Abstract: A method and system for synchronization of pulse groups without a synchronization signal which comprises selecting a plurality of equal time length coherent processing intervals from a stream of data in the time domain, generally analog data. The data in each of the coherent processing intervals is sampled during each of N equal pulse repetition intervals to provide samples of data, each sampling taking place for an equal portion of the pulse repetition interval. Each of the samples of data is identified according to the position thereof in the associated coherent processing interval. The time domain data is converted to frequency domain data on the basis of the position of the time domain data in the coherent processing interval, all of the samples with the same position in a different coherent processing interval being separately collectively converted.

Abstract: A fixed body wide field-of-view conformal antenna array suitable for broadband precision direction finding on missile platforms. The array is configured as multiple sub-arrays of spiral antennas that cover particular regions within the desired field-of-view of the entire array. A lower cost, more reliable and more accurate direction finding solution for missile needs is provided, primarily by the elimination of conventional radomes and antenna gimbal structures. The array can be configured to include multi-mode sensors.

Abstract: A multiple color infrared detector is provided which is formed from a photodiode (13), a photoconductor (24), and an insulating layer of material (20) disposed between the photodiode (13) and the photoconductor (24). The photodiode (13) detects infrared radiation in the spectral band between about 3 .mu.m and about 5 .mu.m, and the photoconductor (24) detects infrared radiation in the spectral band between about 8 .mu.m and about 13 .mu.m.

Abstract: A method of classification of a device by recognizing distorted signals, generally a RF antenna pattern, emanating therefrom wherein a trainable recognition system, preferably a neural network, is provided. Known distorted signals are applied to the trainable recognition system to train the recognition system to recognize individually each of a plurality of different signals having distortion therein. Unknown distorted signals are then provided emanating from a remote device and the unknown distorted signals are then used to classify the remote device by analyzing the received unknown distorted signals in the trained recognition system. The steps of training and classifying each include the step of converting the signals from the time domain to the frequency domain. The steps of training and classifying also can each include the step of down sampling the frequency domain signals to compress the signature content.

Abstract: An aiming system is provided which includes two sensors. The two sensors sense two respective images of the same object relative to a common reference point. An offset is determined between the respective images of the object. An aiming point is provided on the second image and is spaced from the reference point according to the offset. The aiming point indicates the direction and distance to which the first sensor must be moved to be aligned with the object.

Abstract: An infrared lens assembly may comprise a lens set (32) including one or more refractive lenses. The refractive lens may be positioned along an optic axis (30) to receive infrared radiation. The lens set (32) may be designed to focus infrared radiation of a scene (14) at an image plane (15). An athermalization element (34) may be positioned along the optic axis (30) in optical communication with the lens set (32). The athermalization element (34) may include an infrared transmitting member (40) supporting a diffractive pattern (42). The infrared transmitting member (40) may comprise an infrared transmitting polymer. The diffractive pattern (42) may compensate for temperature induced changes in a focal length of the lens set (32) to maintain infrared radiation of the scene (14) in focus at the image plane (15).

Abstract: A P-type substrate for infrared photo diodes can be produced by the present invention. A CdZnTe substrate is utilized. A first layer of HgCdTe is formed by liquid phase epitaxy on the substrate. A CdTe passivation layer is formed over the HgCdTe. A ZnS layer is formed over the CdTe layer. A noble metal is introduced into either the CdTe or ZnS layers. During a subsequent baking of the composite, the noble metal diffuses throughout the composite and into the HgCdTe layer.

Abstract: An acoustic sensor system is provided for detecting failures or terrorist events in commercial aviation and is adapted for assisting in the detection and post event analysis of such events. The system is adapted for use in combination with a comprehensive multi-media safety and surveillance system, utilizing both visual and audio information as well as critical data to the flight crew, and to a ground tracking station, and recording the information and data generated during flight. A plurality of acoustic sensors are strategically and systematically placed about an airframe. The sensors are adapted for communicating with a monitor/recording system and may be hard wired or utilize wireless communications therewith. In the event of a catastrophic event, such as a bomb explosion, a gunshot or structural failure an acoustic event would be recorded for later analysis.

