including artificial intelligence based algorithms and expert systems may be used to examine the flight data and determine its significance.

Abstract: A method and apparatus for calibrating a glide head and detector system performs a pre-screening to ensure the quality of the glide head and the piezoelectric sensor in the detection system. The glide head and the piezoelectric sensor detect a signal when the glide head makes contact with the disk, such as a magnetic recording disk. Calibration of the detection system utilizes a specially made bump disk that has asperities of desired height and size that protrude out of a flat disk surface. The glide head is flown over the bump disk, and by gradually reducing the disk spinning velocity, the head is brought closer to the disk and eventually into contact with the asperity. The onset of contact, as detected by the piezoelectric sensor, defines a disk spinning velocity for the head to fly at the desired height.

Abstract: The object of present invention is to provide a sensitivity calibrating method for a detector of a comparator, which enables easy and highly accurate sensitivity calibration for a first and a second detector for measuring opposing position of an object. Heights of two pairs of reference gauge blocks, a first reference gauge block W1 and a second reference gauge block W2, and the second reference gauge block W2 and a third reference gauge block W3 is first measured, and thereafter, sensitivity coefficients for calibrating the sensitivity of an upper detector 10 and a lower detector 20 are calculated by applying the measured value to a predetermined formula. The calculation is repeated three times, and each value is renewed for the upper and the lower detector 10 and 20 respectively.

Abstract: A gauge block holder that greatly reduces measurement error in calibrating wafer thickness test equipment is described. In a preferred embodiment of the invention, the gauge block holder is compatible with present thickness measurement equipment and provides a central region specially configured for holding a prior art gauge block in a manner that ensures precise, parallel alignment thereof with the equipment and thus precise perpendicular alignment with the equipment's opposing contact pins. Preferably a gauge block-sized and shaped recess and aperture are provided centrally in the holder such that the gauge block rests immobile on and parallel with the precision-machined, planar upper surface of a metal plate of the thickness tester while the thickness tester is being calibrated for a given wafer thickness measurement. The recess and aperture in accordance with their preferred embodiment are rectangular, and the invented gauge block preferably is securely fastened to the metal plate, e.g.

Abstract: A method of calibrating a bonding station involves placing a first surface of calibration tool in contact with a fixed surface of a movable assembly. The position of an adjustable surface of the movable assembly is then changed so that the adjustable surface contacts a second surface of the calibration tool. In addition, a calibration tool for calibrating the bonding station is provided.

Abstract: A measuring method for determining the specific surface area available for reaction of a noble metal catalyst of an electrode for use in a polymer electrolyte membrane fuel cell. The method includes measuring the total specific surface area of the noble metal catalyst and the specific surface area of the noble metal catalyst mixed with a polymer electrolyte by detecting the adsorption amounts of carbon monoxide upon exposure to carbon monoxide after reduction in hydrogen, and subtracting the latter from the former. Also provided is an electrode material for use in a polymer electrolyte membrane fuel cell having excellent polarization characteristics by controlling the utilization of a noble metal catalyst determined from the total specific surface area and specific surface area available for reaction of the noble metal catalyst.

Abstract: In accordance with the disclosed method, an attitude determining device which is installed onboard a mobile craft, like an aircraft, for example, at an unknown orientation with respect to the reference coordinate system of the craft senses its installation orientation with respect to an earth frame coordinate system when the craft is at rest to obtain a static orientation measurement thereof. Thereafter, an attitude of the mobile craft with respect to the earth frame is measured with the attitude determining device and such measurement is compensated with the static orientation measurement to obtain attitude information of the craft's reference coordinate system with respect to the earth frame coordinate system. The installation orientation of the attitude determining device may be sensed while the craft is at rest in either a leveled or unleveled condition.

Abstract: A speed sensor for a ship, more particularly, a thin speed sensor which can be mounted in the hull of the ship and remain flush with the outer surface of the hull. The transducer assembly for the speed sensor is composed of two thin piezoelectric transducers mounted in a spacer plate that locates them in an exact position relative to each other. A baseplate and a coverplate are affixed by appropriate adhesive techniques to each side of the transducers to create a single transducer assembly. Holes through the baseplate and spacer plate permit electrical contact to each side of the transducers so that they may be stimulated to generate acoustic waves. The entire transducer assembly is significantly thinner than the hulls of most watercraft. Thus, a large hole completely through the hull is not necessary. Rather, a shallow recess approximately equal to the thickness of the transducer assembly is made in the hull to countersink the transducer assembly flush with the hull.

