Introduction of the automated hydrographic survey systems for creation of electronic nautical charts of internal waterways in Southern Africa

摘要

Using inland waterway transport is economically justified in any region of the world, however to this day inland waterway freight and passenger transportation in Southern Africa constitutes only a small fraction of the total amount of traffic. One of the major reasons for this situation is a lack of quality nautical charts covering navigable sections of inland waterways. Providing the region with valid electronic, as well as traditional cartographic resources over a short period of time is possible only by introducing innovative technologies. To resolve this issue, we suggest using automated hydrographic survey systems, allowing for prompt conduction of inland surveys at rather low operating costs. Additionally, it will provide an opportunity for partial automation of the chart manufacturing process, which in turn will lead to a wider use of the region's inland waterways by cargo and passenger vessels in the future. This paper describes issues that can be solved by means of automated hydrographic survey systems, equipment used by the systems, and basic algorithms for calculating and correcting measured parameter values (level, antenna lowering, calibration, vessel subsidence in shallow waters, distance between the satellite navigation system and the echo sounder antennae), as well as techniques for the evaluation of the accuracy of depth values received by an echo sounder.