Key Technology Of Rotating Strapdown Inertial Navigation System

With the rapid development of the Fiber optical gyroscope (FOG),the FOG-based strap-down inertial navigation system (SINS) has been widely used in areas like aviation, aerospace,marine and land navigation.As seen from the development trend of the inertial navigationsystem (INS), the SINS will replace the old platform inertial navigation system, and this pro-vides an important historical opportunity and challenge to the development of FOG andFOG-based SINS. With on the existing fiber SINS,it is of great significance to improve theprecision of the fiber SINS with the rotating modulation technology. The dissertation has adeep study on several key technologies of rotary SINS. Based on a laboratory-developed FOGand FOG-based SINS combined with a rotary indexing mechanism,experiments have beenconducted to verify the performance.The dissertation first introduces the basic principle of rotation modulation technique,then analyzed the automatic compensation on the perpendicular axis direction of inertial in-strument errors otherwise the rotation axis inertial instrument error in single-axis rotationmodulation.On this basis,a scheme that the IMU is incline installation has been pro-posed.From the principle analysis this can complete eliminate the inertial instrument errors inthree directions.Then are the simulation analysis.The actual system rotation model of the indexing mechanism has been demonstrated.Taking angular acceleration of the indexing mechanism into the rotation model of the index-ing mechanism, and on the basis, the detailed error propagation characteristics has been de-rived and the simulations analyse the single-axis continuous rotation scheme, continuous re-versible rotation scheme, four-position switch-stop over360°scheme, four-positionswitch-stop less360°scheme and improved four-position switch-stop less360°scheme.Several single-axis rotation modulation scheme has been studied to choose the best indexingscheme, on this basis, the indexing mechanism on the angular acceleration, the modulationangular velocity and the stop time parameter settings have been studied followed by simula-tion analysis.The dissertation researches on the two basic computation structures of rotary SINS, de-rives the error propagation characteristics of indexing mechanism error respectively, andchooses the angle modulation computation structure after comparative analysis. On this basis,the dissertation analyse the time synchronization of the indexing information and the FOGinformation, and derives the attitude error influence by delay time on rotary SINS, providesthe measurement method and the compensation strategy of the delay time, and conducts re- lated experiments. Besides the dissertation analyse the influence of indexing mechanism star-tup process to FOG, makes some compensations by extending angular acceleration and deriv-ative items of angular acceleration to the static error model of FOG, and has related experi-mental verification.The FOG random error model, static error model and accelerometer static error modelhave been introduced, An intelligent optimization algorithm: Artificial fish swarm algorithm(AFSA) have been proposed. Adopting AFSA to FOG random drift model can achieve goodmodeling effect. On the mode square observation of IMU acceleration and angular accelera-tion in the condition of without high-precision turntable, and static error parameters identifi-cation by using AFSA.Algorithm processes of parameters step-by-step fitting and cross itera-tion IMU parameters identification have been presented.By implementing artificial fish sec-ondary initialization optimization idea in artificial swarm iterative process,we can obtain wellfitting effects by through simulation. On this basis, adopting the AFSA to IMU parametersfitting to have on the static navigation experiments, the rotation modulation navigation expe-riments with the laboratory-developed FOG SINS platform respectively, and all the experi-ment results show that the IMU error parameters acquire method could meet the requirementsof high-precision navigation systems. It is an effective IMU parameters identification methodand has an important practical significance.Finally, the dissertation designs several rotation modulation schemes with theself-developed high-precision FOG and the single-axis rate and position turntable SINS, andanalyse the vehicle heading error and the positioning error respectively. Then the dissertationverifies the effectiveness of system modulation schemes. And the experiment results showthat the single-axis rotation modulation scheme can improve positioning accuracy of INS, andalso improve the attitude accuracy after the effective compensation on indexing error.