Research On Carrier Attitude Measurement Technology Based On BeiDou And Its Application In Attitude Determination Test Of EMU

Attitude parameters are important information to characterize the safety of carrier operation,such as attitude measurement and control of spacecraft,yaw angle measurement of aircraft and direction information acquisition of land vehicles,etc.Attitude parameter detection is the basis of developing active motion state security monitoring.Using Bei Dou satellite navigation system can not only obtain the position,speed and time information of the carrier,but also obtain the attitude parameters,so it has a broad application prospect.The carrier phase is usually used as the basic observation measurement in attitude determination based on navigation satellite.And how to solve the integer ambiguity algorithm and attitude algorithm effectively is both related to the reliability of the measurement results and the availability of dynamic working conditions.Therefore,with the characteristics of Bei Dou system and on the basis of the construction of attitude measurement mode,the present study is conducted to study the fixing way of Integer ambiguity and algorithm way of attitude measurement.In addition,the attitude detection test of EMU was carried out at Lan-Xin passenger train.The main contents and contributions of this study could be summarized as follows:Firstly,attitude measurement model was established based on the Bei Dou Carrier phase differential observation in the present study.The measurements of carrier phase differential linear combination is adopted and the deterministic mathematical relationship between it and undetermined parameters(baseline vector,ambiguity,attitude angle)is derived.Furthermore,the mathematical model of attitude measurement is constructed,and the coordinate system and transformation relation are discussed.In addition,the model of attitude measurement system,including the configuration of attitude measurement system and antenna disposition,is analyzed based on the engineering application.Secondly,in the present study,the problem of integer ambiguity fixation and attitude resolution are studied based on double-differenced carrier phase measurements.For the inverse problem of high-order Matrix for based on the multiple epoch joint observation,the QR decomposition technique is applied to remove the coordinate parameters of the directional array in the observation equation.Moreover,the float solution is estimated only in the ambiguity domain,and the amount of calculation is reduced.As for ambiguity search difficulty caused by strong correlation among ambiguity float solutions,the number of possible ambiguity combinations is effectively compressed by means of the Cholesky decomposition and the reversible integer Z transform,and the search efficiency of the ambiguity is improved.The direct method and the least square method are used to estimate the attitude parameters and the attitude measurement platform based on MATLAB is built.The attitude measurement is realized by simulation experiment,which verifies the validity of the method described in is thesis.On the one hand integer ambiguity fixation is effective,on the other hand the least square method improvement of attitude algorithm accuracy compared with the direct method.Thirdly,aiming at the problem of train body attitude angle measurement of safety detection of EMU operation in high speed railway,the Bei Dou attitude measurement technology was introduced for the first time,and the train body attitude measurement test of EMU was completed in Xinjiang under the condition of strong wind.The running state parameters such as train body shaking angle,rolling angle,3D coordinate and real-time speed of the train are effectively collected,which shows the usability of Bei Dou attitude measurement technology.