The Research Of Filter Technic In Inertial Alignment Of Strapdown System

The original alignment precision impacts directly on the precision of the INS (inertial navigation system). The time used in original alignment processing is an important military tactics technique index of the INS. So the original alignment is one of the most important key technical of the INS.At present, the Kalman filter is the most well rounded and widely used filter. Kalman filter requires the known statistical character of system disturbance, which can't be strictly satisfied in practice system usually. H∞ filtering requires the disturbance is energy bounded other than known accurate statistic. H∞ filter has robustness both in uncertain noise and in uncertain system parameter, and it can be completed in the conditions mentioned above. In this paper, Kalman filter is replaced by H∞ filter in the case of the system model existing error, such as the system being with non-white noise and uncertain parameters.In this paper, the MATLAB is used to realize a Kalman filter and aH∞ filter of the initial alignment of strap-down inertial navigation systems. We contrast the two simulation result. In ideal condition, Kalman filter can keep less error precision in the initial alignment than H∞ filter. When the system model exist error, Kalman filter can not complete filtering, but H∞ filter can keep upperprecision all the me .The advantages of H∞ filter are more rapid, more robust, more precision and it can be more applicable in engineering.