| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To prevent a theft by grasping the position of a working machine even if an antenna of the working machine is harmed. <P>SOLUTION: A plurality of antennas 16A and 16B for a GPS are provided, and even if any one of them is forced to a condition impossible to receive a signal, positional information can be received by the residual antenna. A plurality of antennas 18A and 18B are provided, and even if any one them is forced to a condition impossible to communicate, a signal containing positional information can be transmitted to a management server 26 by the residual antenna. Or a dummy antenna is separately provided from the antenna for a GPS and the antenna for data communication, and even if destructing operation is applied to the dummy antenna, a signal for informing the destruction is transmitted to the management server. <P>COPYRIGHT: (C)2005,JPO&NCIPI</p> |
