Abstract: In one aspect, a method to generate radar cross section (RCS) signatures, includes determining a spectrum of an object and using the spectrum of the object to generate RCS signatures of a plurality of objects. In another aspect, an apparatus to generate radar cross section (RCS) signatures includes circuitry to determine a spectrum of an object; and use the spectrum of the object to generate RCS signatures of a plurality of objects. In a further aspect, an article includes a machine-readable medium that stores executable instructions to generate radar cross section signatures (RCS). The executable instructions cause a machine to determine a spectrum of an object and use the spectrum of the object to generate RCS signatures of a plurality of objects.

Abstract: In one aspect, a method to generate radar cross section (RCS) signatures, includes determining a spectrum of an object and using the spectrum of the object to generate RCS signatures of a plurality of objects. In another aspect, an apparatus to generate radar cross section (RCS) signatures includes circuitry to determine a spectrum of an object; and use the spectrum of the object to generate RCS signatures of a plurality of objects. In a further aspect, an article includes a machine-readable medium that stores executable instructions to generate radar cross section signatures (RCS). The executable instructions cause a machine to determine a spectrum of an object and use the spectrum of the object to generate RCS signatures of a plurality of objects.

Abstract: In one aspect, a system to generate radar signatures for multiple objects in real-time includes a first module including at least one processor to perform a shooting and bouncing (SBR) technique to solve for physical optics and multi-bounce characteristics of the objects. The at least one processor includes a central processing unit to perform dynamic ray tracing and a graphics processing unit (GPU) to perform far field calculations. The GPU includes a hit point database to store entries associated with rays that intersect an object.

Abstract: In one aspect, a system to generate a radar signature of an object includes electromagnetic processing modules that include a first module including at least one processing unit to perform a shooting and bouncing (SBR) technique to solve for physical optics and multi-bounce characteristics of the object, a second module including a processing unit to perform a physical theory (PTD) technique to solve for material edges of the object and a third module including a processing unit to perform an incremental length diffraction coefficient (ILDC) to solve for material boss/channel. Results from the first, second and third modules are coherently integrated by frequency to generate radar cross section (RCS) values of the object in real-time. Performance of the system is scalable by adding processing units to at least one of the first, second or third modules.

Abstract: In one aspect, a system to generate a radar signature of an object includes electromagnetic processing modules that include a first module including at least one processing unit to perform a shooting and bouncing (SBR) technique to solve for physical optics and multi-bounce characteristics of the object, a second module including a processing unit to perform a physical theory (PTD) technique to solve for material edges of the object and a third module including a processing unit to perform an incremental length diffraction coefficient (ILDC) to solve for material boss/channel. Results from the first, second and third modules are coherently integrated by frequency to generate radar cross section (RCS) values of the object in real-time. Performance of the system is scalable by adding processing units to at least one of the first, second or third modules.

Abstract: In one aspect, a system to generate radar signatures for multiple objects in real-time includes a first module including at least one processor to perform a shooting and bouncing (SBR) technique to solve for physical optics and multi-bounce characteristics of the objects. The at least one processor includes a central processing unit to perform dynamic ray tracing and a graphics processing unit (GPU) to perform far field calculations. The GPU includes a hit point database to store entries associated with rays that intersect an object.

Abstract: A method and system for analyzing the RCS of an object using N Point signature prediction models is provided. N-point signature prediction models are created for each object in a scenario and stored in lookup tables. Shooting and Bounce trace back techniques are used to determine RCS signatures of multiple objects in modeled scenarios to account for blockage by and coupling phenomena of a scattered field.

Abstract: Apparatus and method for real-time determination of radar cross sections is disclosed using interleaved gridding. Radar cross section calculations are amenable to an implementation on parallel processors wherein the shooting window is subdivided into smaller areal units that are assigned to the parallel processors in an alternating fashion, such that the calculations performed by a single processor are not localized to a single area of the shooting window. As further disclosed, the shooting and bouncing ray technique for calculating radar cross sections is implemented using the apparatus and method disclosed herein.

Abstract: A method to reduce scattering centers (SC) includes receiving a set of SC data points representing an object. The method also includes reducing SC data points associated with a first region based on magnitudes of intensity of the SC data points associated with the first region, reducing SC data points associated with a second region based on magnitudes of intensity of the SC data points associated with the second region, combining the reduced SC data points associated with the first region and the second region to form a reduced set of SC data points, comparing the reduced set of SC data points with the received set of SC data points to determine if the reduced set of SC data points meets a set of comparison metrics and if the reduced set of SC data points meets the set of comparison metrics, performing another iteration of the reducing.

Abstract: In one example, a method to reduce scattering centers (SC) includes receiving a set of SC data points associated with an object in three-dimensional space, partitioning the SC data points into a plurality of volumes, aggregating the SC data points within each volume based on an aggregate threshold and combining the aggregated SC data points associated with each volume to form a reduced set of SC data points. The method also includes comparing the reduced set of SC data points with the received set of SC data points to determine if the reduced set of SC data points meets a set of comparison metrics and if the reduced set of SC data points meets the set of comparison metrics, increasing the size of the volumes and performing another iteration of reducing the SC data points by volume.

Abstract: In one aspect, a method to generate radar signatures for multiple objects includes performing in parallel a shooting and bouncing (SBR) technique to solve for physical optics and multi-bounce characteristics of a plurality of objects in motion, a physical theory (PTD) technique to solve for material edges of the objects and a incremental length diffraction coefficient (ILDC) to solve for material boss/channel. The method also includes coherently integrating the results from the SBR, PTD and ILDC techniques by frequency and generating the radar cross section (RCS) values of the plurality of objects. Performing the SBR technique includes evaluating rays independently.

