A global exponential observer for velocity-aided attitude estimation

TL;DR

This paper introduces a simple nonlinear observer for estimating a rigid body's attitude and velocity using sensor measurements, achieving global exponential convergence and robustness to noise and bias.

Contribution

It presents a novel geometry-free observer that ensures global exponential stability and decouples pitch and roll estimation from magnetic measurements.

Findings

Observer is globally exponentially convergent.

Performs well with noisy and biased measurements.

Decouples pitch and roll estimation from magnetic data.

Abstract

We propose a simple nonlinear observer for estimating the attitude and velocity of a rigid body from the measurements of specific acceleration, angular velocity, magnetic field (in body axes), and linear velocity (in body axes). It is uniformly globally exponentially convergent, and also enjoys other nice properties: global decoupling of pitch and roll estimation from magnetic measurements, good local behavior, and easy tuning. The observer is "geometry-free", in the sense that it respects only asymptotically the rotational geometry. The good behavior of the observer, even when the measurements are noisy and biased is illustrated in simulation.