Research On Indoor Positioning Algorithm Based On UWB

With the rapid development of wireless network technology,people are increasingly demanding indoor positioning technology.Ultra-wideband(UWB)technology is a new type of wireless communication technology that transmits information through Gaussian pulses without carrier.UWB which has the characteristics of high speed,strong multipath resistance,anti-interference,low power consumption,low cost and high-precision positioning can also achieve high-accuracy positioning in complex environments.And it gradually becomes a hot spot in the research direction of wireless positioning systems.In this paper,the basic concepts of UWB are briefly introduced,such as the UWB's definition,the working spectrum range and characteristics.Then the Gaussian pulse waveform,energy spectral density and modulation method of pulse signal of UWB are analyzed from time domain.The transmission characteristics of UWB in each channel are obtained by simulating the channel model.Since there are metal,windows steel and other obstructions in the room,the UWB signal will be reflected and refracted during the propagation process.The receiving end will not only receive the direct path signal,but also receive various reflection path signals.Therefore,this paper proposes an improved algorithm for identifying direct path signals.Based on the channel pulse waveforms of the direct path signal and the reflected path signal,a series of rules are developed to identify the actual direct path signal.The confidence level of the direct path signal is obtained by several identified parameters.And the weight formula is obtained,which is used to reduce the error caused by the unreliable direct path signal.In the scene of line of sight(LOS),the identification rate of success is 95.5% through MATLAB simulation.In the scene of non-line of sight(NLOS)scene,the identification rate of success is 92.4%.In the mixed scene of LOS and NLOS,the identification rate of success is 93.2%.The experiments show that the identification algorithm of direct path signal can effectively identify the direct path signal.In this paper,the positioning method of the received signal strength,the positioning method of the time of arrival,the positioning method of the time difference of arrival and the positioning method of the angle of arrival are compared and analyzed.The positioning method of the time difference of arrival is used as the basis of the UWB positioning algorithm.Then it analyzes the classical C han positioning algorithm.The positioning algorithm of line to approximate hyperbola is proposed,which combines with the weight formula to calculate the final positioning coordinates.The performance of the algorithm is analyzed from error and complexity,which simplifies the calculation process and reduces the time complexity by 34%.Through the comparison experience of MATLAB simulation,the accuracy of this algorithm is 14.1cm in static positioning and 15.3cm in dynamic positioning.The algorithm has good positioning effect.