Study On Fingerprint Positioning Algorithm Based On WSN In The Parking Lot

Internet of vehicle is the main direction of the vehicles in the future.Its application is inseparable from the support of the vehicle position information,the GPS-based positioning technology has achieved good results in outdoor positioning,but it is not suitable for the closed environment,such as parking lot.The RSS fingerprint positioning algorithms based on Wireless Sensor Network(WSN)has been widely concerned due to its advantages of convenient deployment,low cost,low power consumption and environmental adaptability.Traditional RSS fingerprint positioning algorithms has problems of general accuracy of database,large amount of calculation,and low positioning accuracy,the paper proposes an improved method on the basis of the traditional algorithm.The main research are:First,an improved method is made to the existing RSS fingerprint positioning algorithm.The rules of RSS stability and high discrimination are obtained after studying the distribution of wireless signal field,the method of controlling the RSS threshold is proposed to limit the nodes communicating in the near-zone.The positioning unit is divided into the positioning area,and a rough estimation method is proposed to infer the unit of the target using RSS descending queue,so as to narrow the range of the fingerprint database,and reduce the calculation amout in the matching stage.Grubbs criterion is used to filter the sample data to improve the accuracy of the fingerprint database.In addition,reduce the positioning error by judging the RSS queue nad positioning result validity.Then,in view of the application scenario,the paper optimizes the hardware and software of the WSN system based on 433 MHz,it improves the networking and positioning effect,and reduces the power consumption of the terminal nodes.After verifying the feasibility of improved algorithm applied in vehicle positioning based on the wireless network system,this paper analyzes the influence of vehicle on the RSS of positioning node set in the vehicle,the RSS interval compensation method is proposed to modify the RSS of the positioning target to improve vehicle positioning effect,it can meet the positioning requirements of vehicles in a wide range of parking lot when the positioning error is within 5m.In addition,experiments show that the improved algorithm has advantages compared with traditional algorithm in terms of positioning accuracy,algorithm cost,power consumption of terminal node.