| With the wide application of wireless communication technology and the rapid development of Internet of Things technology,location-based services,as one of the basic services of the mobile Internet,have brought great convenience to people’s daily life,especially transportation.At present,the Global Positioning System(GPS)is one of the most widely used location service technologies,which can achieve more accurate positioning in outdoor environments;however,in complex indoor environments,due to the blocking or shielding of satellite signals by buildings,will increase the difficulty of positioning and reduce the accuracy of positioning.In addition,in order to maintain a high real-time position awareness function,the power consumption of the terminal during the positioning process is a crucial indicator;because the GPS terminal needs to receive satellite signals and keep the positioning function turned on at all times,this makes its power consumption relatively large.Generally speaking,the power of wearable devices with GPS functions can only last for a few days or less.Frequent charging and discharging or replacement of devices make positioning technologies such as GPS have many bottlenecks in the application of the Internet of Things.Based on the above two points,the research of indoor positioning technology has become a hot direction,and how to reduce power consumption on the basis of improving positioning accuracy has become the focus of problem solving.Among the mainstream indoor positioning solutions,the Ibeacon positioning method based on low-power Bluetooth has been widely used due to its advantages of low power consumption and easy deployment.At present,most of the Bluetooth indoor positioning devices on the market use Bluetooth acquisition devices and communication gateways+Bluetooth beacons to obtain and transmit location information data.Although the solution is mature,it lacks flexibility.In an easily changing indoor environment,Bluetooth gateways need to be deployed,resulting in Inconvenient and affect use.This paper designed a Bluetooth indoor positioning system based on NB-IoT,connects the NB-IoT module to the Bluetooth 5.0 acquisition module,without the need for a communication gateway,and sent data through the NB-IoT narrowband Internet of Things while collecting Bluetooth beacon data to the back-end system,to achieve a more convenient and easy-to-deploy Bluetooth positioning solution.At the same time,It took advantage of the advantages of NB-IoT in low power consumption,so that the power supply current of the 3.3-volt lithium battery of the device in standby mode is reduced to 4.5 μA,and the small size of the device is convenient for portability and deployment,which reduces the difficulty of deployment and avoids the difficult application problems caused by frequent charging and discharging.This paper also researched and optimized the positioning algorithm,studied the ranging positioning algorithm based on Bluetooth RSSI,and verifies that the accuracy of the triangular centroid positioning algorithm is significantly improved after the weighting factor is improved.At the same time,It built a back-end position data processing system and a frontend positioning demonstration page,and tested the Bluetooth indoor positioning solution based on Ibeacon in the laboratory and corridor environment,and filtered and analyzed the collected position information data.The test results show that the average distance error of the positioning is only 0.7828m after filtering and improving the positioning algorithm under the Bluetooth beacon node density of about 0.192/m2,which completes the precision design requirements under low power consumption and meets the Indoor positioning application requirements.Based on the research results of this thesis,we cooperated with manufacturers to develop an intelligent helmet management system for construction sites,which was applied to the Guanghuali construction site of Beijing Zhuzong Group,and achieved good application results. |
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