Study On Precise Hydrographic Surveys Based On GPS Technology

Hydrographic survey has been continuously developing with human civilization activities extending towards the sea. Hydrographic techniques have been developed dramatically since the earliest navigation with compass, sextant, and rough measuring and description of the topography, to the appearance of Loran system, echo sounder, till the precise satellite positioning system, side scan sonar, remote sensing, multi-beam echo sounder(MBES), air-borne laser sounding system and the wider recognition of electronic nautical charts. The strong contrast, between the improvement of hydrographic hardware mainly contributed by the maturity and use of GPS and MBES and the almost-unchanged theory and methods of the traditional surveys, also the gap between the increasing demands and the shortcomings of traditional hydrographic surveys in its process, products and even service, leads to precise hydrographic surveys based on GPS technology.Following a brief review on the development history of hydrography, the concept and methodology of precise hydrographic survey based on GPS technology is presented. The precise positioning, satellite altometering, Multi-beam echo sounding, synchronization of different elements, offsets correction and modeling of charted sounding etc., are systematically discussed. In addition, the analysis on present situation of precise hydrography proceeding with the statistics of relevant experimental data is carried out, and the future of precise hydrographic surveys is predicted.