Raytheon

About: Raytheon is a company organization based out in Waltham, Massachusetts, United States. It is known for research contribution in the topics: Signal & Antenna (radio). The organization has 15290 authors who have published 18973 publications receiving 300052 citations.

The MAGellanic Inter-Cloud Project (MAGIC). I. Evidence for Intermediate-age Stellar Populations in between the Magellanic Clouds

Abstract: The origin of the gas in between the Magellanic Clouds (MCs)—known as the "Magellanic Bridge" (MB)—is puzzling. Numerical simulations suggest that the MB formed from tidally stripped gas and stars in a recent interaction between the MCs. However, the apparent lack of stripped intermediate- or old-age stars associated with the MB is at odds with this picture. In this paper, we present the first results from the MAGellanic Inter-Cloud program (MAGIC) aimed at probing the stellar populations in the inter-Cloud region. We present observations of the stellar populations in two large fields located in between the Large and Small Magellanic Clouds (LMC/SMC), secured using the WFI camera on the 2.2 m telescope in La Silla. Using a synthetic color-magnitude diagram technique, we present the first quantitative evidence for the presence of intermediate-age and old stars in the inter-Cloud region. The intermediate-age stars—which make up ~28% of all stars in the region—are not present in fields at a similar distance from the SMC in a direction pointing away from the LMC. This provides potential evidence that these intermediate-age stars could have been tidally stripped from the SMC. However, spectroscopic studies will be needed to confirm or rule out the tidal origin for the inter-Cloud gas and stars.

Evaluation of MACH and DCCF correlation filters for SAR ATR using the MSTAR public database

Abstract: The MACH and DCCF correlation filter algorithms are evaluated using the publicly released MSTAR data base. These algorithms can be used as a matching engine for automatic target recognition in SAR imagery. In practice, the required filters can be synthesized using model based signature predictions. In addition, the MACH and DCCF algorithms are optimized to be robust to variations (distortions) in the target's signature. Unlike Matched Filtering or other exhaustive template based methods, the proposed approach requires very few filters. The paper describes the theory of the algorithm, key practical advantages and details of test results on the public MSTAR data base.

Singular basis functions and curvilinear triangles in the solution of the electric field integral equation

Abstract: Basis functions are formulated that account for singularities in the charge density near an edge on a conducting body. The formulation is general and the basis functions are valid for planar as well curvilinear geometries. In principle, singularities of any order can be treated, but best results are obtained for so-called "knife edge" singularities. Results are compared with exact solutions or measurements where available for some simple problems.

Microbolometer uncooled infrared camera with 20-mK NETD

Abstract: Raytheon Systems Company has developed a prototype infrared imaging rifle-sight using an uncooled, microbolometer FPA. The high-sensitivity FPA (SBRC-151) used in the Long-wavelength Staring Sensor (LWSS) was developed by Raytheon Infrared Center of Excellence (IR COE). The NETD (noise equivalent temperature difference) sensitivity of the camera has been measured at 14 mK with f/1 optics and at 74 mK with an f/2.1 aperture stop. Excellent imagery has been demonstrated with the f/2.1 aperture. The 320 X 240 FPA utilizes a high-yield CMOS readout integrated circuit (ROIC) that achieves high sensitivity, low output nonuniformity, and large scene dynamic range. The ROIC provides multi-level, on-chip nonuniformity correction and on-chip temperature compensation. The FPA has 50 micrometer X 50 micrometer pixels and operates at frame rates up to 60 Hz with a single output. The LWSS was characterized by the U.S. Army's NVESD in 1997 using an earlier version of the SBRC-151 FPA. The NVESD measurements validated the Raytheon NETD data. The NVESD evaluation also demonstrated outstanding MRT and spatial noise characteristics. The VOx microbolometer detectors are produced at the Raytheon IR COE facility in Santa Barbara, CA using an advanced dry-etch fabrication process. In addition to the LWSS project, the IR COE has initiated production of the microbolometer FPAs (AE-189) for commercial applications. Over 600 FPAs have been produced on this project, and data is presented for the first 250 FPAs that have been packaged and tested. The pixel operability of the production radiometer FPAs (AE-189) is typically greater than 99.9%.

Interactive computerized witness interrogation recording tool

Abstract: An interactive computerized witness interrogation recording tool (10) which provides a way to rapidly convert verbal descriptions of objects and events into graphical displays. The verbal descriptions are entered into the interrogation recording tool (10) by an operator utilizing a keyboard (16), graphical input device (18) and an icon based control panel (32) in a display device (30). Commands utilized by the operator are stored in a command library (44) or originate from a textual algorithm (54) which can generate a time sequence of objects and events based on the statements. The representation of the object and events are stored in a 3D geometry database (46) which is displayed by using a geometry display generator (52) under control of a command interpreter (42) and on the display device (30). Because the display is created in real time, the individual providing the statements is able to immediately confirm or deny the accuracy of the representation as it is being constructed in its various stages. Further, the textual algorithm (54) can be configured to confirm or deny the plausibility of the statements made.