Abstract: An apparatus for attenuating traveling wave reflections from a surface, due to an impedance mismatch between the surface and free space. The apparatus includes a resistive element having an impedance between that of the surface and free space. The resistive element is positionable relative to the surface so as to minimize the impedance mismatch between the surface and free space. The resistive element is preferably a resistively graded element, which includes a forward end with an impedance approaching the impedance of the surface. An aft end of the resistively graded element has a high impedance relative to free space. The aft end is positionable sufficiently distant from the surface so as to minimize any traveling wave reflection due to impedance mismatch between the surface and free space.

Abstract: The inventive laser radar uses a multiple frequency processing technique for the purpose of extracting relative range information from a received signal by transmitting and receiving two frequencies that are derived from a reference signal source modulated by two modulators that are driven by a different frequency, the reference frequency source also serving as a local oscillator.

Abstract: A focal plane array (FPA) including a layered composite structure having several layers of materials with differing thermal expansion coefficients (TECs) and thicknesses to stabilize and maintain FPA performance during thermal cycling and excursions. An optical substrate is coupled to a multiplexer through a network of indium bumps. The typical TEC mismatch of the layered materials is offset by particularly selecting the types of materials used and the thicknesses of the individual layers of the FPA. Consequently, undesirable deflections and distortion of the multiplexer and the indium bumps are minimized, thereby substantially improving FPA reliability.

Abstract: A process for forming composite hollow crown stiffened skins and panels in which a first layer or skin is placed on a forming surface of a female mold and, after forming a plurality of U-shaped stiffener elements in the first skin, a second skin is placed over the first skin, whereupon the resulting assembly is prepared for autoclave curing. The stiffener elements are formed by pressing the first skin into U-shaped depressions in the female mold surface and inserting a hollow, expandable rubber mandrel into each of the depressions on top of the first skin. Valve stems in the mandrels enable maintaining the pressure inside at atmospheric pressure. The mandrels are maintained in their "pressurized" state during subsequent formation and autoclave curing steps.

Abstract: The present invention is a thrust reversing apparatus for diverting purely rearwardly directed air flowing through an engine nacelle to combined rearward-and-radially-outward flow, and then to a combination of various radially outward angles and forward flow, where in the latter states thrust reversal is effected. The apparatus includes parallel inner and outer air flow blocking members driven by actuators which are coupled to the blocking members for effecting synchronous movement. The inner member includes a first door having fixed vanes and a solid second door pivotably coupled to the first door. The inner member has a closed position in which the two doors are collinear, and various open positions in which the two doors are pivoted relative to one another. The outer member comprises an array of pivotable, parallel vanes, and has a closed position in which the vanes tightly overlap, and various open positions in which the vanes are pivoted out of contact with each other through various amounts of rotation.

Abstract: A radar digital IF (intermediate-frequency) signal is to be complex demodulated, then processed through a two-channel real lowpass filter, prior to Doppler correction, clutter filtering, and other usual processing steps. A particularly efficient form of lowpass filtering for such applications is the so-called CIC (cascaded integrator/comb) filter. The first stage of such a filter is always an integrator. A conventional mechanization would therefore feature a conventional complex demodulator followed by an accumulator on each of the two demodulator outputs, followed by more processing. This invention more efficiently mechanizes this function by replacing the usual pair of multipliers and pair of accumulators (or integrators) with a single two-delay (54, 58) accumulator having an add/subtract control (48) on the input adder (42), and a pair of multiplexer switches (62, 66).

Abstract: The invention is a process for simultaneously improving at least two mechanical properties of mill-processed (.alpha.+.beta.) titanium alloy, which may or may not contain silicon, which includes steps of heat treating the mill-processed titanium alloy such that the (.alpha.+.beta.) microstructure of said alloy is transformed into an (.alpha.+.alpha..sub.2 +.beta.) microstructure, preferably containing no silicides. The heat treating steps involve subjecting the mill-processed titanium alloy to a sequence of thermomechanical process steps, and the mechanical properties which are simultaneously improved include (a) tensile strength at room, cryogenic, and elevated temperatures; (b) fracture toughness; (c) creep resistance; (d) elastic stiffness; (e) thermal stability; (f) hydrogen embrittlement resistance; (g) fatigue; and (h) cryogenic temperature embrittlement resistance. As a consequence of the process, the (.alpha.+.alpha..sub.2 +.beta.) microstructure contains equiaxed alpha phase strengthened with .alpha.

