This paper uses the dual-frequency GNSS observation data of the France's BRST port and the UK's Severn Bridge monitoring system to perform GPS-IR water level inversion in static and high dynamic environments,respectively,to explore the feasibility and accuracy of traditional GNSS monitoring system for water level inversion.The results show that the inversion accuracy of the L1 band is higher than that of the L2 band;in the static scene,the correlation coefficient between the GPS-IR water level inversion results and the tide gauge data is greater than 0.98;in the high dynamic scene,the retrieval accuracy of F001 station is slightly lower.Then the Empirical Mode Decomposition (EMD) is used to improve the accuracy of GPS-IR water level retrieval results in complex bridge environment,which can reduce the root mean square error by about 50%.The EMD-improved GPS-IR water level retrieval approach improves the applicability of GPS-IR technology in different water environments,and has a good application prospect in water level monitoring.