Advances in seamless DTM integration for near-shore surveys

摘要

THE integration of the near shore interface of horizontal and vertical datums has been a persistent source of problems for engineering design of major infrastructure and their construction dimensional survey layout. Compounding the inherent datum integration problems is the different approaches to survey used by offshore and on-shore surveyors despite their often using the same equipment.Offshore surveyors work in a dynamic water environment without fixed monuments so they normally use GNSS survey equipment, GNSS continuously operating reference stations and software operating in full geodetic survey mode. In contrast, on-shore surveyors laying out large plant infrastructure are in a static ground based, very high precision dimensional control environment. They use GNSS to establish accurate geodetic positions on fixed monuments and for real-time machine control of earthwork machines. Overlaying the geodetic survey control is a local horizon plane coordinate system of scale factor 1 established using robotic total stations that is used for engineering design and dimensional survey layout. In addition, benchmark monuments with published national vertical datum information are used as the basis to extend high precision elevation information into the project.