Reserch And Application Of The Positioning Technology Based On UWB

In recent years, with the rapid development of wireless sensor network, the wireless location technology is attracted to people. Traditional wireless location technology such as infrared, bluetooth, ultrasonic, RFID and WiFi, has been widely used, but they cannot satisfy people’s needs in the aspect of positioning accuracy and power consumption, etc. UWB(Ultra-WideBand) technology has low transmission power, strong ability to resistance to multipath interference, strong penetrating power and good secrecy. Because of its high temporal resolution, UWB positioning technology can reach high precision, UWB positioning technology has a wide foreground in indoor loaction. So it has significant application value to do UWB positioning technology research.This paper first introduced the research status of UWB positioning technology, including the status of node algorithm research and the development of UWB positioning products. Then the paper introduces the technologies related to ultra-wideband, including modulation of ultra-wideband signal, ultra-wideband channel, commonly used range acquisition techniques in wireless positioning and ultra wideband signal detection.The paper studies and analyzes the factors affecting the positioning accuracy of UWB and divided them into two categories: geometric accuracy factors and range factors. In detail, they include the geometric layout of reference point, multipath and shielding effect, multi-user interference, co-channel interference. Geometric layout determines the geometric accuracy while other interfering factors affect the range accuracy.For wireless positioning, there has been many classical positioning algorithm. This paper focuses on studying and deduct Fang algorithm, Chan algorithm, least squares method, Taylor series expansion method and other traditional positioning algorithm. Through analyzing their characteristics, an improved algorithm which corrects TOA measurement through BP neural network is put forward. We build a simulation of LOS and NLOS environment in which traditional algorithm and the algorithm put forward in this paper are simulated and analyzed. The results show that the positioning accuracy of our algorithm is higher than that of the traditional algorithm in NLOS environment.Finally, this paper introduces a solution to achieve UWB positioning system which is less complicated in that it uses high speed comparator to achieve single bit sampling, applies parallel processing in digital processing, and uses two-way ranging protocol to weaken the demand on system clock synchronization. The test shows that, relatively good positioning accuracy is achieved in a NLOS environment.