Abstract: A fastener measurement system includes a number of gauge blocks, each having a tapered bore disposed therein. Each gauge block has a number of conical inserts that fit within the tapered bore. The inserts have a central bore of varying sizes to receive fasteners of different shank diameters. The gauge block includes a beveled surface at the point where the bore meets a top surface of the gauge block. The beveled surface reduces wear and allows the gauge block to be easily calibrated. A computer system receives measurements made by a linear transducer that measures the height of the fastener above the surface of the gauge block a correction factor .delta. is added to the height measured to produce an indication of the true head height of the fastener. The computer system prompts the user to test the head heights of a random sample of fasteners and prints a report of the head heights as well as an indication of whether the sample of fasteners meets engineering specifications.

Abstract: In a scanner used in a paper-making process to measure basis weight and other parameters of the fabricated paper sheet, variations in the separation of an opposed pair of sensing heads due to temperature induced deflections of upper and lower beams on which the heads are movably mounted as well as deflections and/or expansions of other portions of the support structure for the sensor are dynamically measured and compensated for. Temperature sensors mounted on carriages for the sensing heads measure the temperatures at different locations within the sensor support structure so that temperature differentials can be determined. The temperature differentials, which provide a measure of beam deflection at any given position of the head carrying carriage, are applied in accordance with a linearizing algorithm to correct the values provided by the sensing heads.

Abstract: A flow meter for use in scuba diving is disclosed. The device has a coil or, alternatively, two coils separated by a predetermined distance and sensors for measuring induced electromotive force. The device is provided with a switch to enable it to be activated. The switch also acts to disable the device and allow compass operation. An embodiment of the device including a compass and a processor allows for navigation functions to be performed.

Abstract: The invention is a method for determining anemobaroclinometric parameters on board an aircraft.The air speed vector (Vp), the static pressure (Ps), and the impact temperature (Ti)are measured, and the other parameters are calculated on the basis of the aforementioned measurements.

Abstract: A method is provided for making crater shaped bumps on a magnetic disk. The crater shaped bumps have a diameter in the range of 10 to 25 .mu.m and a peripheral ridge with a height h.sub.r above a nominal surface of the calibration disk in the range of 75 to 120 nm. Close tolerance crater shaped bumps with this configuration can be made by impinging two or more pulses of laser energy on the same location of the disk. By increasing the number of pulses the height of the peripheral ridge progressively increases. By employing multiple pulses, the height of the peripheral ridge is increased while the diameter of the crater shaped bump stays substantially constant. Further, by employing multiple pulses diameters and heights of crater shaped bumps can be produced with close tolerances within a diameter range of 5 to 20 .mu.m and a height range of 2 to 120 nm.

Abstract: The invention is a system for determining the physical characteristics of an incident fluid flow stream over a surface of a vehicle relative to an axis thereof, the apparatus. In detail, the invention includes at least one first pressure sensor mounted on the surface, the at least one first pressure sensor for receiving dynamic pressure signals generated by the convected boundary layer of the fluid flow stream and providing an output signal representative thereof. At least one array of second pressure sensors (pressure transducers) is positioned down stream of the at least one first pressure sensors, the second sensors of the at least one array each of said second pressure sensors providing a second output signal representative of the above pressure signals received thereby. A computer system is adapted to receive the first and second signals and to calculate the angular direction of the fluid flow relative to the axis and the velocity thereof.

Abstract: A speed sensor for a ship, more particularly, a thin speed sensor which can be mounted in the hull of the ship and remain flush with the outer surface of the hull. The transducer assembly for the speed sensor is composed of two thin piezoelectric transducers mounted in a spacer plate that locates them in an exact position relative to each other. A baseplate and a coverplate are affixed by appropriate adhesive techniques to each side of the transducers to create a single transducer assembly. Holes through the baseplate and spacer plate permit electrical contact to each side of the transducers so that they may be stimulated to generate acoustic waves. The entire transducer assembly is significantly thinner than the hulls of most watercraft. Thus, a large hole completely through the hull is not necessary. Rather, a shallow recess approximately equal to the thickness of the transducer assembly is made in the hull to countersink the transducer assembly flush with the hull.

