| 摘要 |
PROBLEM TO BE SOLVED: To obtain a traffic flow measuring apparatus for automatically emitting radio waves when a vehicle whose speed is to be measured arrives at a speed measurement start point and automatically stopping the radio waves when the vehicle whose speed is to be measured goes out of radio wave beams. SOLUTION: The portable traffic flow measuring apparatus having a radio wave transmission determination section determines the entry of the vehicle whose speed is to be measured within a radio wave beam range by measuring the time interval between transmission gate and reception gate signals before transmitting radio waves, detects that the reception Doppler signal of the vehicle whose speed is to be measured disappeared, and stops the radio waves by determining that the vehicle whose speed is to be measured goes out by radio wave beams, thus transmitting the radio waves or stopping the transmission of the radio waves automatically at appropriate timing. COPYRIGHT: (C)2005,JPO&NCIPI
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