A Study On The Marine Strapdown Navigation System Based On FOG

FOG is an essential device in strapdown navigation system, which is representative in the development of future navigation system. The paper study the marine strapdown navigation system based on FOG. Marine navigation system work longer than any other navigation system, and work in the swaying and vibrating circumstance all the time. It will receive high impact when the rocket and m issile p rojected. H igher r equires w ere p ut to t he F OG d ynamic, d ynamic error and random drift character. Around the realization of FOG digital close-loop detection system, and the identification of dynamic error model, dynamic model(transfer function), random drift error model, some practical conclusions were d rew u nder analyses a nd r esearch, t he w ays o f i mproving t he d esign a nd performance of FOG were mastered by its mathematics model. Through the improvement of system hardware structure and deducing the principle of strapdown compass seeking north, the hardware and software of FOG strapdown compass were designed and realization, which provide the theoretical and practical foundation for the development of marine strapdown navigation based on FOG. The detail discussion and results about the section mentioned above are provided as followings.In the aspect of the realization of FOG and its strapdown navigation system, FOG digital close-loop detection system and the hardware of its strapdown navigation's digital signal processing system were realized. A method of extend of external interrupt and UART was proposed. The timing of the multiple UART working was critically testified and the solution of multiple UART was given out under different conditions. The memory system, Bootloader system, system timing, data bus, decoder and software modules were designed and realized.To meet the need of compensation of the strapdown system dynamic error, the nonlinear modeling method FOG dynamic error mathematics based on artificial neural network was proposed. Under the comparison of the regress analysis, which is the traditional 1 inear system modeling and identification, the merits and the method of neural network modeling in nonlinear system were presented. The neural network model of FOG dynamic error was realized bysoftware. By high precision dynamic error model, the navigation system error compensation was completed.Dynamic model(transfer function) is the foundation of the analyses of FOG dynamic characteristic and the improvement of performance of FOG, a dynamic modeling method of FOG was proposed based on Walsh function and its transition. Modeling method was realized by software. For practical application, the L east Square principle was introduced in the solution. The precision of the identification of dynamic model is improved in the environment of noises. The dynamic model was testified in both emulation mode and real experiments.The random drift error model was researched in the paper. The Allan variance analyses method, which is a frequency stabilization analyses method conducted in time domain, was selected to analysis the FOG random drift error. The applying of window function to Allan variance analyses was proposed. On the discuss of the principle of data analysis, the method of applying variable rectangle window to initial data processing was deduced. Though the test, FOG random drift error was analyzed and the result explain that the method can carefully identify the random drift error which affect the FOG precision greatly.On the precision level of the existing FOG and the theoretical analysis, the realization of FOG strapdown compass was studied in the paper. The mathematics model of strapdown compass was proposed, and the model error was investigated. The principle of strapdown compass seeking north was studied. The FOG strapdown compass system was designed and emulated to testify its performance. The paper mainly discussed the FOG modeling, realization of digital close-loop detecting system, and the research of FOG strapdown navigation system. The realization method of FOG and its strapdown navigation system and the pivotal technique of FOG modeling were achieved.