| Inertial navigation system(INS)is used to identify the position,speed and posture of the carrier,and is widely applied in aviation,aerospace and navigation fields for its main characteristics of concealment,autonomy and globality.It is often used as the main navigation system of integrated navigation system.With the development of modern control theory and computer technology of inertial components,strapdown inertial navigation system is becoming the mainstream and direction of inertial navigation system because of its small volume,low cost,simple structure and high reliability.Before the strapdown inertial navigation system equipment is out of the factory,most of them need to be calibrated and tested through high precision turntable.In the calibration process in the past,it is assumed that the strapdown inertial measurement unit(SIMU)mounted on the carrier coordinate system origin,but actually because of their volume and SIMU installation location restrictions,the sensitivity is not possible with the carrier coordinates the origin of coincidence,so there is a certain distance.According to the rigid body rotation theorem,the values of acceleration at different distances from the point of rotation are different.So,in the case of angular motion,SIMU on various points of acceleration are not the same,because the three accelerometers is SIMU at different points of the acceleration,if the acceleration as the output from the ideal point measurement components of inertial navigation solution,the navigation error caused by the principle.This is called the inner lever arm effect error in this paper.When compare information between different navigation systems,must consider the lever arm effect.This is called the external lever arm effect error.This paper first introduces the error equations of inertial navigation system,the common coordinate system and transformation relationship,the updating method of strapdown matrix,and the basic equations of Kalman filtering,so as to prepare for the compensation algorithm later.Then,based on inertial navigation theory,analyzes the causes of inner lever arm effect,the particle in the two-dimensional plane motion as an example,analysis of particle in circular orbit motion analysis.Assuming SIMU around a rotation axis angular vibration,movement analysis,the existence of proof in which the lever arm effect,analysis of error of lever arm effect.The inner lever arm effect error,proposes two compensation method based on mechanical dynamics principle and compensation method based on compensation method of Kalman filter for these two methods,the validity of the simulation experiments are conducted to verify the compensation method.Under the existing conditions of the laboratory,the swing experiment was designed by using the three axis turntable experiment,and the experimental data were obtained,and the experimental data were analyzed.The validity of the compensation method based on Kalman filtering is verified.The compensation problem and then study the lever arm effect error,first to SINS/DVL integrated navigation system as the research object,analysis of influence of lever arm effect error on the system,the error model is established by simulation experiments,the results were analyzed.The SINS/GPS integrated navigation system as the research object,put forward the compensation method of lever arm effect error,the error model is established for simulation analysis of experimental results.According to the conditions of laboratory equipment,the experimental design of the vehicle,the effectiveness of SINS/GPS lever arm effect error compensation method was validated by the simulation experiment in the form of a half.Finally come to the conclusion of this paper,which is used to produce the lever arm effect error influence navigation system and integrated navigation system of strapdown,error compensation method proposed can effectively improve the navigation accuracy. |
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