Research On Multipath Parameterization Estimation Technology Based On The Signal Polarization Characteristics

Currently, the global satellite navigation system (GNSS, Global Navigation Satellite System) has been widely applied to various fields of life. As the main source of error of GNSS receivers, multipath signals has been a hotspot multipath suppression and difficulties in the field because of its difficult to eliminate through a unified modeling. Polarization characteristics of the signal is a signal important information,but the use of the polarization characteristics of the multipath signal parameter estimation technique is also relatively weak,Therefore taking advantage of the polarization characteristics of the multipath signal parameters are estimated to be very meaningful. This article is based on the research at home and abroad on polarization characteristics of multipath signal and multipath parameterization estimation technologies,then further research is presented.In this paper, taking the most technologically sophisticated GPS system as an example to study, it implements the multipath signal parameters based on an estimate of the signal polarization characteristics, the findings are universal and can be applied to other GNSS systems. Firstly, on the basis of the signal polarization characteristics of the study, it has built the multi-path signals model. According to the direct signal polarization characteristics of the signal model and multipath model, it analyzed the correlation value of the direct signal and multipath signals,with laying the foundation for future research chapter.Secondly,through comparative analysis of the traditional GPS receiver and GPS receiver,taking into account the advantages of the GPS receiver, the paper selected GPS receiver as the proposed algorithm simulation software platform. Basing on the research of the traditional code tracking loop and carrier tracking loop and according to the model of the multipath signal polarization characteristics, it theoretically analysis and simulates the impact of multipath signals on code tracking loop and carrier tracking loop.Then, according to the direct signal model that was created by the polarization characteristics, the paper proposed direct signal parameter estimation algorithm to the direct signal model without considering multipath signal condition. By analysis of the Kalman filter in detail, it constructs the improved algorithm of the traditional carrier tracking loop—Extended Kalman Filter carrier tracking loop. The algorithm implements the estimate of the direct signal amplitude through software GPS receiver's simulation and verification. To obtain the Estimation of signal phase, the extended kalman filter (EKF) tracking loop based on improvement of the extended kalman filter carrier tracking loop was presented, in which the traditional code tracking loop and carrier tracking loop were replaced by an extension of kalman filter . Through verifying the algorithm by simulation estimation of signal amplitude and the code phase were acquired.Finally, by means of using multipath signal correlation value of the signal polarization characteristics to ameliorate the extended kalman filter tracking loop which is only applicable to the direct signal, estimation technique of multipath parameters based on the extended kalman filter multipath signal parameters about signal polarization characteristics was obtained, hence the parameter estimation of multipath signals was achieved. This algorithm can simultaneously achieve the estimation of multipath signal parameters and direct signal parameters. The paper not only does the algorithm analyze in-depth theoretically, but also the performance of the algorithm is simulation and verification. The simulation results show that the algorithm can realize the estimation of multipath parameters effectively.