Translational motion compensation of ballistic target based on radon transform
Ballistic target translational motion compensation is beneficial to motion parameter extraction. Aiming at the problem of multiple scattering points translational motion compensation, an algorithm is proposed to extract the translational motion parameters of ballistic targets based on using the projection transform of the whole micro-frequency curve by Radon transform in this paper. First, establishing and analyzing the typical ballistic target model and the expressions of scattering points' micro-frequency are solved. Second, target signal is pre-compensated based on radar information and time-frequency transform. And Radon transform is applied to the parameter projection of time-frequency curve. Then translational motion parameters are estimated based on minimum entropy criteria and gauss fitting. Finally, translational motion is compensated by making use of the estimated motion parameters. Simulation results verify the validity of the proposed algorithm.
Key parameter estimation for radar rotating object imaging with multi-aspect observations
Rotating object model is commonly used for imaging analysis in high resolution radars such as the inverse synthetic aperture radar (ISAR). For a rotating object, it is known that multi-aspect observations can improve cross-range resolution with the known imaging geometry. For the non-cooperative rotating object with unknown imaging geometry, this paper proposes an integrated scheme to estimate the key parameters, e.g., the rotating velocity and the aspect angle difference between every two observations. Furthermore, convolution back-projection (CBP) method is applied to provide fused imaging result with improved resolution. Also, the accuracy of the ultimate parameter estimation is analyzed, which is strongly related with several important factors like position extraction error of scattering centers and so on. Finally, the results of numerical experiments are provided to demonstrate the effectiveness of the proposed method.
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.