| 摘要 |
<p>A proximity sensing system comprising a stationary sender, a portable transponder, and a portable annunciator. The sender is a base station mountable to a roadway overhead obstruction for sending out a signal to the transponder which signal is receivable when the transponder is within a predetermined signal strength radius. The transponder is mounted on a vehicle and is turned on by an operator when a roof load is placed on the vehicle. Upon being energized, the transponder sends an awakening signal to the annunciator which has been in a rest mode within the vehicle, thus arming the system. The annunciator responds to the next signal from the transponder, which indicates that the vehicle is approaching collision with the obstruction, by generating an alarm for the vehicle driver, allowing the driver to stop the vehicle in time to avoid collision with the overhead obstruction.</p> |
