Positioning And Navigation System In The Port Logistics Park Based Wi-Fi

The lack of satellite signal in the park scene makes GPS and Beidou satellite navigation systems unusable.WiFi signals are covered in the park,which provides new ideas for implementing positioning and navigation systems in the park scene.Different from the outdoor positioning with Line of Sight(LoS)transmission path,due to the problems such as the occlusion of buildings and dense vegetation in the park,there are multipath effects,shadows and fading during the propagation of WiFi signals.This causes the signal distortion at the receiver,and will leads to a serious drop in positioning accuracy,which cannot satisfy the navigation function.In addition,in the path planning part of the navigation system,although many scholars have optimized the cost function of the AStar algorithm and improved the performance of the AS tar algorithm,there are few studies on optimization in the search direction of the AStar algorithm.In response to the above problems,this thesis conducts an in-depth study of WiFi-based positioning and navigation technology,the main work of this thesis is as follows:(1)In the positioning part of the navigation system,for the number of multipath components in the park scene and the angle of arrival(AoA)and time of flight(ToF)pairs of all multipath components,that is(AoA,ToF),due to the outliers generated by noise,it is proposed to use the density-based spatial clustering of applications with noise(DBSCAN)to obtain the direct path AoA.At the same time,the antenna gain and multipath suppression are processed on the received data,and then the relationship between the distance and the signal amplitude is fitted,and then the ranging function is realized.Finally,the triangle geometry principle is used to determine the position of the positioned object.(2)In the path planning part of the navigation system,the advantages and disadvantages of the traditional square AStar algorithm and the traditional regular hexagon AStar algorithm are analyzed.For the traditional square AStar algorithm,there are only 8 search directions,and the traditional regular hexagon has only 6 search directions.An improved AStar algorithm that expands the search direction is proposed.The improved AStar algorithm improves the search direction to 12 search directions,making the total length of the planned path significantly shorter than the traditional AStar algorithm,and because the improved AStar algorithm has more search directions,making the planned path is smoother and reduces the inflection points in the path.(3)Finally,this thesis builds an experimental platform based on the above two key technologies in the positioning and navigation systems,and conducts positioning and navigation experiments in relevant venues,and makes related performance analysis.Experiments show that the median accuracy using CSI positioning has reached 1.3m.The improved AStar algorithm is 8.87%less than the traditional square AStar algorithm in the total length of the planned path,and 3.65%less than the traditional regular hexagon AStar algorithm.