Feature extraction and frequency response recovery based on rational approximation

In order to obtain the target position invariant features and to recover target frequency response accurately, the orthogonal vector fitting (OVF) algorithm is introduced to solve the rational approximation of frequency response problems in target scattering system. By replacing the polynomial basis functions with orthogonal basis functions, the method overcomes the problem of pathological matrix equation. Besides, it also uses the iterative strategy to reduce the linearization error. According to the characteristics that the target conjugate poles of frequency response appears in pairs, the state space analysis method is used to achieve a fast solution to the denominator of the zero point and the concrete realization of the iteration process is given. Theoretical analysis and experimental results prove that, by introducing OVF to target frequency response approximation, the method can effectively solve the morbid normal equation and reduce the linearization error problems. Furthermore, it can also approximate target frequency response accurately and extract the target poles.