Surveying shrublands boundaries using permanent reference stations HEPOS (HEllenic POsitioning System)

The protection of rangeland ecosystems presupposes the boundaries determination of the land they occupy, their recording and their inventory. The Global Positioning System (GPS) contributes to achieving the above purpose. The network of permanent GPS reference stations that developed at global and European level and the implementation of network RTK positioning techniques provide high accuracies in Real-Time positioning. Additional benefits of these developments are the reduction of the time and the cost of surveying. The first Network of Permanent GPS Reference Stations in Greece developed by “Ktimatologio S.A.” company is named HEPOS System (HEllenic POsitioning System). The system provides high accuracy satellite-based positioning services. The aim of the paper is to investigate the positioning accuracy in shrublands boundaries determination using GPS receiver and HEPOS system in real time (Real Time) positioning. The evaluation is carried out by means of a comparison of the results obtained from using the Leica GS09_GNSS receiver and the implementation of RTK techniques Single-Base, VRS and Network DGPS of HEPOS system, with the coordinates extracted from using the total station Leica TRC 407 whose measurements are taken as «true values». The measurements were carried out in the Public Forest of Vertiskos Mountain, manages from the Forest Service of Nigrita Serres and the results of the research shows that the most accurate method is Network DGPS.