Distributed Event-Triggered Attitude Estimation Without Angular Velocity Measurements

In this paper, a distributed event-triggered attitude estimation problem is considered for multiple rigid body systems on <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\mathbb {SO}(3)$</tex-math></inline-formula>. The error in attitude estimation converges asymptotically to a common orientation among multiple rigid body systems, based on relative attitude measurements under undirected graphs. To eliminate the reliance on direct angular velocity measurements, a cascaded estimation scheme is proposed, employing indirected angular velocity estimation through a single vector measurement that is readily accessible using accelerometers or magnetometers. An event-triggered condition (ETC), grounded in clock variables, is proposed to reduce the communication and computation requirements associated with the attitude estimation. Subsequently, a rigorous convergence analysis of the attitude estimation errors is conducted, relying upon a stability criteria of invariant sets for cascade-connected systems. Furthermore, a self-triggered condition is developed to overcome the challenge of continuous monitoring throughout the event detection process. Ultimately, the efficacy of the proposed framework is validated through a numerical simulation encompassing multiple small satellites.