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Precise vehicle positioning is dependent on the availability of a clear line of sight path between a vehicle and four or more satellites. For improved estimation of vehicle positioning in the absence of a complete set of visible satellites, Dedicated Short-Range Communication (DSRC) may offer a temporary position estimate. This paper investigates the feasibility of acquiring position based solely on DSRC signals. First the precision of DSRC signal strength (SI)-based position estimates is analyzed; this is followed by an analysis of position estimates based on time of flight (TOF). SI and TOF methods are compared using an extensive set of outdoor data collected from 30 vehicles on a test track. This research suggests that TOF is a better measure than SI for estimating position information.

When vehicles share certain information wirelessly via Dedicated Short Range Communications (DSRC), they enable a new layer of electronic vehicle safety that, when needed, can generate warnings to drivers and even initiate automatic preventive actions. Vehicle location and velocity provided by Global Navigation Systems (GNSS), including GPS, are key in allowing vehicle path estimation. GNSS is effective in accurately determining a vehicle's location coordinates in most driving environments, but its performance suffers from obstructions in dense urban environments. To combat this, augmentations to GNSS are being contemplated and tested. This testing has been typically done using a reference GNSS system complimented by expensive military-grade inertial sensors, which can still fail to provide adequate reference performance in certain environments.

Cooperative vehicle safety can help prevent vehicle collisions by providing timely warnings to the driver or initiating automatic preventive actions based on vehicle dynamics information exchanged between vehicles. The information is shared wirelessly through the emerging DSRC (Dedicated Short Range Communication) standards. The vehicle dynamics information that is shared, such as vehicle velocity and location, is collected from the vehicle's internal sensor communication network and from Global Navigation Satellite Systems (GNSS), which includes the Global Positioning System (GPS). GNSS is a critical component of this safety system since it has the needed ability to accurately determine a vehicle's location coordinates in most driving environments. However, its performance can suffer from obstructions in dense urban areas. Deficiencies of GNSS can be overcome by complimenting GNSS with other sensors.