Abstract: An infrared lens assembly (16) having a variable F/Number. The infrared lens assembly (16) includes a focusing component (33), a collecting component (37), an aperture stop (46), and a diffracting component (41). The focusing component (33) may include a first and a second focusing zoom lens (34, 36) movably mounted in the infrared lens assembly (16). The focusing component (33) and the collecting component (37) may be formed from high dispersion, low index material. The aperture stop (46) may be mounted to the second focusing zoom lens (36) to vary the F/Number between a retracted zoom position and an extended zoom position. The diffracting component (41) may include a diffractive surface to correct color aberrations associated with an infrared waveband. The focusing component (33) and the collecting component (37) cooperate with the diffracting component (41) to focus infrared radiation at an image plane (15) of an infrared detector (18).

Abstract: A fixed body wide field-of-view conformal antenna array suitable for broadband precision direction finding on missile platforms. The array is configured as multiple sub-arrays of spiral antennas that cover particular regions within the desired field-of-view of the entire array. A lower cost, more reliable and more accurate direction finding solution for missile needs is provided, primarily by the elimination of conventional radomes and antenna gimbal structures. The array can be configured to include multi-mode sensors.

Abstract: An efficient electrically small loop antenna includes a radiation device, an impedance matching network, and a connector that interfaces to associated electronic circuitry. The radiation device includes a conductive planar base element extending in a base plane and a conductive loop connected to the planar base element. The loop connects to the base element so that the electrical current for the antenna flows through both the conductive loop and the planar base element. The impedance matching network matches the radiation device to the associated electronic circuitry. The matching network is integrated into the planar base and is connected to both the conductive loop and the base element so that the electric current supplied to the antenna is conducted through both the base element and the conductive loop.

Abstract: A fixed body wide field-of-view conformal antenna array suitable for broadband precision direction finding on missile platforms. The array is configured as multiple sub-arrays of spiral antennas that cover particular regions within the desired field-of-view of the entire array. A lower cost, more reliable and more accurate direction finding solution for missile needs is provided, primarily by the elimination of conventional radomes and antenna gimbal structures. The array can be configured to include multi-mode sensors.

Abstract: An image detection system (10) uses an optical configuration for both image forming and calibration phases of operation. A field lens (20) has an inner portion (36) of a conventional prescription to allow for collection of scene based energy for an opto-electronic approximation of the infrared detail within the afocal field of view by a focal plane array (32). The field lens (20) also has an outer portion (38) that collects far field energy from a scene area (A.sub.I) through a converging point (P.sub.I). The energy collected from the scene area (A.sub.I) is indicative of the average energy level within the scene. The electrical equivalent values of all energy received from the unique area (A.sub.I) is stored in a multidimensional range used for subsequent gain and offset calibration coefficient calculations.

Abstract: A thermal imaging system (10) for providing an image representative of an amount of thermal radiation incident to the system is provided. The system (10) includes a thermal detector (28 or 30) made from a layer of temperature sensitive material forming a first element of a signal-producing circuit (54). The first element (28 or 30) has either a resistance or capacitance value depending on its temperature. The system (10) also includes an integrated circuit substrate (32) having a second element (56 or 58) of the signal-producing circuit (54) complementary and electrically coupled to the first element (28 or 30). The signal-producing circuit (54) may produce an output signal having a amplitude. The amplitude of the output signal is monitored as representing an absolute temperature of the detector (28 or 30) so as to determine the amount of thermal energy incident to the system (10).

Abstract: A system (10) for calibrating an image detector includes a calibration platform (16) supporting a calibration element (18). The calibration element (18) may be made up of a first lens (20) and a second lens (22), each having a curved surface to appropriately alter characteristics of reference light levels (33) generated by a reference source (24). The second lens (22) may have its surface positioned differently to the focal plane array (14) than the first lens mirror (20) for enhanced calibration operation. The reference source (24) generates the reference light levels (33) over a range of temperatures to mimic the image energy generated by the scene (12). The reference source (24) may also include a reference lens element (26) that transmits reference light energy (33) generated by the reference source (24) or reflects scene base energy (34) generated by the scene (12) and allowed to pass through the first lens (20) and the second lens (22).