Abstract: A patch radiator antenna is described including a sheet of conductive material and a dielectric substrate having a first and second surface, the sheet of conductive material disposed upon the first surface of the dielectric substrate. The patch radiator antenna further includes a plurality of patch radiator elements disposed upon the second surface of the dielectric substrate, each one of the plurality of patch radiator elements having sides with a width and a length. The plurality of patch radiator elements include a first patch radiator element having a feed probe to couple the first patch radiator element to an RF signal source and at least one second patch radiator element including a microstrip feed along the width of the patch radiator element, the at least one second patch radiator element disposed fore of the first patch radiator element.

Abstract: A system for providing advance warning of underwater navigation hazards that threaten safe ship passage is provided. The system includes a sonar transmitter/receiver adapted for mounting on the ship in a forward looking direction. A processor, in response to sonar returns produced by the sonar transmitter/receiver, produces a sonar produced slope profile of a region of the sea bottom in front of the path of the vessel. A memory stores a slope profile of the region of the sea bottom in front of the vessel, such profile being developed from charted depth data. The stored charted depth data developed slope profile is compared with the sonar return produced slope profile to determine whether the sonar produced slope profile and the charted depth data slope profile are consistent with each other.

Abstract: A radio frequency connector for a patch-coupled aperture array antenna is described including a coaxial connector having an outer shield and an inner conductive member with a dielectric material disposed between the outer shield and a portion of the inner conductive member and a dielectric substrate having a first and a second surface with an opening extending from the first surface of the dielectric substrate to the second surface of the dielectric substrate, the inner conductive member extending through at least a portion of the opening of the dielectric substrate. The radio frequency connector further includes a coupling conductive members having a protruding pin, the protruding pin connected to the inner conductive member and a sheet of dielectric material disposed juxtapositional with the dielectric substrate and covering the coupling conductive member. With such an arrangement, a less expensive radio frequency connector for an antenna is provided which can survive a high temperature environment.

Abstract: A dual-band infrared sensor package for use in radar system applications is provided. The package includes two detector arrays, an InSb photodiode array sensitive in the mid-wave infrared radiation range and a HgCdTe photodiode array sensitive in the long-wave infrared radiation range. The package further includes integrated circuits which provide electrical control to and data output from the detector arrays. A three dimensional arrangement of the detector arrays, integrated circuits, and ceramic interconnecting substrates is used to provide a relatively small sensor package suitable for radar system applications so that radar signals are not obscured.

Abstract: A method of interdicting a guided missile equipped with an active radar-controlled guidance system is shown to include generating decoy signals in a transponder on an armed decoy launched from a ship being attacked toward such missile, such decoy signals initially obscuring echo signals from the ship to cause the apparent position of the ship (as measured by the active radar-controlled guidance system) to differ from the actual position of the ship, and, when the decoy and guided missile are in proximity with one another, exploding a warhead on the decoy to destroy the guided missile.

Abstract: A method of interdicting a guided missile equipped with an active radar-controlled guidance system is shown to include generating decoy signals in a transponder on an decoy launched from a ship being attacked, such decoy signals being formed by amplifying echo signals from the ship to cause the apparent position of the ship (as measured by the active radar-controlled guidance system) to differ from the actual position of the ship so that the guided missile ultimately is caused to miss the ship.

Abstract: A spinning projectile is described including a body having a fore section and an aft section and a seeker, connected to the fore section, for providing guidance signals. The spinning projectile further includes a rocket control system, connected to the aft section, for controlling the course of the spinning projectile and means for acoustically coupling through the body of the projectile the guidance signals from the seeker to the rocket control system. With such an arrangement, existing projectiles can be retrofitted with a seeker and a rocket control system without affecting the body of the projectile.

Abstract: A transmit and receive module is described which provides means within the module for switching between two orthogonal linear polarization ports and right and left hand circular polarization ports for both transmission and reception while maintaining very low RF reflections from the module at antenna ports.

Abstract: An imaging optical system is described including an array of photodetectors, each photodetector having a surface, and a focusing system for focusing a beam of electromagnetic infrared energy on the surface of at least one of the photodetectors. The focusing system further includes a technique for periodically defocusing the beam of electromagnetic infrared energy on the surface of at least one of the photodetectors. With such an arrangement, a scanning and focusing system is provided wherein fixed pattern noise can be decreased.

Abstract: A method of operating a radar system is shown to include the steps of transmitting a plurality of signals, each signal having a different frequency, and receiving, if existing, a corresponding return signal for each one of the plurality of signals. The method further includes ascertaining an angle off beam cross-over of a target from each existing return signal, selecting the angle off beam cross-over having the largest magnitude, ascertaining a reduction factor appropriate for the selected angle and reducing the magnitude of the selected angle by the reduction factor. With such an arrangement, a radar system is provided having improved elevation measurement accuracy.

Abstract: A directional ordnance for a missile. The missile contains circuitry to determine the direction of a target relative to the missile and to selectively detonate directing charges to force the blast from the warhead towards the target. The circuitry for determining the direction of the target includes two transmit antennas, each transmitting a different pseudo noise sequence, and two receive antennas; each coupled to a receiver which can determine the level of each pseudo noise sequence at each receive antenna. The relative strengths of the different pseudo noise sequences tell the direction of the target relative to the transmit and receive antennas.

