Research And Application Of Time-Frequency Analysis In The RCS Measuring

Radar Cross Section (RCS) is an important parameter in target signature. RCS measurement has two methods,which are Continuous Wave(CW )and broadband swept frequency mode. The main way to analysis the measured dates is Fourier Transform (FT) and Inverse Fourier Transform (IFT), which just deal with the dates in time domain or frequency domain separately, they can't describe signal comprehensive. Time-Frequency Analysis describes signal in time-frequency domain, this paper researches on the application of Time- Frequency Analysis used in RCS measuring. This paper deals with the measured dates in time-frequency domain based on the Wigner-Ville Distribution (WVD) and its property, and gets the RCS of the standard ball.The main contributions of this thesis have three parts as follow:In part one, General theory of Time-Frequency Analysis is introduced. WVD is mainly discussed. Its definition and properties are presented. Then, the definition and classification of RCS are introduced.In part two, The CW and broadband swept RCS measuring system are introduced. Then, the author uses a broadband swept RCS measuring system, which is constructed by N5242A vector network analyzer. and then select the standard ball as the target, and the measuring parameters is given.In part three, the RCS of standard ball is measured, and analysis the errors of the measured dates in time domain and frequency domain. The author deals with the measured dates by the WVD, and gets the WVD images of the standard ball's RCS, and gets the RCS in measuring frequency band and short frequency band in the measuring frequency band by the energy property of the WVD. The calculated results show that the Time-Frequency Analysis can improve the RCS measured precision.