Comparison and Analysis of Tidal Level Monitoring Accuracy Between GNSS-IR and Satellite Altimetry

The coexistence of multiple methods has become a general trend in tidal level monitoring, especially the Global Navigation Satellite System Interferometric Reflectometry (GNSS-IR) technology and satellite altimetry technology provide a richer database for sea level monitoring. Few studies have carried out the comparison of tidal level accuracy obtained by the two methods. Based on this, this study takes BUR2 station as an example to carry out the research on tidal level monitoring of GNSS-IR and satellite altimetry (HY-2B and Jason-3), and compares them with the measured tidal level data provided by the tidal gauge station (BURTG). First, unify the respective time bases to Coordinated Universal Time (UTC) and the elevation base to Tide Gauge Zero (TGZ). Then, the characteristics of the two methods to monitor the tidal level are compared and analyzed. GNSS-IR technology has higher temporal resolution (R: 0.957, RMSE: 0.257 m, ME: −0.008 m, Number: 73936), while HY-2B (R: 0.994, RMSE: 0.105 m, ME: 0.025 m, Number: 178) and Jason-3 (R: 0.995, RMSE: 0.113 m, ME: −0.040 m, Number: 461) have higher inversion accuracy. This study explored the respective characteristics of GNSS-IR technology and satellite altimetry technology for tidal level monitoring, laying a foundation for the subsequent integration of tidal level monitoring.