Research On Envaluation Mathod Of Vehicle Trajectory Data Quality

The quality of traffic data is directly related to that whether it can provide reliable base for network state perception.Vehicle trajectory data is one of the traffic data which commonly used,due to its sources is different,its availability is different.For data screening,it is urgent to evaluate the quality of vehicle trajectory data.At present,the research on quality evaluation of trajectory data is theoretical and the practicability is weak.In this paper,The trajectory data of taxi is taken as research object and a method of vehicle track data quality assessment based on traffic parameter acquisition is proposed.And considering that the position accuracy of vehicle trajectory data as an important quality attribute of track data is difficult to access,a method is proposed based on existing data to count the position accuracy of vehicle trajectory data.In this paper,it is determind that the equipment and the positioning environment are the mian factors which effect the position accuracy of trajectory data by incorporating the GPS positioning error source.To get the deviation of the equipment,a method is proposed to judge whether the vehicle is still and using the data got from the vehicle stand still the equipment deviation can be got.And a method is proposed to quantify the impact of the environment on positioning accuracy base on the degree of deviation from the road of trajectory data.Based on data collected from the taxis in Harbin,the error of equipment on each taxi has been got and and the influence of positioning bias of part road link in Harbin is quantified.In order to make the method of vehicle trajectory data quality assessment combined with traffic,a method of vehicle trajectory data quality evaluation based on traffic parameter acquisition is proposed.First,the factors that affect the calculation accuracy of traffic parameters are taken as the evaluation indexes.Then,the dimensionless formulas of each index are determined according to the error of the calculated traffic parameters and the relations among each index,and then the weight coefficient of each index is determined by their contribution rate to the cumulative error of the parameter.Considering that there are many studies about the otain of link travel time based on vehicle trajectory data,this paper chooses the calculation of link travel time as an example.The process of evaluating the trajectory data based on the parameters is described in detail.And the effectiveness of the method is verified.