| 摘要 |
<p>PROBLEM TO BE SOLVED: To directly detect if an obstacle exists or not in a railroad crossing on the train side. SOLUTION: A transmitter 1 emits pulses of radio waves 11, 12. A reflector 2 receives the radio wave 12 from the transmitter 1 diagonally crossing a railroad crossing 7 to reach it to be reflected toward a train 3 as a reflection wave 13. In the case where an obstacle is not existing in the railroad crossing 7, a receiver 4 mounted on the train 3 respectively receives the direct wave 11 emitted from the transmitter 1, and the reflection wave 13 reflected by the reflector 2. In the case where an obstacle exists in the railroad crossing 7, the radio wave 12 emitted from the transmitter 1 toward the reflector 2 is shielded, so the reflection wave 13 is not correctly received by the receiver 4 on the train 3. An obstacle detector 5 mounted on the train 3 determines if an obstacle exists or not in the railroad crossing 7 based on the direct wave 11 and the reflection wave 13 received, and generates an alarm when it is determined that the obstacle exists to inform the crew of it.</p> |
