Latitude Determination and Error Analysis for Stationary SINS in Unknow-Position Condition

Area of Science:

• Navigation Systems
• Geodesy
• Control Theory

Background:

• Strapdown inertial navigation systems (SINS) require initial geographic latitude for self-alignment.
• Direct latitude acquisition can be challenging or time-consuming in certain scenarios.

Purpose of the Study:

• To introduce and validate methods for determining latitude using SINS outputs alone.
• To enhance latitude determination accuracy by addressing inherent errors and inertial measurement unit (IMU) biases.

Main Methods:

• Introduced latitude determination (LD) methods: magnitude, geometric, and two analytical approaches.
• Derived LD error through comparative analysis and established its link to IMU bias.
• Implemented a partial bias estimation method integrated with latitude determination.

Main Results:

• Validated the efficiency of proposed LD methods through simulations and experimental tests.
• Demonstrated that compensating for estimated IMU bias further improves LD accuracy.
• Confirmed that latitude accuracy is influenced by the SINS's location.

Conclusions:

• The developed IMU-determined latitude is effective for SINS self-alignment.
• This method can correct long-term SINS navigation latitude, enhancing system autonomy and positioning precision.