| 摘要 |
<p>A collision avoidance system (20) for vehicles (10), the system (20) comprises a monitoring device (22) mounted in each vehicle (10) and a tagging device (28) attachable to an object for monitoring during operation of the vehicles (10). The monitoring devices (10) each include a transmitter (42) which in operation transmits radio frequency signals at a first predetermined frequency, a receiver (44) tuned to receive radio frequency signals at a second predetermined frequency and an indication means arranged to provide an indication when the receiver (44) receives signals. The tagging devices (28) each include a receiver (30) tuned to receive radio frequency signals at said first predetermined frequency and a transmitter (32) which in operation transmits radio frequency signals at said second predetermined frequency when the corresponding receiver (28) receives a signal at said first predetermined frequency. Each of the monitoring devices (22) may include a pseudo-random generator for controlling the transmitter (42) to transmit signals in a random order and at a duty cycle of 10 milliseconds per 100 milliseconds. The tagging devices (28) may include a tag identification code and a group identification code in their transmission signals for discriminating the tagging devices (28).</p> |