Abstract: A voltage variable attenuator is described including a quadrature hybrid coupler having an input port, an output port, a first reflective port and a second reflective port. The voltage variable attenuator further includes a first and a second impedance network, the first impedance network connected to the first reflective port of the quadrature hybrid coupler, the second impedance network connected to the second reflective port of the quadrature hybrid coupler, each impedance network including a first RF propagation network having a first end connected to the respective reflective port of the quadrature hybrid coupler. Each impedance network further includes a second end of the first RF propagation network connected to a field effect transistor having a drain electrode, a source electrode and a gate electrode, the drain electrode connected to the second end of the first RF propagation network.

Abstract: A microwave oscillator is shown to include an oscillator having an output and a control port and a feedback circuit disposed between the output and the control port of the oscillator. The feedback circuit includes a modulated laser, having an input and an output, the input responsive to a portion of a signal from the output of the oscillator and a photo detector having an input and an output, the input of the photo detector responsive to a signal from the output of the modulated laser delayed by a predetermined amount of time. The feedback circuit further includes a detector having a first and a second input and an output, the first input of the detector responsive to a signal from the output of the photo detector, the second input responsive to a portion of the signal from the output of the oscillator shifted in phase to be in phase quadrature with the signal at the first input of the detector and the output of the detector coupled to the control port of the oscillator.

Abstract: A portable underwater mount for magnetic and electric field sensors. The mount has a gimbal-like structure comprising a ball member having a mounting flange for coupling to the magnetometer. The ball member is cast from polyurethane with Teflon powder suspended therein, providing a substantially frictionless surface. The ball member is disposed over a support platform having a spherical contour so that the weighted sensor positions itself to true vertical. A collar having a lock terminating in the support platform rests over the ball member so that once the sensor is oriented to magnetic north, the lock is engaged to secure the sensor in true vertical and magnetic north positions.

Abstract: Apparatus and method for removing unwanted components of a signal received from a radar transmitter. The unwanted components lie in a clutter Doppler frequency band. Such components are removed by first sampling the received signal at a rate sufficient to cause components of the received signal in the clutter Doppler frequency band to be validly sampled and components of the received signal in a desired target Doppler frequency band to be invalidly sampled. A signal equivalent to the values of a polynomial fit to this sampled signal then provides an estimate of the unwanted clutter components. This estimate is subtracted from the original received signal to provide a signal with the unwanted clutter components removed. A significant improvement in receiver sensitivity as well as a reduction in dynamic range requirements of a post detection digital signal processor is achieved through the use of this invention.

Abstract: A switchable, dual channel frequency converter is provided. The converter includes a semiconductor body having formed as a monolithic microwave integrated circuit: a pair of input signal channels; a pair of output signal channels; and, a mixer and multiplexer means, disposed between the pair of input signal channels and the pair of output signal channels, for converting the frequency of signals fed to the pair of input signal channels to a different frequency and for directing the frequency converted signals to the pair of output signal channels selectively in accordance with a control signal. The mixer and multiplexer means includes: a pair of mixers coupled to the pair of input signal channels and a common local oscillator signal; and a multiplexer network. The mixers covert the radio frequency of the signals in the pair of input signal channels into a corresponding pair of intermediate frequency signal channels.

Abstract: A sonar system is provided for mapping the bottom of a body of water to identify a submerged foreign object. A sequence of the sonar pulses is transmitted and directed toward the bottom. The mapping is formed from a sequence of echo returns. Each one of the echo returns is produced as a range scan in a range direction response to a corresponding one of the transmitted sonar pulses. The sonar system stores signals representative of the intensity of the echo returns in a two dimensional array of pixels. Each one of the pixels represents the intensity of the echo return at a predetermined range position from the system in the range direction and a predetermined cross-range position from a reference position of the system in the cross-range direction.

Abstract: An RF switch circuit includes a waveguide transmission line having an input port, an output port, a first wall having a first cavity disposed therein and a second wall having a second cavity disposed therein with the first and second cavities being aligned along a centerline of the waveguide transmission line and means for providing a substantially short circuit impedance characteristic between the first cavity and the waveguide transmission line to RF signals propagating along the waveguide transmission line. The circuit further includes an electrically conductive member disposed in a first region of the second cavity, a diode having a first electrode disposed on a first surface of the electrically conductive member and an electrically conductive post having a first end disposed in the first cavity and having a second end disposed in the second cavity with the second end of the post electrically contacting a second electrode of the diode.

Abstract: A radar system is shown to include a transmitter for transmitting a pulsed electromagnetic signal having a frequency less than 500 Hz and a receiver for receiving a (scattered) reflected signal provided from the pulsed electromagnetic signal (scattered) reflected from an anomaly below the surface of the water. The radar system further includes a switch for inhibiting the receiver from receiving a reflected signal provided from the pulsed electromagnetic signal reflected from the surface of the water and a signal processor for controlling interoperability of the transmitter, the receiver and the switch. With such an arrangement, a radar system is provided for detecting anomalies such as a wake of a moving vessel (if and when this produces a conductivity anomaly), or a plume of oil beneath the surface of water.