A New In-Flight Alignment Method with an Application to the Low-Cost SINS/GPS Integrated Navigation System

Area of Science:

• Navigation Systems
• Inertial Navigation
• Attitude Estimation

Background:

• Optimization-based alignment (OBA) methods are effective for in-flight alignment (IFA).
• Traditional OBA methods struggle with low-cost strap-down inertial navigation systems (SINS) due to gyroscope drift and computational burden.
• Existing methods exhibit slow alignment speeds and accumulated errors in double-vectors.

Purpose of the Study:

• To develop a fast and accurate in-flight alignment (IFA) method for low-cost strap-down inertial navigation systems (SINS).
• To overcome the limitations of traditional OBA methods, including error accumulation and slow computation.
• To enhance the performance of SINS/global positioning system (GPS) integrated navigation systems.

Main Methods:

• Proposing a new fast IFA method using modified double-vectors construction and gradient descent.
• Reducing integration intervals and identifying gyroscope bias during double-vector construction for improved accuracy.
• Employing gradient descent for optimal attitude estimation, avoiding complex matrix operations for increased speed.

Main Results:

• The modified double-vectors construction improves accuracy of vectors and IFA.
• Gradient descent enhances alignment speed by simplifying attitude estimation.
• The proposed method demonstrates superior accuracy and faster alignment compared to traditional methods in simulations and experiments.

Conclusions:

• The developed fast IFA method is suitable for low-cost SINS/GPS integrated navigation.
• Modified double-vectors and gradient descent effectively address MEMS gyroscope drift and computational load.
• The new approach offers a significant improvement in both accuracy and alignment speed for navigation systems.