Research On Dynamic Characteristics Of Fiber Optic Gyroscopes

With the continuous expansion of application and the requirement of navigation precision,the requirements of FOG are getting higher.For practical FOG of engineering,the good dynamic performance is an indispensable condition,especially in the dynamic environment of the FOG,the angular motion of the carrier causes the output error of FOG,which affects the navigation accuracy.Therefore,this paper focuses on the dynamic performance of FOG,establishing the dynamic error model of FOG,studying the testing method of dynamic characteristics,analyzing the dynamic error signal and exploring the dynamic error compensation algorithm of FOG.Firstly,in this paper,the basic situation and research of FOG at home and abroad are described.The current research status of FOG's adaptability to the dynamic environment and the purpose,significance and main research of this paper are described.Then,taking the IFOG as the research object,we master its working principle and main performance indicators.The analysis focuses on function and physical meaning of circuit module,establishing dynamic error model and closed-loop transfer function,simulating the effect of different angular motion on the FOG output.And briefly introduce the dynamic performance test of FOG.Secondly,due to the accuracy of the scale factor in the dynamic environment plays an important role in the gyro output.Try to improve the gyro scale factor accuracy based on this method.Based on the angular rate test,scale factor of angular incremental test is proposed.By comparing experimental results,it is found that the scale factor of angular incremental test is higher than the angular rate test.In addition,from the working principle of FOG,the error mechanism of scale factor is analyzed,especially the effect of temperature on scale factor.By setting up temperature error model and using software compensation method,the accuracy of scale factor is improved.Therefore,the accuracy of FOG is improved.What's more,this paper studies the dynamic performance of FOG.Based on the swing movement,mainly from three aspects: test principle,test procedure and determination of test reference value studies frequency method.Then,according to the dynamic test method,this paper obtains single swing and composite swing test results.Finally,to make sure method of dynamic performance,this paper evaluates dynamic performance by using the separated periodic method and analyses the main components of dynamic error.Because there are some error factors when considering the frequency method test,incremental method test is put forward on.It is found that both methods have their own advantages,but they also have defects at the same time.Finally,this paper analyses the results of FOG dynamic testing.Because dynamic error obtained by the rate test is changing over time,the Allan method,which also named DAVAR method,is used to analyze the error signal.According to the basic principle of DAVAR signal analysis,using DAVAR method to analyze the dynamic error signal,we can intuitively see the periodicity of the error signal and the mutation factors.Then,the decomposed and reconstructed wavelet transform is used to decompose the sinusoidal part and the noisy part of the dynamic error signal to determine the main part of the error.Finally,by analyzing the dynamic error mechanism caused by the swinging motion,a dynamic error compensation algorithm is established and the error coefficient is calibrated,which is validated by experiment.