The Effect of the Canopy of Scots Pines (P. Sylvestris) in Positioning Accuracy Utilizing the Network of Permanent GPS Reference Stations of the Hellenic Positioning System (HEPOS)
Chrysanthi Argiropoulou1, Kosmas-Aristotelis Doucas2

1Chrysanthi Argiropoulou, Forester in Forest Service of Serres, Greece, PhD Candidate, Department of Forestry and Natural Environment, Laboratory of Mechanical Science and Topography, Aristotle University, Thessaloniki, Greece.
2Prof. Kosmas-Aristotelis Doucas, Department of Forestry and Natural Environment, Laboratory of Mechanical Science and Topography, Aristotle University, Thessaloniki, Greece.
Manuscript received on 30 January 2015 | Revised Manuscript received on 12 February 2015 | Manuscript Published on 28 February 2015 | PP: 1-8 | Volume-4 Issue-9, February 2015 | Retrieval Number: I1963024915/15©BEIESP
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© The Authors. Blue Eyes Intelligence Engineering and Sciences Publication (BEIESP). This is an open access article under the CC-BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)

Abstract: The creation of Permanent Reference Stations and the implementation of network positioning techniques can significantly improve the positioning accuracy in forested conditions. The Hellenic Positioning System (HEPOS) is the first Network of Permanent GPS Reference Stations in Greece. The aim of the paper is to test the positioning accuracy within a conifer forest of Scots pines (Pinus sylvestris) using HEPOS system and an implementation of four Real Time (RTK) GPS techniques: the Virtual Reference Stations (VRS), the Master-Auxiliary Concept (MAC) technique, the Single-Base technique and the Network-based DGPS technique. In the study area, pines with normal growth and pines with stunted growth and bushy appearance were found. So three measurement testing courses were established: first under closed canopy of isolated pines with busy appearance, second above canopy of isolated pines with busy appearance (open sky) and finally under closed canopy of pines with normal growth, that are forest cluster with high canopy density. The results were obtained by comparing the measurements of points as recorded by the GPS receiver Leica GS09 GNSS with the measurements of points as recorded by the total station Leica TCR 407, whose measurements are taken as ¨true values¨. The measurements were carried out in the national forest of Lailia, Serres, Macedonia, Northern Greece.
Keywords: Permanent reference station, VRS, MAC, Single Base, Network DGPS

Scope of the Article: GPS and Location-Based Applications