Low-cost multi-GNSS SNR observations and GNSS-IR sea-level retrievals at two tide-influenced coastal stations in China

This dataset contains low-cost multi-GNSS signal-to-noise ratio (SNR) observations and GNSS interferometric reflectometry (GNSS-IR) sea-level retrieval products collected at two tide-influenced coastal water-level monitoring sites in China. The two stations represent different hydrological and reflection environments: GZHC is located near an estuary mouth in Dongguan, Guangdong Province, facing a relatively open coastal water body, whereas NBFH is located along a tidal river channel in Ningbo, Zhejiang Province, connected to the adjacent coastal sea. The field observations were collected using low-cost multi-GNSS equipment and were used to evaluate continuous near-real-time sea-level estimation based on windowed Lomb–Scargle periodogram analysis and sliding-window robust regression. The dataset includes SNR observation data from the two stations, raw WinLSP-derived reflector-height/sea-level retrievals, and reconstructed sea-level estimates obtained using the WinLSP–robust regression method. The GZHC dataset covers 21 days of observations from DOY 243 to DOY 263 in 2025, while the NBFH dataset covers 23 days from DOY 298 to DOY 320 in 2025. The selected elevation and azimuth ranges are station dependent: 3°–15° and 170°–340° for GZHC, and 8°–25° / 5°–25° with azimuth sectors of 90°–180° / 180°–220° for NBFH. These data support the study of low-cost GNSS-IR for continuous near-real-time coastal and estuarine sea-level monitoring. They can be used to reproduce the raw WinLSP retrieval characteristics, robust-regression-based 5 min sea-level reconstruction, residual statistics, and latency–accuracy–coverage trade-off analysis reported in the associated manuscript.