Accurate and precise timekeeping between computers in a distrib- uted survey system is essential to ensure adequate data quality, especially with Multibeam Echosounders (MBES) which can otherwise suffer from significant motion artefacts. We show that clock synchronisation on the order of 100-150ns (rms) is readily achievable in a modern MBES-based survey system utilising an Ethernet-based time synchronisation mechanism and some custom timekeeping software. We also show that improving the timekeeping eliminates motion artefacts in the observed bathymetry, and simplifies the patch-test procedure.
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