Evaluation of GPS-based attitude parameters applied to bathymetric measurements

As the survey vessels normally take bathymetric measurements in a 'dynamic'environment on the sea surface,the attitude parameters of the vessel are basically required to be introduced measurements related to the sounding datum. A multi-antenna GPSsystem, which can be easy-mounted on a vessel, has proved to be able toprecisely determine its attitude parameters through the combinations ofthe GPS vectors. This study aimed at evaluating such a GPS-basedsystem to determine the attitude parameters for the survey vessels, basedon the data collected both in-land for testing and on-sea for practical use.The precision of the estimates was realized to be around 1.6' for heading,2.3' for pitch, 9.9' for roll, and 0.3 cm for heave, based on the testing data. When system was practically applied to the bathymetric measurements made on-board, the sea depth agreements for the check points can be improved by a significant level of 43%, if a complete set of attitude parameters was in use. As the attitude information was provedto be helpful for the bathymetric measurements, it can be suggested thata multi-antenna GPS system is an economic and effective tool for the deter minations of the attitude parameter, and particularly suitable for the applications of hydrographic surveys.