Real-Time Kinematic (RTK) positioning technique, with centimeter-level accuracy, is widely used in landslide deformation and building structural health monitoring. However, in large-height-difference scenarios where the height difference between the base and rover station is generally over 100 m, RTK positioning performance experiences a significant decline, mainly due to the deficiency in tropospheric delay modeling. In this study, we proposed a new method to refine the modeling of relative tropospheric delay corrections for the widely-used GPT3 by using ERA5 reanalysis data. The refined model, referred to as GPT3-e, shows an improvement of ∼33% for relative tropospheric modeling on a global scale compared to GPT3. Large-height-difference RTK positioning experiments further show that the vertical errors were reduced by 2.9 cm in January and 2.4 cm in July, with corresponding accuracy improvements of 64% and 57%, respectively, and slightly improves the ambiguity-fixing rate. As the refined model does not rely on external real-time products, it is compatible with the current RTK devices which makes the model easy to implement and will not significantly increase the cost.
Wu et al. (Fri,) studied this question.