Objectives  In areas with large height differences, the tropospheric delay difference between real time kinematic (RTK) stations is significant.Traditional RTK algorithms ignore the atmospheric delay error between stations, which seriously affects positioning accuracy. Both globally and in China, there are extensive distributions of large height differences in terrain, making the study of large height differen‑ce RTK necessary.

  Methods  As the height parameter is strongly correlated with the tropospheric delay parameter, real time estimation of tropospheric delay is not possible in RTK, and external models are the only means to correct tropospheric delay errors in large height difference RTK. We analyze the special requirements of tropospheric delay models for large height difference RTK and summarize the available empirical tropospheric delay models.To further improve the positioning accuracy of large height difference RTK, real time measured tropospheric delay models based on continuously operating reference stations stations and meteorological stations is proposed.

  Results  Although both methods can improve RTK positioning accuracy, they each have their own shortcomings that need further study.

  Conclusions  On this basis, a method based on networked transport of radio technical commission for maritime services via Internet protocol protocol for small area large height difference RTK service is proposed, which realizes seamless correction of tropospheric delay for RTK users.