International Core Journal of Engineering 2020-26 | Page 93

2019 International Conference on Artificial Intelligence and Advanced Manufacturing (AIAM) High-Accuracy Positioning Algorithm Based on UWB Xizhong Lou Yaqiu Zhao* College of Information Engineering China Jiliang University Hangzhou, China e-mail: [email protected] College of Information Engineering China Jiliang University Hangzhou, China e-mail: [email protected] Abstract—In the indoor positioning, it proposes a line to approximate hyperbola positioning algorithm based on ultra-wideband (UWB) aiming at the problems of low-accuracy positioning, non-line-of-sight (NLOS) phenomenon and multipath propagation in the precise positioning of mobile tags. The paper a method of using some lines to approximate hyperbola. It can convert quadratic hyperbolic equation into linear equation. Then it can achieve the high-accuracy position combining the time difference of arrival (TDOA) and triangle centroid position algorithm. According to MATLAB simulation, the average distance error of the three-line approximate algorithm is 23.7cm, the average distance error of the three-and-four-line approximate positioning algorithm is 17.7cm, and the average distance error of the five-line approximate positioning algorithm is 12.9cm. In the case of ensuring positioning accuracy, the Chan algorithm runs for a period of 14.5s. The maximum time is 7.9s for the algorithm to run one cycle, and the complexity of the algorithm is greatly reduced. calculate the distance difference from each anchor to a mobile tag by the measured TDOA time. It can establish the plurality of hyperbolic equations according to the distance difference. The Chan algorithm [7] is the classical localization method based on the time difference of arrival. It does not require recursion to give a closed solution to the hyperbolic equation. The Taylor algorithm [8] is a recursive algorithm that requires an estimate of the initial position and solves the partial least squares [9] (LS) solution of the TDOA measurement error in each recursion. The Kalman filter [10] is a linear least-mean-squares estimation algorithm which is the best filter in a linear system. In a variety of sensor measurements, Kalman filtering is widely used for state estimation [11]. Assuming that the experimental process and measurement noises are normally distributed, measurement noise of wireless positioning system is not easy to meet the normal distribution condition due to frequent heavy tailing anomalies value. The Fang algorithm [12] can linearize the TDOA hyperbolic equation and then solve the solution of the hyperbolic equations which is the position of the moving tag. The algorithm is easy to understand and the calculation is simple. Keywords—UWB, line to approximate hyperbola, TDOA, positioning accuracy I. I NTRODUCTION This paper proposes a method of approximating the hyperbolic localization model by subsection approach, which is divided into three-line approximate positioning algorithm, three-and-four-line approximate positioning algorithm, and five-line approximate positioning algorithm. It can use the lines to approximate hyperbola. The quadratic curve model is transformed into a linear model and the intersection point of the line segment can be approximated as the intersection point of the hyperbola. Then it can use the triangular centroid positioning algorithm [13]. The centroid is the positioning result of the mobile tag. In recent years, with the continuous development and update of wireless sensor networks (WSNs), indoor positioning technology has been rapidly improved. Indoor positioning [1] refers to the use of wireless mobile communication network which measuring the received wireless signal parameters. According to a specific algorithm, it is easy to define the geographical position of the mobile terminal at a certain time and provide the users with location information services. Ultra-wideband [2] (UWB) is a wireless carrier communication technology which uses nanometer-level pulse as its carrier to transmit data. Ultra-wideband has the advantages of strong anti-interference ability, high transmission rate, and good penetration. It can achieve high-precision positioning in fire rescue, large supermarkets, hospitals, laboratories, and military fields. II. TDOA A LGORITHM P RINCIPLE The positioning principle of TDOA [14] is to obtain the distance difference from each anchor to the mobile tag by using a set of TDOA measurement values. It establishes a hyperbolic equation which takes the base station as the focus. The mobile tag that needs to be located is on a certain branch of the hyperbola. The solution of the hyperbolic equations is determined as the position of the estimated moving tag. The positioning principle is divided into two steps: (1) ranging which is measuring the distance between two points; (2) positioning which determines the location of the mobile tag according to the results of the ranging by a specific algorithm. There are four classic positioning methods which include received signal strength [3] (RSS), signal angle of arrival [4] (AOA), time of arrival [5] (TOA) and time difference of arrival [6] (TDOA). The TOA/TDOA scheme is the main ranging scheme for UWB positioning. It can 978-1-7281-4691-1/19/$31.00 ©2019 IEEE DOI 10.1109/AIAM48774.2019.00021 Assuming that anchor1 ( x 1 , y 1 ), anchor2 ( x 2 , y 2 ), anchor3 ( x 3 , y 3 ) and anchor4 ( x 4 , y 4 ) are the coordinates of the base stations, tag ( x 5 , y 5 ) is the coordinate of the mobile tag, as shown in Fig. 1.The hyperbola in the figure is a 71