| 摘要 |
For example, possible shaking of a vehicle varies positional relations between an on-board communication device and a ground communication device. In such a case, a magnetic field intensity of a signal from the ground communication device received by the on-board communication device may fluctuate across a threshold beyond which the on-board communication device determines that the vehicle has entered a communication range of the ground communication device and that the vehicle has exited the communication range. When this phenomenon occurs, the on-board communication device detects one ground communication device a plurality of times, thus hindering normal vehicle control. For a threshold of the magnetic field intensity for determining detection of the ground communication device, the on-board communication device has two types of thresholds for low speed traveling, that is, a first threshold that is a ground communication device entry side threshold and a second threshold that is a ground communication device exit side threshold. The thresholds thus have a hysteresis property that resists noise, thus preventing possible misdetection of the ground communication device during low speed traveling. |
