Research And Implementation Of The Outdoor UWB Accurate Location System

UWB(Ultra Wideband) is a non-carrier communication technology, using nanosecond to picosecond-level non-sinusoidal narrow pulse to transmit data, which is also known as impulse radio, it can be used for the fields in wireless communication, position detection, radar and so on. Early UWB technology had been used in American military field, while accompanied with the development and mature of wireless communication technology, it promotes the development of much wireless business, requirement for high accuracy positioning becomes more and more in some occasion and the public voice for the UWB technology becomes higher and higher. In February 2002, UWB technology can be used in civilian permitted by the US Federal Communications Commission, UWB technology became the most popular technology in distance measurement and location by its strong penetrating ability, multipath high resolving power, extremely wide bandwidth and other characteristics. UWB technology is generally used to locate small-scale indoor, research on outdoor location is relatively less. The research of this paper is based on UWB outdoor location, mainly on some special occasions such as pony sports fields, training ground, and amusement park, high-precision UWB technology can pinpoint the location of people, and can be used to analyze movement locus of the staff. The application of UWB for outdoor location is wide in range, at present the researches on UWB technology in location are most still in the phase of laboratory in our country, thus, this study is of essential meaning.The basic principle of UWB technology is the foundation of this paper, the author analyzes the implementation of UWB signals and the characteristics of channel model, and then she learns more about the propagation characteristics of UWB signals. By studying on UWB wireless location method, she concludes that location methods of TOA, TDOA are more suitable for UWB channel location. She studies the common localization algorithm of UWB, including Fang, Chan, Taylor algorithm, by analyzing the solving of the least squares method in TOA and TDOA location algorithm, and simulating the specialty of each algorithm under different environmental, the author concludes that each algorithm has its own limitation, she proposed Kalman filter algorithm, improves and simulated it, at last she obtained that the location result of Kalman filter algorithm is better than other’s in different environment, which can effectively control the NLOS error.In the end, the overall framework of the system is put forward in this paper, and the implementation scheme of the whole system is given, by using DW1000 chip, the author designs hardware circuit of the labels and the base station, she tests the label and the base station, whose distance-measuring error is within 10 cm, it is with high precision, and its optical distance is about 350 meters, NLOS distance about 45 meters, which can meet the requirement for outdoor location distance. She analyzes the working status between tags, and calculates the number of working tags, there are many unexpected factors in the location process, so she analyzes the factors that affect the precision of the system. Finally, she concludes that the realization of the outdoor UWB positioning system is feasible.