Research On Accurate Ranging Algorithm And Calibration Technology Of Underground Locomotive Based On UWB Communication

Downhole locomotives can not drive orderly and safely without scheduling system,for the scheduling system,the key question to improve its efficiency and safety is how to achieve the precise calibration of the locomotive,that is,to obtain the precise one-dimensional coordinates of the locomotive in the track.UWB(ultra wideband)is a new type of communication technology that can achieve accurate ranging with its high time resolution,with the help of its precise range measurement results,we can achieve accurate calibration,but the current distance measurement algorithms based on UWB communication technology need to be improved in performance.In addition,the existing calibration methods can not guarantee the high calibration accuracy,and are susceptible to the interference of the underground environment.Therefore,it is of great research value and practical significance to develop a downhole locomotive calibration method based on UWB communication technology.In this thesis,the theoretical and practical research work is made in view of the above situation:1.A time of arrival(TOA)estimation algorithm based on dynamic threshold detection for UWB signals is proposed to improve the UWB ranging accuracy.The algorithm detects the peak of the matched filter output pulse received by the receiver to determine the detection range of direct path(DP),and sets a joint measurement parameter that reflects characteristics of the signal and channel,and then it sets the corresponding optimal threshold factor according to the different parameters,finally,it searches the corresponding moment of the accurate position of DP in the detection interval through the threshold detection to get the estimated value of TOA.The estimation results are compared with the traditional TOA estimation methods in the IEEE802.15.4a standard channel simulation environment,the results show that the proposed algorithm is suitable for different SNR and delay characteristics of the channel,and can take both the computational complexity and algorithm accuracy into account.2.In this thesis,the calibration technology of underground locomotive based on UWB communication is studied,the calibration node with DW1000 as the core module is developed,and the precise calibration system of underground locomotive is built.Firstly,the structure and function of the calibration system are given,then the exact calibration principle of UWB communication in the system is described,and the prototype system is verified.In view of the limitations of the actual situation in the underground,the distance accuracy verification work of DW1000 module is done respectively in the indoor office,office building corridor and open playground three environments,the experimental results show that the module's ranging error are controlled at about 10cm.in the above three scenarios.