Table 4. Comparison of positioning accuracy based on Sage-Husa adaptive filtering algorithm.

Direction	Eastward	Northward	2-D dimensional	3-D dimensional
Data processed by the algorithm (m)	4.72	5.45	6.56	9.73
Raw GPS Data (m)	5.71	6.43	7.65	11.89
Precision improvement ratio (%)	17.34%	15.24%	14.25%	18.17%