A TDOA Localization Scheme Based On IR-UWB And Zigbee

Localization is one of fundamentals for many applications, and also akey technique in terms of theory and research. TDOA, obtained by twotheorems, is one of the strategies in WSN localization. Two techniques,IR-UWB and ZigBee, are applied into two theorems of TDOA, respectively.An improved TDOA-Chan algorithm to localize is first demonstrated basedon cross-correlation with IR-UWB signals in the Voronoi Diagram. Second,a ranging campaign is undertaken about TDOA localization based onZigBee and Ultrasound, then trilateration is adopted to localize in a practicalsituation.First, with respect to Theorem of CRLB, the accuracy of estimation ofTOA/TDOA is proportional to the effective bandwidth of the signal, so thecharacteristic of wide bandwidth of IR-UWB is selected to localize. Second,anchor nodes in WSN are divided into different territories in the VoronoiDiagram dynamically, aiming to establish the architecture to synchronize throughout the entire network. At the same time, three closet anchor nodesto the unknown node are selected in a specific position sequence. Third,regarding high time resolution of IR-UWB, cosine waves are poor substitutefor IR-UWB signals into cross-correlation to acquire TDOA in ChanAlgorithm. Meanwhile, the standard deviation of AWGN appears to have athreshold. Finally, simulations and consequences with respect to the novelalgorithm presented here and the classic trilateration prove that more denserdistribution around the coordinate of an unknown node can be obtained withVoronoi Diagram, than without. Besides, the consequences prove that theRMSE of localization could be achieved much smaller, accuracy oflocalization gets better, and performance of the novel algorithm is betterthan trilateration.With ranging module of ZigBee and Ultrasound based on TDOA,90independent and repeated experiments of ranging campaign are executed,which resolve1~2m distance result in centimeter-level(cm) ranging errorand cm accuracy of localization with trilateration. Simulations and consequences with respect to the ranging module to localize prove that theperformance of localization with ranging module is between the novelalgorithm presented in this dissertation and a trilateration to localize withoutthe Voronoi Diagram.