Equivariant Filter for Radar-Inertial Odometry

Fuente: arXiv
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Bibliographic Details
Main Authors: Delama, Giulio, Michalczyk, Jan, Nissov, Morten, Scheiber, Martin, Fornasier, Alessandro, Alexis, Kostas, Weiss, Stephan
Format: Preprint
Published: 2026
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author Delama, Giulio
Michalczyk, Jan
Nissov, Morten
Scheiber, Martin
Fornasier, Alessandro
Alexis, Kostas
Weiss, Stephan
author_facet Delama, Giulio
Michalczyk, Jan
Nissov, Morten
Scheiber, Martin
Fornasier, Alessandro
Alexis, Kostas
Weiss, Stephan
contents Radar-Inertial Odometry (RIO) based on the Extended Kalman Filter (EKF) relies on accurate extrinsic calibration between the radar and the Inertial Measurement Unit (IMU) and is sensitive to disturbances, as large linearization errors can degrade performance or even cause divergence. To address these limitations, this letter proposes an Equivariant Filter (EqF) for RIO based on a Lie group symmetry that geometrically couples navigation states and IMU biases, extending it to incorporate radar-IMU extrinsic calibration and multi-state constraint updates. This equivariant formulation inherently preserves consistency and enhances robustness, enabling reliable state estimation even under poor or completely wrong initialization of calibration states. Real-world experiments on two different Uncrewed Aerial Vehicles (UAVs) show that the proposed EqF-RIO achieves state-of-the-art accuracy under correct extrinsic calibration and offers improved convergence under large calibration errors, where the conventional EKF-RIO fails. Evaluation code is open-sourced.
format Preprint
id arxiv_https___arxiv_org_abs_2604_23033
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Equivariant Filter for Radar-Inertial Odometry
Delama, Giulio
Michalczyk, Jan
Nissov, Morten
Scheiber, Martin
Fornasier, Alessandro
Alexis, Kostas
Weiss, Stephan
Robotics
Radar-Inertial Odometry (RIO) based on the Extended Kalman Filter (EKF) relies on accurate extrinsic calibration between the radar and the Inertial Measurement Unit (IMU) and is sensitive to disturbances, as large linearization errors can degrade performance or even cause divergence. To address these limitations, this letter proposes an Equivariant Filter (EqF) for RIO based on a Lie group symmetry that geometrically couples navigation states and IMU biases, extending it to incorporate radar-IMU extrinsic calibration and multi-state constraint updates. This equivariant formulation inherently preserves consistency and enhances robustness, enabling reliable state estimation even under poor or completely wrong initialization of calibration states. Real-world experiments on two different Uncrewed Aerial Vehicles (UAVs) show that the proposed EqF-RIO achieves state-of-the-art accuracy under correct extrinsic calibration and offers improved convergence under large calibration errors, where the conventional EKF-RIO fails. Evaluation code is open-sourced.
title Equivariant Filter for Radar-Inertial Odometry
topic Robotics
url https://arxiv.org/abs/2604.23033