| 摘要 |
<p>The system comprises, in each mobile object, a transponder (1) whose receiver (2) is a call-receiving circuit for people with a personal identifying code or codes and whose transmitter (3) is capable of transmitting the identifying code of the transponder (1), a radio network (7-8-9) for calling people and a radio direction- finding assembly (10-11-12) capable of locating, by triangulation, the mobile object in which the transmitter (3) of the transponder (1) transmits an identifying code in response to the calling code sent out by the radio network (7-8-9). The radio direction-finding assembly (10-11-12) is connected to the radio circuit (7-8-9) by transmission means (13) so as to be alerted at each calling code sent out by the network. The radio circuit (7-8-9), after sending a first calling code, will only send out a new calling code to another mobile object after a predetermined time interval. In a variant, the output from the control system (4) of the transponder (1) is validated on reception of a calling code only after a predetermined delay and, during the said predetermined delay, the radio circuit (7-8-9) can sequentially send out new calls. <IMAGE></p> |
