Abstract: A passive, infrared, guided missile fuze, capable of detecting the presence of a target, having an axis which coincides substantially with the direon of forward motion of the missile, comprising three infrared detectors for detecting three separate beams of infrared electromagnetic radiation from the target, the beams forming angles with the axis. More specifically, the missile fuze detects the presence of a target when two of the infrared detectors simultaneously detect two beams of infrared radiation from the target. In a sophisticated embodiment, the fuze is able to determine in which quadrant of space the target is located.

Abstract: Actuating circuitry which may be used with a contact exploder, useful on a orpedo, for example, which is sensitive not only to direct hits but also to abrasive damage or sea water exposure caused by grazing contact, but insensitive to changes in its velocity or momentum or unwanted environmental background, such as shock, vibration and electromagnetic field variation. The exploder includes a normally insulated and shielded wire which traverses that part of the surface of the missile which is most likely to make contact with a target. The wire is so connected into associated actuating circuitry that it will cause explosion if: (1) even grazing contact with a target causes removal of even a small amount of the insulation and shielding of the wire, which causes grounding of the circuitry at the wire; or (2) even grazing contact opens or breaks the wire at any point.

Abstract: A method for determining the positions of the N array elements of a random rray to an accuracy sufficient to accomplish beam forming is provided where the initial positions of the array elements are known to an accuracy of .lambda..sub.min/2, and where .lambda..sub.min is the wavelength of the highest frequency of any of the M cohering sources which are in the field of the array and where the relative directions are unknown. The method includes the steps of: identifying M cohering sources in the field of the array, each of which emits at least one narrowband frequency, each frequency differing from the adjacent frequency by 1/T, where T is the time period of the measurements; a device for measuring the true bearing of one of the M sources; receiving the M cohering signals at the N array elements; performing a Fast Fourier Transform (FFT) on each of the N element signals; examining the spectrum of each of the N received signals; and from the N spectra, selecting M (M>3) lowest angular frequencies, .omega..

Abstract: A system locates the elements of a randomly dispersed, untethered, array of sonobuoys from which are suspended active, transmitting, transducer elets and passive, receiving, transducer elements. The system comprises a data conditioning unit which receives high-frequency element-locating signals from a radio receiver, which may be located on an aircraft, and processes them so that they are quantized at its output. An acoustic delay processor, whose input is connected to the output of the data conditioning unit, correlates a reference signal R received from an active element suspended from the sonobuoy with a corresponding received signal from another element, active or passive, suspended from another sonobuoy.A position tracker, whose input is connnected to the output of the acoustic delay processor, calculates the relative position of each element of the random array from the propagation delays measured by the acoustic delay processor.

Abstract: An apparatus determines the location of a signal source having coordinates x,y). The source may be located as far away as two thousand km and does not require knowledge of ionospheric height or layer structure. The apparatus comprises at least three receivers adapted to receive the signals from the signal source. The coordinates, (x.sub.1,y.sub.1), (x.sub.2,y.sub.2) and (x.sub.3,y.sub.3), of each of the receivers are very precisely known. One receiver is capable of receiving signals from the other two receivers through different means (e.g. a wide-band telephone link). A plurality of at least three timers, one connected to each receiver, measures precisely the time difference of arrival (TDOA) of the signals from the signal source. A plurality of at least three means, connected one to each of the receiving means, determine the vertical angles .phi. at which the signal from the signal source is received by each of the receivers.

Abstract: A mobile magnetometry processing system which scans an area in order to mure the magnetic field strength over the area, comprising:a plurality of N sensors for sensing the magnetic field of the area being scanned, each sensor generating an output signal, for example, a voltage, which is a function of the magnetic field it scans, the sensor being aligned in the general direction of the motion of the system;a plurality of N sets of means for weighting, for receiving and weighting the N signals from the means for sensing, each of the N sets comprising M weighting means;a plurality of M summers, each have N inputs, one from each of the N sets of means for weighting, for summing its N input weighted signals;a plurality of M filters each having an input which is connected to the output of a summer, for delaying the exit of an input signal by an amount of time equal to the time required for a sensor to advance the distance to the nearest adjacent sensor, the filtering process comprising a convolution;means, associat

Abstract: An acoustic, underwater, telemetry system between two vehicles, a free-rung, deep-operating, sonar platform, or Sonaray vehicle, to overcome refraction, and a surface ship to provide processing of the sonar data gathered by the Sonaray vehicle. The telemetry system is required to communicate analog sonar information, digital command to control the platform, and digital information concerning the status of the platform, between the Sonaray vehicle and the surface ship. The Sonaray concept requires more than 32 channels of analog information for sonar data transmission, each corresponding to a particular received azimuthal beam and each having an information bandwidth of 1 kHz. The output of the analog channels consists of raw data from the search sonar. Because of the long range and very high reliability of the transmission required for the status and control channels, sonar processing by cross-correlation is used to search in both range and doppler.

