Compensation of gyroscope errors and GPS/DR integration

In car-navigation, a dead-reckoning (DR) system is required for solving the problem of GPS signal blocking in urban area. The vibrating gyroscope which is widely used to determine the vehicle heading in a DR system, has a low accuracy, hence an error compensation of it is needed. In this paper, an error compensation method for the vibrating gyroscope used in DR is presented. Gyroscope errors can be characterized into two types of error, deterministic and random errors. Each error term is mathematically modeled and an indirect feedback Kalman filter is used for the error compensation. Through laboratory experiment and field-test, it is shown that the error of a vibrating gyroscope can be successfully compensated by the proposed method. Also, as an alternative method for GPS/DR integration in a case that the number of visible GPS satellites is insufficient for the correct determination of a vehicle position, the mixed-measurement algorithm is proposed. It is shown that by using this algorithm, even if the number of visible GPS satellites is 2 or 3, the position error becomes smaller than by using only DR