Seasonal variation of global positioning system (GPS) accuracy within the Tokyo University Forest in Hokkaido [Japan]
2009
Owari, T.(Tokyo Univ. (Japan)) | Kasahara, H. | Oikawa, N. | Fukuoka, S.
In-depth forest ground surveys are indispensable for experiments on the stand-based forest management system at the Tokyo University Forest in Hokkaido. The Global Positioning System (GPS) offers an innovative surveying technology with high accuracy and labor economy. This study compared the positioning accuracy of handy GPS receivers in summer and winter to obtain practical suggestions for the use of GPS in ground-based forest surveys. In July and December 2007, field tests measured the positions of ten points under the forest canopy with two GPS receivers (MobileMapper Pro and GPSMAP 60CSx). Three-way ANOVA was employed to identify factors that affected positioning accuracy. Results indicated that the season was a significant factor for the GPS measurements. Relatively few GPS positional errors were observed during winter. The presence of foliage probably negatively affected positioning accuracy. Among the receiver settings tested, the MobileMapper Pro receiver with a 30 sec. observation time seemed to be a reasonable choice. Despite the severe terrain on which our measurement points were located, both GPS receivers had good satellite signal reception. We concluded that both the MobileMapper Pro and the GPSMAP 60CSx were suitable receivers for GPS survey applications in most areas of the University Forest.
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