Research On Signal Acquisition And Temperature Compensation Of High Precision Accelerometer

In inertial navigation system,the accelerometer can directly measure the ship acceleration as an inertial measuring element,the signal acquisition precision of which will directly affect the precision of the inertial navigation system.In ideal conditions,the output of the accelerometer varies linearly with the input.However,the output will be affected by the measurement errordue to the interference of various factorsinevitably in practice application.This paper focuses on the following two aspects: first,the hardware design of accelerometer and high precision acquisition of temperature signal;second,the temperature compensation of accelerometer.First of all,establish the mathematical model and transfer function model of the accelerometer by analyzing the working principle of the quartz flexible accelerometer.Secondly,analyze the working principle of the analog-to-digital conversion circuit,and then select AD1281 chip which has high precision to realize the hardware design of signal acquisition circuit.Filtering the acquisition signal with the proper combination of resistance and capacitance,so that the signal will be more complete and accurate.At the same time,in order to reduce the temperature interference,select 16 bit precision AD7682 chip to realize the temperature signal acquisition,and Verilog language is used to design FPGA data reading of temperature acquisition circuit.Thirdly,the 24 point calibration method is derived through the analysis of the accelerometer error model,and the calculating equations of the error parameters will be obtained by theoretical derivation.The performance is verified by testing the performance of accelerometer signal acquisition.At last,the change rule of the circuit output variation with temperature is obtained according to the experiment of different temperature and the least square method.And then the error model of accelerometer zero bias and scale factor variation with temperature will be established.The error model is obtained through the simulation analysis,and it is applied to the data calculation of the acceleration temperature change experiment to verify the compensation effect.The experimental results show that the stability and precision of the accelerometer signal acquisition can be effectively improved in the temperature change environment with high precision accelerometer signal acquisition circuit board and temperature compensation model.