RIs-Calib: An Open-Source Spatiotemporal Calibrator for Multiple 3D Radars and IMUs Based on Continuous-Time Estimation

TL;DR

RIs-Calib is an open-source continuous-time spatiotemporal calibrator for multiple 3D radars and IMUs, enabling accurate sensor fusion without additional infrastructure or prior knowledge, validated through simulations and real-world tests.

Contribution

It introduces a robust continuous-time calibration method for multiple radars and IMUs that does not rely on extra infrastructure or prior info, with proven accuracy and consistency.

Findings

Accurate calibration achieved in simulated and real-world experiments.

Robust state initialization and batch optimization ensure global optimality.

Open-source implementation available for community use.

Abstract

Aided inertial navigation system (INS), typically consisting of an inertial measurement unit (IMU) and an exteroceptive sensor, has been widely accepted as a feasible solution for navigation. Compared with vision-aided and LiDAR-aided INS, radar-aided INS could achieve better performance in adverse weather conditions since the radar utilizes low-frequency measuring signals with less attenuation effect in atmospheric gases and rain. For such a radar-aided INS, accurate spatiotemporal transformation is a fundamental prerequisite to achieving optimal information fusion. In this work, we present RIs-Calib: a spatiotemporal calibrator for multiple 3D radars and IMUs based on continuous-time estimation, which enables accurate spatiotemporal calibration and does not require any additional artificial infrastructure or prior knowledge. Our approach starts with a rigorous and robust procedure for state initialization, followed by batch optimizations, where all parameters can be refined to global optimal states steadily. We validate and evaluate RIs-Calib on both simulated and real-world experiments, and the results demonstrate that RIs-Calib is capable of accurate and consistent calibration. We open-source our implementations at (https://github.com/Unsigned-Long/RIs-Calib) to benefit the research community.