Öz Navigation systems have vital importance both in military and civil applications. Hpwever, the error associated with these systems reduces the efficiency of the navigation system. Kalman filter is a tool that is commonly used to address this problem. Recently, the modified wave estimator (MWE) has been proposed as an altemative to Kalman filter for navigation systems. Unlike the Kalman filter, the MWE defines the process noise as deterministic means. Both estimators have advantages and disadvantages with respect to each other. This paper proposes an adaptive MWE and an estimator that fuses estimations from the MWE and Kalman filter. The proposed estimators try to make use of advantages of each estimator in the best way possible. Performance of the MWE, Kalman filter, the fused estimator and adaptive MWE are compared through a navigation simulation and results are discussed.