The Performance Calibration And Error Compensation Technology Of QVBA

Quartz vibrating beam accelerometer(QVBA), based on the force-frequency characteristic of the quartz crystal, can provide the digital signal directly. And the variation of frequency reflects the input acceleration of the QVBA. Because there is no incremental error caused by the analog-digital conversion(ADC) and it can be compatible with the high-speed digital navigation,QVBA has the advantages of size、weight、consumption and cost。QVBA has been widely used in foreign companies which have developed the relevant researches at the same time. However, domestic performance calibration methods of QVBA are still based on the methods of quartz flexible accelerometer because the application and research on QVBA is only short term and the investigation of QVBA performance is not very clear yet. Thus, there isn’t any regular method of the deeper research on the centrifuge experiment and temperature compensation of QVBA etc.With the aim of the performance calibration and error compensation technology of QVBA, this article shows the researches on QVBA testing equipment, gravitational field detecting, centrifuge experiment and temperature compensation technology according to some relevant experiments which have been done, achieving the performance evaluation of QVBA products, providing the data basis of accelerometer development. The main contents in this paper are as follows.According to the QVBA equivalent model which has been found, the up and down resonant beam can be equivalent to the elastic rod, the mass can be equivalent to the rigid body. Through analyzing the structure in statics, the mathematical model from input to out of the accelerometer can be concluded and the calculation formula about the accelerometer bias K0 and the scale factor K1 can be drew. It gives the explanation about the influence factors of the accelerometer bias K0 and the scale factor K1, and the theoretical basis for the accelerometer design.According to the work principle of QVBA and the testing requirements which analyzed the model selection among the dividing head、testing equipment、frequency detecting instrument and so on, the QVBA testing equipment has been constructed successfully. As regards to the analysis and summary on the detecting method of accelerometer frequency output signal especially, it will established foundation for the subsequent frequency detecting technology used in the QVBA independent testing and system application.The testing method about the QVBA in the gravitational field and high g environment has been designed with verifying the effectiveness of testing method. It confirms the basis of performance calibration in the development process of the QVBA. In particular, with comparing many schemes, the simple and feasible centrifuge effective-radius calibration method can be proposed with the contribution to the obvious simplification in centrifuge testing process. By mean of the relevant testing data, we can evaluate the existing performance of the QVBA. It can provide the reference for the future development process of the accelerometer.The QVBA temperature model has been identified with regard to the new type QVBA full temperature working condition which has been studied about the temperature characteristic and compensation. Using the third-order polynomial compensation, the accelerometer full temperature performance can been improved by one order of magnitude.