[en] Global navigation satellite system multipath reflectometry (GNSS-MR) uses signals of opportunity at L-band frequency. GNSS-MR using signal-to-noise ratio (SNR) measured with commercial off-the-shelf geodetic-quality equipment has proved fruitful for sea level monitoring in coastal regions. The instantaneous excess delay of the sea-surface reflections with respect to the line-of-sight propagation can be used to estimate water level with direct connection to the terrestrial reference frame. Vertical velocity of the sea surface is an important correction to consider for the case of large tidal amplitudes, as it is known to cause a bias in reflector heights for rising and setting satellites if unaccounted for. Nevertheless, decimeter-level systematic errors have been reported between velocity-corrected GNSS-MR retrievals and conventional tide gauges (TG). In this contribution, we account additionally for the vertical acceleation of the sea surface. This extended dynamic model allows the use of much wider averaging intervals to mitigate noise and tropospheric effects. We apply the novel model for the analysis of several stations worldwide at various altitudes and tidal regimes, including NSLG in the U.K. and SPEY in Australia. The regression slope between GNSS-MR and tide gauge records is shown to improve, with smaller deviations from the ideal 1:1 relationship after the acceleration correction.
