Abstract: When the scan interval or time between successive potential detections is long with respect to a potential target's maneuvering capability (say on the order of ten seconds for a radar system), there is the possibility that the target may be able to deviate far enough away from its last detected position at scan i-1 that correlation of the target with a detection in scan i may not be possible using conventional tracking methods. The present invention uses a maneuvering gate to monitor a volume in space. The volume is bounded by intersecting ellipsoids and is disposed, preferably uniformly about the target's last estimate velocity vector. The surfaces of the ellipsoids which bound the volume may be determined by determining the loci of a combination of a straight and turning maneuver at a predetermined acceleration, which acceleration may be selected to be the maximum acceleration expected to be achievable by a predetermined target. When target correlation is disturbed or lost, the volume is examined.

Abstract: The invention relates to a self monitoring/calibrating phased array radar in which the operating path for transmission and the operating path for reception may be monitored/calibrated by the addition of a corporate calibration network coupled at the plural end to the antenna elements and at the singular end to the exciter/receiver, and switching means to selectively route the monitoring/calibrating signal derived from the exciter in a transmit path to calibration path sequence or in a calibration path to receive path sequence.In one embodiment of the invention, a phase shifter common to transmit and receive paths is adjustable in increments under active logical control for calibration, while power and gain performance is monitored but not actively controlled. A novel T/R sub-assembly houses the operating electronics for four antenna elements in the form of four T/R modules with a one to four divider network in the transmit/receive path and in the calibration path.

Abstract: An optical signal processing system includes a number of optical time delay units to generate differentially time-delayed optical signals. Each optical time delay unit includes at least an in put polarizing beam splitter (PBS) system having an input system Thompson prism and an output PBS system including an output Thompson prism. Each Thompson prism has a high extinction ratio and is positioned to act as a polarizing beam splitter, providing a high signal to noise ratio optical signal processing system. Selectively polarized light beams are deflected by the polarizing beam splitters onto predetermined paths that cause the respective light beams to be differentially time delayed dependent on the path that they follow through the optical signal processing system.

Abstract: An image processor for use in detecting and tracking a plurality of targets is provided including a plurality of memory locations for storing intensity images and a signal processor coupled to the memory locations. The signal processor comprises a closed loop feedback system for producing a plurality of intensity images for updating externally derived reference intensity images in response to at least one externally derived data image incorporating target detection signals.

Abstract: An enemy radar or transmitter transmits a signal at frequency f1. A tag on a friendly forces target receives frequency f1 and, in response thereto, transmits a signal at frequency f2.noteq.f1 modulated by a code unique to the tag. A friendly forces receiver, in response to receiving frequency f2 provides an indication that (a) the tag has received frequency f1, meaning the enemy is operating in the area, and (b) which specific tag has received a signal at frequency f1. The friendly forces can then take appropriate action.

Abstract: The invention relates to a switchable bidirectional phase shift network exhibiting a desired differential insertion phase suitable for use as a phase bit in a multi-bit phase shifter. The design is economical in its use of components--six field effect transistors, three inductors and no capacitors, and provides in one switching state a band pass network of low insertion phase and in the other switching state a low pass network of high insertion phase. The rate of change of insertion phase over a range of operating frequencies is substantially equal for the two states.

Abstract: The invention discloses a novel method and apparatus for cleaving semiconductor wafers into individual die which comprises mounting the wafer upon an adherent resilient air impermeable membrane while the latter is flat. Cleaving is achieved by using air pressure to inflate the membrane to cause bending and tensile stresses on the wafer brought about by its adhesion to the inflating membrane. These stresses cleave the wafer along the scribe marks to form individual die. The die may be easily removed by the application of a vacuum to the underside of the membrane which draws it against a perforated undulatory grid dimensioned according to the die dimensions to reduce the surface contact. This reduces adhesion of the die to the membrane to facilitate a low stress pick-off of the die.

