Rapid Self-Alignment Method for Fixed-Wing Aircraft Aided by Runway Heading.

To improve the speed and accuracy of airborne inertial navigation systems during ground initial alignment, this paper proposes a rapid self-alignment method suitable for fixed-wing aircraft during the taxi-to-takeoff phase on the runway. This approach leverages pre-surveyed runway heading data to transform the velocity vector calculated in the navigation frame to the runway frame. By utilizing the geometric constraint that the aircraft's actual position during ground taxiing must remain within the runway boundaries and closely follow the runway centerline, the proposed method employs a dedicated Kalman filter to achieve rapid initial alignment. Both simulations and flight tests demonstrate that the proposed method can achieve rapid initial alignment within 30 s during the runway taxiing phase, with attitude, velocity, and position accuracy levels comparable to those of GNSS-aided in-motion alignment. This method eliminates the need for external aiding equipment and can serve as an emergency initial alignment solution for airborne inertial navigation systems under GNSS outage conditions, effectively enhancing the aircraft's autonomy and rapid response capability.