An algorithm about gyro constant drift compensation for SVRS based on Kalman filter

Strap down Vertical Reference System (SVRS) is a kind of Strap down Inertial Navigation System (SINS) based on inertial components. Its main function is providing attitude benchmark reference value for equipment which equipped on large moving carrier. The gyro constant drift which changes over time is the main error source of SVRS navigation. This paper puts forward an algorithm estimating gyro constant drift online based on Kalman filtering. Different to the conventional rotating modulation algorithm, According to the characteristic of the gyro constant drift which changes slowly in every short period, the gyro constant drift can be estimated and compensated on line by this algorithm. In this paper, the author has deduced the theory, analyzed error and validates the effectiveness of the algorithm by semi physical simulation. The simulation results showed that this method could improve the accuracy of pure strap down attitude calculation effectively, and raised the attitude precision of SVRS in long time navigation environment at mean time.