Abstract: A driver circuit for generating a driving signal by pulse-width modulation (PWM) includes a half-bridge circuit formed essentially of a pair of series-connected FETs. When the level of an ultrasonic signal, or of the driving signal, is to be maximized, the individual FETs are switched at a switching frequency matched to the frequency of the driving signal. When the level of the ultrasonic signal, or the driving signal is to be reduced, on the other hand, the individual FETs are switched with specific timing determined based on the frequency of a clock signal of which period is shorter than that of the driving signal.

Abstract: A navigational aid for use as an AIS apparatus includes a memory for storing information about previous use of individual time slots synchronized with transmission schedules of other stations and a signal detector for judging whether an information signal exists in a time slot specified in accordance with a synchronization timing signal based on the information stored in the memory and a result of monitoring of the behavior of a baseband signal obtained from a received signal on an IQ-plane. The navigational aid transmits information about own station based on a result of judgment by the signal detector. The monitoring of the behavior of the received baseband signal plotted on the IQ-plane can be accomplished by performing pattern recognition operation, for which a carrier sense technique, such as a support vector machine, subspace method or neural network, can be used.

Abstract: A sonar emits an ultrasonic wave into the water from a transducer on the basis of a transmission signal outputted from a transmission circuit, receives an echo reflected in the water with the transducer and converts the echo into an electric signal, and displays underwater information on a display unit on the basis of an echo signal extracted by processing the electric signal. A tailing signal removing unit for removing a tailing signal and extracting only the echo signal is provided in the sonar such that a video of a surface layer fish shoal is clearly displayed on a screen of the display unit without being hidden by a video of the tailing signal.

Abstract: An object of the present invention is to provide an automatic steering control apparatus, including an autopilot, which enables a ship to turn around a desired fixed point as a turning center with a desired turning radius without being affected by an extraneous factor, such as a tidal current or the like. To achieve the object, a center position, a turning radius and a turning direction for turning are initially designated by the operator, a tangent to a turning circle at an intersection of a straight line from the turning center to a position of the ship and the turning circle, and a course of the ship is controlled to approach the tangent.

Abstract: A radar includes a transmitter circuit, a receiver circuit, an antenna and a circulator. The receiver circuit includes a low-noise amplifier which amplifies a received signal fed from the antenna through the circulator. A local oscillator provided in the receiver circuit generates a local oscillator signal of which frequency is approximately half the frequency of the received signal, and the local oscillator signal is amplified by a buffer amplifier. An even harmonic mixer including an anti-parallel diode pair also provided in the receiver circuit as a frequency converter mixes the received signal output from the low-noise amplifier with the local oscillator signal output from the buffer amplifier to generate and output an intermediate frequency signal.

Abstract: A residual liquid quantity in a syringe is reduced to the minimum. There are detected with high precision malfunctions due to chokes in pipes and incomplete switchings of an electromagnetic valve and a broken valve without a contamination problem produced. When a syringe pump is powered on, a motor is driven at low speed so that liquid in a syringe is discharged completely. When a desynchronization of the motor is detected by comparing motor driving pulses obtained by a rotary encoder with motor driving pulses supplied to the motor, a stop signal is supplied to a motor driver and the position of a rod is memorized as the origin of the syringe pump in an origin sensor. While the syringe pump is in a normal operating state, the position of the rod is detected to be at the origin to supply a stop signal to the motor driver.

Abstract: A quantitative echo sounder includes delay circuits, phase correction circuits, an incidence angle calculator and a directivity correction unit. The delay circuits adjust transmission start timing or phases of acoustic waves radiated by individual vibrating elements based on pitch and roll angles measured by a motion sensing device so that the direction of an acoustic axis of a transmitting beam matches a sounding direction. The phase correction circuits adjust phases of received echo signals based on the pitch and roll angles so that the direction of an acoustic axis of a receiving beam matches the sounding direction. The incidence angle calculator calculates echo signal incidence angle with respect to the sounding direction from phase differences among receiving beam signals obtained by four vibrating element groups. The directivity correction unit corrects a measured target strength by using the echo signal incidence angle calculated by the incidence angle calculator.

