A Pseudo Inverse Solution Method Applied to an Adaptive Antenna
Fábio A. L. Gomes, Adrião Duarte D. Neto, Aldayr D. Araújo, Wilson da Mata
Evento: 2002 International Telecommunications Symposium (ITS2002)
Keywords: Adaptive Filters Adaptive Antenna Pseudo Inverse Matrix
Abstract"The adaptive antenna theory has been studied in several application fields such as radar, sonar, mobile communications, geophysics exploitation, etc. In all these cases, the different methods used to solve problems in the adaptive antenna approach generally use the same procedure, which is related to the increasing of the directivity of the antenna array and to the interfering signals adaptive cancellation. The research to obtain more efficient methods has motivated the adaptive antennas approach to use traditional Least Mean Square (LMS) method or state space variables methods such as Kalman Filter and State Observers. This work presents an algorithm to obtain the optimum gains of the Generalized Side Lobe Canceller Filter (GSC Filter) using a pseudo inverse matrix. Additionally, the importance of the regularization factor to the robustness of the method is verified. The method is recursive, with low computational complexity and fast calculation of the optimum gains. The method is applied to the cancellation of interfering signals in a non-stationary condition of an adaptive antenna array. A matrix regularization process is developed to get a robust method and a better matrix conditioning. The simulation results show the efficiency of the proposed method to cancel interfering signals in planar antennas. The simulation results were done with a 3x3 half wavelength elements in planar array for both signals (desired and interfering). A 40dB was considered for the relationship between the desired signal and the interfering signal. The irradiation diagrams were obtained in two dimensions for a fixed angular coordinate. The method seems to be efficient to generate null signals in the interfering signal direction. The LMS method was used to compare the performance with the proposed method. "