Abstract: An acoustic array, useful for sonar, comprises a plurality of transducing ements which are free floating and not connected to each other. Means are provided for locating the position of each of the transducer elements. The acoustic array may be one-dimensional, that is, a line array, a two-dimensional array, or a three-dimensional array. In another embodiment of the acoustic array, the transducing elements are free-floating but connected to each other by a flexible tether, which limits the range of separation of one transducing element from any of the others. The locator comprises a centrally located element to which there are attached three horizontal rigid arms. On the end of each arm is a high-frequency acoustic transducer. Periodically, each of the transducers transmits a high-frequency broadband pulse. The pulse from each of the three transducers is unique and identifiable.

Abstract: A transducer assembly comprising: a diaphragm; at least one transducer elnt bonded by its head to the diaphragm; a pressure-resistant means, for supporting the transducer assembly; an acoustic isolator mounted about the transducer element and located between the diaphragm and the pressure-resistant means; the material of the acoustic isolator being elastically linear and equal in thickness to one-quarter wavelength of the corresponding operating frequency of the transducer element.

Abstract: A secure communication system, which may be safely used even in the prese of an enemy interceptor, includes a transmitter and a receiver.The transmitter comprises a first modulo-2 adder, having as one input a sequence of N-bit binary numbers. A first random read-only memory (ROM), comprises a plurality of storage cells. The input of the ROM is connected to the output of the modulo-2 adder. Each of the cells of the ROM, which have distinct addresses, contain a random number, with no two cells containing the same random number. The input to the ROM is a binary number representing a specific address, whereas the output of the ROM is a signal representing a random binary number. A delay line has its input connected to the output of the random read-only memory, its output constituting the second input to the modulo-2 adder. A second random ROM, having the same type of hardware but different random content, has its input connected to the output of the delay line.

Abstract: An apparatus and method is provided wherein a television signal being traitted may be modified by multiplexing in a digital information-bearing signal in a manner that binary pulses are encoded upon horizontal synchronizing pulse windows contained within the composite video signal. The apparatus comprises two primary subsystems, an encoder and a decoder. The encoder is further composed of four components (1) a horizontal synchronous pulse detector, (2) a pulse position modulator, (3) a digital signal conditioner, and (4) a mixer. The decoder consists of three components: (1) a horizontal synchronizing detector, (2) a pulse position demodulator, and (3) a digital signal conditioner. Functionally, the video/digital data multiplexer is a pulse position (PPM) digital communication system which utilizes the leading edge of the horizontal synchronizing pulses of a composite video signal as a marker denoting the location where a pulse will be inserted.

Abstract: A concretized coating which encapsulates canisters of radioactive, heat-producing materials is caused to be formed by immersing said canister in a sea floor sedimentary layer, the sediment containing feldspathic material. The canister heats the surrounding water causing alkali and alkaline materials to be leached from the seabed sediment. An indurated concretized layer of anhydrite and sedimentary particles is then formed by precipitation of anhydrite and other agents from the hot pore water, that is, water in the proximate environment of the canister. This concretized barrier provides protection to the fuel capsule against intrusion by the corrosive seawater.

Abstract: An improved frangible nose cap is presented which in addition to providing echanical protection to the torpedo nose also provides electromagnetic interference (EMI) protection to the torpedo electronics systems. The improved nose cap is made up of a frangible material which may be impregnated, or coated, by methods well known in the prior art, with a conductive layer that can be electrically connected to the torpedo's electronic circuit ground for the EMI shielding.

Abstract: A method of fabricating lines of submicron width, comprising the steps of:providing a substrate,depositing a first layer of metal upon the substrate;spinning a photoresist layer on the metal;patterning the photoresist layer;etching the metal to undercut the photoresist edge, e.g. with a mixture for approximately ten minutes at room temperature;depositing a second layer of metal at an angle .theta..sub.1 to the photoresist edge, thereby defining a long, submicron-wide opening to the underlying substrate;depositing a chosen material, for example, metallic or semiconductor, for the bridge onto the substrate at an angle of .theta..sub.2 through the submicron-wide opening; andremoving undesired material surrounding the bridge by dissolving the photoresist in hot acetone followed by stripping the remaining two layers of metal with etchant.

