Research On Key Technologies Of Pseudo Satellite Positioning In Confined Space

Pseudo-satellite positioning is based on the principle of satellite navigation and positioning system,using pseudo-satellite to increase the coverage of satellite navigation system in complex environments,improve positioning accuracy,and in some complex engineering environments,separate networking to achieve independent relative positioning,to achieve The goal of high-precision spatial positioning in confined spaces.In this paper,the key problems encountered in pseudo-satellite positioning in the constrained space localization process are analyzed.The principle of pseudo-satellite positioning in constrained space is analyzed.Based on this,the key problems affecting the accuracy of pseudo-satellite positioning in confined space are studied.The geometric configuration of time synchronization,multipath effect and pseudo-satellite positioning system,and the above problems are verified and analyzed by two-way time synchronization error model,CNMC(Code Noise Multi-path Correction)and changing geometry configuration.The main contents and results of the thesis are as follows:(1)The pseudo-satellite two-way time synchronization error model is used to study the time synchronization error.In order to improve the ranging accuracy in the bidirectional time synchronization error model,the carrier phase smoothing pseudorange method is used for smoothing.The time-frequency error in the bidirectional time synchronization error model is processed by Kalman filtering model.The research results show that the carrier phase smoothing pseudorange can improve the ranging accuracy;the frequency difference after correction by Kalman filtering model is stable at 6.748 × 10-7Hz,the clock difference reaches ns level,and the overall accuracy ratio of point measurement error after Kalman filtering The filter is increased by 40%before the filter,and the standard deviation is stable below 2m.By improving the time synchronization error,the accuracy and stability of the positioning can be effectively improved.(2)The multipath error in constrained spatial location is studied using the CNMC model.Improve the satellite CNMC model through measured data.The results show that the multipath error improved by the CNMC model decreases with the epoch number gradually increasing from 2.81m to 0.01m,and the variance is close to 0.01m2 from 4m2,which can effectively reduce.Multipath error improves the stability of positioning.(3)Research on the relationship between pseudo-satellite geometry and positioning accuracy.One is to maintain the same number of pseudo-satellites participating in the networking,and to change the relationship between the volumetric analysis and the PDOP value by changing the geometric configuration;the other is to keep the volume of the geometric configuration unchanged,and change the number of pseudo-satellites participating in the networking.The relationship of PDOP values.The simulation experiment is carried out in MATLAB software.The results show that by increasing the geometric volume or increasing the number of pseudolites,the PDOP growth can be effectively controlled,and the PDOP value of the simulation area can be improved to improve the overall positioning accuracy.