1SPRS, Vol.34, Part 2W2, “Dynamic and Multi-Dimensional GIS", Bangkok, May 23-25, 2001 
243 
the 
onstant. 
After the rover position and time are recorded by RTK-GPS rover position is calculated for the Road sign recognition in the 
positioning techniques, some rover position is extract by using next step, 
the time as same as the image recorded time. The extracted 
(5) 
minimum 
each sign 
a target 
the new 
on and the 
v GPS as 
îe digital 
>ign, the 
RTK-GPS 
^vantage of 
ed between 
)reover the 
) antenna is 
noving (see 
Figure 5 Scheme of Road sign position by a new algorithm 
After the position of rover is extracted, it is converted into the 
digital CCD camera position on the vehicle. This position is 
applied to calculate the Road Sign position below: 
P - P + C 
CCD Antenna ' ^ 
(6) 
Where 
Pccois the Digital CCD camera position on the moving vehicle. 
P Antenna is the GPS antenna position on the moving vehicle, 
extracted from Step No.3. 
C is the GPS antenna position and digital CCD camera position 
relationship on the vehicle from sensor calibration. 
C is the GPS antenna and Digital CCD camera position 
relationship on a vehicle from the instrument calibration. 
This formula is divided in 2 axis: x and y axis for a planar 
coordinate (Northing, Easting) based on WGS-84 datum by 
following: 
X CCD ~ ^Antenna + AX 
Y CCD ~ Y Antenna + AY 
(7) 
Where 
Xccd is the Digital CCD coordinate in Easting. 
Y ccd is the Digital CCD coordinate in Northing. 
X Antenna is the GPS coordinate in Easting. 
Y Antenna is the GPS coordinate in Northing. 
AX is the GPS antenna and Digital CCD camera in x-axis. 
AY is the GPS antenna and Digital CCD camera in y-axis. 
The next important parameter for Sign position in this method is 
the distance between the Digital CCD camera position and Sign 
position in the real world by following: 
Fiaure 6 the calculation of the Distance from the CCD Camera to the Road Sian 
Digital CCD Camera 
Position on Vehicle 
Digital CCD Camera 
Position