Research On Positioning Algorithm Based On UWB

With the rapid development of science and technology,people are increasingly dependent on Location Based Service,and higher requirements on location accuracy requirements.In the wisdom of the city,disaster relief,Internet of Things and other correlation areas the industry Location Based Service has a vast market.Nowadays,GPS has solved the problem of outdoor positioning effectively,and with the improvement of living standards,people are increasingly concerned about the safety of some special patients,such as: Alzheimer's disease patients,high-risk infectious diseases and patients with mental disorders,etc.People gradually shift their attention from outdoor to indoor on Location Based Service.As the complex indoor environment,there are a lot of non-line-of-sight factors,the positioning accuracy has been difficult to meet people's needs on traditional indoor wireless positioning technology such as: Radio Frequency Identification,Bluetooth,and Ultrasound.But the Ultra-Wideband technology suitable for indoor positioning with its strong anti-interference ability,strong penetrating ability and high positioning accuracy,and its accurate positioning in the room is a better choice for people.This paper will discuss and study the localization algorithm based on UWB technology.Firstly,the characteristics of UWB signal and indoor transmission signal model are studied,and the IEEE802.15.4a channel model is used as the UWB channel model.Then,several kinds of ranging methods and classical positioning algorithms which commonly used in UWB positioning are introduced.And discussing the main sources of error and studying some methods of discrimination and suppression of non-line-of-sight error.Three non-line-of-sight discrimination and suppression algorithms are introduced in detail: N-Taylor algorithm,geometric area authentication algorithm and residual weighting algorithm base on Chan.Secondly,a TWR / TDOA hybrid ranging method is proposed by combining the Two Way Ranging and the Time Difference of Arrival.This method does not consider the synchronization clock between the reference node and the target node,and reduces the delay error effectively which caused by the node response the signal during the TWR ranging.On the processing of non-line-of-sight error,this paper modifies geometric area authentication algorithm and residual weighting algorithm base on Chan.To reducing the system positioning error,the paper corrects the distance estimation to assure the result under the specified threshold by iterative weighting.Finally,this paper uses the MATLAB software to simulate the classical Chan algorithm,classical Taylor algorithm,geometric area identification algorithm and TWR / TDOA hybrid localization algorithm which proposed in this paper under the same line-of-sight or non-line-of-sight indoor environment.The results show that the hybrid positioning algorithm based on TWR / TDOA proposed in this paper has higher positioning accuracy and better positioning position,both in line-of-sight and non-line-of-sight simulation environment.