On calibration of an aircraft strapdown inertial navigation system using high-precision turntable
Lomonosov Moscow State University, 1, Leninskie Gory, Moscow, 119991, Russia
Calibration is an important stage of the preparation of a strapdown inertial navigation system (SINS) for operation. The calibration consists in the determination of instrumental errors of inertial sensors by conducting special experiments on a turntable. In the Laboratory of control and navigation at Lomonosov Moscow State University new calibration methods based on the implementqtion of low-grade turntable have been developed. Moreover, these methods have been successfully implemented at some specialized enterprises. This article extends the calibration methods that were developed for SINS calibration procedure on low-grade turntable to the case of high-precision turntable application. One can find characteristics of high-precision turntables e.g. in . SINS consists of three accelerometers, three angular rate sensors and an on-board computer, realizing navigation algorithms. Mathematical models of a calibration algorithm include SINS error equations; models of instrumental errors of inertial sensors: angular rate sensors and accelerometers; model and the equations of supporting measurements. We assumed that instrumental errors of each of the accelerometers include a zero offset error, a scale factor error, non-orthogonality errors and a high-frequency noise component, which is assumed as a white noise.
The calibration procedure comprises three cycles in order to obtain the acceptable accuracy. In these three cycles SINS is consistently set on a turntable platform in three different positions. At each cycle the platform’s rotation is characterized by angular velocity Ω, with the law of Ω behavior close to meander.
There is an opportunity to extend the aiding vector for high-precision turntable due to additional angular data, provided by turntable. After that, the corresponding equations should be written. Finally, the observability analysis for all calibration parameters should be carried out in these three cycles of rotation.
The investigation of SINS calibration was based on covariance analysis. Thus, due to simulation the possibility of obtaining an acceptable accuracy for SINS calibration procedure by means of angular data, provided by turntable was shown. So we can recommend to apply the abovementioned methods.
Keywords:strapdown inertial navigation system, calibration, high-precision turntable
Parusnikov N.A. Izvestiya RAN. Mekhanika Tverdogo Tela., 2009, no. 4, pp.3-6.
Golovan A.A., Parusnikov N.A. Matematicheskie osnovy navigatsionnykh sistem.Chast’ II. (Mathematical Foundations of navigation systems. Part II.), Moscow, MAKS Press, 2012, p.170.
Golovan A.A., Parusnikov N.A. Matematicheskie osnovy navigatsionnykh sistem.Chast’ I. (Mathematical Foundations of navigation systems. Part I.), Moscow, MAKS Press, 2011, p.132.
Vasineva I.A., Kalchenko A.O. Vestnik Moskovskogo universiteta. Matematika. Mekhanika., 2014, no. 1, pp. 65-68.