| 摘要 |
[Problem] To monitor an antenna state accurately even if the characteristics of an antenna change over time, said antenna is replaced, or the like. [Solution] This device 1 is provided with a GPS receiver 11, a GPS antenna 12, a modem 10 for transmitting vehicle location information received by the GPS receiver 11, an antenna current source 13 and a current/voltage conversion unit 14 that detect the state of the GPS antenna 12, a storage unit 16 that stores a modifiable threshold for the state of the GPS antenna 12, and a control unit 18 that determines the state of the GPS antenna 12 and modifies the threshold stored in the storage unit 16. |
