Research And Implementation Of Indoor Localization Systems Using Uwb Signals

Global positioning system(GPS) nowadays can not satisfy people’s growing demands of localization due to signal attenuation in a complex environment and vulnerabilities in military applications. Therefore, it is significant that developing a high-accurate localization system, which is independent of GPS. Impulse radio-ultra wideband(UWB) is a promising option for accurate location due to its though-wall propagation and high time resolution. In this dissertation, we research UWB localization and tracking methods in complex environment with few anchors because of its high cost. Research work of the dissertation focus on following paragraph.In this dissertation, we research a non line of sight(NLOS) identification method based on Least Squares Support Vector Machines(LS-SVM), which requires little priori information of line of sight(LOS) and NLOS communication channels. we propose the use of F- value algorithm to perform feature ordering. Then the performance of NLOS identification is evaluated in UWB localization. We mitigate NLOS error based on LS-SVM regressor for most loaciton ranging is in NLOS conditon. K-th nearest neighbor(k-NN), a new NLOS mitigation method, is proposed to reduce the compution complexity, Which can apply to low cost and complexity scenarios. The results certify that the proposed k-NN method is able to achieve results very close to a widely used LS-SVM method. Our work including NLOS identification and mitigation is mainly carried out and evaluated by practical measurements. Some anchor nodes, nevertheless, may stop working due to signal attenuation in location for mobile target. In this condition, ranging result and trajectory prediction are combine to track the agent by Extended Kalman Filter mehod(EKF). We also anlysis the precision of this method. Finally, positioning system frame is designed. Based on UWB ranging nodes, we develop the the location system software and implement the high- precision localization system. In actual positioning scenarios, target can achieve the goal of high-precision positioning for target.Research work of the dissertation can provide some reference methods for the realization of UWB localization system in complicated indoor environment. The design and development is a useful exploration for commercialization of UWB localization system.