Abstract: An apparatus (20) determines a target (e.g., a vehicle occupant 22) beyond a predetermined distance. In an exemplary embodiment, the apparatus (20) determines a distant target for use in control of air bag deployment. The apparatus (20) includes a sensor (44) for emitting and receiving first (52, 56) and second (54, 58) signals in an interspersed predetermined emission sequence toward the target. A controller (60) successively determines a time interval between the emission of a current signal and the reception of an echo. The controller (60) successively compares at least two time intervals to determine whether a sufficient difference exists to indicate that the target is beyond the predetermined distance and outputs a signal to the air bag actuation system (62).

Abstract: A method and apparatus using ultrasonic sensors for determination of the pointing vector described by two points separated in space in the coordinate frame of the measuring system. For measurement, acoustic signals are transmitted from two emitters whose spatially separated coordinates form the desired pointing vector. Three detectors, associated receiver electronics and software are required to compute six distinct spheres from the time of flight measurements. The intersection of the three spheres, associated with each emitter, describe the desired location in the detector coordinate system of that emitter. With the coordinates of each emitter, the pointing vector is computed using standard geometry. A reference is required to determine the time of flight of the signals to each detector. Another embodiment uses an active reflective technique, where the timing is obtained through round trip transmission and reception of the signal with a known fixed delay at the vector points.

Abstract: Methods for controlling deployment of an occupant restraint device in a vehicle and determining whether an object is a child seat in which one ultrasonic transducer is arranged on a ceiling of the vehicle and another ultrasonic transducer is arranged at a different location in the vehicle, ultrasonic waves are transmitted from each transducer into the passenger compartment and received thereby, and the distance from each transducer to the object is calculated based on the time difference between the transmitted waves when transmitted from the transducer and the reflected waves when received at the transducer. Deployment of the occupant restraint device is controlled based on the calculated distances and/or a determination is made whether the object is a child seat based on the calculated distances.

Abstract: In order to locate electromagnetic or acoustic signal sources of a sensor configuration (1a through 1c) fitted with at least two electric outputs, where the incidence-dependent transfer functions between the acoustic signals incident on the input(s) of the sensor configuration (1a through 1c) and the electric output signals are different, the ratio (7x through 7xx) of the output signal is formed and the result then is correlated with the previously determined ratio function (11).

Abstract: GPS satellites broadcast GPS signals with low power transmitters less than 50 watts. Although the GPS broadcast signals are encoded using spread spectrum technology which decreases the effect noise has on the reception of the signal, jamming signals can adversely affect GPS receiver performance. Jamming signals can cause position and velocity indication within the system to be erroneous. These errors can build up within the system and the errors may take a significant time to dissipate even after the jamming signal has gone. These errors can manifest themselves as errors in velocity and errors in position on the order of tens of miles. Methods of detection of the presence of the jamming signal including observing the output of a correlator chain in which the PN code being correlated is delayed in each link in the chain are presented in this disclosure. The present disclosure also proposes countermeasures for dealing with the jamming signal.

Abstract: A synthesizer and method for the generation of underwater background acoustic signals employs digital signal generation and processing in a multiplexed format. The synthesized digital signals comprise components of shaped noise, simple sinusoids, or double-sideband, suppressed-carrier, modulated sinusoids, or a combination of one or more of these signal types. Among the acoustic signals which are digitally synthesized are acoustic signals generated by antisubmarine-warfare hardware such as sonobuoys and hydrophones.

Abstract: Method for producing an image of a submerged object (3), e.g.

Abstract: A method is disclosed for evaluating and/or selecting sonar systems and sonar sensors is provided that results in a performance rating that represents both the magnitude and consistency of detection of targets positioned at different depths. In a preferred embodiment wherein a sonar system includes at least one source and at least one receiver, the performance rating related to target detection, is plotted for each of a plurality of source and receiver depths. A dynamic range sensitivity factor is selected that provides sensitivity in the performance rating with respect to consistency of the detection range at different depths. The dynamic range sensitivity factor is preferably selected between zero and an inverse of a scaling factor related to a maximum detection range and a minimum detection range for a particular source and receiver depth relationship.

Abstract: The present invention provide a pyroacoustic device for protecting submarines or surface vessels, the device being characterized by the fact that it comprises: a structure (240) suitable for forming a positioning device for controlled positioning under water; and a case (100) connected to the positioning device, which case (100) contains: a plurality of charges (110) each suitable for generating an acoustic effect; and control means (125, 126; 140; 121) suitable for initiating said plurality of charges (110) in a controlled sequence.

Abstract: There is described a cMUT array with transducer elements which include a plurality of cells with membranes formed on one surface of a wafer. Voltages applied between said spaced electrodes drive said membranes. The voltages applied to said electrodes are applied from the opposite surface of the wafer through the wafer and through vias formed in the wafer.

Abstract: A relative speed of an object is determined by monitoring random reflective surfaces in water. The system includes a first and second transmitter-receiver pair for producing echo signals of a monitored region. The monitoring pair of transducers are preferably positioned along an axis of motion of the object such that sampled data from the first and second transmitter-receiver pair are substantially similar but shifted in time due to a separation of transducers. Echo signal data from the transducers are then used to generate a time difference correlation function that is used to determine a time difference between the first and second signals. Based on the time difference between the time-shifted echo signals, a speed of a vessel is determined.

