DEVICE FOR PREVENTION OF REVERSE RUN

摘要

PROBLEM TO BE SOLVED: To provide a reverse run prevention device which certainly detects a reversely running vehicle and prevents erroneous detection. SOLUTION: A Doppler module 11 emits microwave to a detection area and detects a Doppler frequency of the reflected wave from a vehicle. A running direction identifying circuit 16 identifies the running direction of the vehicle based on a phase difference between two Doppler frequencies. A counter 17b detects the reversely running vehicle based on the output signals of the running direction identifying circuit 16. A measuring circuit 20 calculates a distance of the running direction of the vehicle in the detection area, based on the output signals from the Doppler module 11 and the counter 17a. COPYRIGHT: (C)2011,JPO&INPIT