Analysis of the Dynamic Height Distribution at the Estuary of the Odra River Based on Gravimetric Measurements Acquired with the Use of a Light Survey Boat—A Case Study

Abstract

This article presents possible applications of a dynamic gravity meter (MGS-6, Micro-g LaCoste) for determining the dynamic height along the Odra River, in northwest Poland. The gravity measurement campaign described in this article was conducted on a small, hybrid-powered survey vessel (overall length: 9.5 m). We discuss a method for processing the results of gravimetric measurements performed on a mobile platform affected by strong external disturbances. Because measurement noise in most cases consists of signals caused by non-ideal observation conditions, careful attempts were made to analyze and eliminate the noise. Two different data processing strategies were implemented, one for a 20 Hz gravity data stream and another for a 1 Hz data stream. A comparison of the achieved results is presented. A height reference level, consistent for the entire estuary, is critical for the construction of a safe waterway system, including 3D navigation with the dynamic estimation of under-keel clearance on the Odra and other Polish rivers. The campaign was conducted in an area where the accuracy of measurements (levelling and gravimetric) is of key importance for shipping safety. The shores in the presented area of interest are swampy, so watercraft-based measurements are preferred. The method described in the article can be successfully applied to measurements in all near-zero-depth areas.

Measurement Methods in the Operation of Ships and Offshore Facilities

“…The second article in this section was prepared by K. Pyrchla et al and is entitled “Analysis of the Dynamic Height Distribution at the Estuary of the Odra River Based on Gravimetric Measurements Acquired with the Use of a Light Survey Boat—A Case Study” [ 16 ]. The authors present possible applications of a dynamic gravity meter for determining the dynamic height along a river.…”

Application of Proton Ionic Liquid in the Process of Obtaining Bioethanol from Hemp Stalks

“…These pretreatments disrupt the compact structure of lignocellulosic biomass by removing hemicellulose/lignin and enhancing the accessible surface area of the cellulose for enzymes [6,7]. The promising pretreatments include methods using solvents that are non-toxic and recoverable after the process, making them more environmentally attractive [8][9][10][11][12]. One problem with using lignocellulosic raw materials for bioethanol production is the presence of lignin, which hinders the further conversion of complex sugars to simple sugars.…”

Spectral Analysis of Compass Errors Based on Fast Fourier Transform and Reduction Absolute Errors Using a Pass-Band Finite Impulse Response Filter

“…These oscillations in the resultant component of the gyroscope principal axis decrease the accuracy of the gyroscope reading, and this phenomenon can be observed when the situation or the destination of the vessel requires intense manoeuvring. Stable and precise heading indications are crucial in hybrid offshore surveys, and especially when ultra-short baseline (USBL) underwater positioning and gravimetric measurements are involved [1], [2]. This situation occurs when there is a need to manoeuvre along designated survey lines or along hydrographic profiles, where the duration of manoeuvring over the measuring sections does not exceed the period of the non-fading oscillations.…”