Modeling Technique Of FOG’s Magnetic Bias Error And Its Application In R-FSINS

Rotating modulation technology is an extremely effective way to improve the precision of anINS(Inertial Nabigation System), It is named RSINS(Rotating Strapdown Inertial Navigation System)which applies rotating modulation technology to a SINS. RSINS is widely used in aviation and sailing.Gyros is a very important part of an INS, RSINS is also called Fiber-optic Rotating Strapdown InertialNavigation System if the system uses FOG(Fiber-Optic Gyroscope). This paper studies the errorcharacteristics of the fiber gyroscope and the key problems when the fiber gyroscope is applied in therotating inertial navigation system.To study the error propagation properties of fiber optic gyroscope in the rotating inertialnavigation system, this paper analyzes the error propagation properties of gyroscope in theconventional strapdown inertial navigation system and then establishes the error propagation model,also the theoretical analysis is proved by the simulations and real test results. This paper analyzes theerror propagation properties of fiber optic gyroscope in the rotating inertial navigation system, andthen establishes the relationship model of systemic error and the indexing schemes by simulations.In order to study the propagation characteristic of the fiber-optic gyro random error in INS,firstly, this paper analyzes the gyro random error from the propagation characteristic of traditionaltheoretical model，the propagation model of random error in long-time INS system is built. Moreover,by using the simulation and experiment, the theoretical model is verified.In order to enhance the reliability of different environment of fiber-optic RSINS, restrain thegyros’ bias caused by different magnetic field, the characteristic of fiber-optic gyros’ system errorbased on magnetics sensitivity theory is studied and simulation model is conducted. This paperanalyzes the Faraday effect which results in the magnetic bias of FOG, and the error of FOG causedby different magnetic fields. The complex environment of magnetic field which may influence theoutput of FOG during actual flight course is studied, geomagnetic field gradient model and ACmagnetic model is established to simulate the FOG’s output error and INS’s error. Closed-loopsimulation model of FOG is established to vertifies the magnetic bias characteristics influenced bydifferent kinds of magnetic field.In order to verify the magnetic properties of FOG and establish the corresponding sensitivitymodel of magnetic field, the high precision magnetic simulator with triaxial helmholtz coil is used. Aseries of experiments to test the magnetic declination repeatability, linearity and sensitive axis areperformed, based on two different types of FOG: VG951and SRS2000from Russia. The foregoingtheoretical simulation model is validated by the experiments, and a corresponding magnetic model is established according to the data fitting of the experimental results.Finally, the paper analyze, simulate and verify the characteristic of system error caused by FOGrandom error and magnetic bias, the finite element software Ansys is used to build the model ofmagnetic field distribution of single axle table, compensatory method in different transpositions isproposed, the results is significant.In a word, based on the background of using the FOG in the RSINS, the propagationcharacteristic of and magnetic bias character is deeply studied, the gyro random error propagationcharacteristic of FOG is conducted, the magnetic bias character is revealed and compensatory methodis conducted. The paper is of great significance to optimize the performance of RSINS in applicationunder different environment.