Research On The Techniques Of Data Acquisition And Temperature Drift Compensation For Accelerometers

With the guidance of technologies for test and measurement and instrument precision theories as well, the issues of measurement precision involved in accelerometers, the inertial transducer elements in inertial navigation system and corresponding accelerometer data acquisition system were studied in details based on the background of research and development for high precision inertial navigation system.Firstly, the accelerometer static error model derived by employing the Second Euler Angle was studied and another acceleration output error model based on feedback closed loop was analyzed, respectively. Then, the principle of quartz-flexible accelerometer was presented and part of research was focused on the source of causes to the errors exist in acceleration output. According to the characteristics in accelerometer output signals and principles of data acquisition, an accelerometer data acquisition system was designed and achieved, which consists of hardware circuits and software running program both.Substantively, inertial navigation system is a sort of high precision measurement apparatus which senses velocity and position of vessels continuously. However, its work circumstance temperature also fluctuates slightly or dramatically incessantly. In general, temperature drift will influence the working status of electric devices in inertial navigation system, so the measurement results of the system can be negatively influenced by the errors due to temperature drift, which decreases measurement precision. In the dissertation, offset drift in amplifier and ADC caused by temperature drift was studied especially, and offset calibration method which can effectively limit the temperature influence on electric devices was put forward. After the research on electric noise and electrical characteristics of devices associated with temperature drift in data acquisition system, the settlement for compensating temperature errors in hardware circuits was achieved. The self-heating effort in accelerometer when power is on and its consequent influence on the measurement precision of accelerometer which was produced by the temperature field introduced through the self-heating effort were exposed. Additionally, the temperature was considered as a variable and it was added into accelerometer static error model. So, a kind of corresponding to the change of temperature was obtained. Consequently, the test and data processing scheme to estimate the parameters in the temperature model was brought forward.The data from experimental results was carefully analyzed and some relative issues connected with apparatus's measurement accuracy and measurement errors were discussed in details. Moreover, the properties of temperature compensation methods, such as linear compensation and orthogonal polynomial compensation techniques were compared as well.