Investigation of calculation/distance measurement method using spread-spectrum communications system

Recently, extensive intelligent transport systems (ITS) studies using spread-spectrum communications have got underway. Such studies have suggested a calculation/distance (c/d) measurement method for securing passengers more efficiently in public transportation systems and the like. This method maintains communication between a base station and a small device, like a card, carried by the passenger. This makes it possible to perform calculations and measurements in real-time. The cards send an individual information in each c/d card (ID information) in response to the base station. The base station calculates the correlation value by using spread-spectrum signals, then performs the calculations and distance measurements. As the result of a simulation, good results were obtained in this study.