Configurable inertial navigation system with dual extended kalman filter modes

A system and method for more accurately and robustly estimating navigation state of a vehicle by adaptively processing signals from an inertial sensor assembly and other sensors. A navigation system receives signals from two or more sensors to evaluate and correct the attitude estimated by an Extended Kalman Filter (EKF). The navigation system selects sensor signals from the other sensor assemblies and processes the selected sensor signals in conjunction with estimates from the inertial navigation module to obtain more accurate estimates of the attitude. The parameters and conditions for using certain sensor signals may be adjusted based on the characteristics and configuration of the vehicle.