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