Abstract: An underwater viewing system includes a dry and wet end. Illumination energy is provided to the wet end where it is scanned and the resulting scanned illumination is directed to a scene of interest. Energy reflected from the scene is received by the wet end where it retraces the path of illumination to the dry end. The received energy is directed to a detector and ultimately to a video processor. The wet end may be disposed in a remote piloted vehicle with optical waveguide payed out from the dry end to supply the illumination and to conduct the received energy. Communication information may be transferred between the dry and wet end may be over the same path followed by the illumination energy but at a different frequency. The illumination and communication energy may be separated based on their frequency. A polarization device may be provided for maximizing the amount of received energy that is provided to the detector.

Abstract: A liquid crystal and acousto-optic based control system for phased array antennas provides independent control of scanning along two axes of the antenna. The optical control system includes a laser source providing polarized laser beams processed in an in-line interferometric optical architecture that uses two acousto-optic deflectors (AODs) driven by separate sidebands of a microwave signal that is a mixture of a drive frequency corresponding to the desired carrier frequency and a variable control frequency for determining a selected sideband frequency. The AODs and associated polarization rotators generate a plurality of optical signal pairs, each pair having one first order positive doppler shifted light beam deflected by a first sideband drive signal and one first order negative doppler shifted light beam deflected by a second sideband drive signal, the positive and negative doppler shifted beams being respectively orthogonally linearly polarized and traveling along almost collinear paths.

Abstract: A phased array antenna system having an optical signal processing system includes a number of optical time delay units to generate differentially time-delayed optical signals. Each optical time delay unit is configured to generate a time delay through the use of either an optical fiber or free-space optical propagation delay assembly. Differentially time delayed optical signals are generated by controlling, with a spatial light modulator, the polarization of each light beam entering each time delay unit so that each respective light beam is deflected along either a direct path or a delay path dependent on its linear polarization. Each time delay unit includes an imaging system having a selected imaging ratio, with spherical lenses disposed in the delayed and direct light paths of the unit to provide imaging between the spatial light modulator planes. High extinction ratio polarizers are positioned in each of the delayed and direct paths. Spatial filters are further disposed in each spherical lens pair.

Abstract: Image data is subjected to a thinning process so as to derive a medial axis for each image. Boolean image data is reduced to lines and/or dots, each line generally being a centroid line of an image. The thinning process uses a change look-up table which is addressed using values from pixels in the neighborhood of a particular pixel which is the target for possible change. Pixels in the neighborhood which are to be evaluated are given a weight by use of a weight look-up table and the weight of the pixel is multiplied by the value of the pixel. Alternately, the weight of the pixel may be added to the pixel value. The pixels in the neighborhood of a target pixel (i.e., pixel which is being evaluated for possible removal) have their weights and values taken into account by a summation of the results of the multiplication (or addition) performed for each pixel so as to provide an address used to address a change look-up table which supplies an output indicative of change in the target pixel.

Abstract: The invention relates to an improved IR imaging system for detecting a target producing an IR signature obscured by an ambient IR background. The imager comprises an objective lens, preferably of a telecentric design, and an area IR detector array. Two narrow wavebands are selected by an unpatterned bandpass filter, and a two part patterned filter, one part a long pass filter and the other part a short pass filter, installed close to the IR detector array. This choice permits the patterned filters to be quite thin, and more readily formed into smaller elements allowing increased image resolution. The use of a telecentric objective lens and the use of filters having higher average indices of refraction permit a wide field of view without compromising filter operation from filter wavelength shift.

Abstract: An improved cold shielding arrangement for a scanned linear IR detector array normally having the pixels arranged in plural columns, is disclosed. The arrangement consists of a first slotted cold shield plate spaced from the array and designed to reduce the angular field of view for all pixels of the array in the scanning direction, and a composite cold shield in proximity to the individual pixels. The first part of the composite cold shield is a thicker plate, typically several mils thick having slots oriented to reduce the angular field of view in the resolution direction for the pixels in a common row.

