Calibration Techniques For High Precision Optical Fiber Strapdown System

Studying on the accurity improvement of strap-down inertial navigation system (SINS) has vital significance with the maturity of Fiber optical gyroscope (FOG) and the rising market share of SINS based on FOG in aviation, spaceflight and voyage.Callibration is the process to correct inertial components and its veracity influences the accurity of SINS directly. This paper excavates calibration technic deeply and makes interrelated experiments with a high precision equipment in different levels, including one FOG and one quartz flexible accelerometer, inertial measurement unit(IMU) and SINS.Firstly, basic theories of FOG and quartz accelerometer are introduced then testing method based on these theories is discussed in this paper. Static statement of inertial components are calculated by Allan variance and the linear degree is given by the impeoved nonlinear testing methods for the coming usage in designning SINS.Secondly, the mathmatical model of FOG is analysized and three layouts based on this model are given. The operating environment of each layout is listed by delibrating the theory of them. Then theoretical analysis and verification test on the influenceof turntable inversion precision, velocity accuracy rate and non-orthogonal degree onthe results of calibration.Thirdly, model of quartz flexible accelerometer is researched and two layous North24Postion and Heaven24Position are given. Influence of inversion precision rateand non-orthogonal degree of turntable is analysized based on the study of FOG. Thecharacteristics of each layout are given by simulation and tested by a physical experiment of North24Position. Furthermore a layout for accelerometer using the norm error to fix original calibration parameter with shortter time is introduced.Finally, the error propagation model of SINS and the model of Kalman filter areintroduced, and combined together to form a SINS-Kalman filter which use calibration error as the stament parameter and velocity error as the observation statement,Thenthe model is combained together with physicial system to improve the calibration parameter.