Abstract: A carrier phase-based relative positioning apparatus includes a plurality of antennas fixedly mounted on a moving body for receiving positioning signals from satellites, an inertial measurement unit (IMU) for measuring accelerations and angular velocities of the moving body, a reference attitude calculator for calculating attitude information about the attitude of the moving body from observables of the IMU at least before an integer ambiguity candidate is initially determined, an integer ambiguity estimator for estimating integer ambiguity candidates from the positioning signals received by the antennas, and an integer ambiguity validator for evaluating correctness of the integer ambiguity candidates estimated by the integer ambiguity estimator.

Abstract: While keeping a propeller located in a negative direction of a y-axis turning, transmission of acoustic waves from vibrating elements of a transducer unit is interrupted. Reference signals “A” and “B” which are receiving beam signals having principal acoustic axes oriented in a propeller direction are generated from received signals obtained by “A” and “B” group vibrating elements, respectively. Next, adjustment factors used for removing propeller noise from received signals obtained by vibrating elements on positive and negative sides of an x-axis are calculated by performing arithmetic operation on time-series data on the received signals obtained by the positive and negative sides vibrating elements and on time-series data on the reference signals “A” and “B”, respectively.

Abstract: In a display system capable of displaying images fed from a plurality of sensing devices on an indicator, horizontal and vertical synchronizing signals of the individual measuring devices are synchronized with one another and desired image signals are selected for on-screen presentation during each successive horizontal scanning period, whereby operator-selected multiple images are displayed.

Abstract: Methods and apparatuses are directed to a transition between a waveguide and a microstrip. One embodiment features an open-ended waveguide having an exposed side at a distal end, a substrate coupled to the open-ended waveguide at a proximate end, a resonator coupled to the substrate, a microstrip line electromagnetically coupled to the resonator, and a backshort coupled to the substrate. Another embodiment features receiving an electromagnetic wave, collecting an incident portion of the received electromagnetic wave, generating first wave having a resonance at a predetermined frequency using the incident portion of the received electromagnetic wave, reflecting a portion of the received electromagnetic wave off of a reduced scale backshort, back towards a collector, generating a second wave having a resonance at a predetermined frequency using the reflected portion of the received electromagnetic wave, and combining the first wave and the second wave in phase.

Abstract: An ultrasonic bone evaluation apparatus includes stationary and movable standoffs fitted with respective ultrasonic transducers for transmitting and receiving ultrasound, a moving mechanism for moving the movable standoff, an encoder, a controller, and an inner temperature sensor for determining the temperature of an inner tissue of a body part. The moving mechanism moves the movable standoff toward the stationary standoff to sandwich the body part therebetween. The encoder measures the distance between the two transducers whereas the controller determines the time required for the ultrasound to travel between the transducers when the body part is sandwiched between the standoffs. The controller calculates the speed of sound propagating through the body part from distance and time measurement values, corrects the speed of sound through the body part based on the temperature of the body part measured by the inner temperature sensor, and evaluates the bone of the body part based on the corrected speed of sound.

Abstract: Antenna elements are arranged in line on a surface of a substrate at specific intervals along a longitudinal direction of the substrate. A phase-inverting distributor is formed on the surface of the substrate in an area located between two antenna elements which are closest to and located on both sides of a vertical centerline, or a reference line, of the substrate. A primary feeder line formed along the longitudinal direction of the substrate extends from the phase-inverting distributor on both left and right sides thereof. The individual antenna elements are connected to the primary feeder line by secondary feeder lines having predetermined impedances. The secondary feeder lines are connected to the respective antenna elements on sides thereof which are perpendicular to the longitudinal direction of the substrate and face the reference line on which the phase-inverting distributor is located.

