Research On FOG Random Error Suppression Method In Hull Deformation Measurement

When shipborne weapons are operating in coordination at sea,hull deformation prevents them from establishing a high-precision uniform attitude reference across the ship.In recent years,hull deformation measurement technology,which can solve this problem effectively,has been developed.Among them,the inertia matching measurement method has the advantages of high measurement accuracy,good autonomy and good concealment,so it has been widely concerned by scholars.In the inertia matching measurement method,the fiber optic gyroscope(FOG)random error may accumulate into the measurement results,which has been restricting the development and application of the hull deformation measurement system.Therefore,this paper makes an in-depth study on the FOG random error suppression method in hull deformation measurement.The main work includes:Firstly,we explore the sources of FOG random error and provide a reasonable simulation method,which can provide conditional support for subsequent computer simulation.In addition,based on the principle of Allan variance and its physical significance,the slope method,a commonly used method for random error coefficient identification,is analyzed in detail.A new identification method,recursive least square(RLS),which can estimate the random error coefficient on-line and has a small amount of computation,is proposed to satisfy the demands of real time signal processing.Secondly,the filtering algorithms of FOG random error are studied in detail,including forward linear prediction(FLP)filtering and wavelet threshold filtering.Considering the nature of each parameter and their influence on the filters,reasonable selection schemes are provided.The simulation experiments based on the static and dynamic FOG simulated data are conducted respectively,by which the feasibility of the algorithms is verified.The results,gained by the experiments,demonstrate how effective the filters improve the SNR of the FOG output.Furthermore,the two methods have a certain degree of dynamic tracking capability.Then,the traditional angular velocity matching method is studied.On the basis of it,in view of the problem of oversimplifying colored noise in the traditional model,the stochastic differential equations for colored noise are provided by the Allan variance analysis method.The accurate model of gyro drift is also derived in detail and combined with the angular velocity matching equation and the hull deformation model to estimate the hull deformation by a Kalman filter.Finally,computer simulation experiments and semi-physical simulation experiments are carried out.We can find that the latter conclusions are almost the same as the former conclusions.And then the conclusions would verify the feasibility and effectiveness of the algorithms in this paper.The work also lays the foundation for the subsequent engineering realization.