Abstract: A portable and hand-held device for making humanly audible sounds responsive to the detecting of ultrasonic sounds. The device includes a hand-held housing and circuitry that is contained in the housing. The circuitry includes a microphone that receives the ultrasonic sound, a first low voltage audio power amplifier that strengthens the signal from the microphone, a second low voltage audio power amplifier that further strengthens the signal from the first low voltage audio power amplifier, a 7-stage ripple carry binary counter that lowers the frequency of the signal from the second low voltage audio power amplifier so as to be humanly audible, a third low voltage audio power amplifier that strengthens the signal from the 7-stage ripple carry binary counter, and a speaker that generates a humanly audible sound from the third low voltage audio power amplifier.

Abstract: A shield for a sonar transducer secured by a flexible clamping band to the bottom of a trolling motor housing. The shield includes a box-like body sized to receive a transducer. The body further includes an open top for flush positioning against a trolling motor housing and an open bottom through which sonar transmissions from the transducer may pass. The body has a pair of slots adjacent its open top for the passage of a clamping band of a hose clamp.

Abstract: A bottom moored and tethered directional frequency analysis and ranging (DIFAR) sensor system deployable in a wide range of water depths. The system includes a mooring platform for anchoring the system to the bottom surface of a body of water. A buoyant chamber containing a DIFAR sensor is tethered to the mooring platform at a pre-determined depth in the body of water. The DIFAR sensor includes two pairs of orthogonally oriented hydrophones and a compass for providing a directional magnetic reference signal. The tethered buoyant chamber is securely positioned such that hydrophones residing within the buoyant chamber are oriented in a plane substantially co-planer to the top surface of the body of water. By determining the angle between the directional magnetic reference signal and the hydrophones, the sensor system is able to compute heading information for a detected object. A transmitter is coupled to the DIFAR sensor for transmitting heading information detected by the DIFAR sensor to a receiver.

Abstract: An ultrasonic probe includes a piezoelectric element for transmitting and receiving ultrasonic waves and an acoustic lens provided on an ultrasonic transmission/reception side of the piezoelectric element. The acoustic lens is formed in an acoustic lens shape by vulcanization formation through addition of 2,5-dimethyl-2,5-di-t-butyl peroxy hexane as a vulcanizing agent to a composition prepared by addition of silica (SiO2) particles in an amount of 40 wt % to 50 wt % to silicone rubber with a dimethylpolysiloxane structure including vinyl groups. Thus, the ultrasonic transmission and reception sensitivity is improved and the degradation in frequency characteristics is diminished. Consequently, higher resolution of an ultrasonic image and higher sensitivity can be achieved.

Abstract: A spark plug system for measuring the thermal profile across the surface of a piston in an operating internal combustion engine in characterizing the combustion process within a combustion chamber of the engine is described that includes a specially constructed spark plug containing a coherent fiber optic bundle and lens system optically connected to a remote sensing thermometer and high-speed triggerable imaging infrared video camera.

Abstract: Corrosion resistant non-polar polymer coatings and method for applying the coatings to substrates is described, wherein a source of non-polar polymer powder is deposited as a coating onto the surface of a substrate by high temperature thermal spray, wherein the non-polar character of the powder and any additives thereto is substantially preserved during the high temperature thermal spray by using a mixture of a non-oxidizing shielding gas or reducing gas, or combination of the two, at one or more locations along the thermal spray to displace or react with ambient oxygen.

Abstract: A utility software program which provides Operational Flight Program and User Data File software files for an AN/ALQ-165 Deceptive Electronic Countermeasures set in a Personal Computer DOS compatible format. The software program is a personal computer based software utility program that emulates a VAX computer based loader program. The software program reads Operational Flight Program and User Data File ATAC Bootstrap Loader format files from personal computer disk files. The software program writes ATAC Download Record format binary files to a personal computer disk. The output file format provided by the software program of the present invention comprises one contiguous block of data having one or more data records, one BIT table and one End- of-File record.

Abstract: A method and apparatus for reducing points of zero intensity, i.e. speckle pattern, emerging from a multimode fiber. The apparatus comprises a beam deflector for rotating an input beam in a conical shape around a launch lens for projecting the beam into the fiber. The rotation of the beam further incorporates the use of two tilting mirrors being 90° out of phase to ensure a conical rotation. The conical rotation of the beam deflector ensures that the lens aberrations, which are rotationally symmetric, do not play a factor in beam alignment into the fiber aperture.

Abstract: A differential property sensitive acoustic lens for non-destructive materials evaluation is described which in a preferred embodiment comprises first and second substantially semicylindrical shaped portions of fused silica disposed in closely spaced relationship along an axial plane, a substantially spherical depression defined in one end of each semicylindrical portion and a flat defined on each semicylindrical portion at the other end, a piezoelectric transducer attached to the flat of each semicylindrical portion, and a paraffin coated aluminum film of preselected thickness disposed between and in laminar contact with the semicylindrical portions for preventing acoustic and electrical cross talk between the transducers and between the semicylindrical portions.