Study On Near Field WiFi Signal Multi Parameter Estimation Algorithms Based On Antenna Array

Indoor positioning of WIFI is a hot topic in recent years, but GPS in indoor positioning is limited, because each GPS positioning need to capture more than four satellites signal. In some indoor and high-rise buildings, the signal block is serious, the TOA, TDOA, RSSI and other algorithms can not reach the requirements of positioning accuracy and real-time. Therefore, it is necessary to research the new indoor positioning algorithm. The needs of people with high precision, low complexity can be met by the new indoor positioning algorithm. DOA multiple parameters joint estimation algorithm based on the angle of arrival angle, pitch angle, distance and other parameters estimation to achieve the purpose of positioning. There are a lot of mature research into use in the field of radar, sonar, electronic reconnaissance. In this paper, the DOA multiple parameters joint estimation algorithm of the near field WiFi signal is studied from the following aspects.Firstly, the multiple parameters joint estimation algorithm based on second-order cumulant is studied, combining the properties with the ESPRIT algorithm in the novel near field source localization algorithm based on two order statistics, creative construction of two second-order cumulant matrices, the algorithm does not need to construct a high dimensional cumulant matrix, and it can realize multiple parameters joint estimation and automatically match the parameters, the algorithm improve the accuracy of the parameter estimation.Secondly, the ML algorithm based on second-order cumulant is studied, the accuracy analysis of multiple parameters joint estimation of the ML algorithm and the MUSIC algorithm, the algorithm of the novel near field source localization algorithm based on two order statistics can be researched, and the complexity of several algorithms are compared.Then, aiming at the problem of poor performance of the second-order cumulant algorithm, the MUSIC algorithm for symmetric arrays and the ESPRIT algorithm for asymmetric arrays be researched based on the advantage of the fourth-order cumulant, compared the advantages and disadvantages of the two algorithms. With a detailed analysis of the array element number, number of snapshots, SNR and other factors change the influences on the accuracy of DOA multiple parameters joint estimation.After that, an improved algorithm for TLS-ESPRIT is proposed, the less fourth-order cumulant matrices construct a new matrix. The combination of TLS-ESPRIT algorithm and MUSIC algorithm, to avoid the problem of parameter matching, to achieve the joint estimation of angle and distance of multiple sources. The improved algorithm can improve the utilization of the array aperture, compared with the original algorithm, the complexity of the two algorithms are close, but the complexity of several algorithms are compared, prove that the improved algorithm can effectively improve the parameter estimation performance. Through simulation, the positioning performance of the second-order cumulant algorithm and the fourth-order cumulant algorithm are compared and analyzed.Finally, the full text work is summarized, and the follow-up research work is prospected.