| At present,the attitude of shipborne radar is generally obtained through attitude transmission.The errors will accumulate in the process of attitude transmission and the attitude accuracy of the radar will be affected.Based on the single-axis rotational laser gyro strapdown inertial navigation system,the paper proposes to install the inertial navigation system(INS)on the radar frame directly.INS can do pitch and yaw motion with radar,and output attitude information of radar in time.The contents of this paper include the following aspects:1.The propagation mechanism of each error parameter in the navigation solution is analyzed.First,a detailed analysis of the errors in the gyro and accelerometer is conducted.Then an error model is established based on the inertial navigation error propagation equation.Finally,a 36-dimension Kalman filter is designed based on Kalman filtering principle to calibrate the errors of INS.2.The attitude estimation error introduced by the accelerometer scale factor error under the overturning cases is analyzed in detail.The horizontal accelerometers will also sense the gravitational acceleration under the overturning cases,and the influence of the accelerometer scale factor error on the attitude estimation will be highlighted.In this paper the equations of attitude estimation errors introduced by accelerometer scale factor error is derived and the theoretical analysis was verified by simulation and experiment.3.Systematic calibration method for INS in the outfield is studied in detail.The pitch of the shipboard radar is limited,and it can be up to 90°.But the traditional calibration method requires the INS can rotate to any orientation.First,the observability of accelerometer parameters is analyzed.Then the rotational path is designed to calibrate the accelerometer parameters.Finally,the validity of the calibration path is proved by simulation and experiment. |
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