Abstract: A marine speedometer system is disclosed which utilizes a short pitot tube or air column. The speedometer system includes an inlet having a short air column, a transducer, a control circuit, and a display. The electric signal from the transducer is representative of the pressure in the short air column. The control circuit preferably utilizes a microprocessor and a look-up table to generate a display signal in response to an electric signal from the transducer. The look-up table includes T-Buoy values and count values. The count values are used to drive a frequency signal for an air core meter. The display provides a needle and a metered background which is easy to read. The microprocessor is coupled to receive calibrate up and calibrate down signals. The microprocessor causes the needle to jump when it receives a signal to provide feedback to the driver. The microprocessor includes an auto zero subroutine which automatically calibrates the speedometer at start up.

Abstract: An improved speed transducer is disclosed. The present invention provides an alternating current coil speed transducer which utilizes the Faraday Effect to generate a voltage. The present invention discloses an improved amplifying circuit that amplifies the low voltages generated by small boats such as rowing shells to permit them to register accurate speed data at low speeds, e.g. between about 0.5 and 10 m/sec although higher speeds can be measured. The present invention also provides an improved technique for connecting a speed transducer to a boat that permits the speed transducer to be mounted and dismounted and the electrical connection broken without requiring extensive reworking of the speed transducer. In this regard, the present invention generally provides an improved technique for mounting and dismounting protruding apparatus that have electrical or other connections that extend into an object.

Abstract: An instrumentation system for measuring airspeed and angle-of-attack (AOA) is provided. The system includes a sensor assembly, a constant voltage anemometer, a microprocessor assembly with software, and an output device suitable for powering conventional cockpit display or for powering other speed AOA devices such as engine inlets and stability augmenters. The sensor assembly is a pair of orthogonal miniature cylinders with embedded micro-thin multielement hot film sensors. Operation of the sensor assembly by the constant voltage anemometer provides detection of cylinder leading edge flow stagnation point and oscillatory frequency. The stagnation point determination provides angle-of-attack data; the oscillatory flow frequency provides data to calculate cylinder shed-vortex frequency which is converted to airspeed data. The sensor assembly is solid-state, having no ports, diaphragms or moving parts and is heated in normal operation.

Abstract: A method and device are disclosed for determining the airspeed of a helicoper, in which, for a plurality of flight configurations of a calibration flight, magnitudes for estimating the airspeed and the collective P.sub.O and cyclic pitches P.sub.X and P.sub.Y of the lift rotor, the pitch P.sub.Z of the antitorque rotor, the angles of bank .theta..sub.X and .theta..sub.Y and the acceleration .gamma..sub.Z are measured. Correlation matrices between the speed estimated with respect to the air and variables related to the pitches, angles and acceleration measured during the calibration flight are then formed. Formulae are derived, for calculating the estimated speed, by a stepwise regression algorithm, which are used in normal flight for calculating, in response to the pitches, angles and acceleration measured during normal flight, the speed with respect to the air, if required after correction of the values of the multiplicative coefficients of these calculation formulae.

Abstract: A dynamic fluid flow sensing system measures relative fluid velocity with respect to a reference member. The system includes a sensor housing supported from the reference member such that the sensor housing is exposed to fluid flowing past the reference member. A solid-state pressure sensing transducer is supported by the sensor housing for generating an electronic output signal in proportion to a sensed dynamic pressure of fluid flowing past the reference member. A central processing unit receives the electronic output signal from the transducer and generates a processed electronic output signal in accordance with a stored control program. A display receives the processed electronic output signal and displays a visual readout of desired fluid flow characteristics based on the processed electronic output signal.

Abstract: The electronic speedometer of this invention accurately calculates and digitally displays a skier's instantaneous speed. The device accomplishes this task by employing the "hot wire" principle using a thermistor and a thermocouple which are exposed to air stream through which the skis move. The device does not contain any moving parts and does not contact the snow or rely on snow contact for its operation. Since the construction of the device minimizes drag, its effect on a skier's performance is negligible. The device can easily be mounted and removed from a ski without the use of tools and without damaging the ski, thereby making it easily transferable to other surfaces, such as snowboards and hangliders.

