A Precise GPS Sensor Subsystem for Vehicle Platoon Control

Abstract

Coordination of vehicles in high-density traffic increases the efficiency of transportation infrastructure usage while improving safety standards. The concept of Collaborative Driving Systems (CDS) addresses this issue by linking several vehicles in a platoon through local communication links and in-vehicle positioning and control systems. A CDS will enable vehicles to communicate and follow a leader vehicle thus forming a platoon of vehicles. As a part of a Canadian initiative to develop technologies for CDS, this paper investigates the performance of carrier phase GPS as a positioning subsystem for a CDS. This includes relative positioning of vehicles with centimeter level accuracy and estimating their relative speeds to an accuracy of a few centimeters per second. This research investigates carrier phase technology applied to a host vehicle positioning itself in a platoon of vehicles using the GPS subsystem. The advantages of the GPS subsystem with inter-vehicle communication in a CDS are illustrated over alternative technologies especially in issues such as maintaining the asymptotic stability in vehicle platoons. Tests were conducted using four instrumented vehicles, each equipped with a precise GPS position and heading determination system using a two-antenna configuration. This enabled the relative position estimation between vehicles as well as between antennas with a known interantenna baseline. Several driving scenarios are presented including joining, leaving, and passing a platoon of vehicles. The achievable accuracy in relative position and velocity is investigated.