Effect of forest vegetation density on the accuracy of GNSS navigation

• Measurement of GNSS-based navigation accuracy of off-road vehicles in varying forest canopy densities. • A precise tachymetric method was used as a reference for measurement of true vehicle paths. • Measurement results show statistically significant differences in positioning accuracy across forest environments. • GNSS deviation metrics ( Q , s Q , σ EN , quantiles) were analysed to evaluate performance under real forest conditions. Global Navigation Satellite Systems (GNSS)-based positioning plays a crucial role in various applications, including navigation, transportation, logistics, mapping, emergency services, agriculture and military. GNSS are one of the basic navigation methods alongside inertial systems and autonomous systems in forest stands. Today, these systems are used for pedestrian orientation and for off-road vehicle navigation. This study deals with methods for testing the navigation accuracy of different off-road vehicles using GNSS navigation in forest stands depending on different tree canopy densities (open space, forest road, and dense forest). For the measurements, the precision method of tachymetry was used as a reference mapping tool to mark the sections of routes on which the vehicles were moving. The Trimble Geo 7X cm edition device with Tornado for 7 × antenna devices was used to measure GNSS signal quality. This study presents the resulting values of lateral Q deviations of the position of individual vehicles recorded by the GNSS receiver from the reference tacheometrically measured paths. The results are evaluated using statistical tests at the α = 0.05 significance level with descriptions of the individual datasets, where histograms of deviations, mean deviations, quadratic means of deviations s Q , quadratic means of standard deviations σ EN and quantiles were determined. These values were determined by different vehicles, in different vehicle positioning modes, and in different densities of temperate forest vegetation.