Shockproof Precision Strapdown Inertial Navigation System Development for Terrestrial Applications

The paper discusses the structure, algorithms and testing results for a hybrid precision strapdown inertial navigation system (SINS) which is resistant to fast extreme impacts. Impact resistance of the precision SINS is provided by incorporating an auxiliary strapdown inertial attitude control system (SIACS) based on rough sensors that can endure fast extreme shocks without losing the attitude accuracy; and by post-processing of inertial sensors data performed in the onboard computer simultaneously with the main navigation task. The post-processing procedure is designed to identify the moment of shock occurrence and to repeat the attitude problem solving in the onboard computer based on the auxiliary SIACS data within the time interval of exposure to the extreme shock. In the absence of shocks, the auxiliary SIACS is calibrated in accordance with the data of the main precision SINS. The main precision SINS is based on precision fiber-optic gyros (FOG) and the auxiliary SIACS—on micromechanical gyros (MMG). Thus, a hybrid-type precision SINS has been constructed, which has demonstrated required accuracy level during on-ground vehicle tests, including shock tests.