Study on Positioning Accuracy of Diferential Global Positioning System

The error distribution law and position precision of the DGPS data in and outside the forest stand were studied in this paper.Experimental results assert that the average value of mean square error of position outside the forest stand is 0.243m,distributed between 0 to 0.5m and the frequency is 92.1% and the frequency whose mean square error is under 1 m is 98.4%.In the forest stand whose crown closure is under 0.5,the average value of mean square error is 0.502m,distributed between 0 to 0.7m and the frequency is 82.8% and the frequency whose mean square error is under 1m is 91.4%.The results show that DGPS could be used to collect GCPS for the high spatial resolution remote sensing images such as QUIKBIRD,IKONOS outside the forest stand and it can be used to do the positional investigation of young trees,old trees and sample plots in the forest whose crown closure is under 0.5.