Design Of Indoor Localization System Based On UWB

In recent years,location-based service(LBS)has covered lots of human dynamic activities,such as safety,emergency rescue,navigation,life convenience,tourism and so on.LBS has a wide range of prospect for development.As one of the core contents of LBS,the design of indoor localization system has become a hot topic in this field.Ultra-wideband(UWB)technology is very suitable for the design of indoor localization system because of its unique advantages,such as the fine time resolution,the ability to resist multi-path interference,and so on.In the indoor localization system based on UWB,Time Difference of Arrival(TDOA)and Two-way Ranging(TWR)are widely used localization schemes.However,the localization system based on TDOA and TWR exists the clock synchronization issue and the limit on the number of users respectively.In order to overcome these problems,a new localization scheme is proposed,and a set of indoor localization system based on UWB is implemented.First,in order to break the limit on the number of users,the system signals exchange mechanism is put forward.In the signals exchange process,all the blind nodes just receive the ranging signals from the anchor nodes to locate themselves so that the system can break the limit on the number of users and locate a large number of users at the same time.Second,a clock model is established to make it possible that the asynchronous clock can be corresponding to the reference clock one by one,so that the high accuracy clock synchronization can be achieved by compensating the model parameters of every clock.In addition,all the blind nodes can compensate their clock frequency though the Kalman filtering algorithm to eliminate the difference between their clock frequency and high accuracy clock synchronization is implemented in the algorithm.Then,the neural network algorithm is designed to compensate the ranging error caused by some uncertain factors,and the parameters of neural network are trained with the distance data and distance error data of the system,which improves localization accuracy of the system significantly.Finally,the indoor static localization experiment results show that the indoor localization system based on UWB can achieve 3-D localization and the localization error in X and Y axis is less than 10 cm.