The Research And Analysis Of The Propagation Properties Of Uwb Indoor Multipath

The Ultra Wideband(UWB) technology is becoming more and more famous due to it's high speed transmission, low transmission power, high multipath resolution and strong anti-interference ability. Especially the high positioning accuracy which is far away beyond the narrow-band signal, and the accuracy makes the UWB signal has a great application prospect in anti-terrorist and our lives. When we use the UWB technology to locate target, help people in disaster and trace object, we find the UWB technology can reach surprising achievement in positioning.This paper further studies the indoor UWB positioning technology and analyzes the four basic methods in estimating the target's coordinates. The four basic methods are the Time of Arrival(TOA), Time Difference of Arrival, Received Signal Strength(RSS) and Angel of Arrival(AOA). Due to the IEEE 802.15.4a supplied channel models, this paper studies the indoor positioning realization and put forward the localization algorithm based on the look-up table.In this paper, main structure and content are as follows:This paper studies UWB signals in theory. First, according to the requirements of ultra-wideband signal, we simulate Gaussian pulse and its multiple differentials in order to find the UWB signal pulse models, which is suitable for indoor detecting. Second, it introduces the UWB classic channel models, concentrate on the signal channel models that the IEEE 802.15 groups provided in different surroundings.Based on the analysis of the several classic UWB positioning technologies, we can conclude that the received signal strength(RSS) location technology is based on fully understand of the emission signal strength and channels, so as to estimate the distance between target and base stations. But because of the complicated and changeful indoor environment and the influence of multipath signals and NLOS, the same distance may appear different transmission loss, thus influence the precision of location. The angle of arrival(AOA) technology is more accurate than the RSS, but it need antenna array in the receiver, so the complexity and cost of base stations may increase to a large extent. What's more under the circumstance of indoor multipath effect and NLOS the accuracy of AOA method is hard to be ensured. The Time of Arrival(TOA/TDOA) uses the signal propagation delay for distance measurement. Because of the UWB signal's good time resolution and in the short period of time the environment channel can be considered to be relatively stable. The AOA method has high precision, so we chose the AOA method, and the method can improve the accuracy of positioning but also easily to be implemented.This paper analyses the multipath effect, the main factors of indoor positioning errors, and restrain the errors. Based on the TOA positioning algorithm, we simulate the relative path method and Fang's algorithm, through the simulation we find the two algorithm's deficiency. And we put forward the lookup table method base on AOA in indoor positioning. This paper simulates the lookup table algorithm through wall. Under the circumstance of indoor LOS model, we analyze the multipath error and the direct path wave, thus to verify the feasibility of rapid lookup table method.