Research on Train Autonomous Positioning Method Based on Long Baseline RTK Resolution

Combining the one-dimensional properties of the actual railway lines with the characteristics of long-distance and high-speed operation of trains, this paper controls the satellite navigation signal simulation source in the laboratory environment, and designs a long baseline dynamic simulation scene of the Qinghai-Tibet Railway train. With the continuous increase of train moving distance, the traditional real-time kinematic (RTK) algorithm gradually can no longer meet the requirements of high precision positioning. Therefore, this article is based on double-difference dual-frequency observations, taking residual relative tropospheric delay and relative ionospheric delay as parameters to be estimated, fixes and restricts the partial ambiguity by setting the judgment criterion of satellite elevation threshold, which improves the success rate and reliability of the integer ambiguity solution. The results show that this method can greatly improve the ratio of fixed ambiguity in long baseline RTK scenes and effectively advance the positioning performance.