![export hypack tide file with trimble business export hypack tide file with trimble business](https://www.mdpi.com/sensors/sensors-19-03939/article_deploy/html/images/sensors-19-03939-g004.png)
It is then concluded that navigation with EGNOS augmentation services and sounding devices ten times cheaper than combined RTK-DGPS with single beam echosounders allow to measure and monitor accurately the nearshore bathymetry.Īarninkhof SGJ, Ruessink BG, Roelvink JA (2005) Nearshore subtidal bathymetry from time-exposure images. Pitch/roll corrections performed with low-cost GPS receivers would be also a valuable addition to the accuracy and precision of the method. Those differences can be diminished by improving the tidal level correction and uncertainties associated to different tidal slopes throughout the survey area. The differences between surveys performed with two different equipment sets and using different methodologies for correcting water elevations are very small both quantitative and qualitatively. Results showed that depth elevation differences between bathymetric surfaces were of 0.10 ± 0.16 m, slightly higher but within the same order of the error attributable to the used interpolator (0.00 ± 0.11 m, triangular surface fitting). Vertical differences were determined assuming no morphological variations between surveys. Two bathymetric data sets were obtained, one by each method, for the same area and survey lines at an ebb tidal delta (Tavira Inlet, Ria Formosa Portugal). (1) a real-time kinematic differential global positioning system (RTK-DGPS) synchronised with a single beam echosounder with real-time tidal elevation correction and (2) a low-cost recreational echosounder-chartplotter system using Global Navigation Satellite Systems (GNSS) with real-time European Geostationary Navigation Overlay Service (EGNOS) augmentation services and depth values post-processed using measured sea level. For that purpose, two hydrographic surveying techniques were compared, i.e. This work intends to determine if low-cost surveying techniques based on recreational echosounders can be used to perform nearshore bathymetry for analysing evolution of coastal sectors.