Abstract: A low PRF pulse doppler radar system utilizing a VIP digital filter bank signal processor to suppress echoes from terrain, rain, and chaff, and pass echoes from aircraft moving at higher speeds is disclosed.Each of a plurality of VIP filters individually provides high attenuation to undesired signals over designated frequency bands, the width of which are a large fraction of 1/T.sub.av where T.sub.av is the average interpulse period. Little or no attenuation of desired signals having doppler frequencies greater than 1/T.sub.av occurs. The outputs of the plurality of filters are desensitized to prevent false alarm from clutter, and the presence of a desired radar pulse echo is determined by a comparison with a threshold level.

Abstract: Disclosed is a device for spreading chaff payloads for radar interference comprising a cartridge having a number of oblong cells in which chaff bundles may be displaced towards the output end of the cartridge. The cells are arranged as units each having a displacement mechanism which is selectively operable. Each unit may be shaped as a self-supporting module preferably having three tube-shaped cells.

Abstract: A synthetic aperture radar in which radial motion compensation is provided by a monopulse null tracking loop which tracks the null position of a stabilized monopulse antenna, and in which tangential motion compensation is provided by a tangential velocity measurement loop which tracks the cross-over angle of the monopulse antenna pattern. Since the motion compensation for the synthetic aperture radar is made in relation to a stabilized monopulse antenna, the imaging process for the synthetic aperture radar may be controlled in response to the angular scan rate of the antenna.

Abstract: A vibratory seismic energy source capable of generating significant energy over a broad frequency band. The vibrating baseplate and associated structure are designed for minimum size and weight, while retaining the structural strength to permit high actuator forces. The weight of the transport vehicle is applied to a substantially horizontal hold-down plate that is interposed between the piston-cylinder assembly and the baseplate. This horizontal plate is coupled to the baseplate through resilient means having compliance such that dynamic motion of the baseplate is decoupled from the hold-down plate and transport vehicle.

Abstract: Determination of the pointing accuracy of a commutated scanning beam aerial is effected by monitoring the phase of the signal received at a point where, at all times during its operation, a field is established by the aerial. The phase of the sampled signal is observed by comparing it with a second signal which is sampled elsewhere in the field region or which is derived from the RF signal source of the aerial. This comparison can be effected by heterodyning the two signals. Pointing accuracy is determined by comparing the signal produced by the heterodyning with a pre-recorded signal typifying that experienced when the pointing error is zero. The technique is applicable to commutated torus aerials and to aerials incorporating a linear array of radiators to which power is supplied from a commutated array of excitation elements via an electromagnetic lens.

Abstract: In one implementation of the inventive method an aircraft with an antenna mounted thereon is compelled to follow a sinuous path. The antenna normally provide 120.degree. coverage on either side of the aircraft. Full 360.degree. coverage is provided by the same antenna as the aircraft traverses the predetermined sinuous path.

Abstract: In a digital weather radar display, of the type which displays information on a cathode ray tube in the form of parallel intensity modulated sweep lines and which displays range marks in the form of a plurality of arcs of concentric circles, the positions of the range marks along each of the sweep lines are determined by utilizing a read only memory which stores, for each sweep line, an indication of the distance between range marks and the distance from the beginning of scan of the line to the first range mark.

Abstract: Disclosed is a cathode ray tube of the postfocusing type for displaying color pictures having an apertured color selection means with an electrostatic postfocusing lens formed in each of the apertures. The electrodes of the color selection means at the higher potential are connected to a high voltage connection of the tube and the electrodes at the lower potential are charged by the electron beams with their voltage being stabilized by a series arrangement of zener diodes connected to the high voltage connection of the tube.

Abstract: A distance measuring system is provided including a ground station transponder continuously transmitting a repeating pseudorandom coded bit pattern, and at least one aircraft interrogator receiving and locking onto the ground station signal. The aircraft interrogator transmits a coded interrogation signal in precise synchronism with an arbitrarily selected any one of the repetitive code words (bit patterns) that comprise the repeating pseudorandom coded bit pattern which are coded identically with the interrogation signal and waits for a reply. If the ground station receives the coded interrogation signal in synchronism with an identically coded word in its continuous transmission, it transmits a reply signal to the aircraft interrogator optionally encoded with synchronism error or interrogation steering information.

Abstract: A protected aircraft having a discrete address beacon transponder includes a ground base air traffic control radar beacon system (ATCRBS) interrogator, a collocated discrete address beacon system (DABS) transponder and a directional antenna on the protected aircraft. The protected aircraft synchronizes a local clock with the pulse repetition frequency (PRF) and scan rate of the ATCRBS interrogating his field of interest from which information the protected aircraft can calculate the azimuth angle of responding intruder aircraft with respect to the ground station. By means of his directional antenna the protected aircraft also determines the azimuth of the intruder with respect to itself. Interrogation by the protected aircraft of a collocated ground DABS transponder or a DME or other suitable means of measuring range provides a data base which together with the aforementioned azimuth angles permits the protected aircraft to calculate instantaneous position of the intruder relative to his own.