Abstract: A float-type flowmeter has a flow detecting surface, such as a fin, for pointing its inlet opening, which receives a portion of the flow to be measured, into the flow. Preferably the flowmeter, its inlet opening, and its fin, are all mounted to rotate as a unit, and the flowmeter is designed for measuring wind velocity on sailboats. This flowmeter is designed to be mounted on, and rotated around, a mast supporting wire, such as a shroud. The flowmeter should have counterweight so that gravity will not tend to prevent it from rotating around its wire when that wire is tilted. Similarly the inlet opening should be relatively small compared to the cross section of the float chamber, so that as the flowmeter tilts, the area of the inlet opening projected into a horizontal wind flow will decrease wind flow into the flowmeter, so as to compensate for the tilt. Preferably the flowmeter is designed so its float will not be visually obscured from upwind by the elongated structure around which it rotates.

Abstract: A velocimeter, comprising a controlled magnetic field source and electric field sensors, the device being flush mounted in a vessel hull. The magnetic source comprises a drive coil which may be energized with either a DC current or an AC current at varous desired frequencies. The turns-area product and applied current are selected based on desired sensitivity. When the drive coil is energized, a uniform magnetic field is produced near the surface of, and normal to, the hull. The thickness of the uniform region is governed by the thickness of the boundary layer in the tubulent region. The magnetic field returns through the vessel hull structure in such a way that divB=0. Inside the coil, near the outboard external surface of the device, a pair of orthogonally disposed electric field sensors are located for measuring the electric field produced as a result of the interaction between the magnetic field and the conductive fluid.

Abstract: A helicopter is provided with a lift rotor (Ros), a tail rotor (Rac), first control means for the longitudinal (Pcx) and lateral (Pcy) cyclic pitch of the lift rotor and second control means for the pitch (Pac) of the tail rotor. The parameters such as the longitudinal cyclic pitch (Pax), the lateral cyclic pitch (Pcy), the longitudinal acceleration (Vx) and the acceleration of the helicopter (Vy) as well as the collective pitch (Pcol) of the lift rotor (Ros) and the pitch of the tail rotor (Rac) are measured. The longitudinal (Vax) and lateral (Vay) speed of the helicopter with respect to the air are determined from a biunivocal function of the measured values, particularly in linear combination.

Abstract: A transducer assembly for a speed measurement device for measuring the speed of a marine vehicle through the water is disclosed. The device comprises a transmitter circuit and a receiver circuit connected to two transducers which are positioned substantially in the direction of travel of a marine vehicle below the water line thereof. Pulse trains are transmitted in both directions between the transducers which are received by the receiver circuitry so that a signal is derived indicative of the time taken for the signals to travel both for and against the direction of travel of the ship, this signal being proportional to ship's speed. The assembly including the transducers includes outwardly projecting ribs for directing the aerated water away from the acoustic path between the transducers when the marine vehicle is moving through water.

Abstract: A method for determining the horizontal airspeed of a helicopter in the high speed (v.sub.e >20 m/s) range. Pitch angle and the longitudinal control signals are recorded by sensors such as an inertial navigation system and a potentiometer connected to the pilot's control lever. Equivalent speed signals are calculated from the measured pitch angle and longitudinal control signals by means of calibration equations. These signals are then filtered and weighted. The horizontal airspeed is then derived from the sum of the weighted signals divided by the sum of weighting factors k.sub..theta. and k.sub..delta.x determined in accordance with the sensed pitch angle and longitudinal control signals. The horizontal velocity signal may be filtered, if necessary.

Abstract: A method is disclosed for determining the horizontal airspeed of helicopters in low speed ranges. At least three control functions, .theta..sub.o,i (collective pitch), .theta..sub.s,i (longitudinal control) and .theta..sub.c,i (lateral control) are measured. The magnitude of the horizontal airspeed, V.sub.H,i, is determined from its known relationship to .theta..sub.o,i. This magnitude is included in non-linear calibration equations .theta..sub.s (V.sub.H, .psi.) and .theta..sub.c (V.sub.H, .psi.) and control profiles .theta..sub.s (V.sub.H,i, .psi.) and .theta..sub.c (V.sub.H,i, .psi.) are derived therefrom. The measured values .theta..sub.s,i and .theta..sub.c,i are applied to the respective control profiles and corresponding phase pairs .psi..sub.s,1, .psi..sub.s,2 and .psi..sub.c,1, and .psi..sub.c,2 located. The pairs are compared and the incident flow angle .psi..sub.i is determined as the value common to the two pairs.

