An Improved In-Motion Coarse Alignment Method for SINS/GPS Integration with Initial Velocity Error Suppression.

Area of Science:

• Navigation Systems Engineering
• Geomatics Engineering
• Aerospace Engineering

Background:

• Strapdown inertial navigation system (SINS) and global positioning system (GPS) integration is a prevalent navigation mode across various fields.
• Accurate initial attitude determination is crucial for SINS/GPS-integrated systems to function correctly.
• Current in-motion alignment methods for SINS/GPS integration often overlook initial velocity errors from GPS outputs.

Purpose of the Study:

• To propose and validate an improved method for SINS/GPS in-motion initial alignment that addresses the issue of initial velocity errors.
• To enhance the accuracy and reliability of SINS/GPS navigation systems by mitigating the impact of velocity inaccuracies.

Main Methods:

• An improved in-motion coarse alignment method is presented, analyzing original observation vectors.
• An averaging operation is employed to construct intermediate vectors.
• A novel observation vector is calculated by subtracting the intermediate vector from the original, effectively eliminating initial velocity errors.

Main Results:

• Simulation and field tests demonstrate the proposed method's superior performance compared to existing techniques when initial velocity errors are present.
• The method achieves comparable results to current methods when initial velocity errors are absent, indicating no loss in accuracy.
• Effective elimination of initial velocity errors and suppression of their interference on the alignment process were confirmed.

Conclusions:

• The proposed method successfully eliminates initial velocity errors in SINS/GPS in-motion alignment.
• This leads to improved alignment accuracy without compromising performance in the absence of velocity errors.
• The findings contribute to more robust and precise navigation solutions in dynamic environments.