Abstract: In one aspect, a method to generate radar signatures for multiple objects in motion, includes performing a shooting and bouncing (SBR) technique to solve for physical optics and multi-bounce characteristics associated with the objects. Performing the SBR technique includes performing dynamic ray tracing to form an image of an object having surfaces and edges. Performing the dynamic ray tracing includes transforming the object in a common coordinate frame of reference to a centered-body axis frame of reference.

Abstract: A method and system for analyzing the RCS of an object using N Point signature prediction models is provided. N-point signature prediction models are created for each object in a scenario and stored in lookup tables. Shooting and Bounce trace back techniques are used to determine RCS signatures of multiple objects in modeled scenarios to account for blockage by and coupling phenomena of a scattered field.

Abstract: Apparatus and method for real-time determination of radar cross sections is disclosed using interleaved gridding. Radar cross section calculations are amenable to an implementation on parallel processors wherein the shooting window is subdivided into smaller areal units that are assigned to the parallel processors in an alternating fashion, such that the calculations performed by a single processor are not localized to a single area of the shooting window. As further disclosed, the shooting and bouncing ray technique for calculating radar cross sections is implemented using the apparatus and method disclosed herein.

Abstract: A highly-oriented acrylic staple fiber prepared by simple extrusion of a PAN/H.sub.2 O melt in a gel crystalline state without spinning is provided. The acrylic fibers according to the present invention are characterized by the following properties: a degree of orientation between 80 and 97% observed by an X-ray diffraction; a length distribution ranging from 5 to 500 mm and a thickness distribution ranging from 5 to 500 .mu.m, a length to thickness ratio ranging from 100 to 100,000 determined by a scanning electromicroscope; a tensile strength of 10 to 70 kg/mm.sup.2 ; an initial tensile modulus of 300 to 1,500 kg/mm.sup.2 ; an elongation of 5 to 20%; and a specific surface area of 1 to 50 m.sup.2 /g.

Abstract: Pulp-like short fibers prepared from liquid crystal polyesters capable of forming an anisotropic melt phase at a temperature of 200.degree. C. to 400.degree. C. and having a molecular weight of 2,000 to 100,000 are provided. These fibers consist of microfibrils and have the following highly-oriented fiber characteristics and properties:(a) Tensile strength: 5-30 g/den.;(b) Modulus of elasticity: 200-1,500 g/den.;(c) Orientation angle as determined by an X-ray diffraction: below 20.degree.;(d) Thickness distribution: 0.1-50 .mu.m;(e) Length distribution: 0.1-50 mm; and(f) Specific surface area as determined by a nitrogen adsorption method: 3-30 m.sup.2 /g.

Abstract: A non-spun fiber of acrylic polymers, characterized by a pulp-like short fiber form of a thickness distribution of 0.1 to 100 .mu.m and a length distribution of 0.1 to 100 mm, and by irregular cross-sections in a plane taken perpendicular to the fiber axis and needle point-like ends similar to those of natural wood pulp fibers. The acrylic fiber of the present invention is made of an acrylonitrile homopolymer or copolymer consisting of a least 70% acrylonitrile (by weight) and at most 30% copolymerizable monomers (by weight) and having a viscosity average molecular weight between 10,000 to 600,000. The acrylic fiber according to the invention is further featured by the following physical properties: a degree of orientation of more than 80% based on X-ray diffraction pattern data, a tensile strength of 3 to 10 g/denier and an initial modulus of 30 to 100 g/denier, and absolutely no cylindrically-shaped filament trunks.

Abstract: A new, pulp-like, acrylic short fiber having excellent heat- and chemical-resistance is provided. The fiber has a thickness distribution of 0.1 .mu.m to 50 .mu.m, a length distribution of 1 mm to 20 mm, and a thermal transition temperature (Tg) of above 200.degree. C. The fiber is produced by heating a mixture of polyacrylonitrile and water of about 5% to 100% by weight to temperatures above hydration-melting temperature under seal to an amorphous melt; cooling the resulting amorphous melt to temperatures between the melting and the solidifying temperatures of the melt to form a supercooled melt; extruding the resulting supercooled melt to give extrudates; heat-stabilizing the resulting extrudates at temperatures between 180.degree. C. and 300.degree. C. for 1 minute to 4 hours after drying and drawing; and cutting and beating the resulting heat-stabilized extrudates into an appropriate size.

Abstract: A process for the production of pulp-like short fibers having a highly-oriented fibril structure without spinning is provided. This process comprises heating a mixture of water and an acrylonitrile homopolymer or copolymer to a temperature above the melting temperature of the mixture under enclosed conditions to form an amorphous melt; cooling the resulting amorphous melt to a temperature below the melting temperature to obtain a supercooled melt phase; extruding the resulting supercooled melt phase through a slit die at a temperature between the melting and the solidifying temperatures of the melt phase into an external atmosphere to give extrudates; and subjecting the resulting extrudates to drawing and heat treatment followed by beating mechanically.

Abstract: Novel wholly aromatic polyamides and copolyamides of the formula: ##STR1## are provided. The aromatic polyamides and copolyamides are prepared by condensation polymerizing an aromatic diamine selected from 3,5-diaminobenzophenone and a mixture of 3,5-diaminobenzophenone and m-phenylenediamine with an aromatic dibasic acid chloride in a chemical equivalent amount. The polymers of the invention can be easily dissolved in an organic solvent to give a molding solution suitable for use in the film casting. The film resulted from the polyamides of the invention has excellent physiochemical properties such as durability, chemical resistance, flexibility, compactness, tenacity, transparency and electric insulation.