Research on vehicle trajectory matching method based on improved HMM

Aiming at the problem that traditional vehicle trajectory matching algorithms based on hidden Markov model(HMM) cannot have both accuracy and time efficiency in complex and special road sections, a vehicle trajectory matching method based on improved HMM modeling was proposed. In the determination of candidate road sections, grid index was generated to improve the overall retrieval efficiency. The improved HMM model integrated heading angle factors in the calculation of launch probability, considered the deviation effect caused by vehicle speed on heading angle, and set empirical factors for adjustment. At the same time, considering the factors such as the excessive error of the observation value before and after and the curve section, the actual travel distance of the vehicle within the unit sampling interval was used instead of the observation distance value to ensure the accuracy of the calculation of the transfer probability. Finally, the measured data was used to conduct experiments to verify the performance of the improved algorithm. The experimental results indicated that the matching accuracy of this method was about 94.0%, which was 2.8% higher than that of the traditional HMM trajectory matching method. It also had certain advantages in improving time efficiency and matching accuracy of complex road sections. The single-point matching time was reduced by about 0.9 ms, suitable for matching under complex road conditions such as intersections, overpasses, and parallel sections.