Cooperative Positioning in Vehicular Networks

Despite the fact that drivers are often blamed for fatal accidents on the roads, the significant number of deaths on the roads indicate a systematic failure to exploit intelligence in the vehicular road system. The need for novel and comprehensive approaches to road safety has led major industrial and government bodies to accept the DSRC (Dedicated Short Range Communication) as a solution for urban safety. DSRC is a 75 MHz bandwidth communication medium between 5.85 GHz and 5.925GHz. It will enable VANET (Vehicular Adhoc NETworks), allowing the spontaneous set up of networks between vehicles, roadside infrastructure and pedestrians, in the form of autonomous message exchanges. Many safety applications can be addressed in the context of VANET; an important example is collision avoidance systems. All the safety applications can be considered to be Location-Based Services (LBS) and require continual position estimation. For the most important applications, such as collision avoidance, position must be estimated at a frequency of 10Hz with an accuracy of no less than 50 cm [1]. Currently satellite-based positioning systems known as GNSS (Global Navigation Satellite Systems) are the only comprehensive positioning tool for vehicles. In spite of the fact that different GNSS systems such as the Global Positioning System (GPS), Russia’s GLOba