Lückenlose Positionsbestimmung zur Georeferenzierung von hydrographischen Messdaten

In order to provide accurate information on the shape of a river bed, it has to be regularly surveyed using hydrographic methods. In general, survey vessels are used for this purpose. Bathymetric data acquired by echosounders has to be georeferenced. Nowadays, GNSS receivers or coupled GNSS/inertial measuring systems are installed on survey vessels to provide the position coordinates kinematically (RTK solution). However, these systems are only suitable to a limited extent for sections of inland waterways where (partial) shading of GNSS signals occurs due to obstacles on the river bank (buildings, vegetation, etc.) or bridges. Also in dead spots of the cellular network, the coordinates cannot be provided with sufficient accuracy. For this reason, the positioning multi-sensor system is extended by different instruments and sensors to an integrated hydrographic positioning system (HydrOs project). So, bathymetric data can be georeferenced even in areas without a valid RTK positioning solution. For this purpose, different evaluation approaches within a Kalman filter-based processing algorithm are tested. In this article the integration of additional information is presented as an example. These are additional observation variables (parame-ters of external orientation from image data), control variables (variables of the ship propulsion and flow velocity) and the modelled water level from a river hydrological model as pseudo-observation. Especially the integration of the latter leads to a height deviation of less than 1 dm in post-processing even with gaps in GNSS reception of up to 60 s.