Signature Analysis & Prediction

Radar Cross Section Design, Analysis, and Computation

August Research Systems specializes in the analysis of radar cross section (RCS) for customer-specified structures.  Using Computer-Aided Design (CAD) software, we model hardbody objects to provide the framework for RCS analysis.

CADFigure 1—A rendered view of a structure designed with CAD software; the rocket is approximately 10 ft long from nose to tail.

Once an object is constructed, meshing creates a wireframe with triangular facets on each surface.  Depending on the curvature and complexity of a structure, meshing properties are adjusted by custom settings to most accurately represent each surface.

image004Figure 2—The meshed wireframe of the rocket designed in CAD is displayed.  When exported to the radar analysis solver, the meshing has triangular facets that enable RCS computation.

The design is run through an RCS solver, which analyzes the triangular facets for signature return.  This RCS software employs computational techniques such as Shooting and Bouncing Rays, Physical Optics, Physical Theory of Diffraction, Method of Moments, and Incremental Length Diffraction Coefficients.

Analysis and interpretation can be performed after RCS calculations are completed.  A variety of RCS plots can be constructed from the data, such as RCS vs. frequency, azimuth, or elevation.  The RCS data for the rocket featured on this page was collected at a frequency of 10 GHz, an elevation of 0° from a plane containing the long axis of the body, and an azimuth swath of –90° to 90°; the nose is at 0° azimuth.  A graph of the RCS in dBsm versus the azimuth angle is shown below in Figure 3.

image006Figure 3—The RCS of the featured rocket as designed in Figure 2 is shown.  This plot shows RCS versus azimuth angle.  The peaks at approximately –50° and 50° represent a strong return from the exhaust cone.

Among various statistical and image analysis options available from the output data, Inverse Synthetic Aperture Radar (ISAR) imaging provides a two-dimensional image of radar scattering.  After selecting a viewing angle, the RCS return is displayed as color or intensity on an image map.  For example, an ISAR image of the missile with the original CAD model shows a strong RCS return from the nose and from the exhaust cone between its fins, as seen in Figure 4.

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Figure 4—ISAR images of the rocket at 0°, 30°, and 90° showing the intensity of the return according to a color map.  Underlaying the original CAD model permits direct observation of surfaces producing high signature return.

Interpreting and analyzing results and statistics, August Research Systems offers guidance in design before construction to avoid costly errors and to save time.  August Research Systems can provide recommendations based on requirements specific to the material, geometry, and manufacturing tolerances of a structure. Where appropriate, the effectiveness of RCS-reducing treatments such as Radar Absorbing Material (RAM) can be evaluated. Such treatments can often make up for geometric constraints and manufacturing accuracies. In summary, August Research Systems provides RCS analysis from model design to the interpretation of predicted and measured signatures with unsurpassed quality. This affords our customers accurate knowledge that leads to efficiency in design, production, and system sustainment.

 

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