Seminar: Synchronous State Estimation for Inertial Navigation Systems
Seminar by Pieter van Goor (University of Twente)
Title: Synchronous State Estimation for Inertial Navigation Systems
Abstract:
An Inertial Navigation System (INS) is a system that integrates acceleration and angular velocity readings from an Inertial Measurement Unit (IMU), along with other sensors such as GNSS position, GNSS velocity, and a magnetometer, to estimate the attitude, velocity, and position of a vehicle. In this talk I demonstrate how the INS problem can be analysed using the automorphisms of the extended special Euclidean group: a new Lie group called the extended similarity group. Using this novel geometric framework, I will derive an observer architecture with synchronous error dynamics; that is, the error is stationary if the observer correction terms are set to zero. I then use this synchrony property to derive a modular, or plug-and-play, observer design for INS that allows different sensors to be added or removed depending on what is available in the vehicle sensor suite. This resulting observer guarantees both almost-global asymptotic and local exponential stability of the error dynamics for the common scenario where at least an IMU and GNSS position sensor are available, and it is the first non-linear observer in the literature to do so. A simulation with extreme initial error demonstrates the almost-global robustness of the system. I also show its real-world capability through demonstrations on data from a fixed-wing UAV, and the solution is compared to the state-of-the-art ArduPilot INS. Finally, I will discuss some extensions to the initial work, including implementation into ArduPilot and compensation of measurement delays.