A cooperative transponder system for improved traffic safety, localizing road users in the 5 GHz band

[摘要] We present a multi-user cooperative mobile transponder system which enablescars to localize pedestrians, bicyclists and other road users in order toimprove traffic safety. The system operates at a center frequency of5.768 GHz, offering the ability to test precision localization technology atfrequencies close to the newly designated automotive safety related bandsaround 5.9 GHz. By carrying out a roundtrip time of flight measurement, thesensor can determine the distance from the onboard localization unit of a carto a road user who is equipped with an active transponder, employing the ideaof a secondary radar and pulse compression. The onboard unit sends out apseudo noise coded interrogation pulse, which is answered by one or moretransponders after a short waiting time. Each transponder uses a differentwaiting time in order to allow for time division multiple access. We presentthe system setup as well as range measurement results, achieving an accuracyup to centimeters for the distance measurement and a range in the order ofhundred meters. We also discuss the effect of clock drift and offset ondistance accuracy for different waiting times and show how the system can beimproved to further increase precision in a multiuser environment.

[学科分类] 电子、光学、磁材料