Abstract: A process invention for protecting alpha-2 and gamma titanium aluminide alloy specimens subjected to high temperature oxidation comprises providing an ion beam having an energy range from about 100 keV to about 170 keV. The ion beam incorporates an elemental species capable of promoting alumina formation. The ion beam is exposed to the specimen so as to implant a dose in a range from about 2.times.10.sup.16 to about 8.times.lO.sup.17 ions/cm.sup.2 for a sufficient time period to form a surface alloy of the elemental species and titanium aluminide near the surface of the specimen.

Abstract: The blade flash signature in a radar return is enhanced and used to detect and classify helicopter targets. The radar return of a target is fast Fourier transformed 34, and the frequencies corresponding to DC and the body of the target are filtered out 38. The filtered signal is inverse transformed 44, moving averaged 52, and auto-correlated 54. Auto-correlation 54 may take place in the frequency domain. If there are significant peaks in the auto-correlation output (other than at zero time delay), then a helicopter is present. The time delay between peaks is the period of the blade. The height of the peak indicates whether it is the main blade or the tail blade which has been detected, and allows a signal indicating both periods to be output. The main blade period and the ratio of the period to that of the tail blade can be compared with a data base to classify the helicopter.

Abstract: A wireless apparatus and communication system for remotely determining the unique identification of individual remote devices, among a plurality of remote devices, and to simultaneously determine the location of each individual remote device, associated with its unique identification number. This invention further provides a wireless signaling response capability for the purpose of relaying generic digital data from a remote device to a host system.

Abstract: A radar lens 14 is made from a conventional Fresnel lens 10, but replaces the conventional curved surface 32 with a stepped approximation thereto 22, 24, 26, preferably of three steps. The thickness of the stepped lens 14, at each step, is a half-wavelength or a multiple half-wavelength of the radar operating frequency in the medium of the lens 14. The half-wavelength or multiple half-wavelength separation of the steps 22, 24, 26 causes reflections from the front 16 and rear 18 surfaces to cancel, thereby minimizing the (undesirable) standing wave between the lens 14 and the feed horn or feed horns 46, 48, 50. This avoids the necessity of reducing the standing wave by presenting the curved or stepped side 18 forward. The planar side 16 of the lens 14 (unlike the stepped side 18) doesn't need to be protected from road debris. The lens 14 can therefore be molded as an integral unit of a radome, desirable in the automotive setting.

Abstract: Sparse sampling of an analog signal is desirable because it allows a large number of analog signals to be monitored using a minimum of electronics. The analog signals may be multiplexed and the multiplexed signal applied to a single analog-to-digital converter (ADC) driving a single digital processor. However, such sparse sampling undesirably lengthens the time it takes to get an accurate measurement of the signal. This delay is minimized by Hilbert transforming the digitized signal 16 to produce an in-phase signal I and a quadrature-phase signal Q, and by measuring I.sup.2 +Q.sup.2. I.sup.2 +Q.sup.2 is the square of the amplitude of the input signal. The input signal 12 is sampled at about four times the signal's frequency. DC bias is eliminated in a two-delay delay-subtracter dc blocker 18B. The de-blocked signal 20 is applied to a two-delay Hilbert transformer 22. Only five samples are required to accurately measure the amplitude of the input signal 12.

Abstract: The object location identification system includes a Receiving Module (RM), an Angular Measuring System (AMS) and a processor. The RM receives information specifying a user's location and provides RM output data in terms of latitude, longitude and altitude. The AMS is connectable to a pointing device for measuring the orientation of the pointing device and providing AMS output data in at least heading and depression angles. The processor processes the RM output data and the AMS output data and provides location data of an object being pointed at by the pointing device.

Abstract: In a broad aspect the present invention comprises a multiple element, multi-throw electronic switch for a fiber optical cable network. The multiple element, multi-throw electronic switch includes a bulk media optical deflector angularly controllable by selectable electronic steering signals. At least one multiple element, multi-throw electronic switch is use to construct a true time delay shifter using rows of a plurality of columns of a plurality of beamsteering optical fiber delay lines, all with a specified antenna scanning coherence center.Distributed beamsteering is performed by selecting from the composite array, subarrays for which a common steering direction cosine can be applied to that subarray. The distributed beamforming is performed by combining elements beamsteered with a common antenna scanning coherence center from an electronically small core fibers with limited available modes into larger core multimode fibers.

