Research On Key Techniques For Integrated Evaluation Of Ballistic Missile Guidance Precision

Precision is the most importmant technical index for ballistic missile,and platform inertial navigation system(PINS)is the most important navigation on ballistic missile.However,the instrumental error of the PINS has the most important influence on the guidance precision.In order to improve the guidance precision,some key techniques for integrated evaluation of ballistic missile guidance precision is carried out in this thesis.The main contents are listed as follows:(1)The method for calibrating the instrumental error coefficients of the PINS based on centrifuge test is studied.Firstly,a complete error modle of the PINS including second-order terms and three-order tems related to acceleration is established,and the applied acceleration equation in centrifuge test is derived.Then,the redundancy of the error coefficients is analyzed and the method to solve this problem is proposed.A six-position calibration scheme is obtaine through observability analysis.Simulation results indicate that the proposed method can calibrate 48 error coefficients and the maximum relative error of the calibration results is less than 4%.(2)An observability analysis method based on correlation coefficient is proposed.The error covariance matrix in the filter process is used to calculate the correlation coefficient of one error parameter with respect to another error parameter.If the correlation coefficient of these two parameters is larger,the observability for them is worse.Compared with other bservability analysis methods,this method is unnecessary to compute the toltal observability matrix and the bad observable parameters can be directly determined.(3)The influence of the centrifuge errors including radius error,angular velocity error and misalignment angles on the calibration accuracy is analyzed by using combined methods of theoretical analysis and numerical simulations.Firstly,the applied acceleration equation and input angular rate equation with the centrifuge errors are derived.Then,the relationship between the calibration errors and the centrifuge errors is established.Based on the observability analysis theory,an approach is proposed by regarding the centrifuge errors as the state parameters to be estimated in the EKF algorithm to reduce the influence of the centrifuge errors on the calibration results.The simulation results show that the error of the misalignment can not exceed 1 arc-minute;the relative change of the rotation radius is less than 0.05%,and the relative error of the rotation velocity is not more than 0.005% in order to ensure the calibration accuracy.(4)The method for calibrating the instrumental error coefficients of the PINS based on linear vibration test is studied.Firstly,the influence of the shock absorber is analyzed and it can be concluded that the amplitude and phase of the applied acceleration is changed.Then,an average model is established.Thirdly,the the output sensitivity theory is used to obtain the maximum excitation positions for each error coefficient and a eight-position calibration scheme is selected.The simulation results indicate that 48 error coefficients can be calibrated in linear vibration test.In order to ensure the calibration accuracy,the misalignment error of linear vibration table can not exceed 0.1 degrees,the amplitude error of the applied acceleration is less than 10-5g.(5)Research on the guidance precision evaluation method based on flight test is conducted.Firstly,a complete guidance instrumental error separation model is established.Then,the incentive degree of the flight trajectory for the instrumental error coefficients is analyzed through the sensitivity theory and the instrument error separation model is simplified based on the analysis result.The recursive least square method is used to solve the simplified modle and better simulation results are obtained.(6)The fusion method for the instrumental error coefficients which are obtained from multi-source tests is carried out.Firstly,the approach of consistency test is discussed.Then,a fusion algorithm for the error coefficient obtained from the same test is proposed based on Bayes network and a fusion algorithm in which the weight coefficients are calcaulated by the covariance matrix is put forward for the error coefficient obtained from different tests.(7)Research on the method for impact point accuracy evaluation of ballistic missile is conducted.Taking circular error probablity(CEP)as accuracy index,the evaluation method for CEP is studied.Based on the traditional probabilistic circle accuracy evaluation method,Bayes probability circle accuracy evaluation method and the double probability circle sequential accuracy evaluation method are proposed.