Numerical methods for modeling of radar wideband signal scattering by aerial, ground and subsurface objects
In our review the developed electrodynamic numerical methods for modeling of scattering characteristics of complex-shaped electrically large and resonant radar objects are considered. Futures of mentioned numerical algorithms and their advantages in comparison with other well known techniques are discussed. Proposed algorithms allow obtaining frequency responses of air, ground, and subsurface radar objects for given sounding conditions. Particular qualities of object ultrawideband impulse response modeling are also briefly discussed. In conclusion we demonstrate some results of numerical modeling of ultrawideband impulse responses of different air, ground, and subsurface objects in VHF, UHF, and SHF bands. Such results have a wide field of application for solving applied problems at the stage of development of effective wideband radars of different types.
Ultrawideband Signal Scattering from a Wirelines Buried in a Ground
Model of ultra wideband signal scattering from the subsurface wirelines which diameter is small in comparison with length of a sounding wave and depth of its location in ground is considered. The created algorithm allows calculating the signals reflected by a cable which axis is parallel to air-ground interface, at any polarization and direction of an illumination. Results of calculations of ultra wideband signals reflected by cables, located in a lossy, dispersive ground, for various conditions of illumination are demonstrated and discussed
Accurate measurements of output characteristics and detonations of motorbike high-speed racing engine and their optimization at actual atmospheric conditions and combusted mixture composition
Abstract At a motorbike high speed racing engine there is very important an output engine characteristics which depends significantly on a detonation combustion rate, atmospheric conditions and a combusted mixture composition. The combustion process has got a relevant influence on a wear degree of main engine parts or on their damage eventually. The detonation combustion rate is very important because this kind of burning can be not only destructive but a useful phenomenon, as well. If the process of detonation burning is kept on a certain level, it can help significantly to the next increasing of an engine power output. In this article there is described the measurements of output characteristics of a high-speed racing engine which were performed by means of a data-recording system and the detonation combustion was evaluated using a quantitative method. The actual values of atmospheric conditions and the mixture composition were added to the measured values. Then the obtained values are compared visually with a damage degree of an engine piston caused by the detonation burning. The result is a limit value expressed in a number of detonation units related to a run distance interval of the vehicle driven by the high-speed racing engine. In framework of this run distance interval there is the process of detonation burning profitable. As well as it increases an engine power output and together it is not destructive with regard to engine design parts.