At first, a plurality of road side data exchange devices are provided separately on {HEAD ~ road sides} to exchange {TAIL ~ satellite calibration data} to form a road side data exchange net 
to exchange
At first , a plurality of road side data exchange devices are provided separately on { HEAD ~ road sides } to exchange { TAIL ~ satellite calibration data } to form a road side data exchange net
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH