Abstract: A system and method for selecting an optimal frequency channel to communicate on in a wireless network is disclosed. The optimal frequency is selected from a predefined set of frequencies for all nodes to communicate on based on an exposure calculation. All underlay nodes collect initial SNR information from initial detection of other nodes and adjust their transmit power for an intended receiver such that the signal is received at the lowest allowable underlay-to-overlay power ratio, thus minimizing exposure. The desired underlay-to-overlay ratio is set based on how much we are capable of cancelling the overlay signal and the SINR at which a signal can be recovered such that the data can be successfully received from the underlay node. The optimal channel selected by this algorithm is the one with the least area of undesired exposure, or least probability of interfering with the primary user. The performance increases as a function of number of nodes, or data points.

Abstract: An adaptive time delay control system is provided for matching the propagation time delay between two samples of a signal traveling through two independent paths so that they can be coherently combined for additional signal processing functions such as cosite interference cancellers, adaptive interference cancellers and adaptive beam formers. The adaptive time delay control system and associated method advantageously provide improved continuous matching of the two channels over a wider adjustment range while preserving both convergence speed over the full range and minimum jitter upon convergence by using composite autocorrelation functions to control (adjusting) a matching time delay in one channel.

Abstract: An apparatus for optical spectrometry utilizes a simplified construction, reducing the number of independent optical elements needed while providing a sizeable dispersed spectrum. The apparatus provides a spectral intensity distribution of an input source wherein individual spectral components in the source can be measured and, in some embodiments, can be manipulated or filtered.

Abstract: Embodiments of the invention are directed to methods and apparatus for infrared imagers including fast electrostatic shutters and offset compensation. Fast electrostatic shutters are used for video image correction including image offset compensation where temporal noise and scene nonuniformity are corrected. This method provides a shutterless experience for the user because the image will be blocked for only one frame at a time. A method of manufacturing an electrostatic infrared shutter includes a conductive infrared-transparent substrate, covering it with an insulating layer, depositing adhesive and a thin film stack, delineating a working area, providing contacts, heat-treating the assembly, and making the polymer non-reflective in the infrared.

Abstract: An apparatus and method improves the fault tolerance of a rocket or missile guidance system which includes a resonant sensor. When improper initialization is detected, the resonant sensor is reinitialized, repeatedly if necessary, until normal operation is achieved. Improper initialization is detected by comparing data from the guidance system with pre-specified physical limits to roll, pitch, yaw, and/or other features of the flight scenario. Embodiments can also detect a fault condition due to an error signal from a “Built-in-Test” (BIT) module. The initialization sequence initiated by the invention can be identical to the power-on sequence, or it can be a separate, reinitiating sequence. Subsequent resets are initiated as needed, for example until the burn of the rocket fuel and the associated vibrations have ceased and the resonant sensor has been successfully initialized.

Abstract: Imaging systems, methods, sensor pods, and vehicles having imaging systems. An imaging system can be coupled to a vehicle and can comprise: a plurality of imaging sensors with multiple spectrums; and a processing unit configured to generate an image model in substantially real-time by: warping, fusing, and stitching images; and two or more displays coupled to the processing unit such that the two or more displays can simultaneously each show a different portion of the image model, and such that a user can manually calibrate via the processing unit at least one of the warping, fusing, or stitching. In some imaging systems, imaging sensors are coupled at different elevations relative to a ground vehicle. The present sensor pods can comprise a housing; two or more first imaging sensors having a first spectrum; and two or more second imaging sensors having a second spectrum that is different than the first spectrum.

Abstract: The replacement and elimination of duplexers in a tightly coupled dipole phased array starts with transmit and receive functions physically separated and having different antenna port feeds. The simple coupling network used with tightly coupled dipole arrays is replaced by a state switch which alternates between a coupling state and a dipole feed connection state. The basic method can be applied to antenna apertures of various kinds, including both linear and dual polarized versions. The ability to locate state switches at various nodes in tightly coupled dipole phased arrays permits flexibility in antenna design and eliminates bulky and lossy components, simplifies the design requirements and allows independent optimization of the components.

Abstract: Techniques and architecture are disclosed for providing an ultra-wideband, multi-channel solid-state power amplifier architecture. In some embodiments, the architecture includes a power divider which splits an input signal and delivers that split signal to a plurality of downstream channel chipsets. Each channel chipset is configured to amplify a sub-band of the original full-band input signal and to provide the resultant amplified sub-band for downstream use, such as for transmission by an antenna operatively coupled with that channel. In the aggregate, the amplified sub-bands provide coverage of the same ultra-wideband frequency range of the original input signal, in some cases. In some embodiments, the architecture provides high radio frequency (RF) power with good amplifying efficiency and ultra-wide instantaneous frequency bandwidth performance in a small-form-factor package.

Abstract: A method of controlling the phases of RF output signals from a number of radio transmitters. A given radio has at least one synthesizer as a source of its RF output signal, and the synthesizer produces an output the phase offset of which relative to a reference signal is controlled by a phase offset command. A path from an antenna port of the radio obtains a fed back RF output signal and a phase difference between the reference signal and the fed back RF output signal is measured. A value of a zero degree phase offset command for the synthesizer is determined such that the phase difference between the reference signal and the fed back RF signal is nominally zero, and the value is stored. A phase offset command for providing a desired phase offset for the RF output signal is then determined based the stored value of the zero degree phase offset command.