Abstract: A speed measurement device for measuring the speed of a ship through the water is disclosed. The device comprises a transmitter circuit and a receiver circuit connected to two transducers T.sub.1, T.sub.2 which are based substantially in the direction of travel of a ship below the water line thereof. Pulse trains are transmitted in both directions between the transducers T.sub.1, T.sub.2 which are received by the receiver circuitry so that a signal is derived indicative of the time taken for the signals to travel both for and against the direction of travel of the ship, this signal being proportional to ship's speed.

Abstract: A Faraday transducer for a marine speed indicator is sealed in a cylindrical housing so that it can be mounted in a boat hull with its base flush with the hull. A horseshoe magnet sealed within the housing has its poles located against the base surface and with 4 electrodes in the base surface located one on each side of each magnetic pole. The electrodes are connected together in such a way as to cancel out stray magnetic fields and to increase the Faraday emf produced by the relative movement of water flowing across the base of the transducer.

Abstract: A method and system for measuring relative speed of a ship through a body of water with improved accuracy and simplicity. It employs a free floating buoy and a pair of tracking scopes. The buoy is launched and tracked by the scopes with electronic circuit arrangements so that the time of relative movement of the buoy between transverse positions opposite the scopes is accurately measured.

Abstract: A device for measuring the velocity of flow of a liquid comprises electrodes over which the liquid flows. A chemical emitting electrode is mounted so as to contact the liquid at a first point and is supplied with periodic input pulses by a current pulse generator such that chemicals are caused to be periodically generated on its surfaces. A second chemical detecting electrode is mounted downstream of the first point. The second electrode is connected to a potentiostatic circuit which produces an output signal when it detects the arrival of chemicals produced by the first electrode. A circuit measures the time between an input pulse and the corresponding output signal such that the velocity of the flow of the liquid can be determined.

Abstract: A single scope method or system for accurate ship speed measurement relative to the water through which it is propelled. There is a free floating buoy beside the ship, and a tracking scope is trained on the buoy. At the same time the height above the water of the scope is measured in addition to the negative elevation and the azimuth angle of the line of sight of the scope relative to the ship. Periodic calculations with time measurements determines the speed of relative movement of the buoy along a path parallel to the center line of the ship. This is the ships speed relative to the water. Calculations may be made by a microprocessor with the measured angles and height above the water as inputs.

Abstract: A marine speed log for providing an indication of the relative velocity of a vessel through water and an indication of the forward or reverse direction of travel. An output indication of total distance travelled can also be provided. The speed log is operable in both salt and fresh water without any change in calibration and incorporates a transducer having an air core. The speed log provides high sensitivity and high rejection of noise.

Abstract: A combined knotmeter, distance/log meter and depth meter including a meter housing, a dial face having indicia symmetrically centered thereabout, an analog speed indicator having a pointer for cooperating with the indicia; upper and lower openings in the dial face in alignment with digital log and depth meters of the electro-mechanical and LCD-type, respectively; the upper opening interrupting the indicia centered about a twelve o'clock position and actuators for the indicators responsive to sensed variables of speed, distance and water depth.

Abstract: An electrical flowmeter having signal electrodes laterally spaced along a line perpendicular to fluid flow and sensitive to a voltage field set up in the fluid by a magnetic field is provided with a plurality of planar helically coiled conductive windings disposed in stacked arrangement parallel to the direction of fluid flow. The spiral windings are connected to a push-pull current drive source. The signal electrodes are spaced proximate to the outer coil winding of the coil closest to the fluid. The windings of the coils are alternately oriented in opposite, clockwise-counterclockwise disposition. Each spiral coil ends in an inner and an outer terminus, and the inner termini of all coils are connected together, while the outer termini of the clockwise disposed coils are connected in parallel with each other. The outer termini of the counterclockwise disposed coils are also connected in parallel with each other.

Abstract: An electrical flowmeter having signal electrodes laterally spaced along a line perpendicular to fluid flow and sensitive to a voltage field set up in the fluid by a magnetic field is provided with helically coiled conductive windings disposed in a laminar arrangement in a plane parallel to the direction of fluid flow and wound in a helical spiral and connected to receive alternating current. The signal electrodes are spaced proximate to the outer coil windings, and a neutral electrode is provided at the helical vertex of the windings. The electrical field set up in the fluid impresses a voltage field across the signal electrodes proportional to relative fluid velocity and immune from quandrature and hydrodynamic effects.