An accuracy measurement method for star trackers based on direct astronomic observation

Area of Science:

• Spacecraft engineering
• Optical instrumentation
• Astrodynamics

Background:

• Star trackers are vital for spacecraft attitude determination due to their high accuracy.
• Verifying the accuracy of star trackers is a critical, yet unresolved challenge.
• The method used for accuracy measurement directly impacts satellite performance.

Purpose of the Study:

• To propose a novel and robust method for verifying star tracker accuracy.
• To establish a more authoritative and authentic measurement technique compared to conventional methods.
• To develop a direct astronomical observation-based approach for star tracker calibration.

Main Methods:

• Utilizing real navigation stars as observation targets for direct astronomical observation.
• Implementing coordinate system transformations accounting for Earth's precise movements.
• Analyzing error curves of directional vectors along three axes.

Main Results:

• A three-axis accuracy evaluation criterion has been developed.
• The proposed method directly determines the pointing and rolling accuracy of star trackers.
• Experimental validation confirms the method's effectiveness and convenience.

Conclusions:

• The direct astronomical observation method offers a more authentic accuracy verification for star trackers.
• The new evaluation criterion enables direct assessment of pointing and rolling accuracy.
• This approach simulates in-orbit conditions, meeting stringent high-accuracy requirements.