Vibration Test Methods Of Acceleration-Squared-Sensitive Coefficients Of Gyroscopic Drift Error

Inertial navigation is important in the military field due to its strong autonomy,good concealment and no limitation of environment.From a very large extent,the accuracy of long-range missiles depends on the precision of inertial system,while the precision of inertial system depends on the accuracy of inertial measurement units(gyroscope and accelerometer).By the limitation of technology,materials and electronic technology,it is hard to improve the absolute accuracy of gyroscope.Meanwhile,whatever technology adopted,it is impossible to completely eliminate the error of gyroscope.Thus the study of test technology is an important aspect to improve the accuracy of gyroscope.The test technology of gyroscope developed late in China.The researches on the nonlinear errors and dynamic errors of gyroscope are not in-depth,that restricts the accuracy of gyroscope.Therefore,it is necessary to carry out the further study on relevant test technology.This paper studies the test methods of acceleration-squared-sensitive coefficients of gyroscopic drift error based on vibration table.Due to the mechanical errors and control errors in manufacture,installation,and operation,the actual output of vibration table is not totally the same as theoretical output,errors are inevitable.For mitigating the negative error influence on the objects under test,the output error models of vibration table are established based on the mechanical structure analysis and measured data.The error models are used to study the influence on the test method of gyroscopic errors,meanwhile,the compensation methods are proposed.The compensation methods can effectively improve the accuracy of test results and reduce the adverse effects of error.But these compensation methods need a complete measurement of vibration table output errors,which is unable to be achieved under current equipment condition.In order to improve test accuracy under current condition,the nonlinear parametric model optimize method is proposed to deal with the nonlinear model which is the gyroscopic output that influence by vibration output errors.Major contributions and novelties of this dissertation can be summarized as following:The test method of the acceleration-squared-sensitive coefficients of gyroscopic drift error is studied and analyzed based on the ideal condition of vibration table output.To delve into the test technology,the test equipment,the tested object and the test method are explored.Integral periodic integral method,harmonic analysis method and least squares maximum likelihood estimation method are studied,meanwhile,the detailed calculation process,relative merits and application conditions in practice of these three methods are provided via data simulation.According to the analysis of the error sources,the physical models of output error are obtained,which state the relationship between internal error sources and output errors.However,parts of the internal error sources are difficult to be measured,thus the mathematical models are established through the analysis the physical models and they are validated by experimental data.The mathematical models are utilized to analyze the error influence on the test method of gyroscope.Based on the established mathematical models,the influence of vibration table output errors(including angular velocity errors and acceleration errors)on the test methods of gyroscopic drift error is studied,and the modified error compensation methods are obtained.The modified error compensation method can reduce the adverse effects of error and effectively improve the accuracy of test results.The modified error compensation method is unrealized under current engineering practice equipment condition.In order to improve the test accuracy under current experimental conditions,the nonlinear model of gyroscope output that under the influence of equipment output errors is established,the least-squares iteration optimize method is adopted to deal with the nonlinear model.Both the under test coefficients and the unmeasured equipment errors are solved by the optimize method.Simulation results show that the optimize method significantly improves the estimation accuracy of the accelerationsquared-sensitive coefficients of gyroscopic drift error,and this method is practicable under current experimental conditions.