Abstract-The electromagnetic scattering mechanism of radar targets in the high-frequency domain can be characterized exactly by geometrical theory of diffraction (GTD) model. In this paper, we propose a novel parameter estimation method for GTD model based on compressed sensing. The sparse characteristic of radar echoes is analyzed, and the parameter estimation problem is converted to one of sparse signal reconstruction. Furthermore, clustering and linear least-minimum-squares algorithms are utilized to improve the accuracy of the result. Compared with several modern spectral estimation techniques, the proposed method gives a more precise estimation of the GTD model parameters, especially the scattering centers. Simulations with synthetic and measured data in an anechoic chamber confirm the effectiveness of the method.

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In this paper, we focus on the 3D SC model reconstruction from data with wide azimuthal aperture at a single elevation. Since the existing method is difficult to implement for high-frequency signal or large-size target, we propose a modified RANSAC method for the extraction. In our approach, the 3D positions of the SCs are estimated from the 1D SCs via a modified RANSAC method. Then the scattering coefficients are refined via a linear least squares algorithm. The approach is robust with noise because the RANSAC method is able to tolerate a tremendous fraction of outliers. Moreover, it does not suffer from limited accuracy caused by the discretization of the parameter space in [13]. Experiments demonstrate the effectiveness of the proposed approach.

Experimental teaching plays an import part in quality education which devotes to cultivating students with innovative spirit, strong technological talents and practical ability. However, in the traditional experimental teaching mode, the experiments are treated as a vassal or supplementary mean of theoretical teaching, and students prefer focus on theory to practice. Therefore, the traditional experimental teaching mode is difficult to meet the requirements of quality education. To address this issue, the reform of experimental teaching is introduced in this paper taking the photoelectric detector experiment as the example. The new experimental teaching mode is designed from such aspects as experimental content, teaching method and experimental evaluation. With the purpose of cultivating students' practical ability, two different-level experimental content is designed. Not only the basic experiments used to verify the theory are set to consolidate the students' learned theoretical knowledge, but also comprehensive experiments are designed to encourage the students to apply their learned knowledge to solve practical problems. In the teaching process, heuristic teaching thought is adopt and the traditional 'teachercentered' teaching form is replaced by 'student-centered' form, which aims to encourage students to design the experimental systems by their own with the teacher's guidance. In addition to depending on stimulating the students' interest of science research, experimental evaluation is necessary to urge students to complete the experiments efficiently. Multifaceted evaluation method is proposed to test the students' mastery of theoretical knowledge, practice ability, troubleshooting and problem solving skills, and innovation capability comprehensively. Practices demonstrated the satisfying effect of our experimental teaching mode.

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