329 
- 
ìMsmm 
èmmm 
- 
The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Voi. XXXVII. Part B4. Beijing 2008 
Method 
Position 
Error 
<2 m 
Position 
Error 
<5 m 
Positio 
n 
Error 
<10 m 
Positio 
n 
Error 
> 
10 m 
SPP 
8 
7.3% 
22 
18.2% 
81 
73.6% 
1 
0.9% 
DGPS <5 Km 
108 
98.2% 
2 
1.8% 
DGPS <10-25 
Km 
107 
97.3% 
2 
1.8% 
1 
0.9% 
Table 2. The estimated location error by single and differential 
GPS positioning 
Several static and RTK tests (via internet) will be applied in the 
near future in order to evaluate the capability of the network on 
longer baseline distances using all the proposed permanent 
stations. 
Using the VRS station concept with our developed software 
“3VRS” similar accuracies can be achieved in distances of up to 
20 Km from the nearest reference station as for short baselines 
in the single station concept. This can be done also with few 
epochs. Therefore the distances between the reference stations 
in a permanent GPS network can be enlarged which results in 
large cost savings for the establishment and maintenance. 
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