Wireless communication device

A wireless communication system comprising at least a first vehicle and a second vehicle, wherein

• the first vehicle has at least a first GPS receiver, and is configured to acquire first position information of the first vehicle, first traveling direction information of the first vehicle, first speed information of the first vehicle, and first elevation information of the first vehicle from the first GPS receiver,
• the second vehicle has at least a second GPS receiver, and is configured to acquire second position information of the second vehicle, second traveling direction information of the second vehicle, second speed information of the second vehicle, and second elevation information of the second vehicle from the second GPS receiver,
• the first vehicle is configured to receive packet signals from the second vehicle, each of the packet signals including at least the second position information of the second vehicle, the second traveling direction information of the second vehicle, the second speed information of the second vehicle, and the second elevation information of the second vehicle,
• while there is a possibility that the first vehicle, traveling on a first road, collides with the second vehicle, traveling on a second road, at a point where one of the first and second roads crosses over another of the first and second roads, based on at least one of the first position information, the first traveling direction information, the first speed information, the second position information, the second traveling direction information, and the second speed information, when a difference in elevation between the first vehicle and the second vehicle based on the first elevation information of the first vehicle and the second elevation information of at least one of the packet signals received from the second vehicle, is smaller than a threshold value, the first vehicle notifies a driver of the first vehicle of a presence of the second vehicle,
• while there is the possibility that the first vehicle collides with the second vehicle at the point of crossing based on at least one of the first position information, the first traveling direction information, the first speed information, the second position information, the second traveling direction information, and the second speed information, when the difference in elevation between the first vehicle and the second vehicle based on the first elevation information of the first vehicle and the second elevation information of at least one of the packet signals received from the second vehicle, is greater than the threshold value, the first vehicle does not notify the driver of the first vehicle of the presence of the second vehicle,
• the first vehicle is configured to perform an estimation process, the estimation process including:
• estimating that there is no overpass at the point where one of the first and second roads crosses over another of the first and second roads when the difference in elevation between the first vehicle and the second vehicle based on the first elevation information of the first vehicle and the second elevation information of at least one of the packet signals received from the second vehicle, is smaller than the threshold value;
• and
• estimating that there is an overpass at the point where one of the first and second roads crosses over another of the first and second roads when the difference in elevation between the first vehicle and the second vehicle based on the first elevation information of the first vehicle and the second elevation information of at least one of the packet signals received from the second vehicle, is greater than the threshold value,
• the first vehicle is configured to store an estimation result of the estimation process, and
• when the first vehicle travels the vicinity of the point next time, the first vehicle is configured to omit the estimation process by using the stored estimation result.