Abstract: A method and apparatus for telemetering information from the bottom of a borehole to the surface while drilling wherein a wireline is used to transmit the information from the bottom of the borehole to an intermediate position in the drill string, and a special drilling string, having an insulated electrical conductor, is used to transmit the information from the intermediate position to the surface. In an alternate arrangement, an electro-magnetic method may be used to transmit information from the intermediate position to the surface. There is also disclosed special equipment that permits removal of the jumper wire from the surface without removing the drill string from the borehold.

Abstract: An antenna system in which the antennas are not mechanically rotated generates an amplitude-modulated signal of equal intensity in all horizontal directions with the phase of the amplitude modulation varying directly with bearing or azimuth to the antenna system. The antenna system uses a central antenna which radiates a carrier signal and a plurality of sideband antennas, 4 in number, which radiate upper and lower sideband signals. The phase of the upper sideband signal is advanced in increments of .pi./2 radians processing around the sideband antennas in a chosen direction, while the phase of the lower sideband signal is delayed in increments of .pi./2 radians proceeding around the sideband antennas in the chosen direction.

Abstract: A device for measuring vehicle speed by utilizing the Doppler effect includes a microwave oscillator element radiating microwaves to a wave guide, a mixer diode, and a strip line of approximately a Y-shape having two upper portions positioned within the wave guide for receiving the microwaves including both radiated and reflected waves. The two upper branch portions of the strip line are so arranged that both are spaced axially from each other by a distance of a quarter wave length of the microwave existing within the wave guide (.lambda./4), and induce electic power of equal level upon the receipt of the respective radiated and reflected waves. Futher, a first of the two upper branch portions of the strip line is shorter than the other by .lambda./4.

Abstract: In a plasma type display panel of the type having a plurality of parallel row and parallel column electrical conductors forming an array of matrix cross points for providing discrete discharge and light emitting sites upon selection and addressing one or more said sites by selection and addressing circuit means electrically connected to the panel conductors, an improved method and apparatus for providing all or part of the selection and addressing circuit means in one or more high density thick film circuit modules adapted to be detachably engaged with the panel and having conductors thereon in superposed relationship with the parallel panel conductors.

Abstract: In apparatus for discriminating targets from clutter, a high threshold circuit for passing only signals with sufficient amplitude and a lower threshold circuit passing signals of a sufficient amplitude to range extent circuitry, which passes only signals within a predetermined duration and which do not have other range signals adjacent thereto, and to frequency extent circuitry, which passes only signals within a predetermined bandwidth and which do not have other frequency signals adjacent thereto. Signals which satisfy the amplitude, range and frequency requirements then provide an output indicative of a target; all other signals are rejected as clutter.

Abstract: An acoustic direction finder which identifies and displays bearing of an underwater received signal without the requirement of scanning the ambient space. The output signals of hydrophones at the ends of a pair of orthogonally located dipoles are applied to differential amplifiers to provide orthogonal dipole response characteristics, and an in-phase sum of the signal at the center of the dipoles is obtained. The differential amplifier output signals are integrated and the resultant signals are applied to individual multiplying means with the sum signal whereby a pair of X and Y coordinate deflection signals are obtained, which are applied to a display device.

Abstract: A line sweep magnetic deflection system is triggered to display ultrasonic echo impulses during line by line scanning of a body region. Each trigger impulse produces a nonlinear saw-tooth voltage waveform as a function of time which when converted to a corresponding current waveform in the deflection coil produces a constant line deflection velocity for accurate display of echo signals in spite of nonlinearities in the electron optics of the oscilloscope, for example. High gain differential amplifier means force the coil current to conform to the voltage waveform during active line trace, and deviations during retrace intervals cause the application of an overvoltage to the coil driver stage, blocking a normal operating supply voltage therefor, and rapidly driving the coil to its initial energy state, thereby enabling a higher line sweep frequency with consequent optimum display resolution.

Abstract: Pulse radar apparatus particularly for marine use has a dispersive antenna so that transmitted pulses sequentially of two or more different frequencies are radiated in different azimuthal directions. The antenna is continuously rotated and the receiver has separate channels for the different frequencies and display means correlating information received on different frequencies from the same azimuth thereby to reduce sea-clutter on the display.

Abstract: In an electro-optical display device having a persistence property, a driving voltage is immediately applied to each display element after both electrodes of the display element are short-circuited in anticipation of a driving operation intended to reverse the state of a display.

Abstract: An electromagnetic energy pulse-echo system combined with a data processing unit and a memory storing the locations of a number of fixed echo reflectors relative to a waterway so that the pulse-echo system operating from a boat can register the echo reflectors and positions in the waterway can be calculated by the data processing unit.