Carrier Phase Tracking Technology Based On Vector Structure

Beidou navigation satellite system(BDS)has gradually realized the three-step strategy.Scholars at home and abroad have carried out research on many aspects of BDS,including baseband processing links focusing on acquisition and tracking and solution links for navigation and positioning.Stable tracking of carrier phase is the premise of high-precision positioning,It directly determines the effect of GNSS high-precision navigation solution.Due to the relatively fragile traditional carrier tracking loop and the influence of harsh environment such as occlusion,it will significantly deteriorate the stability of carrier phase tracking.Exploring new carrier phase tracking methods has important practical significance for the development and application of satellite navigation high-precision positioning technology.Taking Beidou B1I and B3I dual frequency signals as examples,this paper explores the feasibility of carrier phase tracking based on vector structure by introducing precision single point positioning module.The main research contents include:Firstly,the paper analyzes the correlation structure of Beidou B1I and B3I signals from three aspects:carrier,ranging code and navigation data,studies the traditional positioning method based on pseudo range and the high-precision positioning method based on carrier phase,deduces the correlation positioning solution model,and studies the relevant theory of the receiver combined with the processing flow of IF signal.Secondly,establish the positioning observation model for the high-precision positioning algorithm based on carrier phase,summarize and sort out the correction algorithm and empirical model for various error correction models in precision single point positioning,establish the vector tracking structure combined with high-precision positioning,and input the carrier phase and pseudo range observations in the vector tracking loop into the high-precision positioning as measurement update,The dual frequency combination model is established,and the stability and effectiveness of the output observation of the vector tracking loop are verified by the positioning results.Thirdly,aiming at the instability of traditional structure tracking loop tracking,the vector structure is established based on scalar tracking,and the vector closed-loop feedback design is carried out based on extended Kalman filter(EKF).Through the tracking experiment of Beidou satellite signal,the effectiveness of the vector tracking algorithm proposed in this paper and the performance of carrier loop tracking are verified,The experimental results show that the carrier phase closed-loop feedback tracking design based on vector structure can achieve better accuracy in carrier loop tracking,and can realize the stable tracking of carrier loop.Finally,the experimental platform is built to complete the data acquisition and preprocessing in the occlusion environment,and the software receiver is used to track the carrier.By comparing the scalar structure and vector structure tracking loop,the stability of signal tracking loop and the continuity of carrier phase tracking in the occlusion non ideal environment are analyzed.The measurement results show that compared with the traditional scalar tracking method,The vector tracking method has significantly improved the carrier tracking stability and positioning accuracy.