林冠开阔度对GNSS RTK在森林中定位可用性及初始化时间的影响

Abstract

Abstract:

Though RTK is a satellite positioning technology with high precision, GPS RTK technology is seldom used in forests due to the obstruction of forest canopy to the satellite signal. GNSS RTK with two satellite systems has broad application prospects. The effects of canopy openness on positioning availability and initialization time of GNSS RTK were studied in secondary poplar-birch forests in mountain land in north Hebei, positioning with GPS+GLONASS RTK system, measuring forest canopy openness with hemispherical photograph. The results showed that canopy openness was the most fitting indicator, since hemispherical photograph could represent well forest environment and most satellite had medium elevation angle. Satellite number was enough to meet the positioning requirements. Forest canopy openness had significant positive correlation with common satellite numbers. PDOP value more than 92.4% was less than 4, and there was a good satellite geometric distribution. SNR was significantly positively correlated to canopy openness, and was affected greatly by forest environment. All indicator of positioning availability were good when canopy openness was more than 0.25. Average initialization time of RTK was becoming shorter with the increasing canopy openness. The suitable occupation time was 15 min with regard to surveying duration and surveying efficiency.

Key words: RTK, canopy openness, global navigation satellite system(GNSS), SNR, initialization time, PDOP

CLC Number:

S757

Li Yongning, Liu Limin, Cui Liyan, Huang Longsheng, Zhao Zhongkai, Huang Xuanrui. Effects of Canopy Openness on Positioning Availability and Initialization Time of GNSS RTK in Forests[J]. Scientia Silvae Sinicae, 2014, 50(2): 78-84.

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Effects of Canopy Openness on Positioning Availability and Initialization Time of GNSS RTK in Forests

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