Abstract
At present, the design and manufacturing technology of mechanically dithered ring laser gyroscope (MDRLG) have matured, the strapdown inertial navigation systems (SINS) with MDRLG have been widely used in military and business scope. When the MDRLG is working, high-frequency dithering is introduced, which will cause the size effect error of the accelerometer. The accelerometer signal has a time delay relative to the system, which will cause the accelerometer time delay error. In this article, in order to solve the above-mentioned problem: (1) we model the size effect error of the mechanically dithering of the MDRLG and perform an error analysis for the size effect error of the mechanically dithering of the MDRLG; (2) we model the time delay error of accelerometer and perform an error analysis for the time delay error of accelerometer; (3) we derive a continuous linear 43-D SINS error model considering the above-mentioned two error parameters and expand the temperature coefficients of accelerometers, inner lever arm error, outer lever arm error parameters to achieve high-precision calibration of SINS. We use the piecewise linear constant system (PWCS) method during the calibration process to prove that all calibration parameters are observable. Finally, the SINS with MDRLG is used in laboratory conditions to test the validity of the calibration method.
Highlights
Error parameters of the inertial device are important factors affecting the navigation accuracy of strapdown inertial navigation systems (SINS)
Aiming at the problem of high-precision calibration of SINS, in this article we propose a systematic calibration method based on a 43 dimensional (43-D) Kalman filter
Algorithm analysis and experimental results show that: (1) The size effect error of dithering of the mechanically dithered ring laser gyroscope (MDRLG) compensation method derived in this article can effectively improve navigation accuracy
Summary
Error parameters of the inertial device are important factors affecting the navigation accuracy of SINS. Error parameter calibration methods mainly include discrete calibration and systematic calibration. The discrete calibration relies on the accurate azimuth, position, and angular rate reference provided by the high-precision turntable, and by referring to the local gravity acceleration and the earth’s rotation angular rate, placing the IMU in different positions can calibrate the error terms of the gyroscopes and accelerometers [1,2]. Systematic calibration does not rely on high-precision turntables, so it has been widely used in self-calibration and field calibration of SINS. Pittman [4] pointed out the four major advantages of the systematic calibration method: it can realize the on-site calibration of the SINS; it can realize the self-calibration of the SINS; it does not require high-precision turntables and other high-precision test equipment; it does not need to measure and record the output of the gyroscope or accelerometer. Chamberlain L [7] designed an
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