Abstract: A double truss structural armor component includes a first face sheet, an intermediate sheet opposing the first face sheet, a first truss core member sandwiched between the first face sheet and the intermediate sheet, a second face sheet opposing the intermediate sheet, a second truss core member sandwiched between the second face sheet and the intermediate sheet, and laminate materials disposed within interior flutes of the first and second truss core members. The first tress core member has a flute axis. The second truss core member has a flute axis which is oriented in a range of about 45.degree. to 90.degree. from the flute axis of the first truss core member. Thus, a biaxially redundant load path is formed. The first and second face sheets, the intermediate sheet, and the first and second truss core members are formed of high toughness, high strength titanium alloys.

Abstract: The invention is a method of forming a conductive coating on a structural substrate. The method involves depositing a relatively non-conductive precursor material in a solution state on the structural substrate using inkjet apparatus. The solution is dried to leave a film. Then, the dried film is heated to a level at which a chemical (pyrolysis) reaction is triggered to convert the dried precursor material to a conductive material. The precursor solution can be dried in a manner which does not result in its transformation to the conductive state, as for example through the use of microwave apparatus. The precursor material can be applied on the substrate in such a manner as to control the conductivity of the coating and to provide a coating which exhibits one of uniform characteristics, discrete patterns, or gradient characteristics.

Abstract: The seeker of a guided missile may be tested by a simulator. The simulator mimics the reflection of a pulsed laser beam from a target. The simulator has a low power IR emitting LED 18. This IR emitting LED 18 is pulsed by an energy storing capacitor 22. The pulse is controlled by an SCR 16 driven by a pulse repetition oscillator 12. A collimating lens 26 collects light from the IR emitting LED 18 and directs it to the seeker. When being self tested, IR from the IR emitting LED 18 is reflected by a mirror 40 onto a detector 24. The output of the detector 24 is passed through a high pass filter 30. This removes signals from IR noise sources (fluorescent bulbs, the sun, incandescent bulbs), and passes only signals from the IR emitting LED 18. A first buffer 32, preferably an amplifier, provides power between the high pass filter 30 and the gate of a second SCR 34. This second SCR 34 drives a visible light LED 36 through a second buffer 38. The visible light LED 36 acts as a positive self test indication.

Abstract: An optics assembly for observing a panoramic scene. The optics assembly includes a plurality of optical elements. A first element redirects light from the panoramic scene. The optical power of the first element forms an imaginary pupil. The energy from the first element is redirected about 90 degrees, forming an annular path. A second element receives the redirected light and re-images the imaginary pupil to form a real pupil. This portion of the energy continues to be in an annular form. A third element includes an optical relay system having a group of reimaging optics. The third element receives light from the second element while relaying the real pupil into the reimaging optics. It also establishes the focal length of the optics assembly, corrects pupil aberrations produced at the real pupil, corrects field aberrations and produces an annular image on a flat focal plane. The optical relay system interfaces with the second element through the use of the real pupil.

Abstract: A process for forming composite hollow crown stiffened skins and panels in which a first layer or skin is placed on a forming surface of a female mold and, after forming a plurality of U-shaped stiffener elements in the first skin, a second skin is placed over the first skin, whereupon the resulting assembly is prepared for autoclave curing. The stiffener elements are formed by pressing the first skin into U-shaped depressions in the female mold surface and inserting a hollow, expandable rubber mandrel into each of the depressions on top of the first skin. Valve stems in the mandrels enable maintaining the pressure inside at atmospheric pressure. The mandrels are maintained in their "pressurized" state during subsequent formation and autoclave curing steps.

Abstract: A process for producing a fiber reinforced, staged resin composite or repair patch containing a staged and cobonded adhesive, comprises providing a composite or patch formed of one or more layers of a fiber reinforced thermosetting resin such as a graphite-epoxy material and applying a layer of a thermosetting resin adhesive, e.g. an epoxy adhesive, to a surface of the fiber reinforced resin material. The arrangement is then placed in a vacuum environment such as a nonautoclave tool, to draw off volatiles from the resin, and the temperature is raised under conditions to stage the thermosetting resin of the adhesive and of the composite or patch, and cobonding the staged adhesive to the staged composite or patch. The resulting cobonded and staged composite-adhesive can be stored until ready for use, e.g. in repairing a damaged substrate.