radar cross section
diagram of back scattering
In the article questions of mathematical and digital modelling of power characteristics of scattering of complex shape objects in a near zone of a radar location are considered. Mathematical models of characteristics of scattering of the target can be used at calculation of input signals of systems of a near radar-location which are components of onboard systems of making of decision. Thus mathematical model of an input signal of an onboard radar should be adequate to real physical process.
For calculation of power characteristics of scattering of complex shape large-scale objects probably use of methods of physical optics, the physical theory of diffraction and a method of shooting and bouncing rays. Thus the geometrical shape of objects is represented in the form of polygonal model which is created in modern CAD system. With use of this method interaction of electromagnetic fields of onboard radar and the targets is formalized in the form of polarising model of an electromagnetic field of scattering of the target.
For an estimation of adequacy of model characteristics of scattering of a etalon reflector – perfectly conductive sphere have been considered. On the basis of the exact decision of a problem of diffraction on sphere in the form of known Mie series analytical dependence of RCS of sphere on distance to the reception antenna in the field of a near zone of a location is received. Dependence of RCS on the distance, received of analytical formulae, completely coincides with the similar dependence calculated by a method of digital modelling on the basis of polygonal model of sphere that shows adequacy and reliability of mathematical model of characteristics of scattering of the targets in a near zone of a location on the basis of their polygonal models.
In the article the 3D-model and polygonal model of rocket AGM-88 «Harm» is developed. The polygonal model has been made in ProEngineer Wildfire 5.0 and fully corresponds to its original. It can be used for calculation of input signals of onboard radars. Features of calculation of characteristics of scattering of a rocket «Harm» are analysed. Values of RCS of a rocket in various conditions of location in far and near zones of a location are received.