160 
7. CONCLUSIONS. 
We have presented the current state of our research in 
order to develope a low cost mobile mapping system, 
providing sufficient accuracy to perform road surveys 
for GIS applications. The lack of the INS has lead us to 
implement a georeferencing algorithm by which the 
istantaneous position and orientation of the van can be 
recovered by the differentially corrected GPS data 
only. For the same reason above, we can't get the 3D 
coordinates of any object selected on corresponding 
images, but rather its 2D coordinates on a projection 
map, therefore the object elevation cannot be restituted. 
Anyway, the capability to locate on a map any feature 
of interest through rapid road survey has represented 
our primary goal in developing such a MMS. 
At the present we have carried out only separated tests 
for the various modules which make up GeoVision, but 
we have in plan to assess the performances of the 
whole surveying system in real environment, testing it 
capabilities for real time data acquisition and the final 
accuracy for object position as derived by post-proces 
sing step. 
Through the contribution provided us by the VRG 
(Virtual Reality Group) of NRC Canada, this mobile 
mapping system can be integrated with the BIRIS 
sensor, in order to detect the road surface deformations. 
ACKNOWLEDGMENTS 
We acknowledge J. A. Beraldin and F. Blais of VR 
Group of NRC Canada, for the use of BIRIS sensor in 
road survey applications, and ing. A. Menin of Buil 
ding and Transports Department of Padua University, 
for the help spent to assemble the system. 
This work was developed with the project "Digital 
surface modeling by laser scanning and GPS for 3D 
city models and digital orthophotos", partly financed 
by MURST (Italian Ministry of University and 
Research) in 1999 as a project of relevant national 
interest. National coordinator: Riccardo Galetto, Head 
of the research unit: Antonio Vettore. 
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