Abstract: A transducer includes an acoustic radiating member for generating acoustic energy in a transmitting medium and a driver member that is pivotally connected to the radiating member. The driver member is for urging movement of the radiating member, wherein such movement generates the energy. Pivoting of the driver member with respect to the radiating member relieves predetermined stress in the driver member. The radiating member may include, for example, a flat element such as a bar, plate or disk, or an I-shaped element. The driver element may include an electroactive material. The driver element may be connected to the radiating element by support apparatus that is fixedly coupled to the radiating element includes a screw having a predeterminedly contoured end that engages a complimentarily contoured recess connected to the driver element for permitting the pivoting. When the support apparatus includes a screw it may be adjusted for supplying a predetermined force on the driver element.

Abstract: The transition interconnects microstrip transmission lines whose finite-width conductors are formed on the upper surface and whose ground planes are formed on the under surface of a ceramic substrate. A patternable metallizable multilayer thick film dielectric is applied to the under surface of the ceramic substrate. The transition comprises first and second vias which penetrate the ceramic substrate inside and outside a hermetic enclosure. The upper ends of the vias are connected to the finite-width transmission line conductors, and the lower ends of the vias are interconnected by a finite-width conductor formed on the under surface of the substrate. The lower conductor then forms a transmission line of either a microstrip or coplanar nature with a ground plane available on the underside of the assembly. The thick film dielectric facilitates sealing, and attachment of a metal base plate. All steps are performed using thick film processing.

Abstract: A transducer includes a first and second spaced apart member, each member having a radiating surface for producing a wave of energy in a transmitting medium in response to a driving force, a plurality of containment devices coupled to each member and extending outwardly beyond at least one radiating surface for communicating the driving force to each member, and a corresponding plurality of driving devices respectively disposed within the containment devices for generating the driving force in response to a change in a predetermined dimension of the driving device. The distance between the members and corresponding distance between the radiating surfaces may be reduced for increasing the bandwidth of the transducer, while the length of the containment device may be increased for accommodating the driving devices in order to maintain a constant driving force. A method for selecting the bandwidth of operation of a transducer is also described.

Abstract: A visual simulation system in combination with a radar simulation system may be used for generating full radar or synthetic aperture radar (SAR) radar images from a common data base that are correlated to video images of the visual system while facilitating radar image processing. The combination of visual and radar simulation systems in accordance with the present invention obviates the need for a separate stand-alone radar processor and dedicated radar data base. Simulated electronic tactical map data may also be provided.

Abstract: In a real-time computer-image generation system, processing resources for manipulating polygons that define objects are generally limited. This results in a trade-off with respect to the amount of detail to be displayed in an object versus the number and type of objects to be displayed. The value of a predetermined viewing criterion is used to determine when an object can be represented by a single polygon. The single polygon is rotatable about a predetermined number of axes for maintaining a predetermined relationship with respect to a view point. Since processing resources are saved by using a single polygon, additional objects and/or more detail may be included in a display.

Abstract: The invention relates to the provision of an RF shield for an individual or a collection of integrated circuit chips in a module containing a plurality of hybrid interconnected chips generating interfering RF fields that would interfere with operation of that chip if unshielded. The chips in the module may function in the analog and/or digital mode. The RF shield comprises separate metallizations under and over the chip, the two metallizations being interconnected by a line of discrete electrically conductive vias forming cage-like sides to complete an electrically conductive enclosure about the chip. The vias are spaced closely enough to prevent the escape or entry of RF waves at the frequencies of interest. The RF shield is advantageously fabricated using metallizations and vias that are optically patterned by the same process steps used to effect hybrid interconnection of the chips.

Abstract: In a time continuous transmit active sonar system the frequency of the transmitted waveform is interrupted at predetermined intervals so that a frequency discontinuity in the transmitted waveform occurs at each interruption. The starting and ending frequencies at the beginning and end of the interruptions provide indications for properly resolving the range/Doppler ambiguity that is inherent in prior continuous transmit sonar systems. The transmitted signal may be frequency modulated. Further, the frequency of the transmitted waveform may be rapidly changed and/or multiple frequency waveforms may be transmitted within the same time interval. An existing passive sonar detection system may be modified to include an active continuous transmit sonar system whose echo returns may be processed by the passive system, thereby achieving benefits over conventional active pulsed sonar systems.