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

Area of Science:

• Aerospace Engineering
• Navigation Systems
• Signal Processing

Background:

• Inertial navigation systems (INS) require accurate initial alignment for optimal performance.
• Current ground alignment methods can be time-consuming or rely on external aids like GPS.
• Fixed-wing aircraft need rapid alignment during the taxi phase for improved operational efficiency.

Purpose of the Study:

• To develop a fast and accurate self-alignment method for airborne INS during the taxi-to-takeoff phase.
• To enhance the autonomy and rapid response capabilities of aircraft navigation systems.
• To provide a viable alternative to GNSS-aided alignment, particularly during signal outages.

Main Methods:

• Utilizing pre-surveyed runway heading data for frame transformation.
• Employing geometric constraints of aircraft taxiing along the runway centerline.
• Implementing a dedicated Kalman filter for rapid initial alignment.
• Transforming the velocity vector from the navigation frame to the runway frame.

Main Results:

• Achieved rapid initial alignment within 30 seconds during runway taxiing.
• Demonstrated attitude, velocity, and position accuracy comparable to GNSS-aided in-motion alignment.
• Validated through both simulations and flight tests.
• Eliminated the need for external aiding equipment.

Conclusions:

• The proposed method offers a significant improvement in the speed and accuracy of INS ground initial alignment.
• This self-alignment technique enhances aircraft autonomy and provides a crucial emergency solution during GNSS outages.
• The method is suitable for fixed-wing aircraft and contributes to improved operational readiness.