Toward standardizing hydrographic vessel offset surveys: angular offset determination of hydrographic sensors at short-range using total station observations

Abstract

Vessel offset surveys (VOS) are essential for accurately integrating hydrographic systems, ensuring correct positioning and mounting angles for sonars, and positioning and orientation systems within specified manufacturer accuracies, which are necessary to meet the expected hydrographic survey standards summarized in the International Hydrographic Organization’s publication S-44. This study examines factors affecting VOS accuracy, such as the number of station setups, baseline lengths, least square plane fitting, and instrument accuracies. Results indicate that multiple setups are required to achieve accurate mounting angles. Longer baselines improve accuracy, particularly for small sensors like an inertial measurement unit, while circular transducers benefit from fitting a plane with multiple points. This analysis supports standardizing VOS procedures to enhance VOS reliability and accuracy.