Patent ID: 8706392

Claim:
A distance detection device which is mounted in a vehicle and detects a distance to an other vehicle through information communicated with the other vehicle, the distance detection device comprising: a time measurement part having a time measurement function; a first information generation part for generating first output information which is information to be transmitted to the other vehicle, by acquiring time information from the time measurement part and associating own vehicle time information representing an own vehicle time, which is the acquired time information, with own vehicle identification information, which is predetermined identification information of an own vehicle; a transmission part for, each time the first information generation part generates the first output information, transmitting the generated first output information by broadcasting; a reception part for receiving own vehicle time information representing an own vehicle time and own vehicle identification information, which are included in first output information transmitted from the other vehicle by broadcasting, as other vehicle time information which represents an other vehicle time of the other vehicle and other vehicle identification information which is identification information of the other vehicle, respectively; a reception time acquisition part for, when the reception part receives the first output information from the other vehicle, acquiring, from the time measurement part, time information as reception time information representing a reception time; a distance calculation part for obtaining a distance to the other vehicle, based on the other vehicle time information included in the first output information received by the reception part, and the reception time information acquired by the reception time acquisition part, when the reception part receives the first output information of the other vehicle which has been transmitted from the other vehicle to the own vehicle in response to the first transmission information of the own vehicle transmitted from the own vehicle to the other vehicle; and a time difference calculation part for, when the reception part receives the first output information from the other vehicle, obtaining, as a first time difference, a time difference resulting from the other vehicle time included in the first output information being subtracted from the reception time acquired by the reception time acquisition part, wherein the distance calculation part obtains a distance to the other vehicle, by exchanging, with the other vehicle, first time difference information representing the first time difference obtained by the time difference calculation part.