Abstract: An onboard equipment network system comprises a radar core device, a GPS core device, an echo sounder core device and a sonar core device and display devices which are connected to a network through a hub. Each core device includes a detecting section or a positioning section, as well as a control section, a power supply section and a data transmitter for transmitting detecting signals or positioning signals, while each display device includes a command section for transmitting command data to the individual core devices for setting their operating conditions and a display section for displaying image data received from the individual core devices. The command data is transmitted using Transmission Control Protocol (TCP) while the image data is transmitted using User Datagram Protocol (UDP).

Abstract: A vehicle information display apparatus receives multiple pieces of information on mobile vehicles, determines degrees of importance of the individual pieces of information according to specific conditions, and displays symbols of only those mobile vehicles of which importance falls within a predefined range or symbols of only a specific number of mobile vehicles selected according to their importance in graphic form with enhanced visibility.

Abstract: An attitude sensing apparatus for determining the attitude of a mobile unit is provided that can reliably estimate an alignment angle between a GPS antenna coordinate system and an IMU coordinate system with good accuracy regardless of the magnitude of the alignment angle. Based on observation of the difference between a GPS angular velocity and an IMU angular velocity, an alignment angle estimating section estimates an alignment angle and sensor errors. An alignment angle adder and a sensor error adder cumulatively add and update the estimated alignment angle and sensor errors, respectively. The estimated alignment angle is fed back to an inertia data converter while the estimated sensor errors are fed back to an inertia data correcting section. The apparatus repeatedly performs estimation until the estimated alignment angle gradually approaches a true alignment angle by successively feeding back estimated values to a flow of alignment angle estimation process.

Abstract: A vehicle information display apparatus receives multiple pieces of information on mobile vehicles, determines degrees of importance of the individual pieces of information according to specific conditions, and displays symbols of only those mobile vehicles of which importance falls within a predefined range or symbols of only a specific number of mobile vehicles selected according to their importance in graphic form with enhanced visibility.

Abstract: A display having a screen providing historical water depth information and a screen providing fish school detection information is presented. The water depth information and the fish school detection information may be derived from an echo signal, and can be displayed simultaneously or alternated separately on the display by switching. When the water depth reaches or is less than a predetermined value, an alarm may be provided on the display and/or an alarm sound may be generated. As the alarm is displayed the brilliance of the display may be raised to a maximum brilliance, making the display brighter so the contents are easier to see.

Abstract: An automatically tracking scanning sonar alternately performs horizontal scanning and vertical scanning and a target lock processor calculates a predicted position of a target based on an echo signal previously received from the target when the echo signal from the target is interrupted. A selector sets a range, tilt angle and sounding direction and outputs them to a transmit-receive controller such that the scanning sonar can scan the predicted target position. As the depth of the target is determined by performing the vertical scanning, the tilt angle of an umbrellalike beam pattern produced by the horizontal scanning can be varied to follow the target by controlling the tilt angle based on target depth information even when the target moves in vertical directions. It is therefore possible to automatically track the target in a reliable fashion.

Abstract: A receiving beam is formed using 60 elements arranged in a 90° sector area of a cylindrical receiving array. Receiving beam 0 is formed with elements 0-59 divided into two (front and rear) groups. Specifically, the elements 0-59 are divided into rear group 1 (elements 0-8, 51-59) and front group 2 (elements 9-50) in the beam direction, and the receiving beam is formed by using sample data obtained from the transducer elements 0-8, 51-59 of group 1 in a current scanning cycle as well as sample data obtained from the transducer elements 9-50 of group 2 in a preceding scanning cycle. This approach makes it possible to form the receiving beam such that incoming waves of a short-pulse signal would simultaneously hit the relevant transducer elements of the receiving array and thereby improve directivity and sensitivity of the receiving beam for the reception of short-pulse waves.