This paper addresses the challenge of vehicle selection in a Vehicular Ad-hoc Network (VANET) used to assist vehicles with limited satellite visibility in urban environments. In [1], we proposed a Non-Range cooperative positioning system which uses pseudoranges from only one assisting vehicle at any given time. However, many vehicles are within the communication zone of the target vehicle especially in dense urban canyons. In this paper, we elevate the performance of our cooperative system by proposing a distributed vehicle selection criterion named Absolute Sum of Single Differencing (ASOSD). To test the viability of the proposed system, we design a cooperative experiment using three NovAtel receivers and show that the Positioning Accuracy Gain (PAG) of our system has increased by 60% compared to a system that averages Artificial Candidate Pseudoranges (ACPs) from two assisting receivers. Moreover, we study the effect of; the number of assisting vehicles, multipath, receiver noise, satellite clock bias, ionospheric and tropospheric errors on the selectivity of the proposed system. We show that as the number of assisting vehicles increase, the Root-Mean-Square-Error (RMSE) of the generated ACP decreases. Moreover, the selectivity of the ASOSD selector is not affected by the common errors in the shared pseudoranges.
['Anas Mahmoud', 'Aboelmagd Noureldin', 'Hossam S. Hassanein']
Distributed vehicle selection for non-range based cooperative positioning in urban environments