Ground Feature Descriptor-Based Loop Closure Detection for Substations

Abstract

Loop closure detection plays a crucial role in LiDAR-based simultaneous localization and mapping (SLAM) by reducing accumulated drift and ensuring global map consistency. However, in substation inspection environments, repetitive equipment structures, complex ground conditions, and the limited discriminative capability of conventional point cloud descriptors often lead to degraded loop closure performance. To address these challenges, this paper proposes a ground-aware loop closure detection method for substation inspection. Ground segmentation is first applied to separate ground and non-ground points. Inspired by the polar-coordinate representation of Scan Context, a ground-aware descriptor is then constructed to jointly encode the geometric properties of ground regions and the height characteristics of surrounding structures. Furthermore, a loop closure matching strategy based on ring key retrieval, sector key alignment, and descriptor similarity evaluation is designed to achieve robust place recognition under viewpoint variations.