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Research On Integrated Train Positioning Optimization Method Based On IMU Compensation

Posted on:2021-03-01Degree:MasterType:Thesis
Country:ChinaCandidate:C X XieFull Text:PDF
GTID:2392330614972587Subject:Traffic Information Engineering & Control
Abstract/Summary:PDF Full Text Request
In recent years,with the continuous deepening of satellite navigation systems in the field of railway positioning,the multi-sensor integrated positioning method based on inertial sensors has become the future development trend,in which MEMS-IMU has the characteristics of low cost,miniaturization and anti-interference.However,due to the limitations of structural processing technology and circuit technology,MEMS inertial devices have extreme measurement errors.At present,in the accuracy of existing MEMS inertial devices,compensating and correcting the existing errors will be one of the effective methods to improve the accuracy of integrated navigation,and it will also bring certain economic benefits.In this paper,the errors are divided into systematic errors and random errors according to the error characteristics of MEMS-IMU in the actual application environment,and we conducts research on compensation schemes from different perspectives such as model building methods,calibration layout schemes,and online compensation.In addition,this paper proposes the attitude determination principle and combined technology of the magnetometer to make up for the problem of the attitude divergence of the pure inertial navigation system,thereby optimizing the integrated navigation system and improving accuracy,reliability and continuity.The main research contents of this thesis include:(1)This thesis studies and analyzes the system error and calibration scheme of low-cost MEMS-IMU.This thesis studies the sources of system errors in MEMS inertial devices,and determines the main error terms and establishes error equations.On this basis,a calibration scheme is proposed to accurately calibrate the error parameters of the error equation.Simultaneously,the actual application scene data is used to simulate the error model and calibration method to verify the effectiveness of the method.(2)This thesis studies the random error model and online compensation scheme of MEMS-IMU.Traditionally,random noise is directly treated as white Gaussian noise,but the random noise of inertial devices also contains colored noise.In this paper,the random noise of the inertial device is decomposed into a combination of colored noise and white noise,then the colored noise is modeled to obtain a differential equation,and a satellite-based colored noise online compensation scheme is designed.Finally,the scheme is verified.(3)This thesis studies the attitude determination scheme and integrated model of the magnetometer.In order to improve the accuracy of the integrated system and maintain the positioning accuracy of the pure inertial navigation system for a long time,a magnetometer was introduced to increase the attitude observation and maintain the stability of the attitude.Firstly,the attitude determination equation and magnetic declination model and calculation method of the magnetometer were studied.Secondly,based on the traditional filtering equations,the mesoscopic measurement is expanded and the measurement model is updated and upgraded.(4)This thesis designs and completes the experimental verification platform.Combined with the receiver board and MEMS-IMU equipment owned by the laboratory,a test verification platform was built to verify the above algorithm content in practical applications.The results show that through the compensation of the MEMS inertial device system error,the measurement output accuracy of the inertial device is increased by more than 80%,and the navigation results are effectively improved in both static and dynamic operating environments.On this basis,the random error model based on GNSS-assisted further improves the positioning accuracy of the integrated navigation system and accelerates the convergence speed of the position accuracy when the visibility of the satellite changes.The enhanced integrated positioning system formed by the introduction of the magnetometer provides stability for attitude maintenance and ensures the pure positioning continuity.This thesis contains 66 figures,20 tables and 76 reference.
Keywords/Search Tags:Integrated positioning, MEMS-IMU, Sensor calibration, Dynamic error, Magnetometer, Attitude determination scheme
PDF Full Text Request
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