Vehicle-to-vehicle communications and ranging system using spread spectrum techniques

A vehicle‐to‐vehicle communications and ranging system able to perform communications and ranging simultaneously using spread spectrum techniques is proposed in this paper. In this system, a vehicle (Vehicle‐A) can obtain information on a target vehicle (Vehicle‐B) by spread spectrum demodulation based on information calculated and retransmitted by Vehicle‐B in response to a PN signal transmitted by Vehicle‐A. The distance between Vehicle‐A and Vehicle‐B can be measured accurately by detecting the phase difference of the sent and received PN signals. In addition, Vehicle‐A can measure the distance between the two vehicles only through the waves reflected from the transmitted PN signal (as in the case of conventional spread spectrum radar), even if the target vehicle system is not a system‐loaded vehicle. This system not only prevents accidents but also allows safe driving without delay by communicating vehicle information and operator information and then measuring the distance between two vehicles effectively. Computer simulation results confirmed that the proposed system allows Vehicle‐A to demodulate information from Vehicle‐B and measure the distance between the vehicles simultaneously even when interference signals from vehicles running in the same or opposite direction exist.