Real-time positioning in logging: Effects of forest stand characteristics, topography, and line-of-sight obstructions on GNSS-RF transponder accuracy and radio signal propagation

• Published in: PloS one 2018-01, Vol.13 (1), p.e0191017-e0191017
• Main Authors: Zimbelman, Eloise G, Keefe, Robert F
• Format: Article
• Language: English
• Subjects: Accuracy; Analysis; Antennas; Biology and Life Sciences; Communications satellites; Data processing; Earth Sciences; Ecology and Environmental Sciences; Electronic devices; Engineering and Technology; Environment models; Forest ecology; Forestry; Forests; Geofences; Geographic Information Systems; Global navigation satellite system; Global positioning systems; GPS; Humans; Idaho; Influence; Internet; Line of sight; Logging; Motion detection; Navigation satellites; Navigation systems; Obstructions; Physical Sciences; Public safety; Radio frequency; Radio signals; Radio spectrum; Radio transmission; Radio Waves; Radios; Real time; Receivers & amplifiers; Safety; Satellite Communications; Situational awareness; Studies; Technology application; Topography; Transponders; Workers
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0191017

Real-time positioning on mobile devices using global navigation satellite system (GNSS) technology paired with radio frequency (RF) transmission (GNSS-RF) may help to improve safety on logging operations by increasing situational awareness. However, GNSS positional accuracy for ground workers in motion may be reduced by multipath error, satellite signal obstruction, or other factors. Radio propagation of GNSS locations may also be impacted due to line-of-sight (LOS) obstruction in remote, forested areas. The objective of this study was to characterize the effects of forest stand characteristics, topography, and other LOS obstructions on the GNSS accuracy and radio signal propagation quality of multiple Raveon Atlas PT GNSS-RF transponders functioning as a network in a range of forest conditions. Because most previous research with GNSS in forestry has focused on stationary units, we chose to analyze units in motion by evaluating the time-to-signal accuracy of geofence crossings in 21 randomly-selected stands on the University of Idaho Experimental Forest. Specifically, we studied the effects of forest stand characteristics, topography, and LOS obstructions on (1) the odds of missed GNSS-RF signals, (2) the root mean squared error (RMSE) of Atlas PTs, and (3) the time-to-signal accuracy of safety geofence crossings in forested environments. Mixed-effects models used to analyze the data showed that stand characteristics, topography, and obstructions in the LOS affected the odds of missed radio signals while stand variables alone affected RMSE. Both stand characteristics and topography affected the accuracy of geofence alerts.