Hybrid Nonlinear Observers for Inertial Navigation Using Landmark Measurements

This article considers the problem of attitude, position, and linear velocity estimation for rigid body systems relying on inertial measurement unit and landmark measurements. We propose two hybrid nonlinear observers on the matrix Lie group SE
₂
(3), leading to global exponential stability. The first observer relies on fixed gains, while the second one uses variable gains depending on the solution of a continuous Riccati equation. These observers are then extended to handle biased angular velocity and linear acceleration measurements. Both simulation and experimental results are presented to illustrate the performance of the proposed observers.