Abstract: Techniques are disclosed for radiation sensors that generate current signal to provide flexible placement of one or more integration intervals between resets of an integration capacitor. With flexible timing, an embodiment of the present invention provides several modes of operation including: multiple stray light blanking interval to occur during the integration cycle; range gating for LIDAR applications; time-delay-integration (TDI) with multiple short integration periods between frame resets; and hyper-resolution gating that provides better resolution than is normally possible with a fixed gate width. Numerous variations will be apparent in light of this disclosure.

Abstract: An electronic countermeasures product includes flexible packaging of diodes that operate in the infrared portion of the electromagnetic spectrum to replace flares, lamps and directed lasers with an inexpensive easily deployed countermeasure systems.

Abstract: A ring oscillator is disclosed. The ring oscillator includes a first tri-path inverter, a second tri-path inverter and a third tri-path inverter. The second tri-path inverter is connected to the first tri-path inverter. The third tri-path inverter is connected to the first and second tri-path inverters to provide feedback for oscillations.

Abstract: A system and method capable of providing a cooperative network for applying countermeasures to airborne threats is provided. The system contains at least one aircraft having an airborne countermeasures system (ACS) capable of controlling deployment of countermeasures located on the aircraft. The system also contains a central countermeasures management system (CCMS) capable of communicating with the ACS to control the ACS in deployment of the countermeasures located on the aircraft. The aircraft may be one of a series of aircrafts, where each aircraft within the series of aircrafts has a separate ACS thereon, and where each separate ACS is capable of controlling deployment of countermeasures located on an aircraft within the series of aircrafts on which the separate ACS is located. When multiple aircrafts are within the network, the CCMS is capable of communicating with each separate ACS in response to the airborne threat, to control deployment of the countermeasures.

Abstract: A modular multi-use thermal imaging system is disclosed. In one embodiment, the modular multi-user thermal imaging system includes a modular mounting structure and a modular multi-use thermal imaging device configured to attach to one or more structures via the modular mounting structure.

Abstract: A method for finding the launch of a ManPADS missile comprising the steps of installing a network of electro optical (EO) and infrared (IR) cameras with a triggering receiver and pointing the EO and IR cameras in the direction of a suspicious emission, wherein the EO camera provides high resolution video and the IR camera finds the ManPADS and tracks its user.

Abstract: A 3D wafer-integration uncooled infrared (IR) microbolometer focal plane array (FPA) sensor includes a first die with an FPA of uncooled IR microbolometers, a second die signal-processing layer. The dies are vertically aligned, stacked with 3D wafer bonding, and interconnected. Interconnection include vertical electrical interconnects. Separate optimized manufacturing processes are used for die, so that additional processing costs of the FPA die are leveraged and 3D integration is completed at wafer level, minimizing total device cost and maximizing die count per wafer.

Abstract: A high-power and high-gain ultra-short gate HEMT device has exceptional gain and an exceptionally high breakdown voltage provided by an increased width asymmetric recess for the gate electrode, by a composite channel layer including a thin indium arsenide layer embedded in the indium gallium arsenide channel layer and by double doping through the use of an additional silicon doping spike. The improved transistor has an exceptional 14 dB gain at 110 GHz and exhibits an exceptionally high 3.5-4 V breakdown voltage, thus to provide high gain, high-power and ultra-high frequency in an ultra-short gate device.

Abstract: A lens with a graded index of refraction is presented. The lens is formed out of a sheet of material having a uniform thickness with a top surface and a bottom surface. Elongated openings are formed in the top surface extending downwardly to the bottom surface. Material of the elongated sheet is left between adjacent openings. A width of the material between adjacent openings is less than a wavelength of electromagnet energy the lens is configured to refract. The density and distribution openings varies across the sheet of material so that the refractive index of the lens varies across the sheet of material.

Abstract: A system and method for linearizing underwater sensor arrays is disclosed. The sensor array comprises slightly positive or negative buoyant sensors that are positioned along a cable. A weight is positioned at a deep end of the cable or a buoyant object is positioned at a shallow end of the cable, but not both. Distributing buoyant elements throughout the length of the array generates more consistent, uniformly distributed tension, enabling the sensor array to maintain a linear shape in currents of all strengths and speeds.

Abstract: A compact, lightweight, laser target designator uses a TIR bounce geometry to place an end-pumped gain element functionally in the center of the resonator path, thereby allowing the resonator path to be terminated by a pair of crossed Porro prisms, so that the designator produces a high quality beam that is insensitive to alignment and temperature, and is low in manufacturing cost. Some embodiments fold the Porro legs of the resonator path back toward the gain element for compactness. Embodiments use a single gain element as both an oscillator gain element with TIR and as an output amplifier gain element without TIR. Various embodiments use block optical elements in a planar layout on a standard support medium such as aluminum to facilitate automated manufacturing.