Angle-Only Cooperative Orbit Determination Considering Attitude Uncertainty.

Area of Science:

• Spacecraft dynamics and control
• Astrodynamics
• Satellite navigation

Background:

• Cooperative orbit determination (OD) traditionally focuses on estimating orbit states.
• Incorporating observer spacecraft attitude into OD is a novel approach.
• Inter-spacecraft angle-only measurements present unique challenges for simultaneous orbit and attitude estimation.

Purpose of the Study:

• To propose a novel concept for cooperative orbit determination using inter-spacecraft angle-only measurements.
• To analyze the observability of a two-spacecraft system considering both orbit and attitude states.
• To investigate methods for improving observability in such systems.

Main Methods:

• Development of a cooperative orbit determination framework incorporating observer attitude.
• Analysis of system observability using the observability matrix for a two-spacecraft system.
• Simulation of orbit estimation under various conditions, including attitude uncertainty.

Main Results:

• Inter-spacecraft angle-only measurements are insufficient for estimating both attitude and orbit states in a two-body system.
• Observability can be enhanced by considering high-order gravitational perturbations.
• Executing an attitude maneuver on the observer spacecraft also improves system observability.

Conclusions:

• The proposed method effectively estimates orbit states when attitude uncertainty is considered.
• The findings are crucial for autonomous spacecraft constellation and formation management.
• This research pioneers the analysis of observability and orbit estimation for two-spacecraft systems with attitude uncertainty.