| At present,the fiber strapdown intertial navigation system is widely used in aviation,aerospace,navigation and on-board navigation system.However,its main devices will aging with increasing use time,changing the calibration parameters and affecting the navigation accuracy.Therefore,the inertial navigation system generally specifies a calibration cycle,requiring the recalibration of the device parameters.However,many important weapons and equipment do not allow the system to stop in use for a long time,requiring the fiber strapdown intertial navigation equipment to complete the calibration in a short time in the outfield.In the outfield,the high-precision calibration equipment of the manufacturer is often not provided,and only some simple calibration equipment is provided to complete the calibration of the system.Therefore,the project focuses on the calibration technology of the fiber strapdown intertial navigation system and the calibration of changed parameters under external field conditions.The specific studies are as follows:Analyze the composition of the fiber strapdown inertial navigation system,give the definition of calibration parameters,and further establish the mathematical model and error model of inertial components.Focus on the analysis of whether each model parameters are affected by the environment with time,and the specific factors that cause the change of parameters,we will give the parameters of each calibration method studied in this paper and the reasons to choose this parameter.For the rapid verification of the discrete calibration results,a turntable-based multi-position systematic calibration method is studied.The error parameters are coupled to 6 items by merging error parameters,the navigation error is calculated using the positioning error information,the Kalman filter is designed to estimate the coupling error parameters,and the calibration path is further designed according to mathematical analysis so that all the error parameters can be decoupled,and the coupling formula is derived.The experiments show that the multi-position system-level calibration method can improve the efficiency of discrete calibration,and calibration results are comparable for both methods.Based on the infield calibration,for the scale factor and zero bias of the fiber strapdown inertial navigation system over time,a site calibration method for dismantling the inertial navigation system is proposed.Using the simple auxiliary equipment as the benchmark,the principle of rotation integration is used to calibrate the scale factor of the optical fiber gyroscope,the zero deviation of the optical fiber gyroscope is adopted to cancel the principle of symmetry position,and design the simple position to calibrate the error parameters of the accelerometer with the least square principle.The experiment proves that the site calibration accuracy can meet the system use requirements,and can be used to conduct regular calibration of the fiber strapdown intertial navigation system.To solve the problem that the zero bias of the fiber strapdown intertial navigation system is more likely to change with time,a not disassembled systematic calibration is studied.We can analyze the connection of attitude error and horizontal zero bias in the alignment of the fiber strapdown intertial navigation system,and the calibration path is designed to establish the horizontal zero deviation of the Kalman filter estimation system,using the triaxial angular rate and the acceleration output to calculate the sky-zero deviation of the system.Experiments show that the not disassembled systematic calibration is more convenient than the field calibration,which can achieve the correction of the zero-bias in a short period,and effectively inhibit the effect of the zero-bias change on the navigation accuracy. |