Abstract: A real-time amplitude histogram shaper transforms an input analog signal with a corresponding input amplitude histogram to an output signal with a specified output histogram. The histogram shaper comprises a histogram estimator, which estimates the amplitude histogram of an input analog signal. A calculator, whose input is connected to the output of the estimator, computes the transfer function required to transform the input signal to an output signal with the desired amplitude histogram. A controller, whose input is connected to the output of the calculator, generates control signals. A transfer function generator, whose input is connected to the output of the control signal generator, modifies its input signals by a ratio P.sub.out /P.sub.in. The gain P.sub.out /P.sub.in is a function of P.sub.in, that is, P.sub.out /P.sub.in =g(P.sub.in).P.sub.out is the magnitude of the output parameter and P.sub.in is the magnitude of the input parameter, the output signal thereby having the desired amplitude histogram.

Abstract: A correlator which is capable of correlating two or more signals of unknown frequency and bandwidth receives inputs on each of two or more channels. For the case of a two-channel, or pairwise, correlator the two channels are designated a first channel and a second channel. For the pairwise correlator, a first adaptive linear predictive (ALP) filter filters the input signal from the first channel and a second ALP filter filters the input signal from the second channel, the two output signals of the filters being x(k) and y(k). The adaptive linear predictive filter is an adaptive time-domain digital filter which adapts its impulse response according to a certain algorithm. The filter output represents an adaptive linear predictive estimate of the current input value, based on many past inputs. The input signals to the two channels of the pairwise correlator may correspond to sensor outputs from two or more widely separated sensors.

Abstract: An array convolver and/or correlator comprises first and second two-dimennal shift registers defined by N rows and M columns, corresponding columns, the first, the second, etc., of the two registers being aligned. N and M are generally in the range of 4 to 512. Data is capable of entering at least one of the left or right columns of each of the two shift registers. The data shifts downward to the bottom row in the first, upper, shift register and upward to the top row in the second, lower, shift register.A plurality of M analog multipliers each has an input from corresponding, aligned columns of each of the two registers. An analog summer has M inputs, one from each of the multipliers. The output of the summer is a correlation or convolution, depending upon which specific columns the data enters.

Abstract: An apparatus multiplies two sequences of digital numbers a.sub.i and b.su, which may represent signal pulses of various amplitudes. A first plurality of t read-only memories (ROMs), have a common input adapted to receive the sequence of numbers a.sub.i, each ROM coding the numbers a.sub.i into a.sub.j,i =a.sub.j modulo m.sub.i, 0.ltoreq.a.sub.j,i .ltoreq.m.sub.i -1. A first plurality of t means, extend the digital signal with zero values, the number of zeroes being determined by the length N of the sequences being convolved. A first plurality of t D/A converters, convert the digital quantity received from the extender into its corresponding analog value.Similar ROMs, extending means, and D/A converters process the sequence numbers b.sub.i.A plurality of t means convolve two input analog signals, one from each of the first and second D/A converters, the output of each convolving means being an analog signal, approximately equal to the convolution (a.sub.j,i) * (b.sub.j,i) modulo m.sub.i.

Abstract: A discrete chirp generator produces discrete chirp signals which correspond o either of two exponential functions, namely the functions exp [j.pi.(m.sup.2 +.alpha.)/N] or exp (j.pi.[m(m+.beta.)+.alpha.]/N), where m=0, 1, 2, . . . , M. Typically, M and N might both have the value 256.Similarly, a discrete chirp filter is described by its impulse response which has one of these same two functional forms.These two new components (discrete chirp generator and discrete chirp filter) can be used to implement(a) an improved type of frequency synthesizer, and(b) an improved type of discrete Fourier transformer.In the former, a single generator is used in conjunction with delay, conjugation, multiplication, and low-pass filter components to achieve an improved synthesizer. In the latter, either of the two discrete chirp function generators is combined with an input signal g.sub.n in a multiplier.

Abstract: A programmable frequency synthesizer (PFS) consists of three serially conted stages: an accumulator, a triangle converter, and a sine shaper. The accumulator is the frequency-generating stage of the synthesizer. It consists of an input latch to store the binary programmed frequency, an adder, an output latch to store the output of the adder, and a clock oscillator. The output frequency of the accumulator can be directly scaled by changing its clocking frequency. The square wave output of the accumulator is divided in frequency by the triangle converter, which produces a triangularly shaped staircase waveform. The sine shaper stage employs diode limiters and filters to produce low-harmonic sinusoids from the triangular staircase.