Study On Road Vehicle Location Method Based On Low Power Bluetooth Positioning Technology

Vehicle positioning is an important part of the intelligent transportation system,and it is the basis for the intelligent transportation system to achieve correct control and efficient scheduling of vehicles.At present,the commonly used vehicle positioning is based on GPS positioning,but it has blind location and its accuracy cannot meet the requirements of high-precision vehicle positioning.Other vehicle positioning technologies also have their own limitations and cannot be promoted on a large scale.By analyzing and summarizing the main advantages and disadvantages of various current vehicle positioning technologies,this paper proposes a road vehicle positioning method based on low-power Bluetooth positioning technology,which can meet the requirements of high-precision vehicle positioning and realize acquisition and transmission of traffic information through Bluetooth network.In the positioning method proposed by the paper,the Bluetooth beacon adopts the way of lane dividing line layout,and periodically transmits broadcast data at intervals of 100 ms which includes signal strength value and latitude and longitude information for positioning.The to-be-positioned vehicle receives broadcast data of the Bluetooth beacon through the Bluetooth mobile terminal,extracts the positioning information therein,implements the horizontal lane positioning and the longitudinal positioning by the weighted centroid algorithm based on the received signal strength value,and corrects the longitudinal positioning result by using Kalman fi lter.The results of the actual data test are: the lateral lane positioning accuracy is 83.25%,and the vertical positioning error is 3.5m.The positioning method achieves better road vehicle positioning effect.Aiming at the problem that the signal strength value is susceptible to multipath effect in complex road environment,this paper proposes a method of acquiring signal strength in single channel by analyzing the characteristics of Bluetooth broadcast channel.The actual data shows that the method can mitigate the fluctuation of signal strength and prevent the occurrence of outliers.Aiming at the problem that the Bluetooth beacon’s power consumption is too high due to continuously transmitting broadcast,the paper proposes a scheme of the triggering Bluetooth beacon.The solution combines the functions of geomagnetic sensors and Bluetooth,uses geomagnetic sensors to detect vehicle and trigger Bluetooth broadcastting.The power consumption of Bluetooth beacons under this scheme has dropped by 85%.Based on the scheme of the triggered Bluetooth beacon,the positioning algorithm is improved base on the original.The algorithm adopts different positioning strategies according to the different positioning scenarios.The actual data test result of the improved positioning algorithm is the accuracy of the horizontal lane positioning is 87.06% which is 3.81% higher than the one before the improvement;the longitudinal positioning error is 3m,which is 0.5m lower than the one before the improvement.The road vehicle positioning method based on the triggered Bluetooth beacon greatly reduces the power consumption required for positioning,and at the same time achieves a good positioning effect,and has certain application value.