Quartz Accelerometers Temperature Error Modeling And Compensation Techniques

Inertial navigation accelerometer is one of the important inertial instruments in the inertial system and its precision will directly influence the precision of inertial system. Under the ideal condition, the output of accelerometer shall be in proportion to the specific force of input. But actually, error in measurement will be caused inevitably due to many disturbing factors. On one hand, the imperfect structure of accelerometer will cause error; on the other hand, error may occur due to the working environment and condition of the accelerometer. For the existing accelerometer, the research in rule of influence of its working environment and condition is an important method of improving accelerometer test and use precision. Among the various environmental factors that influence the precision of accelerometer, the influence of temperature shall not be neglected. The article mainly focuses on the characteristics of static temperature of Q-FLEX accelerometer.The article firstly theoretically analyses the error model of Q-FLEX accelerometer in the conditions of line motion and angle motion according to the structural characteristics of Q-FLEX accelerometer. Secondly, A/D conversion circuit is selected in the temperature test of accelerometer for data sampling. Change of temperature will affect the data acquisition precision of A/D conversion circuit.In this paper,the principle of ADC and the effect of the factors of A/D conversion circuit are analyzed,and the relation model of A/D conversion circuit temperature and accelerometer output is established.After compensating the temperature error by using the temperature model,the data acquisition precision of the accelerometer has been improved observably.Thirdly, in the temperature control turntable, we perform the static temperature experiment of orthogonal accelerometers. A batch least-squares maximum likelihood estimator is employed to calibrate the model coefficients of accelerometer and a polynomial post-fit method is used to establish temperature models of these coefficients. The temperature models of accelerometer bias and scale factor of accelerometer are established between -20oC and 50 oC. After compensating the temperature error by using these models,the post-fit residuals of the accelerometer output have been improved to 10?5 g, and the trend term of accelerometer changing with temperature basically vanished. The metrical precision of the accelerometer has been improved observably.The results of our experiment demonstrate that establishing the temperature models of accelerometer and compensating these models is an efficient way to enhance the accuracy of accelerometer.