Study On The Polarization Scattering Characteristics Of The Target

Target polarization information is widely used in areas such as microwave remote sensing, radar target detection, discrimination and classification.The accuracy of polarization scattering characteristics of the target acquisition is a key factor to improve the radar abilities, such as radar target detection and anti-jamming. The polarization measurement is the precondition of polarization information processing. Active polarization radar often uses time-sharing polarization measurement technolog y, which is not so applicable for the high-speed moving targets and polarized fast fluc tuating target. In response to this shortcoming, the theory of instantaneous polarization measurement have been proposed to provide an important theoretical support for representing and processing the variable, wideband and dynamic polarization information.First, this thesis describes the basic theory on polarization information processing. These concepts are the theoretic basis for follow-up research of scattering characteristics of target. Secondly, two measurement methods and technologies of polarization scattering matrix is mainly studied. Finally, base on instantaneous polarization measurement, mixed frequency modulated orthogonal waveform is presented, in which a non-linear frequency modulated signal is applied and optimized according to the chirp signal parameters. As we all know, Peak-to-Sidelobe-Level (PSL) and orthogonal signal isolation (isolation, Ⅰ) are the two important factors affecting the polarization measurement results. Therefore, the polarization measurement accuracy can be improved along with the increasement of PSL and I. The calculation and simulation results show that, compared with the chirp signal, the level of I can increase to 1.5dB, and the PSL of the non-linear frequency modulated signal can improve 7dB in the proposed signal pairs. Obviously, it is easy to separate the signal echo, to facilitate accurate measurement of the scattering matrix, to improve the polarization measurement accuracy. The results of this paper can promote the development of target measurement and feature extraction techniques on instantaneous polarization radar, and can be of important reference value for these issues of application perspectives and engineering implementation in instantaneous polarization measurement.